Invited Review Anticholinesterases: dramatic aspects of their use and misuse

NEUROCHEMISTRY International Neurochem[ Int[ 21 "0887# 390Ð300

Invited Review Anticholinesterases] dramatic aspects of their use and misuse A[ Karczmar Research Service\ Hines VA Hospital\ Hines\ ILL 59030\ U[S[A[ and Department of Pharmacolo`y\ Loyola University Medical Center\ Maywood\ ILL 59042\ U[S[A[ Received 18 July 0886^ accepted 15 October 0886

Abstract While the lore of anticholinesterases "antiChEs#\ particularly physostigmine and its natural source\ the Calabar bean\ is a subject of ethnomedicine and predates our scienti_c era\ the pharmacological development of physostigmine analogues and related agents and of the antiChEs of the organophosphorus "OP# type\ is a matter of the last two centuries^ this development has reached an exponential character in the last _fty years[ This explosion relates to certain uses and misuses of these drugs and this aspect of antiChEs is the main focus of this article[ Firstly\ there is the matter of Senile Dementia of Alzheimer|s Type "SDAT#^ while there are several clinical applications of antiChEs\ their employment in the treatment of SDAT is the last and most intense foray in their medical history and this article will focus on the uses and misuses of antiChEs in this area[ Secondly\ the applied use of antiChEs as insecticides which coincided with the historical development of OP antiChEs was and is\ of major signi_cance for the agricultural economy of both advanced and underdeveloped countries\ as this employment may mean the di}erence between life and starvation[ However\ there are notable dangers with this application of OP drugs\ as will be emphasized in this article[ Thirdly\ there is the signi_cant and tragic development of the OP drugs as warfare agents and tools for terrorists and rogue states and this article will discuss the several types of toxicity of OP agents and their mechanisms\ the enigma of the Persian Gulf War Syndrome being particularly stressed[ Altogether\ the immense range of antiChE topics includes areas of great basic interest and of practical applications that are of signi_cant bene_t to mankind as well as of potential danger[ Þ 0887 Elsevier Science Ltd[ All rights reserved[

0[ Introduction Cholinesterase inhibitors "antiChEs# of carbamate\ ami! noacridine and related structures\ or organophosphorus "OP# type\ are among the most widely used and most intensely studied agents[ For several milennia\ carbamate antiChEs have been widely employed on several con! tinents in their natural form*as the so!called Calabar bean*in primitive medicine and rituals as well as hunting devices "Holmstedt\ 0861^ Holmstedt et al[\ 0874^ Karczmar\ 0869#[ Since the 08th and particularly in this century\ carbamate and related antiChEs as well as OP drugs have been used in the treatment of a number of illnesses and as antidotes of atropine and tricyclic anti! depressant poisoning[ Most interesting of all is the recent use of antiChEs in Alzheimer|s Disease "Senile Dementia of Alzheimer Type^ SDAT#[ Another use of these drugs\ both in the case of the OP and carbamate agents\ is as insecticides and pesticides\ a use which is not devoid of danger[ Finally\ the potential of the OP drugs as war gases was realized quite early[ This article focuses on the recent uses and misuses of 9086Ð9075:87 ,08[99 Þ 0887 Elsevier Science Ltd[ All rights reserved PII] S 9 0 8 6 Ð 9 0 7 5 " 8 6 # 9 9 0 1 2 Ð X

antiChEs[ Firstly\ the current status of antiChEs and their actions will be summarized[ Secondly\ to clarify actions of antiChEs a brief summary of behavioral cor! relates will be provided[ Thirdly\ the toxicity of antiChEs\ as a byproduct of their insecticidal use\ and fourthly\ their status as war gases*a subject made {hot| because of their possible generation of the so!called Persian Gulf Syndrome*will be described[ Lastly\ antiSDAT therapy with these agents will be discussed[ This article is dedicated to Edith Heilbronn[ While she was involved in the course of her illustrious career in many aspects of the cholinergic system\ her research con! cerned especially antiChEs\ whether of OP or non!OP type^ thus\ the aims of this article should be of interest to Edith[

1[ The current status of anti!ChEs and their actions The isolation of physostigmine or eserine from the extract of calabar bean\ Physosti`ma venenosum "Jobst and

391

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

Hesse\ 0753# and work on its structure by Stedmans and colleagues led to the synthesis of physostigmine and other carbamate and related antiChEs which are reversible or competitive inhibitors "Long\ 0852#[ Their synthesis is easy^ furthermore\ their development was speeded by the discovery of their e}ectiveness in myasthenia gravis\ cer! tain autonomic and ophthalmological dysfunctions\ as well as the demonstration of their usefulness as insec! ticides "see Section 3#[ More recently\ this synthetic pro! duction was intensi_ed by their employment in the treatment of SDAT[ Beginning with physostigmine itself "Peters and Levin\ 0868#\ other carbamates and related agents were developed for this use[ The compounds in question include piperidines\ such as donepezil "Aricept# and aminopyridines^ and acridines\ such as tetrahydro! aminoacridine "THA\ tacrine#[ Aricept and tacrine have recently been introduced as popular anti!SDAT agents[ Certain naturally occurring anti!ChEs\ the heterocyclic acridines and phenantridines such as huperzine "Hanin et al[\ 0880#\ are also potential antiSDAT agents "Section 4#[ OP drugs are as numerous as the carbamates and their relatives\ again because they are easily synthesized but\ above all\ because they are useful as insecticides\ pes! ticides and wormicides and also because they may serve as war gases[Tetraethypyrophosphate "TEPP# was the _rst OP drug that was synthesized "De Clermont\ 0743#[ Subsequent synthesis of OP drugs was carried out in Germany\ by Michaelis and colleagues including that of the prototypes of war gases such as Tabun and in Russia by the Arbusovs "Holmstedt\ 0848\ 0852^ Karczmar\ 0869#[ De_nitive knowledge of ChEs and of their active sites is needed to understand the e}ects of antiChEs[ The studies of Alles and Hawes\ Mendel and Rudney\ Whittaker\ Nachmansohn and Wilson\ and Augustinsson "Augustinsson\ 0852# established the exis! tence of true or speci_c vs pseudo or serum ChE ðtoday referred to as acetyl or propionyl ChE "AChE^ 2[0[0[6# and butyryl ChE "BuChE#\ respectivelyŁ^ furthermore\ several physical forms of ChEs were established by the Israeli and French investigators "Masssoulie et al[\ 0885^ Aziz!Aloya et al[\ 0882#[ It was proposed by Bodansky\ Nachmansohn\ Wilson\ Heilbronn and others that the action of antiChEs is due to their carbamylation or phos! phorylation of a serine!containing esteratic or {working| site of the molecule of ChEs "Karczmar\ 0869^ Holmstedt\ 0848^ Usdin\ 0869#[ Currently\ the esteratic site is con! ceived as a {gorge| "Massoulie et al[\ 0882# that contains\ besides serine\ an aromatic residue and aspartate or glutamate^ the site in question is reversibly ligated by carbamylation in the case of carbamate antiChEs and irreversibly phosphorylated in that of OP antiChEs[ The anionic site is involved in the ligation of quaternary inhibitors such as edrophonium or prostigmine^ an indole {plane| and several de_ned aminoacid sequences were

identi_ed at this site "Massoulie et al[\ 0882^ Heilbronn\ 0882#[ While certain carbamate or OP antiChEs show a preferential e}ect on either BuChEs or AChEs\ it is not clear\ as yet\ how the e}ects of antiChEs di}er with regard to the subtypes of these enzymes[

2[ Cholinergic pathways and cholinergic behavioral correlates Present understanding of central cholinergic pathways is based particularly on localizing the subtypes of mus! carinic and nicotinic postsynaptic receptors and pre! synaptic\ auto and hetero!receptors\ on histochemistry of AChE "Koelle\ 0852# and immunochemical de_nition of the sites of CAT\ combined with positron emission tomography "McGeer et al[\ 0876^ Butcher et al[\ 0882^ Mesulam\ 0885#[ These pathways are ubiquitous^ they emanate from the medial forebrain cholinergic systems and radiate to the limbic system\ cortex and the hypo! thalamus^ they include medioseptal nuclei and pathways\ nucleus basalis of Meynert\ medial habenular nuclei and the neopontine tegmental nuclei\ including pontine\ med! ullary and reticular formation systems[ In addition\ chol! inergic networks are located in the retina and basal ganglia[ Less well de_ned are the descending cholinergic pathways and the spinal circuitry concerning the chol! inergic preganglionic and motor neurons "Butcher et al[\ 0882^ Mesulam\ 0885^ McGeer et al[\ 0873\ 0876^ De Groat\ 0865#[ While this description of the central chol! inergic pathways is derived mainly from the work with rodents and cats\ it needs stressing that it applies as well to the central cholinergic of the primates including man "Mesulam\ 0885#[ In view of this ubiquity of the central cholinergic path! ways it is not surprising that all functions and behaviors that were ever studied exhibit cholinergic correlates; Thus\ signi_cant cholinergic correlates are exhibited by {organic| central functions\ including hypothalamically regulated appetitive\ thermostatic\ autonomic and car! diovascular activities\ as well as respiratory\ convulsive and re~exogenic phenomena "Karczmar\ 0889\ 0885#[ These latter e}ects center on the pontine and medullary cholinergic pathways and are pertinent for toxic e}ects of antiChEs\ including OP drugs "see Section 3#[ Similarly\ signi_cant cholinergic correlates are shown by {psycho! logical| functions or behaviors "Karczmar\ op[ cit[#^ these include many forms of aggression\ emotional behavior and fear\ addiction and {schizoid| behavior\ many forms of cognition\ including learning and memory and REM sleep^ there are evoked potential and EEG correlates of these behaviors that also exhibit cholinergic charac! teristics[ This particular aspect of the study is pertinent to the focus of this article on SDAT treatment "see Section 4#[

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

3[ Anticholinesterase insecticides and war gasses 3[0[ Toxicity of antiChE dru`s In the Western World\ the _rst notion of toxicity of antiChEs arose from Christison|s "0744# self!exper! imentation with the calabar bean[ Of particular interest in the context of this article is the _rst case of antiChE poisoning that occurred in the Western World[ In 0753\ 35 children consumed the Calabar bean which they obtained from a {heap of rubbishÐthe sweepings of a ship which [ [ [ brought a considerable quantity of [ [ [ the beans [ [ [ from the West Coast of Africa| "Cameron\ 0753#[ Cameron "op[cit[# treated the resulting toxicity with {emetics and a plentiful supply of warm water and brandy| "rather than with atropine\ although this use of atropine was known at the time#^ ultimately\ one child died[ The development in the 0819s and 0829s of OP anti! ChEs in Germany led to the recognition of their toxicity and potential as war gases by Lange\ Schrader\ Holz and Kruger "Holmstedt\ 0848\ 0852#[ These phenomena were studied at several centers in Germany and particularly at Duehernfurt in Silesia "Koelle\ 0870#[ As the knowledge of the German e}ort in this area became recognized else! where\ pertinent research was initiated in the 0839s at the Institute of Animal Research in Babraham\ at Porton Down Defence Research Center in the U[K[\ at Aberdeen Army Chemical Center in the U[S[A[\ at the Research Institute of National Defense in Sweden and at the Leningrad "St Petersburg# Institute for Biology in Russia[ This and subsequent research yielded complete under! standing of the toxicity of OP and carbamate antiChEs[ While rodents and dogs die\ following their exposure to antiChEs due to {asthmatic| death that involves per! ipheral e}ects upon the smooth muscle of the bronchi and the skeletal respiratory musculature\ cats and man die because of the block of the medullary respiratory centers resulting from ACh accumulation "Wills\ 0869^ Glenn et al[\ 0876^ Rickett and Beers\ 0876#[ This block is caused by prolonged ACh!induced depolarization\ which is then converted into desensitization or receptor inactivation\ a phenomenon that results from receptor phosphorylation "Karczmar\ 0882#[ A direct desensitizing e}ect of OP agents on the channel may also contribute to the block in question "Karczmar and Ohta\ 0870^ Albuquerque et al[\ 0885#[ Another toxicity that follows cholinergic activation consists of neuromyal and CNS neuropathy and damage "Petras\ 0870^ Dettbarn\ 0873#[ Dettbarn and his associ! ates related this neuropathy to cholinergically!induced hyperactivity\ Ca¦¦ mobilization and formation of free radicals "Yang and Dettbarn\ 0886#[ At least at the CNS level\ certain direct actions of the OP drugs may be involved in these neuropathies "Van Meter et al[\ 0867^ Karczmar\ 0873a#[

392

Still another type of neuropathy that may follow the exposure to at least some OP drugs is the Organ! ophosphorus Ester!Induced Delayed Neurotoxicity "OPIDN#[ This neuropathology\ which is quite similar in several species\ including man\ involves the brain and spinal ascending and descending\ sensory and motor tracts\ the anterior horns being the particular target[ Par! alysis results^ it is termed {ginger!Jake| paralysis\ as the original case at the end of the 08th century was due to the consumption of tetra!o!cresyl phosphate "TOCP#! adulterated extract of ginger^ Davies\ 0852^ Abou!Donia and Lapadula\ 0889Ł[ Since the late 08th century\ some 49\999 cases of OPIDN were reported in man "Abou! Donia and Lapadula\ op[ cit[#[ While certain OP com! pounds*classically TOCP*which cause OPIDN are not potent antiChEs\ many OP drugs\ whether insecticides or potential war gases\ such as DFP\ may induce OPIDN^ among insecticides\ OPIDN may be caused by mipafox\ parathion\ fenthion and others "Abou!Donia and Lapa! dula\ op[ cit[#[ OPIDN may be caused either by OP inhi! bition of a {Neurotoxic Esterase| "Johnson\ 0879#\ or via interference by the OP compounds with the Ca¦¦! calmodulin kinase II and resulting hyper release of Ca¦¦ "Abou!Donia and Lapdula\ 0889#[ Other considerations should be applied to the problem of OP toxicity[ First\ there is the potentiation that arises from combined administration of OP drugs[ This may arise as one OP drug interferes with the detoxi_cation\ via esterases\ of another OP drug^ this may be the case with the potentiation of malathion toxicity by joint appli! cation of ethylÐnitrophenylÐphenylphosphothionate "EPN^ O|Brien\ 0856^ Hayes\ 0871#[ However\ the potent! iation in question also arises independently of the detox! i_cation phenomena "Karczmar et al[\ 0851#[ Similar potentiative e}ects may arise from combined admin! istration of pyridostigmine\ a carbamate and an OP drug and this may be of importance with respect to the Persian Gulf War Syndrome "PGWS#\ as pyridostigmine is employed as protective agent in the antidotal {cocktail| that can be administered to pertinent personnel "see later#[ Second\ OP and carbamate antiChEs damage the blood!brain barrier\ a well substantiated _nding that is not emphasized in the current literature "Karczmar\ 0856#[ This e}ect may lead to accumulation in the CNS of toxic substances that normally cannot gain access to the brain[ Finally\ there is the delayed cognitive toxicity "DCT# that is not akin to OPIDN[ Du}y et al[ "0865# and Du}y and Burch_el "0879# reported that industrial workers that were exposed in the process of OP manufacture to OP agents showed EEG\ sleep\ memory and personality changes sometimes two years after the possible exposure[ It appears that these delayed OP!induced changes*obvi! ously\ not correlatable with inhibition of ChEs*may be duplicated in primates "Du}y and Burch_el\ 0879^

393

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

Karczmar\ 0873a^ Steenland et al[\ 0883#[ Again\ these _ndings are pertinent for the Persian Gulf War Syndrome "PGWS# problem "see later#[

3[1[ Anticholinesterase insecticides and pesticides Besides recognizing the toxic potential of antiChEs "see Section 3[0#\ German and Russian investigators dis! covered the pesticidal e}ects of both carabamates and OP drugs "Eto\ 0868^ Chadwick\ 0852#[ Following the introduction in the 0839s and 0849s\ _rst in Germany ðas exempli_ed by schradan "OMPA# and bladan "TEPP#Ł and then in Switzerland ðas\ for example\ isolan "Geigy patent of 0841#Ł\ the U[S[A[ "malathion was the early insecticide developed by American Cyanamid Co[# and Japan of OP and carbamate insecticides "Eto\ 0868^ Hayes\ 0871#\ the development\ manufacture and dis! tribution of these compounds became a major industry in these four countries as well as in Australia\ Russia\ Canada and elsewhere[ Incredibly\ already in the late 0849s over 49\999 such compounds had already been synthesized and tested "Moore_eld and Lanham\ 0848#[ In the U[S[A[ alone\ currently some 099\999 pounds of OP insecticides are produced yearly\ particularly by such companies as Dow\ CIBA\ Cyanamid and others[ Their use is even more intense in underdeveloped countries which desire to increase their agricultural crops and exports\ including Russia and the past members of the U[S[S[R[^ thus\ in southern Siberia and in Bieloruss a few thousands of pounds of OP insecticides per 0\999 of the population\ may be used annually "Feshbach\ 0884#[ The drugs in question may be used as insecticides\ fungicides and herbicides\ as well as pesticides as they exhibit acaricidal\ nematocidal and other anthelminthic activities^ in fact\ they may also serve as rodenticides "Eto\ 0868^ Hayes\ 0871^ O|Brien\ 0859\ 0856#[ It must be stressed that many agriculturally useful OP drugs do not exhibit antiChE action\ at least not to a degree such that their toxicity in man or animals may relate to ChE inhibition^ this is particularly true for certain pesticides[ On the other hand\ most of the insecticide carbamate and OP drugs exhibit potent antiAChE e}ects and at a recent Workshop of the International Life Sciences Institute "Mileson\ 0886^ Sheets et al[\ 0886#\ it was agreed to refer to the compounds in question as {antiChE insecticides|^ however\ there is a controversy here\ as will be referred to later in this Subsection[ On the other hand\ there is little doubt that the e}ectiveness of these compounds as insecticides is exerted via the inhibition of insect nervous system AChE "Casida\ 0845^ Chadwick\ 0852^ Usdin\ 0869#[ The incentives for this intense synthetic activity were many\ including the ease and relative inexpensiveness of production of the agents in question\ e}ectiveness and\ at least at the initiation of their agricultural use\ the

impression that they exert no human toxicity^ further! more\ in the 0849s it was realized that insects develop tolerance to the then popular insecticide DDT and that DDT produces environmental pollution[ It is of interest that\ at that time\ Workshops were instituted to consider environmental and ecological consequences that may arise from a sudden substitution of OP and carbamate agents for DDT "Zendzian\ pers[ comm[#[ However\ soon after their introduction into agric! ulture\ reports of their accidental toxicity in man were forthcoming from all sites of the globe[ The accidents in question were and are particularly frequent in Japan\ Russia and Eastern Europe\ Indonesia and Australia[ For example\ a serious episode of poisoning from barley contaminated with parathion occurred in 0848 in Sing! apore^ it involved 42 individuals "Weber\ 0886#[ When! ever attempted\ the atropine treatment was e}ective[ It appears also*the pertinent information is not readily obtainable and it is published rather rarely "Chen and Hamerlink\ pers[ comm[#*that currently there may be some 099 cases of accidental toxicity caused annually by the agents in question in the U[S[A[[ At the Workshop of the International Risk Science Institute "Mileson\ 0886# the consensus of opinion was that these accidents are generally due to the improper use of the compounds in question by the professional personnel\ rather than to accidental exposure to these compounds by the general public^ this was true in the case of a recent episode of human toxicity in Chicago\ Illinois\ U[S[A[ caused by methylparathion[ Whenever AChE activity of the victims was measured\ in most cases in the blood\ the toxic e}ects or death appeared to be accountable to inhibition of AChE^ however\ at the recent Workshop of the International Life Sciences Institute "Mileson\ 0886# some doubts were raised as to the strict relation between the ChE inhibition and the human toxicity of the compounds in question[ The controversy is\ at least partially\ due to the fact that AChE inhibition was measured relatively rarely and when carried out\ the quality of the measurement and the appropriateness of the assay used were frequently not above board[ Furthermore\ there is evidence that OPIDN was present in several cases of accidental poisoning with the OP drugs "Abou!Donia and Lapadula\ 0889#[ Currently\ more than 39 antiChE OP insecticides are licensed for agricultural use in the U[S[A[ "Mileson\ 0886^ Carlock et al[\ 0886#[ To be thus licensed and to receive a CAS registry number\ the compounds have to pass a battery of animal tests de_ned in 0880 by the U[S[A[ Environmental Protection Agency "EPA#[ This battery concerns chronic experiments in several species with dose levels de_ned as the {no!observable!e}ect!level| "NOEL# or {no!observable!adverse!e}ect!level| "NOAEL# and the relationship of these dose levels to red blood cell and:or brain AChE inhibition must be established[ It appears that\ at least in the past\ human volunteers were employed

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

in assessing the safety of the compounds in question "Zendzian\ pers[ comm[# Additional requirements were posited governmentally in the U[S[A[ Thus\ the Food Quality Protection Act "FQPA# of 0885 requires EPA {to perform a combined risk assessment for chemicals that produce adverse e}ects by a common mechanism of toxicity[ Central to per! forming this task is the process of identi_cation of those pesticide chemicals that can be grouped based on a com! mon mechanism of action| "Mileson\ 0886#[ This par! ticular requirement focuses not only on establishing\ for the compounds in question\ of a {common mechanism of toxicity| but also describing the qualitative and quan! titative*additive vs potentiative*aspects of exposure to several such compounds simultaneously[ Certain rec! ommendations were made to the EPA by a panel of pharmaceutical and industrial companies involved in production of antiChE insecticides "Carlock et al[\ 0886# to improve the evaluation in question^ for example\ it was recommended to use red blood cell AChE as the marker of potential toxicity in man[ The panel also de_ned the 09) inhibition of animal brain AChE as of {regulatory| signi_cance "an argument may be raised with respect to this particular value#[ Additional rec! ommendations are prepared for the EPA by several con! current workshops "Mileson\ 0886#[ It proved di.cult for these various panels and work! shops to reach a consensus as to the understanding of the language of the FQPA[ For example\ while it was generally agreed that OP insecticides exhibit a common molecular mechanism of their primary e}ects\ this mech! anism being {phosphorylation| and {inhibition of AChE| "Mileson\ 0886#\ it was di.cult to reach an agreement as to the {common mechanism of toxicity| in man\ toxicity being understood by some members of the panels as a parameter that may be independent from the primary {molecular mechanism|^ indeed\ it was pointed out that while all insecticides are antiChEs and thus exhibit a common mechanism of action\ they may cause di}erent toxicities\ as these toxicities may be\ for a given compound\ either peripheral\ central or idiosyncratic[ This matter will be further discussed prior to the sub! mission of the consensus and recommendations of the various panels and workshops to EPA[ 3[2[ War `ases and the Persian Gulf War Syndrome While apparently in the 0839s the U[S[A[\ Germany\ Russia and U[K[ were capable of using OP compounds\ it seems that they were not employed in the Second World War[ This situation changed subsequently\ although the per! tinent information is\ as can be expected\ not readily forthcoming[ First\ these four countries continued their development of new OP war gases and particularly\ that of the antidotal aspects of the matter[ Intensi_cation of

394

the pertinent studies would occur at certain times when one country sensed that another is ahead research wise\ or is likely to employ the agents in question[ The U[S[A[ Department of Defense "DOD# conducted\ in its own laboratories "such as at the Walter Reed Hospital in Washington\ D[C[ or at the Army Chemical Center\ Edgewood\ Maryland#\ or via subcontracting vigorous research concerning the development of better antidotes "Karczmar et al[\ 0854#[ This research led to the devel! opment of a treatment {cocktail|\ to be used at the time of\ or subsequent to\ exposure to war gases\ and of the tools for its self!administration^ generally\ the cocktail consisted of a combination of pyridostigmine\ a reversible carbamate antiChE capable of protecting AChE from an OP challenge\ a reactivator of phosphorylated AChE of the oxime type and atropine[ Prior to an expected attack\ pyridostigmine could be used alone[ Additional antidotal measures were explored at Workshops organized by the DOD^ these measures included the {sponging| or {sink| compounds that would eliminate or sidetrack the OP drugs prior to their arrival at the targets\ immunizing approaches\ speci_c receptor antagonists and means to prevent or treat delayed behavioral responses to the OP agents "Karczmar\ 0873b^ Gunderson et al[\ 0881#[ Interestingly\ there was a volunteer program in the U[S[A[ concerning _eld use of carbamate protectors of AChE from phosphorylation\ large doses of atropine and additional agents "Karczmar\ 0870#^ it appears that certain mood\ cognition and sleep changes occurred in some cases and that they persisted for a long time[ In this context it should be added that testing or manufacturing of OP drugs may have led to accidents involving man or animals^ thus\ possibly lethal e}ects on sheep of the compounds in question may have occurred in the state of Utah^ this and other similar accidents were reported from time to time in the U[S[A[ press[ Second\ there is the question of the combat use of OP drugs[ As could be expected\ this is a grey area and no solid evidence may be cited for such an occurrence[ There is anecdotal information concerning the use of these agents by Iraq\ in the course of Iraq|s con~ict with the Kurds^ additional notions arise with respect to other nations and sites\ as for example\ in the course of the recent con~ict in Yugoslavia\ where Bosnians\ Serbs and Croatians were accused of using OP and related agents "Jane|s Defence Weekly\ 0882^ Hedges\ 0884^ Hogen! doorn\ pers[ comm[#[ It must be added that many nations\ in Europe\ Asia and the Americas have the capacity to\ or actually produce\ war gases[ Only with time and with the opening of certain classi_ed information to the public\ the truth of the matter may become discovered[ Third\ there is the actual and potential use of OP war gases by rogue nations and more likely\ by terrorist organizations[ Thus\ the Tokyo subway tragedy of 0885 involving the use of sarin is a well!documented example of such a use^ fatalities and many cases of serious

395

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

poisoning resulted[ The symptoms and mechanisms were those that would be expected from sarin poisoning "Gerrity\ personal information#[ And then\ there is the matter of the Operation Desert Shield "ODS#\ or the Persian Gulf War that lasted from August 0889 to late February\ 0880 and the related Per! sian Gulf War Syndrome "PGWS# or {mystery illness|[ The total number of the U[S[A[ military personnel that was involved in this operation amounted to almost 699\999 ðDepartment of Veterans A}airs "DVA#\ 0885\ 0886Ł[ Soon thereafter a signi_cant number of returning veterans complained of a variety of symptoms^ later\ a certain pattern and certain characteristics of these symp! toms could be discerned and suspicion arose as to the possible causes of the syndrome\ including exposure to OP agents\ whether via Iraqi attacks on the U[S[A[ forces or via other means[ One of the problems that immediately arose and is still with us is that the DOD was not consistent in its reports on this matter[ Initially the DOD representatives or spo! kespersons denied any possibility of chemical warfare or exposure to toxic chemicals during the ODS[ Progress! ively\ this stand was changed\ in response to public\ media and congressional pressure\ as well as reports\ adverse to the DOD information process\ by the General Account! ing O.ce "GAO#\ U[S[A[ There is still little de_nitive information as to the use of chemical warfare by the Iraq military in the course of the ODS^ some notions on this matter were raised by academic and government sources in France and Czech Republic[ However\ the DOD reported in 0885 and 0886 that the allied bombing of Iraq plants and ammunition depots\ in the course of the ODS and shortly after its termination\ may have caused a release of sarin and:or other chemical and biological war! fare tools and recently\ a spokesman for the Presidential Blue Ribbon Committee stated that some 099\999 veterans may have been exposed to war gases\ fuel fumes and other toxic chemicals[ Yet\ the Pentagon Panels\ NIH Workshops\ and the Presidential Advisory Committee on Gulf War Veterans "see later# still hold to the opinion that chemical and biological warfare agents are not responsible for the PGWS\ a view not shared by GAO "New York Times\ 0886#[ As this controversy grew in size and was augmented by copious media coverage and reporting "see the interesting bibliography of newspaper and magazine articles\ pub! lished by DVA\ 0885\ 0886# and as the number of com! plaints by the Veterans of the ODS augmented\ the U[S[A[ government\ the DVA and the U[S[A[ Congress became involved[ As a result\ a number of actions were taken[ First\ the DOD and DVA established in 0882 a registry and a voluntary referral program for the ODS veterans in the VA Hospitals of the U[S[A[^ this registry\ originally provided for two years is still in full force[ The registry and:or the referral programs involve screening tests of

various depths\ which may include questionnaires\ super! _cial or in!depth physical examination involving certain functional and cognitive tests\ and means to ascertain the location and the type of service during the ODS of the veterans in question[ There may be some 59\999 ODS veterans that are currently registered as of this time in various U[S[A[ VA Hospitals\ and this number is grow! ing[ The data collected are collated and analysed by the O.ce of Public Health and Environmental Hazards and related DVA agencies[ Finally\ this year a new National Health Survey of Persian Gulf Veterans and Their Fam! ilies was initiated "VA Cooperative Study 347#[ Second\ the Congress directed the DVA and DOD to communicate with the Medical Follow!up Agency of the U[S[A[ Institute of Medicine with respect to reviewing pertinent information on the sequelae of the ODS[ In due time\ this directive resulted in the formation of an appropriate Committee of the Institute of Medicine[ In the same context\ a number of {Blue!Ribbon| panels and workshops were established to further deal with the matter\ gather information and make appropriate recom! mendations\ whether to the Congress\ the President or various U[S[A[ agencies*a veritable bureaucratic pleth! ora which may have hindered as much as facilitated pro! gress with respect to the understanding of the PGWS "DVA\ 0885\ 0886^ Gerrity\ 0886#[ Third\ on the basis of an appropriate Congressional bill\ President Clinton requested\ on August 20\ 0882\ that the Secretary of the DVA should co!ordinate research in the area of PGWS^ this then led to allocating funds to conduct\ at the federal and academic level\ appropriate research and to establish multiproject Centers at several VA Hospitals[ The research in question has two thrusts] _rst\ there is the clinical evaluation of appropriate ODS veterans^ second\ there is animal research[[ It cannot be stated that there is a general consensus of the recent clinical studies[ A number of such studies*including evaluations carried out in the U[K[*support {the hypothesis that clusters of symptoms of many Gulf War veterans represent discrete factor analysis!derived syndromes that appear to re~ect a spectrum of neurological injury involving the central\ peripheral\ and autonomic nervous system| "Jamal et al[\ 0884^ Haley et al[\ 0886a\ 0886b^ Haley and Kurt\ 0886^ Schwartz\ 0886#[ However\ the conclusions of the studies in question include many caveats[ Furthermore\ contrary opinions are also available\ including the relatively early report of a NIH Technology Assessment Workshop Panel "0883#[ Independently of this controversy\ most if not all of the evaluations\ including that conducted by the Registry Agency de_ne similar symptoms that are exhibited or described by ODS veterans[ In the context of this paper some of these symptoms in particular should be recog! nized\ namely fatigue\ certain muscular and neuromyal abnormalites "Jamal et al[\ 0884#\ headache\ neuro!

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

psychologic complaints that include cognition defects\ forgetfullness "Haley et al[\ 0886a\ 0886b# and sleep dis! turbances^ the triad of headache\ neuropsychologic com! plaints and sleep disturbances was exhibited by some 29) of the registrants[ There is a characteristic delayed nature of these and other complaints\ as they appeared at various intervals after possible exposure[ The studies saliented important features that may have characterized the environment of the ODS and that may be suspected as causes of the PGWS[ These include OP drugs and AChE protectors such as pyridostigmine\ OP and other pesticides\ DEET!containing insect repellants\ biological warfare agents and viruses\ fumes resulting from jet fuel and burning oil well _res and sand particles "silica#[ Stress arising either from combat or other con! ditions of the ODS was also listed as possibly causing or contributing to PGWS[ The animal research concerns models that may apply to the PGWS[ This research is carried out currently at a number of Environmental Hazards VA Centers as well as academic and federal laboratories^ for example\ there may be currently some 04 or more projects concerning the possible role of pyridostigmine\ whether alone\ or combined with stress or other agents[ A number of studies deal with direct "channel# e}ects of whether pyri! dostigmine or OP agents\ neurotoxic phenomena\ and interaction between OP drugs and non!cholinergic trans! mitter systems\ particularly those that involve excitatory transmitters and their exocytoxicity "Edson Albu! querque\ pers[ comm[#[ Other programs concern stress^ pulmonary abnormalities^ viruses "known or unknown#\ infections and parasites^ OP agents alone or in com! bination with other compounds\ neurotoxins\ silica\ herbicides and other toxicants^ and immunological and endocrine factors "DVA\ 0885\ 0886#[ In many cases this research has been barely initiated and only a few pertinent publications are available cur! rently^ any conclusions will\ therefore\ be premature at this time[ In the case of clinical research a great number of variables must be recognized\ including the location and type of service of the personnel involved^ the length of service and possible exposure data^ demography and physical\ health\ age\ sex and other individual charac! teristics of the personnel^ types of tests and questionnaires "not standardized between the various evaluations#^ etc[ Thus\ the statistics needed are forbidding and it is extremely di.cult for the evaluators to reach valid con! clusions[ A conclusion that may be reached safely is that the problem may not be solved soon and that\ indeed\ it may prove unsolvable[ It is the speculative opinion of this author that several cohorts of ODS veterans will be identi_ed\ each cohort relating to a cluster of symptoms and to a distinct syndrome^ furthermore\ the feeling is that one of these cohorts will be shown to su}er from delayed OP toxicity\ whether in the form of OPIDN or DCT "see earlier#[

396

4[ Anticholinesterase treatment of SDAT 4[0[ Co`nitive functions and choliner`ic a`onists As already stated "Section 3#\ cholinergic agonists and antiChEs facilitate learning and memory in animals\ as known since the work in the 0839s of William Funderburk and Karl Pfei}er in animals and in man since the 0859s work of David Drachman "Karczmar\ 0882\ 0885#[ This facilitation is linked with facilitatory e}ects of these drugs on alertness and awareness[ These e}ects are blocked by lesioning\ surgically or chemically\ appropriate brain sites "Cuello\ 0882^ Hanin\ 0885^ Kar! czmar\ 0882\ 0885# and by atropinics[ These compounds also evoke cortical potential and EEG changes that di}er from those accompanying the so!called EEG and behavioral arousal\ but are consistent with cognitive facilitation and alertness[ Karczmar "0882\ 0884# pointed out that this concatenation between cognitive and aware! ness e}ects and the EEG signs of cholinergic agonists "Hobson and Stickgold\ 0883# amounts to cholinergic facilitation of organism!environment interaction^ he referred to this syndrome as Cholinergic Alert Non! Mobile Behavior "CANMB#[ 4[1[ Anticholinesterases and choliner`ic a`onists and SDAT In the 0869s and 0879s the Perrys et al[ "0867#\ McGeer et al[ "0873# and Whitehouse et al[ "0870# "Karczmar\ 0885^ Thal\ 0883# demonstrated that cholinergic path! ways\ particularly those emanating from the basal fore! brain are damaged or abolished in SDAT patients[ These _ndings\ as well as the realization that the cognitive de_cit is exhibited by SDAT patients led to the _rst use in 0868 of physostigmine in SDAT "Peters and Levin\ 0868#[ The early enthusiasm with this treatment was unwar! ranted "Davis and Mohs\ 0875#[ However\ as pointed out by Giacobini "0880\ 0882\ 0885#\ physostigmine as well as several other antiChEs\ do not present a favorable pro_le with respect to SDAT treatment] they do not penetrate su.ciently into the brain and:or inhibit brain AChE to a limited degree only^ their inhibition of AChE activity is short!lived^ and they show limited selectivity whether with respect to types of AChEs or\ indirectly\ appropriate cholinergic receptors[ Furthermore\ Gia! cobini "Hallack and Giacobini\ 0878# developed inter! esting animal models useful for the preclinical development of clinically useful antiChEs[ Following these and related suggestions and studies\ a number of _rst\ second and third generation of antiChEs were developed^ at this time there may be some 19 new compounds in preclinical trials[ Among the _rst were heptyl!physostigmine\ huperzine "a natural product iso! lated from a Chinese moss\ which presents structural analogies with physostigmine^ Hanin et al[\ 0880# and an

397

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

OP drug\ metrifonate[ The new antiChEs approved by FDA at this time are tetrahydroaminoacridine "THA\ tacrine# and donepezil "Aricept#[ It is of interest that tacrine was synthesized in 0834 by Albert\ studied in animals by Edith Heilbronn in 0850 and employed in the treatment of schizophrenia by Sam Gershon and Turan Itil "Summers et al[\ 0877#[ Aricept was sought to replace Tacrine in view of gastrointestinal\ liver and other toxi! cities exhibited by the latter "Gauthier and Gauthier\ 0882#[ The assessment of the drugs in question in SDAT is complicated and di.cult[ A number of cognitive\ includ! ing memory tests and scales\ such as Alzheimer Disease Assessment Scale have to be used^ evaluations of behavioral and mood pro_le\ as well as of the quality of life are also needed[ Moreover the e}ectiveness of the drugs in question ideally should be tested longitudinally to assess the outcome against the rate of decline expected in SDAT "Thal\ 0883^ Reisberg et al[\ 0855#[ Finally\ the clinical identi_cation of SDAT is not easy\ as a number of organic\ cognitive and emotional criteria\ age of onset and longitudinal evaluation of the progress of the disease are needed^ and there are several subtypes of SDAT "Corey!Bloom et al[\ 0884#[ Actually\ till autopsy can be performed\ the de_nitive di}erential diagnosis of SDAT probably cannot be established[ All this would not constitute a problem with the out! come evaluation of the drugs in question\ if their e}ect was marked*but it does not appear that this really occurs; Generally\ statistically signi_cant e}ects were obtained with respect to one or two of the evaluations in question\ these e}ects were limited\ restricted to a rela! tively small number of patients among those treated and not resulting in signi_cant improvement in daily activities or quality of life[ Thus\ while Rogers and Friedho} "0885#\ in a study notable for establishing a relation between certain behavioral e}ects of donepezil and its inhibition of red blood cell AChE\ found that a signi_cant improvement in certain evaluations occurred in patients su}ering from mild to moderately severe SDAT and that there was a {49) reduction in the percentage of patients showing clinical decline with donepezil| compared to pla! cebo\ yet this _gure is less convincing when it is realized that it refers to 00) vs 19) of the population of patients\ with donepezil and placebo respectively[ Furthermore\ the quality of life was not greatly improved\ and\ while certain optimistic opinions are stated as to the antiChE treatment of SDAT "Schneider\ 0885#\ it is the consensus of the majority of investigators that the capacity for inde! pendent life is not restored by antiChE treatment and that\ in severe SDAT patients antiChEs are not helpful[ It must be\ however\ added that donepezil appears\ as of today\ to exhibit less side actions than tacrine "Rogers and Friedho}\ 0855#[ There are suggestions as to improving this status of the matters[ Thus\ Giacobini "0885# and Enz et al[ "0882#

feel that further development of the antiChEs for the treatment of SDAT may bring about selective inhibition of strategically important brain AChEs\ and that the new compounds may inhibit development of abnormal proteins "a hope that is speculative#[ Another cholinergic approach is to use muscarinic and nicotinic agonists\ particularly those that may act selec! tively on strategic brain receptors subtypes "Schwartz et al[\ 0880#[ As postsynaptic cholinomimetic receptors may be spared in SDAT\ this approach may be constructive^ yet\ there is evidence that changes and:or decrease in number of nicotinic and muscarinic receptors occur in SDAT and that they may interfere with the e.cacy of such drugs "Aquilonius\ 0882#[ There are problems with the antiChE and cholinergic agonists therapy of SDAT[ First\ animal models employed in the development of the pertinent drugs fre! quently re~ect a speci_c cholinergic de_cit rather than serve as a model of SDAT^ thus\ Hanin "0885# stressed that the cholinergic neurotoxin\ AF53A\ while useful in animals for screening of anti!SDAT drugs\ does not serve as a faithful model of SDAT[ Probably\ models involving the formation or application of abnormal peptides may be more pertinent "Pepeu et al[\ 0885#[ Second\ many current animal models do not show a longitudinal decline of cognition which is characteristic of SDAT "Karczmar\ 0880^ Karczmar and Dun\ 0877^ Andres et al[\ 0883#[ Then\ cholinergic agonists and antiChEs may\ par! ticularly when there is a cholinergic neuronal de_cit\ evoke negative feedback that would be detrimental to the treatment "Karczmar and Dun\ 0877^ Karczmar\ 0882#[ Finally\ cholinergic therapy cannot be e}ective when the cholinergic neurons are gone and there is a diminution or change of cholinoceptivity "Karczmar\ op[ cit[^ Karczmar and Dun\ op[ cit[#[ Altogether\ it is the belief of this author that a full therapeutic success and a signi_cant improvement of the quality of life cannot be achieved with cholinergic\ particularly antiChE therapy in SDAT[ The basic problem with the cholinergic approach to SDAT therapy is as follows[ SDAT is not\ primarily a cholinergic disease\ but a disease due to damage and apoptosis of several types of neurons\ leading to the atro! phy of several brain parts\ particularly the cortex\ limbic areas and generally\ posterior hemispheres[ As this important matter is outside of the scope of this article\ it su.ces to say that this damage is caused by cellular abnormal proteins of amyloid nature\ at least three chro! mosomes being involved in the formation of these pro! teins "Hall\ 0855^ Landon et al[\ 0886#[ The formation of these amyloids is complex and involves mutations that interfere and interact with the cell cycle system and apop! tosis^ this system includes presinilins\ proteases\ precursor proteins and a number of regulatory processes that may involve active radicals "Hardy\ 0886#[ The amyloid! and active radicals!induced damage results in neuronal death and in the de_cit in several\ besides the cholinergic\ trans!

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

mitter systems\ as\ for example\ certain peptidergic systems[ This notion of SDAT as a hereditary amyloid disease does not mean that signi_cant cholinergic de_cit that occurs in SDAT is unimportant\ but it suggests that there should not be undue attention and expenditure a}orded pure cholinergic therapy[ Rather\ cholinergic agonists and antiChEs should be applied in a novel way\ perhaps in combination with other agents\ an expedient that is attempted in our clinic "Karczmar\ Siegel and Crayton\ 0887#[ Nor it should be forgotten that non!cholinergic ther! apies should be of importance[ Thus\ several trophic sub! stances and fetal brain implants "Olson\ 0885#\ hormones and regulators of both peptide and steroid nature\ anti! oxidants and anti!in~ammatory substances "Rice\ 0882# were either suggested or sporadically tried as antiSDAT treatment[ Finally\ the hereditary nature of SDAT\ involvement of presenilins\ etc[\ calls for exploration of these phenomena both for diagnostic and treatment purposes[

5[ Envoi When Edith Heilbronn initiated many decades ago her studies of the cholinergic system\ ChEs\ antiChEs\ react! ivators and receptors she must have felt\ as did many other of her colleagues and {cholinergikers|\ that an air of excitement and potential emanates from the _eld[ Indeed\ as in the past\ so also today\ the cholinergic _eld has a tremendous range and scope\ and the excitement that it generates is due to its signi_cance on the molecular and synaptic level all the way to its meaning for behavior and mentalization[ But even as good a prognosticator as Professor Heilbronn could not predict that as she contributed so heuristically to the _eld\ she helped it in becoming\ as illustrated in this article\ not only a cor! nucopia of plenty\ but also a Pandora|s box of calamities[

Acknowledgements Some of the research from this and Dr N[ J[ Dun|s laboratory referred to in this article was supported by NIH grants NS5344\ NS04747\ RR94257\ NS05237 and GM66^ VA grant 3279^ grants from Potts\ Fidia and M[ E[ Ballweber Foundations^ and Guggenheim "0858# and Senior Fullbright "0874# Fellowships[ In addition\ help a}orded by CARES\ Chicago\ and AMVETS of Illinois is gratefully acknowledged[ The author also wishes to thank Ms J[ Mixter and Dr L[ Logan\ LUMC Library and Mr Ron Flink and Mss S[ Zwiesler\ C[ Burnick\ M[ Smith\ Jean Seidel and M[!A[ Pike\ Research Services\ Hines VA Hospital\ for their support and expert help[

398

References Abou!Donia\ M[B[\ Lapadula\ D[M[\ 0889[ Mechanisms of organ! ophosphorus ester!induced delayed neurotoxicity] Type I and Type II[ Annu[ Rev[ Pharmacol[ Toxicol[ 29\ 394Ð339[ Albuquerque\ E[X[\ Pereira\ E[F[R[\ Bonfante!Cabarcas\ R[\ Marchioro\ M[\ Matsubayashi\ H[\ Alkondon\ M[\ Maelicke\ A[\ 0885[ Nicotonic acetylcholine receptors on hippocampal neurons\ cell compartment!speci_c expression and modulatory control of channel activity[ In Klein\ J[\ Lo}elhholz\ K[ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam\ pp[ 000Ð013[ Andres\ C[\ Beeri\ R[\ Huberman\ T[\ Shani\ M[\ Soreq\ H[\ 0885[ Cholinergic drug resistance and impaired spatial learning in trans! genic mice overexpressing human brain acetylcholinesterase[ In Klein\ J[\ Loe}elholz\ K[ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam\ pp[ 154Ð161[ Aquilonius\ S[!M[\ 0882[ CNS distribution of cholinergic receptors* some questions from a clinical neuroscientist[ In Cuello\ A[C[\ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 62Ð64[ Augustinsson\ K[!B[\ 0852[ Classi_cation and comparative enzymology of the cholinesterases and methods for their determination[ In Koelle\ G[B[ "Ed[#\ Cholinesterases and Anticholinesterase Agents[ Handbch[ d[ exper[ Pharmakol[\ vol[ 04[ SpringerÐVerlag\ Berlin\ pp[ 78Ð017[ Aziz!Aloya\ R[B[\ Sternfeld\ M[\ Soreq\ H[\ 0882[ Promoter elements and alternative splicing in the human ACHE gene[ In Cuello\ A[C[\ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 036Ð043[ Butcher\ L[L[\ Justin\ D[O[\ Woolf\ N[J[\ 0882[ Cholinergic neurons identi_ed by in situ hybridization histochemistry[ In Cuello\ A[C[\ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 0Ð7[ Cameron\ J[\ 0753[ The recent cases of poisoning by Calabar bean[ Med[ Tms[ Gaz[ 0753\ 395Ð309[ Carlock\ L[\ Chen\ W[L[\ Gordon\ E[\ Killeen\ J[\ Manley\ A[\ Meyer\ L[\ Mullin\ L[\ Pendino\ K[\ Percy\ A[\ Sargent\ D[\ Seaman\ L[\ Svanborg\ N[K[\ Stanton\ R[\ Telone\ K[\ Van Goethem\ D[\ 0886[ Risk Assessment for Cholinesterase Inhibiting Pesticides\ Less than Life Exposures\ Acute Cholinesterase Risk Assessment Work Group "ACRA#\ Washington\ D[C[\ pp[ 0Ð015[ Casida\ J[E[\ 0845[ Comparative enzymology of certain insect ace! tylesterases in relation to poisoning by organophosphorus insec! ticides[ Biochem[ J[ 59\ 376Ð385[ Chadwick\ L[E[\ 0852[ Actions on insects and other invertebrates[ In Koelle\ G[B[ "Ed[#\ Cholinesterases and Anticholinesterase Agents[ Handbch[ d[ exper[ Pharmakol[\ vol[ 04\ SpringerÐVerlag\ Berlin\ pp[ 630Ð687[ Christison\ R[\ 0744[ On the properties of the ordeal bean of Old Calabar[ Monthly J[ Med[ 19\ 082Ð193[ Clermont\ de Ph[\ 0743[ Note sur la preparation de quelques ethers[ Comptes Rend[ 28\ 227Ð239[ Corey!Bloom\ J[\ Thal\ L[J[\ Galasko\ D[\ Folstein\ M[\ Drachman\ D[\ Raskind\ M[\ Lanska\ D[J[\ 0884[ Diagnosis and evaluation of dementia[ Neurol[ 34\ 100Ð107[ Cuello\ A[C[\ Ed[\ 0882[ Cholinergic Function and Dysfunction\ Else! vier\ Amsterdam[ Davies\ D[R[\ 0852[ Neurotoxicity of organophosphorus compounds[ In Koelle\ G[B[ "Ed[#\ Cholinesterases and Anticholinesterases Agents[ Handbch[ d[ exper[ Pharmakol[\ vol[ 04\ SpringerÐVerlag\ Berlin\ pp[ 759Ð771[ Davis\ K[L[\ Mohs\ R[C[\ 0875[ Cholinergic drugs in Alzheimer|s disease[ N[ Engl[ J[ Med[ 204\ 0175Ð0176[ De Groat\ W[G[\ 0865[ Mechanisms underlying recurrent inhibition in

309

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300

the sacral parasympathetic out~ow to the urinary bladder[ J[ Physiol[ 146\ 492Ð404[ Department of Veterans A}airs "DVA# 0885 and 0886[ Health Conse! quences of Service During the Persian Gulf War\ Recommendations for Research and Information Systems "DVA\ The Research Work! ing Group of the Persian Gulf Veterans Coordinating Board#\ National Academy Press\ Washington\ D[C[ pp[ 0Ð72 and 0Ð003[ Dettbarn\ W[!D[\ 0873[ Pesticide!induced muscle necrosis\ Mechanisms and prevention[ Fund[ Appl[ Toxicol[ 3\ 07Ð15[ Du}y\ F[H[\ Burch_el\ J[L[\ 0879[ Long term e}ects of the organ! ophosphate Sarin on EEG in monkeys and humans[ Neurotoxicol[ 0\ 556Ð578[ Du}y\ F[H[\ Burch_el\ J[L[\ Sim\ V[M[\ 0865[ Persistent e}ects of organ! ophosphate exposure as evidenced by electroencephalographic measurements[ In Baron\ R[L[ "Ed[#\ Pesticide Induced Delayed Neurotoxicity[ U[S[ Environmental Protection Agency\ EPA!599:0! 65!914\ July\ p[ 091[ Enz\ A[\ Amstutz\ R[\ Boddeke\ H[\ Gmelin\ G[\ Malanowski\ J[\ 0882[ Brain selective inhibition of acetylcholinesterase\ a novel approach to therapy for Alzheimer|s disease[ In Cuello\ A[C[\ "Ed[#\ Chol! inergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 320Ð 327[ Eto\ M[\ 0868[ Organophosphorus Pesticides\ Organic and Biological Chemistry[ CRC Press\ Cleveland[ Feshbach\ M[ Ed[\ 0884[ Environmental and Health Atlas of Russia[ PAIMS Publ[ House\ Moscow[ Gauthier\ S[\ Gauthier\ L[\ 0882[ What we learned from the THA trials to facilitate testing of new AChE inhibitors[ In Cuello\ A[C[ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 316Ð318[ Gerrity\ T[\ Convener\ 0886[ Health E}ects of Low!Level Chemical Warfare Nerve Agent Exposure[ Workshop sponsored by DVA\ March 0886\ Cincinnati\ Ohio[ Giacobini\ E[\ 0880[ The second generation of cholinesterases inhibi! tors\ Pharmacological aspects[ In Becker\ R[\ Giacobini\ E[ "Eds#\ Cholinergic Basis for Alzheimer Therapy[ Birkhauser\ Boston\ pp[ 136Ð151[ Giacobini\ E[\ 0882[ Pharmacotherapy of Alzheimer disease\ new drugs and novel strategies[ In Cuello\ A[C[ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 336Ð343[ Giacobini\ E[\ 0885[ New trends in cholinergic therapy for Alzheimer disease\ nicotinic agonists or cholinesterase inhibitors< In Klein\ J[\ Lo}elholz\ K[ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam\ pp[ 200Ð212[ Glenn\ J[F[\ Hinman\ D[J[\ McMaster 0876[ Electroencephalographic correlates of nerve agent poisoning[ In Dun\ N[J[\ Perlman\ R[L[ "Eds#\ Neurobiology of Acetylcholine\ A Symposium in Honor of A[ G[ Karczmar[ Plenum Press\ New York\ pp[ 492Ð423[ Gunderson\ C[H[\ Lehmann\ C[R[\ Sidell\ F[R[\ 0881[ Nerve agents\ a review[ Neurol[ 31\ 839Ð849[ Haley\ R[W[\ Kurt\ T[L[\ 0886[ Self!reported exposure to neurotoxic chemical combinations in the Gulf War[ JAMA 166\ 120Ð126[ Haley\ R[W[\ Hom\ J[\ Roland\ P[S[\ Bryan\ W[M[\ Van Ness\ P[C[\ Bonte\ F[J[\ Devous\ M[D[\ Matthews\ D[\ Fleckenstein\ J[L[\ Wians\ F[H[\ Wolfe\ G[B[\ Kurt\ T[L[\ 0886a[ Evaluation of neu! rologic function in Gulf War Veterans[ JAMA 166\ 112Ð129[ Haley\ R[W[\ Kurt\ T[L[\ Hom\ J[\ 0886b[ Is there a Gulf War syn! drome< Searching for syndromes by factor analysis of symptoms[ JAMA 166\ 104Ð111[ Hall\ L[ L[ Ed[\ 0885[ Genetics and Mental Illness[ Plenum Press\ New York[ Hallak\ M[\ Giacobini\ E[\ 0878[ Physostigmine\ tacrine and metri! fonate*the e}ect of multiple doses on acetylcholine metabolism in rat brain[ Neuropharmacol[ 17\ 088Ð195[ Hanin\ I[\ 0885[ The AF53A model of cholinergic hypofunction\ an update[ Life Sciences 47\ 0844Ð0853[ Hanin\ I[\ Tang\ XiC[\ Kozikowski\ A[P[\ 0880[ Clinical and preclinical

studies with huperzine[ In Becker\ R[\ Giacobini\ E[ "Eds#\ Chol! inergic Basis for Alzheimer Therapy[ Bikhauser\ Boston\ pp[ 294Ð 202[ Hardy\ J[\ 0886[ Amyloid\ the presenilins and Alzheimer|s disease[ TINS 19\ 043Ð048[ Hayes\ W[J[\ 0871[ Pesticides Studied in Man[ Williams and Wilkins\ Baltimore[ Hedges\ C[\ 0884[ Bosnia troops cite gassings at Zepa[ New York Times\ July 16\ p[ 5Ð6[ Heilbronn\ E[\ 0850[ Inhibition of cholinesterases by tetrahydro! aminoacridin[ Acta Chem[ Scand[ 04\ 0275Ð0289[ Heilbronn\ E[\ 0882[ Molecular biology of cholinesterases\ a back! ground and an introduction[ In Cuello\ A[C[ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ pp[ 022Ð027[ Hobson\ J[A[\ Stickgold\ R[\ 0883[ Dreaming\ A neurocognitive approach[ Consciousn[ + Cogn[ 2\ 0Ð4[ Holmstedt\ B[\ 0848[ Pharmacology of organophosphorus chol! inesterase inhibitors[ Pharmacol[ Rev[ 00\ 456Ð577[ Holmstedt\ B[\ 0852[ Structure!activity relationship of the organ! ophosphorus anticholinesterase agents[ In Koelle\ G[B[ "Ed[#\ Chol! inesterases and Anticholinesterase Agents[ Handbch[ d[ exper[ Pharmakol[\ vol[ 04\ SpringerÐVerlag\ Berlin\ pp[ 317Ð374[ Holmstedt\ B[\ 0861[ The ordeal bean of old calabar\ The pageant of Physostigma venenosum in medicine[ In Swain\ T[ "Ed[#\ Plants in the Development of Modern Medicine[ Cambridge University Press\ Cambridge\ pp[ 292Ð259[ Holmstedt\ B[\ Wassen\ S[H[\ Chanh\ P[!H[\ Clavel\ P[\ Lasserre\ B[\ 0874[ Alleged native antidote to curare[ Goteborgs Etnogra_ska Museum Ann[ 0872Ð0873\ 08Ð14[ Jamal\ G[A[\ Hansen\ S[\ Apartopoulos\ F[\ Peden\ A[\ 0884[ The {Gulf Syndrome|[ Is there evidence of dysfunction in the nervous system< J[ Neurol[\ Neurosurg[\ and Psychiat[ 59\ 338Ð340[ Jane|s Defence Weekly "anonymous# 10 August\ 0882\ p[ 4[ Ý ber die Boehne von Calabar[ Ann[ Chem[ Jobst\ J[\ Hesse\ O[\ 0753[ U Pharm[ 018\ 004Ð010[ Johnson\ M[K[\ 0871[ The target for initiation of delayed neurotoxicity by organophosphorus ester\ Biochemical studies and toxicological applications[ Rev[ Biochem[ Toxicol[ 3\ 030Ð191[ Karczmar\ A[G[\ 0856[ Pharmacologic\ toxicologic and therapeutic properties of anticholinesterase agents[ In Root\ W[S[\ Ho}man\ F[G[ "Eds#\ Physiological Pharmacology\ Vol[2[ Academic Press\ New York\ pp[ 056Ð211[ Karczmar\ A[G[\ 0869[ History of the research with anticholinesterase agents[ In Karczmar\ A[G[ "Ed[#\ Anticholinesterase Agents[ Intern[ Encyclop[ Pharmacol[ Therap[\ Vol[ 0\ Section 02[ Pergamon Press\ Oxford\ pp[ 0Ð33[ Karczmar\ A[G[\ 0870[ Basic phenomena underlying novel use of chol! inergic agents\ anticholinesterases and precursors in neurological including peripheral and psychiatric disease[ In Pepeu\ G[\ Ladin! sky\ H[ "Eds#\ Cholinergic Mechanisms[ Plenum Press\ New York\ pp[ 742Ð758[ Karczmar\ A[G[\ 0873a[ Acute and long lasting central actions of organ! ophosphorus agents[ Fund[ Appl[ Toxicol[ 3\ 0Ð06[ Karczmar\ A[G[\ Convener 0873b[ Workshop on New Conceptual Approaches to Prophylaxis in Therapy of rganophosphorus Poison! ing[ Port St Lucie\ Florida[ Document in the Files of the Department of Defense[ Karczmar\ A[G[\ 0889[ Physiological cholinergic functions in the CNS[ In Aquilonius\ S[!M[\ Gillberg\ P[!G[ "Eds[#\ Cholinergic Neu! rotransmission\ Functional and Clinical Aspects[ Elsevier\ Amster! dam\ pp[ 326Ð355[ Karczmar\ A[G[\ 0880[ SDAT models and their dynamics[ In Becker\ R[\ Giacobini\ E[ "Eds#\ Cholinergic Basis for Alzheimer Therapy[ Birkhauser\ Boston\ pp[ 030Ð041[ Karczmar\ A[G[\ 0882[ Brief presentation of the story and present status of studies of the vertebrate cholinergic system[ Neu! ropsychopharmacol[ 8\ 070Ð088[

A[ Karczmar:Neurochem[ Int[ 21 "0887# 390Ð300 Karczmar\ A[G[\ 0884[ Cholinergic substrates of cognition and organ! ism!environment interaction[ Prog[ Neuro!Psychopharmacol[ Biol[ Psychiat[ 08\ 076Ð100[ Karczmar\ A[G[\ 0885[ Loewi|s discovery and the XXI Century[ In Klein\ J[\ Lo}elholz\ K[ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam\ pp[ 0Ð16[ Karczmar\ A[G[\ Awad\ O[\ Blachut\ K[\ 0851[ Toxicity arising from joint intravenous administration of EPN and Malathion to dogs[ Toxicol[ Appl[ Pharmacol[ 3\ 022Ð026[ Karczmar\ A[G[\ Dun\ N[J[\ 0877[ E}ects of anticholinesterases per! tinent for SDAT treatment but not necessarily underlying their clinical e}ectiveness[ In Giacobini\ E[\ Becker\ R[ "Eds#\ Current Research in Alzheimer Therapy[ Taylor and Francis\ New York\ pp[ 04Ð18[ Karczmar\ A[G[\ Koketsu\ K[\ Nishi\ S[\ 0854[ Reports\ Subcontract No[ 14\ MELPAR Inc[ Documents in the Files of the Department of Defense\ U[S[A[ Karczmar\ A[G[\ Ohta\ Y[\ 0870[ Neuromyopharmacology as related to anticholinesterase action[ Fund[ Appl[ Toxicol[ 0\ 024Ð039[ Karczmar\ A[G[\ Siegel\ G[\ Crayton\ J[\ 0887[ Novel combined treat! ment for Alzheimer|s disease and for stroke[ Abstracts\ Xth Inter! national Symposium on Cholinergic Systems "to be published#[ Koelle\ G[B[\ 0852[ Cytological distributions and physiological func! tions of cholinesterases[ In Koelle\ G[B[\ "Ed[#\ Cholinesterases and Anticholinesterase Agents[ Handbch[ d[ exper[ Pharmakol[\ SpringerÐVerlag\ Berlin\ pp[ 076Ð187[ Koelle\ G[B[\ 0870[ Organophosphorus poisoning*an overview[ Fund[ Appl[ Toxicol[ 0\ 018Ð026[ Landon\ C[L[\ Ashall\ F[\ Goate\ A[M[\ 0886[ Exploring the etiology of Alzheimer disease using molecular genetics[ JAMA 166\ 714Ð720[ Long\ J[P[\ 0852[ Structure!activity relationships of the reversible antic! holinesterase agents[ In Koelle\ G[B[ "Ed[#\ Cholinesterases and Anticholinesterase Agents[ Handbch[ d[ exper[ Pharmakol[\ Vol[ 04\ SpringerÐVerlag\ Berlin\ 0852\ pp[ 263Ð316[ Massoulie\ J[\ Sussman\ J[\ Bon\ S[\ Silman\ I[\ 0882[ Structure and functions of acetylcholinesterase and butyrylcholinesterase[ In Cuello\ A[C[ "Ed[#\ Cholinergic Function and Dysfunction[ Elsevier\ Amsterdam\ 0882\ pp[ 028Ð035[ Massoulie\ J[\ Legay\ C[\ Anselmet\ A[\ Krejci\ E[\ Coussen\ F[\ Bon\ S[\ 0885[ Biosynthesis and integration of acetylcholinesterase in the cholinergic synapse[ In Klein\ J[\ Lo}elholz\ K[ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam\ pp[ 44Ð54[ McGeer\ P[L[\ McGeer\ E[G[\ Suzuki\ J[\ Dolman\ C[E[\ Nagai\ T[\ 0873[ Aging\ Alzheimer|s disease and the cholinergic system of the basal forebrain[ Neurol[ 23\ 630[ McGeer\ P[L[\ McGeer\ E[G[\ Mizukawa\ K[\ Tago\ H[\ Peng\ J[H[\ 0876[ Distribution of cholinergic neurons in human brain[ In Dun\ N[J[\ Perlman\ R[L[ "Eds#\ Neurobiology of Acetylcholine\ A Sym! posium in Honor of A[ G[ Karczmar[ Plenum Press\ New York\ pp[ 2Ð05[ Mesulam\ M[!M[\ 0885[ The systems!level organization of cholinergic innervation in the human cerebral cortex and its alterations in Alzheimer|s disease[ In Klein\ J[\ Lo}elholz\ K[\ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam\ pp[ 174Ð186[ Mileson\ B[\ Convener 0886[ Workshop on Common Mechanism of Toxicity + Organophosphate Pesticides[ International Life Sciences Institute + Risk Science Institute\ Washington\ D[C[ Moore_eld\ H[H[\ Lanham\ W[M[\ 0848[ A new class of cyclic phos! phate insecticides[ First Joint Meeting entom[ Soc[ Canad[\ entom[ Soc[ Amer[\ Detroit[ NIH Technology Assessment Panel on Persian Gulf Experience and Health\ 0883[ JAMA 161\ 280Ð285[ O|Brien\ R[D[\ 0859[ Toxic Phosphorus Esters[ Chemistry\ Metabolism and Biological E}ects[ Academic Press\ New York[

300

O|Brien\ R[D[\ 0856[ E}ects of induction by pentobarbital upon the susceptibility of mice to insecticides[ Bull[ Environm[ Contam[ Toxicol[ 1\ 051Ð057[ Olson\ L[\ 0885[ Neurotrofa faktorer I CNS[ Allt ~er proteiner med klinisk potential[ Nord[ Med[ 000\ 2Ð5[ Pepeu\ G[\ Giovanelli\ L[\ Casamenti\ F[\ Scali\ C[\ Bartolini\ L[\ 0885[ Amyloid b!peptides injection into the cholinergic nuclei\ mor! phological\ neurochemical and behavioral e}ects[ In Klein\ J[\ Lo}elholz\ K[ "Eds#\ Cholinergic Mechanisms\ From Molecular Biology to Clinical Signi_cance[ Elsevier\ Amsterdam[ pp[ 162Ð171[ Perry\ E[K[\ Tomlison\ B[E[\ Blessed\ K[\ Bergman\ K[\ Gibson\ P[H[\ Perry\ R[H[\ 0867[ Correlation of cholinergic abnormalities with senile plaques and mental test scores in senile dementia[ Brit[ Med[ J[ 1\ 0346Ð0348[ Peters\ B[H[\ Levin\ H[S[\ 0868[ E}ects of physostigmine and lecithin on memory in Alzheimer|s disease[ Ann[ Neurol[ 5\ 108Ð110[ Petras\ J[M[\ 0870[ Soman neurotoxicity[ Fund[ Appl[ Toxicol[ 0\ 131[ Reisberg\ B[\ Burns\ A[\ Gauthier\ S[\ Schneider\ L[S[ Eds[\ 0885[ Out! come methodologies for pharmacologic trials in mild\ moderate\ and severe Alzheimer|s disease[ Intern[ Psychogeriatrics 7\ 044Ð233[ Rice\ J[L[\ 0882[ Clinical trial of indomethacin in Alzheimer|s disease[ Neurol[ 32\ 0598Ð0500[ Rickett\ D[L[\ Beers\ E[T[\ 0876[ Di}erentiation of medullary and neuromuscular e}ects of nerve agents[ In Dun\ N[J[\ Perlman\ R[L[ "Eds#\ Neurobiology of Acetylcholine\ A Symposium in Honor of A[ G[ Karczmar[ Plenum Press\ New York\ pp[ 424Ð449[ Rogers\ S[L[\ Friedho}\ L[T[\ 0885[ The e.cacy and safety of donpezil in patients with Alzheimer|s disease\ results of a U[S[ Multicentre\ double!blind\ placebo!controlled trial[ Dementia 6\ 182Ð292[ Schneider\ L[S[\ 0885[ New therapeutic approaches to Alzheimer|s disease[ J[ Clin[ Psychiat[ 46\ Suppl[ 03\ 29Ð25[ Schwartz\ D[A[\ 0886[ Self!reported illness and health status among Gulf War veterans[ JAMA 166\ 127Ð134[ Sheets\ L[P[\ Hamilton\ B[F[\ Sangha\ G[K[\ Thyssen\ J[H[\ 0886[ Sub! chronic neurotoxicity screening studies with six organophosphate insecticides] An assessment of behavior and morphology relative to cholinesterase inhibition[ Fund[ Appl[ Toxicol[ 24\ 090Ð008[ Shenon\ P[\ 0886[ Document faults Gulf War studies[ New York Times\ July 16\ pp[ 0 and 06[ Steenland K[\ Jenkins\ B[\ Ames\ R[G[\ O|Malley\ M[\ Chrislip\ D[\ Russo\ J[\ 0883[ Chronic neurological sequelae to organophosphate pesticide poisoning[ Am[ J[ Public Health 73\ 620Ð625[ Summers\ W[K[\ Majovski\ L[V[\ Marsh\ G[M[\ Tachiki\ K[\ Kling\ A[\ 0877[ Tacrine\ back to future< In Becker\ R[\ Giacobini\ E[ "Eds#\ Current Research in Alzheimer Therapy[ Taylor and Francis\ New York\ pp[ 148Ð154[ Thal\ L[J[\ 0883[ Clinical trials in Alzheimer disease[ In Terry\ R[D[\ Katzman\ R[\ Bick\ K[L[ "Eds#\ Alzheimer Disease[ Raven Press\ New York\ pp[ 320Ð333[ Usdin\ E[\ 0869[ Reactions of cholinesterases with substrates\ inhibitors and reactivators[ In "Karczmar\ A[G[ Ed[#\ Anticholinesterases Agents[ Intern[ Encyclop[ Pharmacol[ Therap[\ Section 02\ Vol[0\ Pergamon Press\ Oxford\ pp[ 32Ð243[ Van Meter\ W[G[\ Karczmar\ A[G[\ 0867[ CNS e}ects of antic! holinesterases in the presence of inhibited cholinesterases[ Arch[ int[ Pharmacodyn[ 120\ 138Ð259[ Whitehouse\ P[J[\ Price\ D[ Clark\ A[\ Coyle\ J[K[\ DeLong\ M[R[\ 0870[ Alzheimer|s disease evidence for a selective loss of cholinergic neurons in the nucleus basalis[ Ann[ Neurol[ 09\ 011Ð015[ Wills\ J[H[\ 0869[ Toxicity of anticholinesterases and treatment of poi! soning[ In Karczmar\ A[G[ "Ed[#\ Anticholinesterase Agents[ Intern[ Encyclop[ Pharmacol[ Exper[ Therap[\ Section 02\ Vol[ 0\ Pergamon Press\ Oxford\ pp[ 244Ð358[ Yang\ T[P[\ Dettbarn\ W[!D[\ 0886[ Mechanisms for radical oxygen species formation during diisopropylphospho~uoridate!induced muscle hyperactivity[ In press[