Therapeutic potential of cannabis-related drugs

    Therapeutic potential of cannabis-related drugs Stephen P.H. Alexander PII: DOI: Reference:

S0278-5846(15)30010-5 doi: 10.1016/j.pnpbp.2015.07.001 PNP 8799

To appear in:

Progress in Neuropsychopharmacology & Biological Psychiatry

Received date: Revised date: Accepted date:

23 March 2015 2 July 2015 2 July 2015

Please cite this article as: Alexander Stephen P.H., Therapeutic potential of cannabisrelated drugs, Progress in Neuropsychopharmacology & Biological Psychiatry (2015), doi: 10.1016/j.pnpbp.2015.07.001

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT Progress in NeuroPsychopharmacology and Biological Psychiatry

T

Therapeutic potential of cannabis-related drugs

IP

Stephen PH Alexander Associate Professor in Molecular Pharmacology,

SC R

Life Sciences University of Nottingham Medical School Nottingham NG7 2UH

[email protected]

NU

ENGLAND

Abbreviations

MA

Conflict of interest statement: the Author states that there are no conflicts of interest.

2-Arachidonoylglycerol

AEA

Anandamide

CBD

Cannabidiol

FAAH

Fatty acid amide hydrolase

FAAH-2

Fatty acid amide hydrolase-2

MGL

Monoacylglycerol lipase

NAAA

N-Acylethanolamine acid amidase

NAPE-PLD

N-Acylphosphatidylethanolamine phospholipase D

THCV

TE

CE P

AC

THC

D

2AG

Δ9-Tetrahydrocannabinol Δ9-Tetrahydrocannabivarin

Page | 1

ACCEPTED MANUSCRIPT Abstract In this review, I will consider the dual nature of Cannabis and cannabinoids. The duality arises from the potential and actuality of cannabinoids in the laboratory and clinic and the ‘abuse’ of

T

Cannabis outside the clinic. The therapeutic areas currently best associated with exploitation of

IP

Cannabis-related medicines include pain, epilepsy, feeding disorders, multiple sclerosis and glaucoma. As with every other medicinal drug of course, the ‘trick’ will be to maximise the benefit

SC R

and minimise the cost. After millennia of proximity and exploitation of the Cannabis plant, we are still playing catch up with an understanding of its potential influence for medicinal benefit.

Review outline and introduction

NU

Cannabis has a global familiarity, which is most commonly associated with its abuse. However, there is considerable potential (some of it realised) for therapeutic benefit to be had from

MA

plant-derived drugs and related agents which exploit the system linked to the best understood effects of Cannabis-derived drugs. In this review, I look at the complexity of the plant, the complexity of the endocannabinoid system and the exploitation of these for therapeutic benefit.

D

The Cannabis plant, which may be different species (principally Cannabis sativa and Cannabis

TE

indica) or variants of the same species, is a dioecious entity, where the draft genome has been described (van Bakel et al. 2011). It contains a number of unique resorcinol metabolites. Estimates

CE P

vary as to the precise number (60-110) and the value for the plant of generating these entities is unclear, although a role as protection against pathogens has been claimed. The most recognisable cannabinoid (defined as unique metabolites from the Cannabis plant) is Δ9-tetrahydrocannabinol (THC, Figure 1). Although many other members of the cannabinoid family have been identified over

AC

the last 50 years, there is still only superficial knowledge about the molecular targets with which they may interact. A recent review described the pharmacology of two of these agents, cannabidiol (CBD, Figure 1) and Δ9-tetrahydrocannabivarin (THCV) and concluded that these compounds exhibited complex interactions with the endocannabinoid system (see below). In particular, the authors concluded that there were discrepancies between the actions of CBD and THCV in vivo and the mechanistic understanding gained from their in vitro profile (McPartland et al. 2015). Aside from these three compounds, other cannabinoids with the beginnings of pharmacological characterisation include cannabigerol, cannabidivarin, cannabidiolic acid and cannabichromene (Mechoulam et al. 2014). What this highlights is one of the central complexities of working with Cannabis or interpreting data obtained from human studies using the plant or its extracts. In dealing with what is effectively a natural product, there is inevitably a considerable amount of variability in genetic background, growth conditions, harvesting times, preparation handling and so on. The quality Page | 2

ACCEPTED MANUSCRIPT control of Cannabis preparations is limited at best for those locations where the sale is legal. Where the sale is illegal (most of the world), there is inevitably huge variation in the chemical constituents. This is compounded by the variation in the temporal pattern of exposure to these various

T

components, with periods of abstinence, periods of “bingeing” and periods of low level, daily

IP

administration being a common scenario, This means that the balance between ‘positive’ and ‘negative’ compounds, of desirable and undesirable properties of the chemical constituents is highly

SC R

unpredictable. Plainly there is a lot more to be understood about the cannabinoids derived from the Cannabis plant and even more about the potential for interaction between them in the preparations administered to humans.

NU

A brief history of Cannabis usage and abuse

There is an imprecision about the history of Cannabis usage, but evidently it has been

MA

cultivated for thousands of years (for review, see (Russo 2007)). From ancient China, India and Egypt, there is evidence for medicinal use. The hemp plant has also been used across the globe for centuries in the production of rope, sail, cloth and paper. What is defined vaguely as abuse is a

D

relatively recent viewpoint. In the 1970s, there was widespread availability in Europe and North

TE

America of Cannabis extracts as a ‘recreational drug’. The leaves (variously referred to as marijuana or herbal cannabis, amongst many other names) or resin derived mostly from the buds (known as hashish, or many other names) is typically mixed with tobacco and rolled into a cigarette (known as a

CE P

joint, or many other names). Smoking involves measures of volatilisation and pyrolysis, and results in a relatively poor delivery of metabolites, but a reasonably rapid latency to onset of symptoms (2-3 min) with a variable duration of action (30-120 min) (for review, see (Hollister 1986)). More minor

AC

routes of delivery include the mixing of extracts with food products, either baked (as ‘hash brownies’) or as an alcoholic extract (a tincture often added to tea). This oral route also has low bioavailability and is more unpredictable, both in terms of latency of onset (30-120 min) and duration of action (120-240 min). A more recent alternative is the use of vaporisers, which allow a controlled increase in temperature to allow volatilisation of cannabis extracts for inhalation, reducing pyrolysis of the metabolites and, in theory at least, increasing the delivery of the metabolites. The symptoms of Cannabis inhalation in man are notoriously variable (for review, see (Hollister 1986)). Objective measures, which are relatively reliable, include an elevation in pulse rate and reddening of the conjunctiva of the eye. In contrast to the opiates, there is no change in pupil diameter or respiration rate. The subjective, psychological impact is where the variability arises. There appears to be a major influence of environment, the context, on the perceived ‘positive’ or ‘negative’ impact of Cannabis administration. Typically, though, there is an initial period of Page | 3

ACCEPTED MANUSCRIPT euphoria, the ‘high’, followed by a period of drowsiness, the ‘dope’. Frequently, there is an altered sense of time passing, associated with difficulty in concentrating and thinking, reflective of short term memory impairment. There is a depersonalization and dissociation from the environment,

T

with mild impairment of hearing, visual distortions and ‘mild’ hallucinations.

IP

In general, there are good data on the acute effects of Cannabis ingestion. However, and of greater significance due to the repeated (and variable) nature of Cannabis exposure both in the

SC R

clinic and outside, there is much less solidity about chronic usage. Symptomology reported includes dependence/addiction, panic attacks, depression, mania, psychotic episodes and respiratory disorders.

NU

More recent developments in the Cannabis area include the availability of ‘designer drugs’ or ‘legal highs’, which include the ‘synthetic cannabinoids’ (for review, see (Castaneto et al. 2014)) . These are often suggested to be mixed with tobacco and smoked to provide the same sort of

MA

subjective effects as smoking Cannabis. Many are early synthesised cannabimimetics, compounds which were generated to provide a synthetic alternative to THC (see below). The toxicity of these compounds, the potential derivatives generated by pyrolysis on their chemical constitution and

D

their metabolites has, at best, only been superficially explored.

TE

A brief overview of the endocannabinoid system Early observations of the effects of THC suggested it to be the primary psychoactive

CE P

component of the Cannabis plant (Gaoni and Mechoulam 1964). The stereoselectivity of cannabinoid analogue action at rat brain membranes suggested the existence of a cannabinoid receptor (Howlett et al. 1988). The cloning of the CB1 cannabinoid receptor in 1990 identified it to

AC

be a G protein-coupled receptor (Matsuda et al. 1990), found to very high levels in the CNS, and to lower densities in peripheral neural and other tissues. Radioligand binding studies identified high levels of CB1 cannabinoid receptor expression in the substantia nigra, globus pallidus, hippocampus and cerebellum, with little expression in the brainstem (Herkenham et al. 1990). A second cannabinoid receptor, the CB2 cannabinoid receptor, was cloned soon afterwards (Munro et al. 1993) and associated primarily with immune-related tissues. CB1 and CB2 receptors are members of the rhodopsin family of G protein-coupled receptors, where effects are mediated primarily through G proteins. CB1 receptor sequences are reasonably well-conserved across higher mammals; in contrast, human CB2 cannabinoid receptors show limited homology to human CB1 receptors (<50 %) and to CB2 receptors of other species. The endocannabinoid system consists of these cannabinoid receptors, the endocannabinoids themselves (exemplified by anandamide, AEA, and 2-arachidonoylglycerol, 2AG; Figure 1), the enzymes that generate them and the enzymes that degrade or transform them (Alexander and Page | 4

ACCEPTED MANUSCRIPT Kendall 2007). A component that remains unproven is the existence of endocannabinoid transporters, which may allow the movement of these endocannabinoids across the plasma membrane (Fowler 2013).

T

The endocannabinoids identified divide into amides and esters, which are synthesised and

IP

hydrolysed through distinct pathways (Figure 2). Thus, the best evidence for a precursor for AEA suggests a minor phospholipid component, N-arachidonoylphosphatidylethanolamine, as the likely

SC R

entity, which is hydrolysed by a selective phospholipase D (NAPE-PLD). There are three enzymes identified which are able to hydrolyse AEA: fatty acid amide hydrolase (FAAH), FAAH-2 and Nacylethanolamine acid amidase (NAAA), allowing the generation of arachidonic acid and

NU

ethanolamine (Figure 2). FAAH is associated with intracellular membranes (Schmid et al. 1985), while FAAH2 has been suggested to associate with lipid droplets (Kaczocha et al. 2010) and NAAA is a lysosomal enzyme (Ueda et al. 1999). Of the three enzymes, FAAH has been the most intensively

MA

studied. FAAH2, however, remains poorly characterised. This probably derives, at least in part from its unusual species distribution, being absent from the most common laboratory animals, mice and rats (Wei et al. 2006). Genetic studies have suggested a link with a relatively rare disorder, termed

D

X-linked intellectual disability (Whibley et al. 2010) and a kidney cancer subtype (Durinck et al.

TE

2015).

The ester endocannabinoid 2AG, by contrast, is generated from a ubiquitous signalling

CE P

component, 1,2-diacylglycerol, generated by phospholipase C activity (Figure 2). Diacylglcyerol lipase in neurones has a postjunctional location and is characterised as an enzyme associated with dendritic spines (Yoshida et al. 2006). Evidence from electrophysiological studies have implicated

AC

2AG synthesis in short-term plasticity at hippocampal synapses (Hashimotodani et al. 2008;Hashimotodani et al. 2013;Zachariou et al. 2013). 2AG is hydrolysed by monoacylglycerol lipase (MGL). Analysis of particulate preparations from mouse brain identified that 2AG hydrolysis was mediated primarily (~90 %) by MGL, although further serine hydrolases, ABHD6 and ABHD12, could also metabolise 2AG (Figure 2), albeit to a much lesser extent (Blankman et al. 2007). MGL is the most studied of these three enzymes, a predominantly cytosolic enzyme which can associate with membranes (Dinh et al. 2002). AEA and 2AG are arachidonic acid derivatives (Figure 1) and, as such, are also metabolised through routes of arachidonic acid metabolism. The evidence for cyclooxygenase-2, lipoxygenase and epoxygenase (cytochrome P450) metabolism of endocannabinoids (identified as Transformation in Figure 2) has recently been reviewed (Urquhart et al. 2015). The products of oxidative metabolism are biologically active, but apparently not acting through cannabinoid receptors. Page | 5

ACCEPTED MANUSCRIPT The primary molecular targets of THC and the endocannabinoids are two G protein-coupled receptors. The CB1 cannabinoid receptor is associated primarily, although not exclusively, with the nervous system, with a very high expression level and an association with the presynaptic nerve

T

terminal. Activation of the CB1 receptor leads to inhibition of transmitter release, principally

IP

through the activation of potassium channels and inhibition of voltage-gated calcium channels. In addition, CB1 receptors inhibit adenylyl cyclase activity and activate extracellular signal-regulated

SC R

kinases.

The CB2 receptor shows a similar signalling pattern to the CB1 receptor, coupling to both inhibition of adenylyl cyclase activity and stimulation of extracellular signal-regulated kinase activity.

NU

However, the CB2 receptor fails to couple to ion channels in recombinant expression (Felder et al. 1995).

Pharmacological tools and their selectivity

MA

There are selective agonists and antagonists available which are able to define pharmacologically the involvement of CB1 or CB2 cannabinoid receptors. HU210, WIN55212-2 and

D

CP55940 are all high potency (nanomolar) agonists at both CB1 and CB2 cannabinoid receptors (Felder et al. 1995). Furthermore, they represent three structurally distinct classes of agonist (Figure

TE

3). They are, therefore, useful tools to apply in situations where the involvement of a cannabinoid receptor is suspected, with a view to latter examination of more selective tools. In particular, N-

CE P

arachidonoyl-2’-chloroethylamine is a >4000-fold selective, nanomolar potency CB1 cannabinoid receptor agonist (Hillard et al. 1999), and is a simple analogue of the endocannabinoid AEA (Figure 3). Intriguingly, JWH133, an analogue of the cannabinoid THC (Figure 3), is a 200-fold selective CB2

AC

cannabinoid receptor agonist, with nanomolar affinity at human receptors (Huffman et al. 1999). At the moment, there are no non-selective antagonists available which are able to block both CB1 and CB2 cannabinoid receptors, which is intriguing given the number of non-selective agonists. However, selective antagonists for the two subtypes are available. Rimonabant (Figure 3) shows high affinity at CB1 cannabinoid receptors, with a selectivity index of over 80-fold for human CB1 receptors (Felder et al. 1995). AM251 is a close structural analogue of rimonabant with a similar pharmacological profile (Lan et al. 1999), while LY320135 is structurally distinct with lower affinity and >70-fold selectivity for the CB1 cannabinoid receptor (Felder et al. 1998). SR144528 is a CB2selective antagonist (Figure 3) with a sub-nanomolar affinity and 700-fold selectivity (RinaldiCarmona et al. 1998;Ross et al. 1999). AM630 (also known as 6-iodopravadoline) is a structurallydistinct CB2 cannabinoid receptor-selective antagonist with slightly lower affinity and selectivity (Ross et al. 1999).

Page | 6

ACCEPTED MANUSCRIPT All of these antagonists appear to have properties of inverse agonists, in that they are able to exert effects in the opposite direction to agonists in the absence of added agonist. Of the enzymes associated with endocannabinoid turnover, the most numerous inhibitors

T

have been directed against FAAH. These include the irreversible agent URB597 (Mor et al. 2004),

IP

which has become a ‘Gold Standard’ inhibitor to define the activity of FAAH. Intriguingly, URB597 is also an inhibitor of FAAH2 (Wei et al. 2006), but not NAAA (Sun et al. 2005). Selective NAAA

SC R

inhibitors have been recently reviewed (Bandiera et al. 2014). JZL184 is an irreversible inhibitor of MGL (Long et al. 2009), and has become established as the ‘Gold Standard’ inhibitor to define its activity.

NU

On this basis, therefore, it appears to be the case that there are a number of useful, selective pharmacological tools to define the primary targets for therapeutic exploitation of the endocannabinoid system. However, the situation is more complex.

MA

Further targets of cannabinoid ligands and complexity of cannabinoid actions Although the focus of this review has been the CB1 and CB2 cannabinoid receptors (and the

D

endocannabinoid-metabolising enzymes), further complexity of cannabinoid action exists (for review, see (Alexander and Kendall 2007;Pertwee et al. 2010)). GPR18, GPR55 and GPR119 are

TE

‘orphan’ GPCR with some evidence for endogenous ligands (for review, see (Davenport et al. 2013)). They are often linked with the conventional CB1 and CB2 cannabinoid receptors, not for any

CE P

sequence similarities, but with some overlap in the ligand pharmacology, sufficient for them to be regarded as cannabinoid receptor-like receptors of cannabinoid receptor foster children. Thus, GPR18 has been reported to be activated by THC (McHugh et al. 2012), while the endogenous

AC

agonist might well prove to be an oxidation product of AEA, N-arachidonoylglycine (Console-Bram et al. 2014;Kohno et al. 2006;McHugh et al. 2012). GPR55 has proved difficult to pin down precisely in its pharmacology for reasons which are obscure (for review, see (Ross 2009)). However, a reasonably reliable agonist at GPR55 is the CB1 cannabinoid receptor antagonist AM251 (Henstridge et al. 2009;Kapur et al. 2009;Ryberg et al. 2007). Lysophosphatidylinositol is a good candidate for the endogenous agonist, with the possibility that 2-arachidonoyl-glycerophosphatidylinositol, and analogue of 2AG, is the preferred species (Oka et al. 2009). GPR119 is a target of satiety and obesity-related therapeutic investigations (for review, see (Kang 2013;Kleberg et al. 2014). The best candidates for endogenous ligands are N-oleoylethanolamine and 2-oleoylglycerol, although AEA and 2AG appear to be poor candidates for endogenous activators (Hansen et al. 2011;Overton et al. 2006). Adding further to the complexity of working in the cannabinoid area, the endocannabinoids are not only ligands at CB1 and CB2 receptors, but they can activate TRPV1 ion channels, leading to Page | 7

ACCEPTED MANUSCRIPT the suggestion that this represents an ionotropic cannabinoid receptor. Further, the TRPV1 channel can also be activated by cannabinoids from the plant, including CBD and cannabidivarin (Iannotti et al. 2014). TRPV2 channels can be activated by a number of plant cannabinoids (De Petrocellis et al.

T

2011), as can TRPV3 and TRPV4 channels (De Petrocellis et al. 2012), as well as TRPA1 channels (De

IP

Petrocellis et al. 2011). Since TRP channels are non-selective cation channels, many of which are highly expressed in sensory neurones, there is a major potential for complexity of action of plant

SC R

extracts at this level.

Endocannabinoids are also active at members of the nuclear hormone receptor family; in particular, peroxisome proliferator-activated receptors (PPARs) respond to multiple endogenous

NU

fatty acid derivatives (for review, see (Michalik et al. 2006)). It was, with hindsight, no surprise that the fatty acid derivative endocannabinoids, including AEA and 2AG, are also active at PPARs (for review, see (O'Sullivan 2007)). Further, cannabinoids from the Cannabis plant (O'Sullivan et al.

MA

2009;O'Sullivan et al. 2005) and synthetic cannabinoids (Downer et al. 2012;Liu et al. 2003) are also able to activate PPARs. In the main, PPARα and PPARγ have been focussed upon, with respect to activation by cannabinoids, with evidence for in vivo roles of these receptors (Jhaveri et al.

D

2008;Melis et al. 2008;Sagar et al. 2008;Vara et al. 2013).

TE

The nuclear location of these targets of cannabinoid agents implies the need for trafficking of the ligands. Fatty acid binding proteins move lipids, prominently fatty acids, around the cell to

CE P

activate PPARs or for metabolism (for review, see (Moulle et al. 2012;Schroeder et al. 2008;Storch and Thumser 2010). They are also reported to deliver plant cannabinoids and endocannabinoids to intracellular targets (Elmes et al. 2015;Kaczocha et al. 2009). Pharmacological exploitation of these

AC

molecular targets is still limited, but there is the promise of future manipulation to alter or enact effects of cannabinoid-related ligands. Thus, cannabinoid ligands are able to regulate the activity of three of the four superfamilies of receptors: GPCR, ligand-gated ion channels and nuclear hormone receptors, but not catalytic receptors (at least, not yet).

Therapeutic exploitation Although the anecdotal history of Cannabis use as a medication is centuries old, the application of an evidence base for medicinal use of cannabinoid agents is much more recent. In this section, I will provide a brief overview of the better established disorders in which cannabinoid ligands have clinical potential (Figure 3). The consequences of administration of Cannabis preparations or pure THC has been extensively studied in laboratory animals, principally in rats and mice, where there is an established pattern of behaviours identified. The classical tetrad consists of tests for hypoactivity, hypothermia, antinociception and catalepsy (Martin et al. 1991). This pattern Page | 8

ACCEPTED MANUSCRIPT is not observed in animals where the CB1 receptor has been genetically disrupted (Ledent et al. 1999). Further, the CB1-selective antagonist rimonabant was able to block these effects (RinaldiCarmona et al. 1995). These studies implicate an exclusive relationship between the psychoactivity

T

of THC and Cannabis preparations with the CB1 cannabinoid receptor.

IP

Pain

Cannabinoids have been shown to be active in animal models of pain. Thus, THC,

SC R

endocannabinoids and synthetic cannabinoids are all able to alleviate pain behaviours in models of inflammatory and neuropathic pain. Indeed, one of the most common topics for cannabinoid action in preclinical disease models is pain. An alleviation of pain behaviours has been observed in both

NU

acute and chronic models; for review, see (Burston and Woodhams 2014;Rea et al. 2007;Sagar et al. 2012). Whilst the majority of studies implicate the CB1 receptor heavily in the analgesic effects of cannabinoids, there is also good evidence that CB2 cannabinoid receptors can contribute to these

MA

effects; for review, see (Atwood and Mackie 2010;Guindon and Hohmann 2008). The effects of exogenous cannabinoids can also be mimicked by amplifying endogenous cannabinoid tone through

D

the use of selective inhibitors of FAAH or MGL; for review, see (Fowler 2012;Fowler et al. 2001;Jhaveri et al. 2007;Mulvihill and Nomura 2013;Roques et al. 2012).

TE

Intriguingly, a number of non-steroidal anti-inflammatory drugs (NSAIDs), identified initially as cyclooxygenase inhibitors, are also inhibitors of FAAH (Fowler 2007;Fowler et al. 2009). This

CE P

raises the possibility that part of the therapeutic effect of these drugs is not solely to prevent the oxidation of arachidonic acid (and the endocannabinoids, see above), thereby reducing the formation of prostaglandins (and prostaglandin analogues of endocannabinoids), but also to prevent

AC

the hydrolysis of AEA (and other N-acylethanolamines). The opportunity for Cannabis-related medicines as analgesics seems positive. The existing analgesics for chronic pain, opioids and NSAIDs, are associated with significant adverse effects, including dependence, risk of overdose and gastric ulceration. The challenge for Cannabis-related analgesics is to produce agents which relieve pain, without intolerable adverse effects, such as psychoactivity, for example. A meta-analysis of the evidence from clinical trials suggested that Cannabis preparations provide moderate efficacy in chronic pain (Martin-Sanchez et al. 2009). The profile of FAAH inhibitors seems appropriate for pain relief, although a lack of effect of repeated administration has been reported in a pre-clinical model (Okine et al. 2012). Even more telling is the failure of an irreversible FAAH inhibitor, PF04457845, in clinical trials for osteoarthritis (Huggins et al. 2012). This was despite a long-lasting inhibition of leukocyte FAAH activity and increase in plasma Nacylethanolamines.

Page | 9

ACCEPTED MANUSCRIPT Nausea and vomitting In animal models of nausea and vomiting, cannabinoid agonists are effective through a CNSdirected action (Limebeer et al. 2012). In animal models, CP55940 is more potent than THC and the

T

CB1 receptor antagonist rimonabant is able to reverse these effects (Darmani 2001). As with pain,

IP

the inhibition of FAAH and MAGL appear to produce similar effects to the direct activation of cannabinoid receptors in models of nausea and vomiting (Cross-Mellor et al. 2007;Sticht et al. 2012).

SC R

Synthetic analogues of THC are used alongside chemotherapy in cancer sufferers to reduce nausea and vomiting.

Cannabidiolic acid has also been observed to reduce vomitting in in an animal model; an

NU

effect independent of cannabinoid receptors and apparently mediated through altering 5HT1A receptors (Bolognini et al. 2013).

The market for cannabinoid-related medicines as anti-emetics is limited. The major

MA

competitors are 5HT3 receptor antagonists, such as ondansetron, which are generally pretty effective medicines. The likely usage of cannabinoids would be in those patients who are refractory

D

to other medication.

TE

Feeding Disorders

A commonly-reported side effect of Cannabis ingestion is the stimulation of appetite particularly of palatable foods. Administration of either anandamide (Hao et al. 2000) or 2AG

CE P

(Kirkham et al. 2002) in animal models also stimulates eating behaviours, while rimonabant inhibited sucrose feeding (Arnone et al. 1997). In mice with disrupted CB1 cannabinoid receptors, basal food intake was reduced and the effects of rimonabant were lost (Wiley et al. 2005). Rimonabant was

AC

approved in 2006 for use in Europe (but not in the US) as a treatment for obesity or ‘metabolic syndrome’. This followed on from clinical trials which showed a long-lasting reduction in weight and waist size (Van Gaal et al. 2005). However, it was withdrawn in 2008 due to concerns of an association with an increased incidence of depression and suicidal ideation.

Glaucoma The raised intraocular pressure of glaucoma gives rise to damage to the retina, potentially leading to blindness. The ciliary body in man expresses CB1 receptor mRNA and immunoreactivity (Porcella et al. 2000). Administration of topical WIN55212-2 in glaucoma patients refractory to other medications allowed a rapid reduction in intraocular pressure (Porcella et al. 2001). This follows on from more anecdotal evidence for the use of Cannabis and cannabinoids delivered by a variety of other methods (for review, see (Yazulla 2008)). The market for cannabinoid medicines for treating glaucoma appears limited. There are multiple existing molecular targets for anti-glaucoma therapy, including β-adrenoceptors, α2Page | 10

ACCEPTED MANUSCRIPT adrenoceptors and carbonic anhydrase. The relatively transient nature of effectiveness of existing cannabinoid medications for glaucoma means that improved alternatives need to be found if they are to be successful.

T

Neurodegeneration/neuroprotection

IP

There is good evidence to suggest that the exploitation of CB1 and/or CB2 cannabinoid receptors might be of benefit in a variety of neurodegenerative disorders; for a recent review, see

SC R

(Fagan and Campbell 2014). In Huntington's patients, there is a reduced expression of CB1 receptors in brain regions associated with locomotor function (Glass et al. 1993;Richfield and Herkenham 1994), while microglial cell CB2 receptors have been reported to be neuroprotective in this disorder

NU

(Palazuelos et al. 2009). Similarly, Parkinsons patients have a loss of CB1 receptors in locomotor areas of the brain (Van Laere et al. 2012). Intriguingly, a recent report identified that the human nigral neurones that degenerate in Parkinsons patients express CB2 cannabinoid receptors (Garcia et

MA

al. 2015). The effects on CB1 receptors of Alzheimers disease appear to be contradictory. A report suggesting increased CB1 receptors in early, asymptomatic patients (Farkas et al. 2011), contrasts

D

with reports of a generalised loss of CB1 receptors around plaques (Ramirez et al. 2005). Cannabinoid agonists have efficacy in models of cerebral ischaemia/stroke; for review, see

TE

(England et al. 2015). CB1 receptors are induced following stroke (Jin et al. 2000), and in mice with disrupted CB1 cannabinoid receptors, the severity of stroke is exacerbated suggesting a role for

CE P

these receptors in the pathology of ischemic damage (Parmentier-Batteur et al. 2002). Given the paucity of agents available to treat any of these disorders, the market is open for cannabinoid-related medicines in this area; it should be noted, however, that there is a very high

AC

attrition in progressing potential molecular targets active in pre-clinical studies of stroke to the clinic.

Multiple sclerosis Animal models of multiple sclerosis have been employed to show that cannabinoids are able to control spasticity (Baker et al. 2000). This evidence has translated to the clinic, where a combination of plant-derived cannabinoids, mostly THC and cannabidiol, is now licensed in many countries for the treatment of multiple sclerosis. Sativex®, also known as Nabiximols, is an oral spray to be taken as needed for sufferers of multiple sclerosis, particularly where other oral treatments fail (Novotna et al. 2011). In one pre-clinical model of chronic relapsing experimental allergic autoimmune encephalomyelitis, a combination of THC and cannabidiol was as effective as baclofen in reducing spasticity (Hilliard et al. 2012). Using Sativex-like cannabinoids in a distinct model (virally-induced encephalitis) showed an improvement in motor function, as well as histological markers (Feliu et al. 2015). Intriguingly, applied separately, there appeared to be

Page | 11

ACCEPTED MANUSCRIPT beneficial effects of both cannabidiol and THC, mediated through PPARs and CB1/CB2 cannabinoid receptors, respectively. One recent clinical trial with 30 multiple sclerosis patients undergoing a month long

T

exposure to Sativex, identified an improvement in spasticity together with positive changes in

IP

neurological parameters (Russo et al. 2015). Intriguingly, a randomised clinical trial conducted with THC alone (Cannabinoid Use in Progressive Inflammatory brain Disease, CUPID) failed to

SC R

show a significant treatment effect (Ball et al. 2015). A meta-analysis from the American Academy of Neurology suggested that oral cannabis extract, Sativex and THC were “probably effective, for reducing patient-centred measures” (Koppel et al. 2014).

NU

The paucity of alternative therapeutic interventions and the positive profile of cannabinoids in terms of tolerance means that it’s likely that multiple sclerosis will remain a target for the development of Cannabis-related medicines.

MA

Schizophrenia

Anecdotal evidence suggests an association between schizophrenia and high Cannabis use,

D

particularly of stronger strains such as ‘skunk’. Whilst this is not an unequivocal association, partly because of the complexity of the disorder and the variation in Cannabis, there is a logic about the

TE

chronic exposure of the incompletely developed brain (in younger adults) to such a psychoactive substance producing effects similar to this neurodevelopmental disorder. A working hypothesis

CE P

suggests a beneficial effect of cannabidiol as an antipsychotic (Iseger and Bossong 2015); a theory supported, in part, by the lower levels of this cannabinoid in Cannabis strains such as ‘skunk’. A recent Cochrane review on Cannabis and schizophrenia concluded that there was

AC

insufficient data from good clinical trials to identify whether Cannabis promoted schizophrenia or cannabidiol was effective as an antipsychotic (McLoughlin et al. 2014). In a human fMRI study, THC and cannabidiol evoked reciprocal effects on neuronal activity in the striatum, hippocampus and prefrontal cortex during a test of attentional salience processing; these effects were consistent with pro- and anti-psychotic effects of the two cannabinoids, respectively (Bhattacharyya et al. 2012).

Cancer Cannabinoids have promising anti-tumoral actions in pre-clinical models. For example, THC induces apoptosis of transformed neural cells in culture while WIN55212-2 causes regression of malignant gliomas in rats via an action involving both CB1 and CB2 receptors (GalveRoperh et al., 2000). Cannabidiol has been suggested to have anti-tumour effects through a multitude of molecular targets, against breast, cancer, glioma, leukemia, thyroid thyroma, lung and colon cancer (Massi et al. 2013). A recent review (Cridge and Rosengren Page | 12

ACCEPTED MANUSCRIPT 2013) concluded that many apparent contradictions remain in the literature about the potential benefit of cannabinoid-related medicines in cancer. Clinical trials with cannabinoids in cancer are extremely limited (Kramer 2015); in a pilot clinical trial, direct

T

intratumoural administration of THC appeared to reduce proliferation rate on

IP

glioblastoma multiforme in patients (Guzman et al. 2006). Thus, although there is clearly a lot to find out in terms of cannabinoid selection and molecular target, the poor prognosis

SC R

of patients currently suffering from a variety of cancer types, combined with the positive tolerability of cannabinoids, suggests that research on anti-tumour cannabinoids should persevere.

NU

Epilepsy

Another area of high promise for cannabinoid-related medicines is epilepsy. In a number of US states, Cannabis is approved for use as an anti-epilepsy therapy. A recent meta-analysis of

MA

published data suggested that there was only poor-quality data available at the time of review on clinical efficacy, in particular of cannabidiol, although there appeared to be an absence of adverse

D

effects (Gloss and Vickrey 2014). The absence of effective medications to treat intractable forms of epilepsy, together with anecdotal evidence for the efficacy of cannabidiol in these patients, suggests

CE P

Stress and anxiety

TE

a fruitful future for cannabinoid-related medicines in this indication (Devinsky et al. 2014).

There is a not uncommon association of Cannabis administration and anxiety; this is a complex, poorly-understood association, since justification for Cannabis use often includes the desire to reduce stress levels. There is evidence from pre-clinical models to suggest that stress-

AC

induced anxiety is associated with a reduction in CNS levels of AEA (Bluett et al. 2014). Indeed, acute administration of an FAAH inhibitor was able to relieve the anxiety-inducing effects of stress; this effect appeared to be mediated solely through the CB1 cannabinoid receptor (Bluett et al. 2014). Intriguingly, using a mouse model to express a common variation in the human FAAH gene resulted in lower CNS FAAH activity, a change in the neuronal circuitry and decreased anxiety-like behaviours (Dincheva et al. 2015). Given the persistent and widespread nature of stress and anxiety, and their enormous human and economic costs, there seems to be a positive potential for cannabinoid therapeutics in this area.

Concluding remarks We stand at an interesting crossroads for Cannabis-related drugs. To describe the plant as having a chequered history would be a simplification and the task ahead is to extract the maximum benefit for the least cost from the huge potential which Cannabis-related drugs undoubtedly represent. At the current moment, there are good footholds in translating the promise, Page | 13

ACCEPTED MANUSCRIPT particularly in terms of multiple sclerosis and epilepsy; time will tell whether the range of realistic

AC

CE P

TE

D

MA

NU

SC R

IP

T

therapeutic areas for Cannabis-related medicinal drugs is as broad as the promise.

Page | 14

ACCEPTED MANUSCRIPT Reference List

Alexander,SPH, Kendall,DA. The complications of promiscuity: endocannabinoid action and

IP

T

metabolism. Br. J. Pharmacol. 2007;152: 602-623.

SC R

Arnone,M, Maruani,J, Chaperon,F, Thiébot,M-H, Poncelet,M, Soubrié,P, Le Fur,G. Selective inhibition of sucrose and ethanol intake by SR 141716, an antagonist of central cannabinoid (CB1) receptors.

NU

Psychopharmacol. 1997;132: 104-106.

Atwood,BK, Mackie,K. CB2: a cannabinoid receptor with an identity crisis. Br. J. Pharmacol. 2010;160:

MA

467-479.

Baker,D, Pryce,G, Croxford,JL, Brown,P, Pertwee,RG, Huffman,JW, Layward,L. Cannabinoids control

TE

D

spasticity and tremor in a multiple sclerosis model. Nature 2000;404: 84-87.

Ball,S, Vickery,J, Hobart,J, Wright,D, Green,C, Shearer,J, Nunn,A, Gomez,CM, Macmanus,D, Miller,D,

CE P

Mallik,S, Zajicek,J. The Cannabinoid Use in Progressive Inflammatory brain Disease (CUPID) trial: a randomised double-blind placebo-controlled parallel-group multicentre trial and economic

1-188.

AC

evaluation of cannabinoids to slow progression in multiple sclerosis. Health Technol Assess 2015;19:

Bandiera,T, Ponzano,S, Piomelli,D. Advances in the discovery of N-acylethanolamine acid amidase inhibitors. Pharmacol. Res. 2014;86: 11-17.

Bhattacharyya,S, Crippa,JA, Allen,P, Martin-Santos,R, Borgwardt,S, Fusar-Poli,P, Rubia,K, Kambeitz,J, O'Carroll,C, Seal,ML, Giampietro,V, Brammer,M, Zuardi,AW, Atakan,Z, McGuire,PK. Induction of psychosis by 9-tetrahydrocannabinol reflects modulation of prefrontal and striatal function during attentional salience processing. Arch Gen Psychiatry 2012;69: 27-36.

Page | 15

ACCEPTED MANUSCRIPT Blankman,JL, Simon,GM, Cravatt,BF. A comprehensive profile of brain enzymes that hydrolyze the endocannabinoid 2-arachidonoylglycerol. Chem. Biol. 2007;14: 1347-1356.

T

Bluett,RJ, Gamble-George,JC, Hermanson,DJ, Hartley,ND, Marnett,LJ, Patel,S. Central anandamide

IP

deficiency predicts stress-induced anxiety: behavioral reversal through endocannabinoid

SC R

augmentation. Transl Psychiatry 2014;4: e408.

Bolognini,D, Rock,E, Cluny,N, Cascio,M, Limebeer,C, Duncan,M, Stott,C, Javid,F, Parker,L, Pertwee,R.

NU

Cannabidiolic acid prevents vomiting in Suncus murinus and nausea-induced behaviour in rats by

MA

enhancing 5-HT(1A) receptor activation. Br. J. Pharmacol. 2013;168: 1456-1470.

Burston,JJ, Woodhams,SG. Endocannabinoid system and pain: an introduction. Proc Nutr Soc

D

2014;73: 106-117.

TE

Castaneto,MS, Gorelick,DA, Desrosiers,NA, Hartman,RL, Pirard,S, Huestis,MA. Synthetic

2014;144: 12-41.

CE P

cannabinoids: Epidemiology, pharmacodynamics, and clinical implications. Drug Alcohol Depend.

Console-Bram,L, Brailoiu,E, Brailoiu,GC, Sharir,H, Abood,ME. Activation of GPR18 by cannabinoid

AC

compounds: a tale of biased agonism. Br. J. Pharmacol. 2014;171: 3908-3917.

Cridge,BJ, Rosengren,RJ. Critical appraisal of the potential use of cannabinoids in cancer management. Cancer Manag Res 2013;5: 301-313.

Cross-Mellor,SK, Ossenkopp,KP, Piomelli,D, Parker,LA. Effects of the FAAH inhibitor, URB597, and anandamide on lithium-induced taste reactivity responses: a measure of nausea in the rat. Psychopharmacology 2007;190: 135-143.

Darmani,NA. The cannabinoid CB1 receptor antagonist SR 141716A reverses the antiemetic and motor depressant actions of WIN 55, 212-2. Eur. J. Pharmacol. 2001;430: 49-58. Page | 16

ACCEPTED MANUSCRIPT Davenport,AP, Alexander,SPH, Sharman,JL, Pawson,AJ, Benson,HE, Monaghan,AE, Liew,WC, Mpamhanga,CP, Bonner,TI, Neubig,RR, Pin,J-P, Spedding,M, Harmar,AJ. International Union of Basic

T

and Clinical Pharmacology. LXXXVIII. G Protein-Coupled Receptor List: Recommendations for New

IP

Pairings with Cognate Ligands. Pharmacol. Rev. 2013;65: 967-986.

SC R

De Petrocellis,L, Ligresti,A, Moriello,AS, Allara,M, Bisogno,T, Petrosino,S, Stott,CG, Di Marzo,V. Effects of cannabinoids and cannabinoid-enriched Cannabis extracts on TRP channels and

NU

endocannabinoid metabolic enzymes. Br. J. Pharmacol. 2011;163: 1479-1494.

De Petrocellis,L, Orlando,P, Moriello,AS, Aviello,G, Stott,C, Izzo,AA, Di Marzo,V. Cannabinoid actions

MA

at TRPV channels: effects on TRPV3 and TRPV4 and their potential relevance to gastrointestinal

D

inflammation. Acta Physiol (Oxf) 2012;204: 255-266.

TE

Devinsky,O, Cilio,MR, Cross,H, Fernandez-Ruiz,J, French,J, Hill,C, Katz,R, Di Marzo,V, Jutras-Aswad,D, Notcutt,WG, Martinez-Orgado,J, Robson,PJ, Rohrback,BG, Thiele,E, Whalley,B, Friedman,D.

CE P

Cannabidiol: Pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders. Epilepsia 2014;55: 791-802.

AC

Dincheva,I, Drysdale,AT, Hartley,CA, Johnson,DC, Jing,D, King,EC, Ra,S, Gray,JM, Yang,R, DeGruccio,AM, Huang,C, Cravatt,BF, Glatt,CE, Hill,MN, Casey,BJ, Lee,FS. FAAH genetic variation enhances fronto-amygdala function in mouse and human. Nat. Commun. 2015;6: 6395.

Dinh,TP, Carpenter,D, Leslie,FM, Freund,TF, Katona,I, Sensi,SL, Kathuria,S, Piomelli,D. Brain monoglyceride lipase participating in endocannabinoid inactivation. Proc. Natl. Acad. Sci. U. S. A. 2002;99: 10819-10824.

Downer,EJ, Clifford,E, Amu,S, Fallon,PG, Moynagh,PN. The synthetic cannabinoid R(+)WIN55,212-2 augments interferon-beta expression via peroxisome proliferator-activated receptor-alpha. J. Biol. Chem. 2012;287: 25440-25453. Page | 17

ACCEPTED MANUSCRIPT Durinck,S, Stawiski,EW, Pavia-Jimenez,A, Modrusan,Z, Kapur,P, Jaiswal,BS, Zhang,N, ToffessiTcheuyap,V, Nguyen,TT, Pahuja,KB, Chen,YJ, Saleem,S, Chaudhuri,S, Heldens,S, Jackson,M, Pena-

T

Llopis,S, Guillory,J, Toy,K, Ha,C, Harris,CJ, Holloman,E, Hill,HM, Stinson,J, Rivers,CS, Janakiraman,V,

IP

Wang,W, Kinch,LN, Grishin,NV, Haverty,PM, Chow,B, Gehring,JS, Reeder,J, Pau,G, Wu,TD,

SC R

Margulis,V, Lotan,Y, Sagalowsky,A, Pedrosa,I, de Sauvage,FJ, Brugarolas,J, Seshagiri,S. Spectrum of diverse genomic alterations define non-clear cell renal carcinoma subtypes. Nat Genet 2015;47: 13-

NU

21.

Elmes,MW, Kaczocha,M, Berger,WT, Leung,K, Ralph,BP, Wang,L, Sweeney,JM, Miyauchi,JT, Tsirka,SE,

MA

Ojima,I, Deutsch,DG. Fatty Acid Binding Proteins (FABPs) are Intracellular Carriers for Delta9Tetrahydrocannabinol (THC) and Cannabidiol (CBD). Journal Of Biological Chemistry . 9-2-2015.

D

Ref Type: In Press

TE

England,TJ, Hind,WH, Rasid,NA, O'Sullivan,SE. Cannabinoids in experimental stroke: a systematic

CE P

review and meta-analysis. J Cereb Blood Flow Metab 2015;35: 348-358.

Fagan,SG, Campbell,VA. The influence of cannabinoids on generic traits of neurodegeneration. Br. J.

AC

Pharmacol. 2014;171: 1347-1360.

Farkas,S, Nagy,K, Palkovits,M, Kovacs,GG, Jia,Z, Donohue,S, Pike,V, Halldin,C, Mathe,D, Harkany,T, Gulyas,B, Csiba,L. [125I]SD-7015 reveals fine modalities of CB1 cannabinoid receptor density in the prefrontal cortex during progression of Alzheimer's disease. Neurochem. Int. 2011;60: 286-291.

Felder,CC, Joyce,KE, Briley,EM, Glass,M, Mackie,KP, Fahey,KJ, Cullinan,GJ, Hunden,DC, Johnson,DW, Chaney,MO, Koppel,GA, Brownstein,M. LY320135, a novel cannabinoid CB1 receptor antagonist, unmasks coupling of the CB1 receptor to stimulation of cAMP accumulation. J. Pharmacol. Exp. Ther. 1998;284: 291-297.

Page | 18

ACCEPTED MANUSCRIPT Felder,CC, Joyce,KE, Briley,EM, Mansouri,J, Mackie,K, Blond,O, Lai,Y, Ma,AL, Mitchell,RL. Comparison of the pharmacology and signal transduction of the human cannabinoid CB1 and CB2 receptors. Mol.

T

Pharmacol. 1995;48: 443-450.

IP

Feliu,A, Moreno-Martet,M, Mecha,M, Carrillo-Salinas,FJ, de Lago,E, Fernandez-Ruiz,J, Guaza,C. A

multiple sclerosis. Br J Pharmacol 2015;172: 3579-3595.

SC R

Sativex -like combination of phytocannabinoids as a disease-modifying therapy in a viral model of

NU

Fowler,CJ. The contribution of cyclooxygenase-2 to endocannabinoid metabolism and action. Br. J.

MA

Pharmacol. 2007;152: 594-601.

Fowler,CJ. Monoacylglycerol lipase - a target for drug development? Br. J. Pharmacol. 2012;166:

D

1568-1585.

CE P

2013;280: 1895-1904.

TE

Fowler,CJ. Transport of endocannabinoids across the plasma membrane and within the cell. FEBS J.

Fowler,CJ, Jonsson,KO, Tiger,G. Fatty acid amide hydrolase: biochemistry, pharmacology, and therapeutic possibilities for an enzyme hydrolyzing anandamide, 2-arachidonoylglycerol,

AC

palmitoylethanolamide, and oleamide. Biochem. Pharmacol. 2001;62: 517-526.

Fowler,CJ, Naidu,PS, Lichtman,A, Onnis,V. The case for the development of novel analgesic agents targeting both fatty acid amide hydrolase and either cyclooxygenase or TRPV1. Br. J. Pharmacol. 2009;156: 412-419.

Gaoni,Y, Mechoulam,R. Isolation, structure and partial synthesis of active constituent of hashish. J. Am. Chem. Soc. 1964;86: 1646-1647.

Garcia,MC, Cinquina,V, Palomo-Garo,C, Rabano,A, Fernandez-Ruiz,J. Identification of CB2 receptors in human nigral neurons that degenerate in Parkinson's disease. Neurosci. Lett. 2015;587: 1-4. Page | 19

ACCEPTED MANUSCRIPT Glass,M, Faull,RL, Dragunow,M. Loss of cannabinoid receptors in the substantia nigra in Huntington's disease. Neuroscience 1993;56: 523-527.

IP

T

Gloss,D, Vickrey,B. Cannabinoids for epilepsy. Cochrane Database Syst Rev 2014;3: CD009270.

SC R

Guindon,J, Hohmann,AG. Cannabinoid CB2 receptors: a therapeutic target for the treatment of inflammatory and neuropathic pain. Br. J. Pharmacol. 2008;153: 319-334.

Guzman,M, Duarte,MJ, Blazquez,C, Ravina,J, Rosa,MC, Galve-Roperh,I, Sanchez,C, Velasco,G,

NU

Gonzalez-Feria,L. A pilot clinical study of 9-tetrahydrocannabinol in patients with recurrent

MA

glioblastoma multiforme. Br J Cancer 2006;95: 197-203.

Hansen,KB, Rosenkilde,MM, Knop,FK, Wellner,N, Diep,TA, Rehfeld,JF, Andersen,UB, Holst,JJ,

D

Hansen,HS. 2-Oleoyl glycerol is a GPR119 agonist and signals GLP-1 release in humans. J. Clin.

TE

Endocrinol. Metab. 2011;96: E1409-E1417.

CE P

Hao,SZ, Avraham,Y, Mechoulam,R, Berry,EM. Low dose anandamide affects food intake, cognitive function, neurotransmitter and corticosterone levels in diet-restricted mice. Eur. J. Pharmacol.

AC

2000;392: 147-156.

Hashimotodani,Y, Ohno-Shosaku,T, Maejima,T, Fukami,K, Kano,M. Pharmacological evidence for the involvement of diacylglycerol lipase in depolarization-induced endocanabinoid release. Neuropharmacol 2008;54: 58-67.

Hashimotodani,Y, Ohno-Shosaku,T, Tanimura,A, Kita,Y, Sano,Y, Shimizu,T, Di Marzo,V, Kano,M. Acute inhibition of diacylglycerol lipase blocks endocannabinoid-mediated retrograde synaptic suppression: evidence for on-demand biosynthesis of 2-arachidonoylglycerol. J. Physiol. 2013;591: 4765-4776.

Page | 20

ACCEPTED MANUSCRIPT Henstridge,CM, Balenga,NAB, Ford,LA, Ross,RA, Waldhoer,M, Irving,AJ. The GPR55 ligand L-lysophosphatidylinositol promotes RhoA-dependent Ca2+ signaling and NFAT activation. FASEB J.

T

2009;23: 183-193.

IP

Herkenham,M, Lynn,AB, Little,MD, Johnson,MR, Melvin,LS, De Costa,BR, Rice,KC. Cannabinoid

SC R

receptor localization in brain. Proc. Natl. Acad. Sci. U. S. A. 1990;87: 1932-1936.

Hillard,CJ, Manna,S, Greenberg,MJ, Dicamelli,R, Ross,RA, Stevenson,LA, Murphy,V, Pertwee,RG,

NU

Campbell,WB. Synthesis and characterization of potent and selective agonists of the neuronal

MA

cannabinoid receptor (CB1). J. Pharmacol. Exp. Ther. 1999;289: 1427-1433.

Hilliard,A, Stott,C, Wright,S, Guy,G, Pryce,G, Al-Izki,S, Bolton,C, Giovannoni,G. Evaluation of the

D

Effects of Sativex (THC BDS: CBD BDS) on Inhibition of Spasticity in a Chronic Relapsing Experimental

TE

Allergic Autoimmune Encephalomyelitis: A Model of Multiple Sclerosis. ISRN Neurol 2012;2012:

CE P

802649.

Hollister,LE. Health aspects of cannabis. Pharmacol. Rev. 1986;38: 1-20.

Howlett,AC, Johnson,MR, Melvin,LS, Milne,GM. Nonclassical cannabinoid analgetics inhibit

302.

AC

adenylate-cyclase: development of a cannabinoid receptor model. Mol. Pharmacol. 1988;33: 297-

Huffman,JW, Liddle,J, Yu,S, Aung,MM, Abood,ME, Wiley,JL, Martin,BR. 3-(1',1'-Dimethylbutyl)-1deoxy-8-THC and related compounds: synthesis of selective ligands for the CB2 receptor. Bioorg. Med. Chem. 1999;7: 2905-2914.

Huggins,JP, Smart,TS, Langman,S, Taylor,L, Young,T. An efficient randomised, placebo-controlled clinical trial with the irreversible fatty acid amide hydrolase-1 inhibitor PF-04457845, which modulates endocannabinoids but fails to induce effective analgesia in patients with pain due to osteoarthritis of the knee. Pain 2012;153: 1837-1846. Page | 21

ACCEPTED MANUSCRIPT Iannotti,FA, Hill,CL, Leo,A, Alhusaini,A, Soubrane,C, Mazzarella,E, Russo,E, Whalley,BJ, Di Marzo,V, Stephens,GJ. Nonpsychotropic Plant Cannabinoids, Cannabidivarin (CBDV) and Cannabidiol (CBD),

T

Activate and Desensitize Transient Receptor Potential Vanilloid 1 (TRPV1) Channels in Vitro:

IP

Potential for the Treatment of Neuronal Hyperexcitability. ACS Chem Neurosci 2014;5: 1131-1141.

SC R

Iseger,TA, Bossong,MG. A systematic review of the antipsychotic properties of cannabidiol in humans. Schizophr Res . 6-2-2015.

NU

Ref Type: In Press

Jhaveri,MD, Richardson,D, Chapman,V. Endocannabinoid metabolism and uptake: novel targets for

MA

neuropathic and inflammatory pain. Br. J. Pharmacol. 2007;152: 624-632.

D

Jhaveri,MD, Richardson,D, Robinson,I, Garle,MJ, Patel,A, Sun,Y, Sagar,DR, Bennett,AJ,

TE

Alexander,SPH, Kendall,DA, Barrett,DA, Chapman,V. Inhibition of fatty acid amide hydrolase and cycloxygenase-2 increases levels of endocannabinoids and produces analgesia via peroxisome

93.

CE P

proliferator-activated receptor-alpha in a model of inflammatory pain. Neuropharmacol 2008;55: 85-

AC

Jin,KL, Mao,XO, Goldsmith,PC, Greenberg,DA. CB1 cannabinoid receptor induction in experimental stroke. Ann. Neurol. 2000;48: 257-261.

Kaczocha,M, Glaser,ST, Chae,J, Brown,DA, Deutsch,DG. Lipid droplets are novel sites of Nacylethanolamine inactivation by fatty acid amide hydrolase-2. J. Biol. Chem. 2010;285: 2795-2806.

Kaczocha,M, Glaser,ST, Deutsch,DG. Identification of intracellular carriers for the endocannabinoid anandamide. Proc. Natl. Acad. Sci. U. S. A. 2009;106: 6375-6380.

Kang,SU. GPR119 agonists: a promising approach for T2DM treatment? A SWOT analysis of GPR119. Drug Discov. Today 2013;18: 1309-1315.

Page | 22

ACCEPTED MANUSCRIPT Kapur,A, Zhao,P, Sharir,H, Bai,Y, Caron,MG, Barak,LS, Abood,ME. Atypical responsiveness of the orphan receptor GPR55 to cannabinoid ligands. J. Biol. Chem. 2009;284: 29817-29827.

T

Kirkham,TC, Williams,CM, Fezza,F, Di Marzo,V. Endocannabinoid levels in rat limbic forebrain and

IP

hypothalamus in relation to fasting, feeding and satiation: stimulation of eating by 2-arachidonoyl

SC R

glycerol. Br. J. Pharmacol. 2002;136: 550-557.

Kleberg,K, Hassing,HA, Hansen,HS. Classical endocannabinoid-like compounds and their regulation

NU

by nutrients. Biofactors 2014;40: 363-372.

MA

Kohno,M, Hasegawa,H, Inoue,A, Muraoka,M, Miyazaki,T, Oka,K, Yasukawa,M. Identification of Narachidonylglycine as the endogenous ligand for orphan G-protein-coupled receptor GPR18.

D

Biochem. Biophys. Res. Commun. 2006;347: 827-832.

TE

Koppel,BS, Brust,JC, Fife,T, Bronstein,J, Youssof,S, Gronseth,G, Gloss,D. Systematic review: efficacy

CE P

and safety of medical marijuana in selected neurologic disorders: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2014;82: 15561563.

AC

Kramer,JL. Medical marijuana for cancer. CA Cancer J Clin 2015;65: 109-122.

Lan,RX, Liu,Q, Fan,PS, Lin,SY, Fernando,SR, McCallion,D, Pertwee,R, Makriyannis,A. Structure-activity relationships of pyrazole derivatives as cannabinoid receptor antagonists. J. Med. Chem. 1999;42: 769-776.

Ledent,C, Valverde,O, Cossu,C, Petitet,F, Aubert,LF, Beslot,F, Böhme,GA, Imperato,A, Pedrazzini,T, Roques,BP, Vassart,G, Fratta,W, Parmentier,M. Unresponsiveness to cannabinoids and reduced addictive effects of opiates in CB1 receptor knockout mice. Science 1999;283: 401-404.

Page | 23

ACCEPTED MANUSCRIPT Limebeer,CL, Rock,EM, Mechoulam,R, Parker,LA. The anti-nausea effects of CB1 agonists are mediated by an action at the visceral insular cortex. Br. J. Pharmacol. 2012;167: 1126-1136.

T

Liu,J, Li,H, Burstein,SH, Zurier,RB, Chen,JD. Activation and binding of peroxisome proliferator-

SC R

IP

activated receptor by synthetic cannabinoid ajulemic acid. Mol. Pharmacol. 2003;63: 983-992.

Long,JZ, Li,W, Booker,L, Burston,JJ, Kinsey,SG, Schlosburg,JE, Pavon,FJ, Serrano,AM, Selley,DE, Parsons,LH, Lichtman,AH, Cravatt,BF. Selective blockade of 2-arachidonoylglycerol hydrolysis

NU

produces cannabinoid behavioral effects. Nat. Chem. Biol. 2009;5: 37-44.

MA

Martin,BR, Compton,DR, Thomas,BF, Prescott,WR, Little,PJ, Razdan,RK, Johnson,MR, Melvin,LS, Mechoulam,R, Ward,SJ. Behavioral, biochemical, and molecular modeling evaluations of

D

cannabinoid analogs. Pharmacol. Biochem. Behav. 1991;40: 471-478.

TE

Martin-Sanchez,E, Furukawa,TA, Taylor,J, Martin,JL. Systematic review and meta-analysis of cannabis

CE P

treatment for chronic pain. Pain Med 2009;10: 1353-1368.

Massi,P, Solinas,M, Cinquina,V, Parolaro,D. Cannabidiol as potential anticancer drug. Br. J. Clin.

AC

Pharmacol. 2013;75: 303-312.

Matsuda,LA, Lolait,SJ, Brownstein,MJ, Young,AC, Bonner,TI. Structure of a cannabinoid receptor and functional expression of the cloned cDNA. Nature 1990;346: 561-564. McHugh,D, Page,J, Dunn,E, Bradshaw,HB. 9-THC and N-arachidonyl glycine are full agonists at GPR18 and cause migration in the human endometrial cell line, HEC-1B. Br. J. Pharmacol. 2012;165: 2414-2424.

McLoughlin,BC, Pushpa-Rajah,JA, Gillies,D, Rathbone,J, Variend,H, Kalakouti,E, Kyprianou,K. Cannabis and schizophrenia. Cochrane Database Syst Rev 2014;10: CD004837.

Page | 24

ACCEPTED MANUSCRIPT McPartland,JM, Duncan,M, Di Marzo,V, Pertwee,RG. Are cannabidiol and 9-tetrahydrocannabivarin negative modulators of the endocannabinoid system? A systematic review. Br. J. Pharmacol.

T

2015;172: 737-753.

IP

Mechoulam,R, Hanus,LO, Pertwee,R, Howlett,AC. Early phytocannabinoid chemistry to

SC R

endocannabinoids and beyond. Nat. Rev. Neurosci. 2014;15: 757-764.

Melis,M, Pillolla,G, Luchicchi,A, Muntoni,AL, Yasar,S, Goldberg,SR, Pistis,M. Endogenous fatty acid

NU

ethanolamides suppress nicotine-induced activation of mesolimbic dopamine neurons through

MA

nuclear receptors. J. Neurosci. 2008;28: 13985-13994.

Michalik,L, Auwerx,J, Berger,JP, Chatterjee,VK, Glass,CK, Gonzalez,FJ, Grimaldi,PA, Kadowaki,T,

D

Lazar,MA, O'Rahilly,S, Palmer,CN, Plutzky,J, Reddy,JK, Spiegelman,BM, Staels,B, Wahli,W.

CE P

Rev. 2006;58: 726-741.

TE

International Union of Pharmacology. LXI. Peroxisome proliferator-activated receptors. Pharmacol.

Mor,M, Rivara,S, Lodola,A, Plazzi,PV, Tarzia,G, Duranti,A, Tontini,A, Piersanti,G, Kathuria,S, Piomelli,D. Cyclohexylcarbamic acid 3'- or 4'-substituted biphenyl-3-yl esters as fatty acid amide

AC

hydrolase inhibitors: synthesis, quantitative structure-activity relationships, and molecular modeling studies. J. Med. Chem. 2004;47: 4998-5008.

Moulle,VS, Cansell,C, Luquet,S, Cruciani-Guglielmacci,C. The multiple roles of fatty acid handling proteins in brain. Front Physiol 2012;3: 385.

Mulvihill,MM, Nomura,DK. Therapeutic Potential of Monoacylglycerol Lipase Inhibitors. Life Sci. 2013;92: 492-497.

Munro,S, Thomas,KL, Abu-Shaar,M. Molecular characterization of a peripheral receptor for cannabinoids. Nature 1993;365: 61-65.

Page | 25

ACCEPTED MANUSCRIPT Novotna,A, Mares,J, Ratcliffe,S, Novakova,I, Vachova,M, Zapletalova,O, Gasperini,C, Pozzilli,C, Cefaro,L, Comi,G, Rossi,P, Ambler,Z, Stelmasiak,Z, Erdmann,A, Montalban,X, Klimek,A, Davies,P. A

T

randomized, double-blind, placebo-controlled, parallel-group, enriched-design study of nabiximols*

IP

(Sativex((R)) ), as add-on therapy, in subjects with refractory spasticity caused by multiple sclerosis.

SC R

Eur J Neurol 2011;18: 1122-1131.

O'Sullivan,SE. Cannabinoids go nuclear: evidence for activation of peroxisome proliferator-activated

NU

receptors. Br. J. Pharmacol. 2007;152: 576-582.

O'Sullivan,SE, Sun,Y, Bennett,AJ, Randall,MD, Kendall,DA. Time-dependent vascular actions of

MA

cannabidiol in the rat aorta. Eur. J. Pharmacol. 2009;612: 61-68.

O'Sullivan,SE, Tarling,EJ, Bennett,AJ, Kendall,DA, Randall,MD. Novel time-dependent vascular actions

TE

D

of 9-tetrahydrocannabinol mediated by peroxisome proliferator-activated receptor . Biochem.

CE P

Biophys. Res. Commun. 2005;337: 824-831.

Oka,S, Toshida,T, Maruyama,K, Nakajima,K, Yamashita,A, Sugiura,T. 2-Arachidonoyl-sn-glycero-3phosphoinositol: a possible natural ligand for GPR55. J. Biochem. 2009;145: 13-20.

AC

Okine,BN, Norris,LM, Woodhams,S, Burston,J, Patel,A, Alexander,SPH, Barrett,DA, Kendall,DA, Bennett,AJ, Chapman,V. Lack of effect of chronic pre-treatment with the FAAH inhibitor URB597 on inflammatory pain behaviour: evidence for plastic changes in the endocannabinoid system. Br. J. Pharmacol. 2012;167: 627-640.

Overton,HA, Babbs,AJ, Doel,SM, Fyfe,MC, Gardner,LS, Griffin,G, Jackson,HC, Procter,MJ, Rasamison,CM, Tang-Christensen,M, Widdowson,PS, Williams,GM, Reynet,C. Deorphanization of a G protein-coupled receptor for oleoylethanolamide and its use in the discovery of small-molecule hypophagic agents. Cell Metab 2006;3: 167-175.

Page | 26

ACCEPTED MANUSCRIPT Palazuelos,J, Aguado,T, Pazos,MR, Julien,B, Carrasco,C, Resel,E, Sagredo,O, Benito,C, Romero,J, Azcoitia,I, Fernandez-Ruiz,J, Guzman,M, Galve-Roperh,I. Microglial CB2 cannabinoid receptors are

T

neuroprotective in Huntington's disease excitotoxicity. Brain 2009;132: 3152-3164.

IP

Parmentier-Batteur,S, Jin,K, Mao,XO, Xie,L, Greenberg,DA. Increased severity of stroke in CB1

SC R

cannabinoid receptor knock-out mice. J. Neurosci. 2002;22: 9771-9775.

Pertwee,RG, Howlett,AC, Abood,ME, Alexander,SPH, Di Marzo,V, Elphick,MR, Greasley,PJ,

NU

Hansen,HS, Kunos,G, Mackie,K, Mechoulam,R, Ross,RA. International Union of Basic and Clinical Pharmacology. LXXIX. Cannabinoid Receptors and Their Ligands: Beyond CB1 and CB2. Pharmacol.

MA

Rev. 2010;62: 588-631.

D

Porcella,A, Maxia,C, Gessa,GL, Pani,L. The human eye expresses high levels of CB1 cannabinoid

TE

receptor mRNA and protein. Eur. J. Neurosci. 2000;12: 1123-1127.

CE P

Porcella,A, Maxia,C, Gessa,GL, Pani,L. The synthetic cannabinoid WIN55212-2 decreases the intraocular pressure in human glaucoma resistant to conventional therapies. Eur. J. Neurosci. 2001;13: 409-412.

AC

Ramirez,BG, Blazquez,C, Gomez Del Pulgar,T, Guzman,M, de Ceballos,ML. Prevention of Alzheimer's disease pathology by cannabinoids: neuroprotection mediated by blockade of microglial activation. J. Neurosci. 2005;25: 1904-1913.

Rea,K, Roche,M, Finn,DP. Supraspinal modulation of pain by cannabinoids: the role of GABA and glutamate. Br. J. Pharmacol. 2007;152: 633-648.

Richfield,EK, Herkenham,M. Selective vulnerability in Huntington's disease: preferential loss of cannabinoid receptors in lateral globus pallidus. Ann. Neurol 1994;36: 577-584.

Page | 27

ACCEPTED MANUSCRIPT Rinaldi-Carmona,M, Barth,F, Heaulme,M, Alonso,R, Shire,D, Congy,C, Soubrie,P, Breliere,JC, Le Fur,G. Biochemical and pharmacological characterisation of SR141716A, the first potent and selective brain

T

cannabinoid receptor antagonist. Life Sci. 1995;56: 1941-1947.

IP

Rinaldi-Carmona,M, Barth,F, Millan,J, Derocq,J-M, Casellas,P, Congy,C, Oustric,D, Sarran,M,

SC R

Bouaboula,M, Calandra,B, Portier,M, Shire,D, Brelière,J-C, Le Fur,G. SR 144528, the first potent and selective antagonist of the CB2 cannabinoid receptor. J. Pharmacol. Exp. Ther. 1998;284: 644-650.

NU

Roques,BP, Fournie-Zaluski,MC, Wurm,M. Inhibiting the breakdown of endogenous opioids and

MA

cannabinoids to alleviate pain. Nat. Rev. Drug Discovery 2012;11: 292-310.

Ross,RA. The enigmatic pharmacology of GPR55. Trends Pharmacol. Sci. 2009;30: 156-163.

D

Ross,RA, Brockie,HC, Stevenson,LA, Murphy,VL, Templeton,F, Makriyannis,A, Pertwee,RG. Agonist-

TE

inverse agonist characterization at CB1 and CB2 cannabinoid receptors of L759633, L759656 and

CE P

AM630. Br. J. Pharmacol. 1999;126: 665-672.

Russo,EB. History of cannabis and its preparations in saga, science, and sobriquet. Chem. Biodivers.

AC

2007;4: 1614-1648.

Russo,M, Calabro,RS, Naro,A, Sessa,E, Rifici,C, D'Aleo,G, Leo,A, De Luca,R, Quartarone,A, Bramanti,P. Sativex in the management of multiple sclerosis-related spasticity: role of the corticospinal modulation. Neural Plast 2015;2015: 656582.

Ryberg,E, Larsson,N, Sjogren,S, Hjorth,S, Hermansson,NO, Leonova,J, Elebring,T, Nilsson,K, Drmota,T, Greasley,PJ. The orphan receptor GPR55 is a novel cannabinoid receptor. Br. J. Pharmacol. 2007;152: 1092-1101.

Sagar,DR, Burston,JJ, Woodhams,SG, Chapman,V. Dynamic changes to the endocannabinoid system in models of chronic pain. Philos Trans R Soc Lond B Biol Sci 2012;367: 3300-3311. Page | 28

ACCEPTED MANUSCRIPT Sagar,DR, Kendall,DA, Chapman,V. Inhibition of fatty acid amide hydrolase produces PPAR-mediated analgesia in a rat model of inflammatory pain. Br. J. Pharmacol. 2008;155: 1297-1306.

T

Schmid,PC, Zuzarte-Augustin,ML, Schmid,HH. Properties of rat liver N-acylethanolamine

SC R

IP

amidohydrolase. J. Biol. Chem. 1985;260: 14145-14149.

Schroeder,F, Petrescu,AD, Huang,H, Atshaves,BP, McIntosh,AL, Martin,GG, Hostetler,HA, Vespa,A, Landrock,D, Landrock,KK, Payne,HR, Kier,AB. Role of fatty acid binding proteins and long chain fatty

NU

acids in modulating nuclear receptors and gene transcription. Lipids 2008;43: 1-17.

MA

Sticht,MA, Long,JZ, Rock,EM, Limebeer,CL, Mechoulam,R, Cravatt,BF, Parker,LA. Inhibition of monoacylglycerol lipase attenuates vomiting in Suncus murinus and 2-arachidonoyl glycerol

D

attenuates nausea in rats. Br. J. Pharmacol. 2012;165: 2425-2435.

CE P

2010;285: 32679-32683.

TE

Storch,J, Thumser,AE. Tissue-specific functions in the fatty acid-binding protein family. J. Biol. Chem.

Sun,YX, Tsuboi,K, Zhao,LY, Okamoto,Y, Lambert,DM, Ueda,N. Involvement of N-acylethanolaminehydrolyzing acid amidase in the degradation of anandamide and other N-acylethanolamines in

AC

macrophages. Biochim. Biophys. Acta 2005;1736: 211-220.

Ueda,N, Yamanaka,K, Terasawa,Y, Yamamoto,S. An acid amidase hydrolyzing anandamide as an endogenous ligand for cannabinoid receptors. FEBS Lett. 1999;454: 267-270.

Urquhart,P, Nicolaou,A, Woodward,DF. Endocannabinoids and their oxygenation by cyclooxygenases, lipoxygenases and other oxygenases. Biochim. Biophys. Acta 2015;1851: 366-376.

van Bakel,H, Stout,JM, Cote,AG, Tallon,CM, Sharpe,AG, Hughes,TR, Page,JE. The draft genome and transcriptome of Cannabis sativa. Genome Biol 2011;12: R102.

Page | 29

ACCEPTED MANUSCRIPT Van Gaal,LF, Rissanen,AM, Scheen,AJ, Ziegler,O, Rossner,S. Effects of the cannabinoid-1 receptor blocker rimonabant on weight reduction and cardiovascular risk factors in overweight patients: 1-

T

year experience from the RIO-Europe study. Lancet 2005;365: 1389-1397.

IP

Van Laere,K, Casteels,C, Lunskens,S, Goffin,K, Grachev,ID, Bormans,G, Vandenberghe,W. Regional

SC R

changes in type 1 cannabinoid receptor availability in Parkinson's disease in vivo. Neurobiol. Aging 2012;33: 620.e1.

NU

Vara,D, Morell,C, Rodriguez-Henche,N, Diaz-Laviada,I. Involvement of PPAR in the antitumoral

MA

action of cannabinoids on hepatocellular carcinoma. Cell Death Dis 2013;4: e618.

Wei,BQ, Mikkelsen,TS, McKinney,MK, Lander,ES, Cravatt,BF. A second fatty acid amide hydrolase

D

with variable distribution among placental mammals. J. Biol. Chem. 2006;281: 36569-36578.

TE

Whibley,AC, Plagnol,V, Tarpey,PS, Abidi,F, Fullston,T, Choma,MK, Boucher,CA, Shepherd,L, Willatt,L,

CE P

Parkin,G, Smith,R, Futreal,PA, Shaw,M, Boyle,J, Licata,A, Skinner,C, Stevenson,RE, Turner,G, Field,M, Hackett,A, Schwartz,CE, Gecz,J, Stratton,MR, Raymond,FL. Fine-scale survey of X chromosome copy number variants and indels underlying intellectual disability. Am J Hum Genet 2010;87: 173-188.

AC

Wiley,JL, Burston,JJ, Leggett,DC, Alekseeva,OO, Razdan,RK, Mahadevan,A, Martin,BR. CB1 cannabinoid receptor-mediated modulation of food intake in mice. Br. J. Pharmacol. 2005;145: 293300.

Yazulla,S. Endocannabinoids in the retina: from marijuana to neuroprotection. Prog Retin Eye Res 2008;27: 501-526.

Yoshida,T, Fukaya,M, Uchigashima,M, Miura,E, Kamiya,H, Kano,M, Watanabe,M. Localization of diacylglycerol lipase- around postsynaptic spine suggests close proximity between production site of an endocannabinoid, 2-arachidonoyl-glycerol, and presynaptic cannabinoid CB1 receptor. J. Neurosci. 2006;26: 4740-4751. Page | 30

ACCEPTED MANUSCRIPT Zachariou,M, Alexander,SPH, Coombes,S, Christodoulou,C. A biophysical model of endocannabinoid-

T

mediated short term depression in hippocampal inhibition. PLoS One 2013;8: e5892.

IP

Legend to figures

Figure 1: Examples of the structures of plant-derived cannabinoids and endocannabinoids

SC R

Figure 2: A summary illustrating the parallel pathways of synthesis, hydrolysis and transformation of the endocannabinoids

Figure 3: Selective agonists and antagonists at CB1 and CB2 cannabinoid receptors

NU

Figure 4: Examples of the potential and realised therapeutic potential of Cannabis-related

AC

CE P

TE

D

MA

drugs

Page | 31

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

Fig. 1

Page | 32

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

Fig. 2

Page | 33

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

Fig. 3

Page | 34

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

Fig. 4

Page | 35