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actions, while infralimbic PFC is necessary for the expression of habitual behavior. Here, we use chemogenetic strategies to demonstrate that habitual behaviors can be rescued via silencing of infralimbic projections to the nucleus accumbens shell after the acquisition of habitual behavior. In contrast, silencing prelimbic-core projections during training promotes the development of habits and reduces goal-directed actions, mimicking chronic ethanol effects on response strategy selection. These findings indicate that specific prefrontal-accumbens projections have opposing effects on response strategy selection, suggesting targets for treatment and further investigation of ethanol-induced dysregulation in prefrontal function.
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seek to understand the psychological mechanisms that allow one to overcome negative consequences and continue drinking, and whether the neural signatures of these mechanisms are apparent in specific aINS projections. Supported by AA021445, AA017072 and AA024109.
Symposium IX Brain Stress Systems in Excessive Alcohol Drinking. Chair: Robert O. Messing, M.D. Co-Chair: Igor Spigelman, Ph.D., University of California, Los Angeles
S34 ALTERED COMMUNICATION OF MPFC NEURONAL NETWORKS IN POSTDEPENDENT RATS STATE
S36 CHRONIC ALCOHOL DISRUPTS GLUTAMATERGIC SYNAPTIC PLASTICITY OF HYPOTHALAMIC PARVOCELLULAR NEUROSECRETORY CELLS, AND HORMONAL AS WELL AS BEHAVIORAL RESPONSES TO REPEATED STRESS
Wolfgang H. Sommer. Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany
~ a, S. Yee, I. Spigelman. School V.N. Marty, Y. Mulpuri, D.H. Terry, M. Pempen of Dentistry, University of California, Los Angeles, CA, USA
Despite its limited immediate reinforcement value, alcohol has a potent ability to induce neuroadaptations that promote its increased incentive salience, escalation of voluntary alcohol intake and aversion resistant alcohol seeking. A constellation of these traits, collectively called “postdependent”, emerges following brain exposure to repeated cycles of intoxication and withdrawal, and likely comprises a “relapse-prone” state of brain networks. We have demonstrated that the post-dependent syndrome in rats is associated with lasting reprogramming of transcriptional activity and function in the medial prefrontal cortex (mPFC), a brain region that exerts top-down regulation of approach and avoidance behaviors, including those that lead to alcohol intake. Thus, mPFC appears as a critical node of the relapse-prone network. We now seek to understand how these molecular alterations impact on information processing by mPFC neurons, both within local networks and for long-range connectivity. To build predictive models of the ‘relapse-prone’ network topology we use restingstate fMRI combined with genetic control of local circuits. Furthermore, the relationship of local network dynamics within mPFC and the expression of postdependent behaviors is investigated by in vivo calcium imaging. The ultimate goal is to to understand how aberrant network states could be normalized, and to translate this knowledge to the human condition.
The chronic inability of alcoholics to effectively cope with relapseinducing stressors has been linked to a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and corticotropin-releasing factor (CRF) signaling. However, the cellular mechanisms underlying the dysregulation of the HPA axis response to stress in alcohol dependence are yet to be identified. Using whole-cell patch-clamp recordings, we showed that stress induces a CRF-dependent depression of NMDAR function in parvocellular neurosecretory cells (PNCs) in the paraventricular nucleus of the hypothalamus (PVN), which allows for short-term potentiation (STP) of AMPAR-mediated evoked excitatory postsynaptic currents (eEPSCs) following high-frequency stimulation (HFS, 100Hz for 1sec, x4). This stress-induced STP can be evoked for several days and provides a mechanism by which the HPA axis responds adaptively to subsequent stressors. Here, we found that chronic intermittent EtOH (CIE, 30 doses, 5-6 g/kg EtOH, oral gavage) followed by prolonged (>40 days) withdrawal potentiated NMDAR function in PNCs. CRF-induced depression of NMDAR function was absent in CIE rats. Moreover, CIE treatment was also associated with the impairment of stress-induced CRF/NMDAR-dependent STP, which could be reversed by intracellular blockade of PNC NMDARs with MK801. CIE treatment also blunted the HPA axis hormonal responses to repeated restraint stress and impaired the stress-induced increases in self-grooming behaviors, an adaptive response modulated by glutamatergic transmission of PNCs that reflects the process of dearousal following stressful events. These findings provide a plausible cellular mechanism by which chronic alcohol dysregulates the hormonal and behavioral responses to repetitive stressors. Support contributed by: NIH grants AA022408, AA022707 & AA024527.
S35 HOW DO WE DRINK DESPITE CONSEQUENCES: EXPLORING THE HYPOTHESIS THAT THE INSULA INSTIGATES AUDS Kelly Lei, Taban Seif, Jeffrey A. Simms, Scott Wegner, Bing Hu, Antonello Bonci, Robert O. Messing, F. Woodward Hopf. University of California, San Francisco, CA, USA Compulsive alcohol intake, where drinking continues despite negative social, legal and physical consequences, is a major obstacle to treating alcohol use disorders. There is particular interest in identifying circuits and molecules which drive compulsive intake, which could help develop novel therapeutic interventions. Activity in the anterior Insula cortex (aINS) during alcohol or drug cues predicts future intake and relapse in humans, and thus we hypothesize that aINS regulates activity across other brain regions, which together promotes compulsion. In rats, we find that aINS inputs to the Nucleus Accumbens core (NAc), and D-serine-inhibited noncanonical NMDARs in NAc, promote compulsion-like alcohol drinking but have no role in alcohol consumption without overt negative consequences (“regular” intake). Importantly, aINS promotion of compulsion-like but not regular drinking agrees with clinical theories that compulsive intake is characterized by conflict (e.g., between wanting alcohol and avoiding negative consequences), and that this conflict recruits cortical regions. More recently, we found that aINS inputs within brain regions that mediate adaptive responding to stress and conflict (Locus Coeruleus, LC, and central amygdala, CeA), and a1-adrenergic receptors (inhibited by prazosin), all promote compulsion-like but not regular drinking. Also, aINS neurons primarily project to a single projection target. Thus, we seek to understand the specific role of each aINS projection, and how these projections work together during compulsion-like intake. In particular, we
S37 INTERACTION OF CRF AND KAPPA OPIOID SYSTEMS ON GABAERGIC NEUROTRANSMISSION IN THE MOUSE CENTRAL AMYGDALA Scott D. Moore M.D., Ph.D. Duke University Medical Center, Durham, NC, USA The corticotropin-releasing factor (CRF) and kappa-opioid receptor (KOR) systems are implicated in stress-related behaviors and drug dependence. Although previous studies suggest that antagonism of each system blocks aspects of experimental models of drug dependence, the possible interaction between these systems at the neuronal level has not been completely examined. We used an in vitro brain slice preparation to investigate the interaction of these two peptide systems on inhibitory neurotransmission in the central amygdala (CeA). Application of exogenous CRF increased the mean frequency of GABAergic miniature inhibitory postsynaptic currents (mIPSCS) by 20.2%, suggesting an increase in presynaptic GABA release. Pharmacological blockade of KORs by norBNI alone did not significantly affect mIPSC frequency, though it significantly enhanced the effect of CRF. Similarly, CRF effects in slices from KOR knockout (KO) mice were significantly greater than in wild-type (WT) mice. There was no significant difference in baseline mIPSC frequency between slices from KOR KO and WT mice. We hypothesize that CRF facilitates the release of an endogenous ligand for KORs, likely dynorphin.
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these findings show excessive alcohol-related alterations in brain and peripheral stress pathways in human patients and also demonstrate that such changes are useful in identifying those individuals most vulnerable to alcohol relapse in order to develop novel treatments to normalize these stress-related changes and improve alcoholism recovery outcomes. Supported by UL1-DE019586, R01-AA013892; PL1-DA24859.
Thus, subsequent activation of KOR receptors may modulate presynaptic effects of CRF in CeA. These results suggest that potential pharmacotherapies aimed at addictive disorders may need to involve both the KOR/ dynorphin and the CRF systems in CeA. We also note that acute ethanol exposure induces activation of multiple neuropeptide systems in CeA. We have since been using this preparation to further elucidate the mechanism(s) underlying release of neuropeptides from central neurons, whether in response to physiological stimulation or ethanol.
Symposium X
S38 A DISTRIBUTED CRF NETWORK IN RAT EXTENDED AMYGDALA REGULATES ANXIETY AND EXCESSIVE ALCOHOL DRINKING
Stress vulnerability and alcohol use and consequences from human laboratory studies to clinical outcomes. Chair: Vijay A. Ramchandani, Ph.D. Discussant: Samir Zakhari, Ph.D.
Robert O. Messing, Matthew B. Pomrenze, Giordano de Guglielmo, Marsida Kallupi, George F. Koob, Olivier George. The University of Texas at Austin, Austin, TX, USA; The Scripps Research Institute, La Jolla, CA, USA; NIDA/ NIH, Baltimore, MD, USA
S40 A NOVEL HUMAN EXPERIMENTAL MODEL OF STRESS-INDUCED ALCOHOL SELF-ADMINISTRATION IN BINGE AND NON-BINGE DRINKERS
Corticotropin-releasing factor (CRF) is a central regulator of the stress response. Neurons that express CRF are particularly concentrated in the central amygdala (CeA), and bed nucleus of the stria terminalis (BNST). The role of CeA CRF neurons in anxiety remains controversial. To examine the role of CRF neurons in behavior, we generated a BAC transgenic Crh-Cre rat in which Cre recombinase is expressed from the Crh promoter. Cre+ neurons of these rats are immunoreactive for CRF and are clustered in the lateral CeA (CeL) and in dorsal BNST. Chemogenetic inhibition of CeL Cre+ neurons prevented anxiety-like behavior induced by immobilization stress. Conversely, chemogenetic stimulation of CeL Cre+ neurons or their projections to BNST provoked anxiety-like behavior, which required CRF1 receptor activation. Simultaneous inhibition of Cre+ neurons in the dorsal BNST blocked this induced anxiety. Similar manipulations were used to test the role of CRF neurons in alcohol drinking. Chemogenetic inhibition of CeL Cre+ neurons reduced alcohol drinking after 10 weeks of intermittent (Monday, Wednesday, Friday) access to alcohol, but not after 4 weeks. Optogenetic inhibition of these neurons or their projections to BNST, but not to brainstem, reduced operant administration of ethanol following chronic intermittent ethanol exposure. These results indicate that CeL CRF neurons are sufficient to drive anxiety when excited by stress or chemogenetic stimulation, and their projections to the dorsal BNST are critical for evoking anxiety and for high levels of alcohol consumption in dependent animals.
Bethany L. Stangl, Laura Kwako, Rajita Sinha, Vijay A. Ramchandani. Human Psychopharmacology, NIAAA/NIH, Bethesda, MD, USA
S39 CHRONIC ALCOHOL-RELATED NEURAL AND PERIPHERAL STRESS SYSTEM DYSFUNCTION: EFFECTS ON ALCOHOL CRAVING, RELAPSE AND RECOVERY Rajita Sinha Ph.D. Yale University School of Medicine, New Haven, CT, USA Chronic heavy alcohol use disrupts multilevel peripheral and brain adaptations in stress and homeostatic pathways but it is not clear which, if any, changes promote compulsive alcohol craving and relapse risk. Inpatient and outpatient early abstinent treatment engaged alcohol dependent (AD) patients and healthy social drinking controls were studied in separate laboratory and neuroimaging experiments in which their basal tonic and phasic stress and alcohol craving responses to acute stress, alcohol and neutral relaxing cues states were assessed. Patients were followed prospectively after treatment with repeated assessment of alcohol relapse over a 90 day followup and recovery period. Findings indicate hyperactive basal and neutral state autonomic and hypothalamic-pituitary-adrenal (HPA) axis measures (heart rate, cortisol, cortisol/ACTH ratio), lower medial frontal brain volume and hyperactive neutral state ventromedial prefrontal cortex (VmPFC) and blunted VmPFC and cortisol response to stress and alcohol cues each predicted greater risk of future relapse and poor recovery outcomes (p’s<0.01). Higher tonic cortisol and blunted stress cortisol responses each were associated with neural VmPFC responses to acute stress (p<0.01). Short-term abstinence and recovery over an 8-week period was associated with improved VmPFC responses to stress compared to relapsed and non-abstinent AD patients (p<0.05 whole brain corrected). Together,
Studies show that craving and physiological responses to cues mimicking real-world alcohol and stress triggers can predict relapse to alcohol use in alcohol-dependent individuals. The association between this cue reactivity and alcohol consumption in non-dependent drinkers is less clear. Our objective was to characterize acute stress and alcohol-cue reactivity, using guided-imaging scripts, and their relationship to craving and IV alcohol self-administration (IV-ASA) in non-dependent drinkers. Participants (N ¼ 23) included non-dependent binge and non-binge drinkers that completed three experimental IV-ASA sessions. Each session began with exposure to a 5-min personalized guided-imagery script to induce either acute stress, alcohol-craving, or a neutral-relaxing state. Serial blood samples included cortisol (CORT) and adrenocorticotropic hormone (ACTH). Subjective measures of stress and craving were also obtained. Following this, participants were able to press a button to receive IV infusions of alcohol for a 2-hr period. The imagery scripts successfully induced reactivity, with increases in reactivity following the stress-cue compared with the neutral-cue. Binge drinkers had significantly higher craving and IV-ASA following stress and alcohol cues compared to nonbingers. Maximum ACTH and CORT levels following stress and alcohol cues were higher in binge-drinkers. These results are the first demonstration, to our knowledge, of stress-induced increases in IV-ASA in binge drinkers. These data may provide important information on the relationship between stress and alcohol-seeking behavior that may underlie risk for alcohol-related problems. This experimental model may serve as a translational tool to screen novel pharmacological agents that target brain stress systems in reducing drinking and relapse in AUD. Supported by NIAAA DICBR Z1A000466. S41 BINGE-HEAVY ALCOHOL ALTERS CORTISOL AND SUBJECTIVE CRAVING: IMPACT ON COMPULSIVE ALCOHOL MOTIVATION AND INTAKE S. Blaine Ph.D., D Seo Ph.D., R Sinha Ph.D. Yale University, New Haven, CT, USA In this study, we examined whether alcohol-related neuroendocrine adaptations drive compulsive alcohol motivation and intake in moderate, non-binging (MD) and binge/heavy (BH) non-smoking social drinkers who participated in an experiment that measured the specific effects of stress, alcohol cue, and neutral cue exposure, followed by discrete alcohol cues, on neuroendocrine function, subjective alcohol craving, and behavioral alcohol motivation and intake. The “alcohol taste test” (ATT) was used as an implicit measure of behavioral alcohol motivation and intake. Participants also underwent a separate neuroimaging experiment to examine whether high alcohol motivation and intake in the laboratory influenced neural responses to stress cues. Increased stress-induced alcohol craving (p<0.01) and blunted stress-induced cortisol (p<0.05) was observed in the BH vs MD group. Both the increased craving and blunted cortisol response