Athina Markou - US grants

The career development and research program described in this proposal support the application for an ADAMHA Scientist Development Award (SDA, K21) for Dr. Athina Markou, and is intended to provide the candidate with the background knowledge, research experience, and research management skills that will take place in the Department of Neuropharmacology (Dr. Floyd E. Bloom, Chair) of The Scripps Research Institute, under the direct supervision of Dr. George F. Koob and Dr. Friedbert Weiss. Dr Koob is highly qualified to serve as Preceptor for the Candidate, because of his experience with the research methodologies to be used, his active research program in drug abuse, and his commitment to the development of junior research scientists. The Department of Neuropharmacology emphasizes a multi-disciplinary approach to problems of drug addiction and mental disorders. Thus, this is an ideal environment for the Candidate to materialize her goal of a multidisciplinary research approach to the neurobiology of drug abuse. The overall objective of the research plan is to explore the role of the amygdala, and amygdala- accumbens and amygdala-hypothalamus interactions in incentive- motivational paradigms that assess the incentive-motivational and reward values of reinforcers (e.g., cocaine and intracranial self-stimulation) with state-of-the-art neurochemical and neuroanatomical techniques. The proposed studies will explore the potential role(s) of dopamine and serotonin release in the amygdala in cocaine self-administration behavior, using the in vivo microdialysis technique. Further, through the use of selective neurotoxic and excitotoxic lesions, the role of the amygdala connection to the accumbens in cocaine self-administration behavior will be investigated. Moreover, the role(s) of the amygdala, the nucleus accumbens, and the amygdala-accumbens interaction in the control exerted over behavior by conditioned stimuli associated with cocaine infusions will be explored. The study of the neurobiological substrates of conditioned reinforcers may provide valuable insights about the neurobiological processes mediating drug-seeking behavior (i.e., drug craving). Similar microdialysis and lesion studies will be conducted with intracranial self-stimulation as the reinforcer to further explore the role of the amygdala accumbens and amygdala-hypothalamus interactions in incentive-motivational and reward processes. These studies promise to yield new insights regarding the role of the amygdala and its efferent in reward processes and drug abuse and have implications for the etiology, prevention, and treatment of drug dependence.

The career development and research program described in this proposal support the application for an ADAMHA Scientist Development Award (SDA, K21) for Dr. Athina Markou, and is intended to provide the candidate with the background knowledge, research experience, and research management skills that will take place in the Department of Neuropharmacology (Dr. Floyd E. Bloom, Chair) of The Scripps Research Institute, under the direct supervision of Dr. George F. Koob and Dr. Friedbert Weiss. Dr Koob is highly qualified to serve as Preceptor for the Candidate, because of his experience with the research methodologies to be used, his active research program in drug abuse, and his commitment to the development of junior research scientists. The Department of Neuropharmacology emphasizes a multi-disciplinary approach to problems of drug addiction and mental disorders. Thus, this is an ideal environment for the Candidate to materialize her goal of a multidisciplinary research approach to the neurobiology of drug abuse. The overall objective of the research plan is to explore the role of the amygdala, and amygdala- accumbens and amygdala-hypothalamus interactions in incentive- motivational paradigms that assess the incentive-motivational and reward values of reinforcers (e.g., cocaine and intracranial self-stimulation) with state-of-the-art neurochemical and neuroanatomical techniques. The proposed studies will explore the potential role(s) of dopamine and serotonin release in the amygdala in cocaine self-administration behavior, using the in vivo microdialysis technique. Further, through the use of selective neurotoxic and excitotoxic lesions, the role of the amygdala connection to the accumbens in cocaine self-administration behavior will be investigated. Moreover, the role(s) of the amygdala, the nucleus accumbens, and the amygdala-accumbens interaction in the control exerted over behavior by conditioned stimuli associated with cocaine infusions will be explored. The study of the neurobiological substrates of conditioned reinforcers may provide valuable insights about the neurobiological processes mediating drug-seeking behavior (i.e., drug craving). Similar microdialysis and lesion studies will be conducted with intracranial self-stimulation as the reinforcer to further explore the role of the amygdala accumbens and amygdala-hypothalamus interactions in incentive-motivational and reward processes. These studies promise to yield new insights regarding the role of the amygdala and its efferent in reward processes and drug abuse and have implications for the etiology, prevention, and treatment of drug dependence.

DESCRIPTION (provided by applicant): This is a renewal grant application for grant DA011946 in response to Program Announcement PA-02-085 (Neuroscience Research on Drug Addiction). Tobacco smoking, attributed at least partly to the addictive properties of nicotine, is a worldwide health problem that contributes to significant medical costs, deaths and human suffering. Research investigating the mechanisms of nicotine dependence will provide insights into the development of novel behavioral and pharmacological approaches to treat nicotine dependence and habitual tobacco smoking. During the previous funding period, the critical involvement of the glutamate system in both the reinforcing effects of nicotine and the development of nicotine dependence was shown. These data suggested that: a) decreasing glutamate transmission at postsynaptic metabotropic (mGluR) and ionotropic (iGluR) glutamate receptors decreases the reinforcing effects of nicotine;and b) during the development of nicotine dependence there are adaptations in glutamate system function, involving changes in the activity of pre- and post-synaptic glutamate receptors, to counteract the stimulatory effects of nicotine on glutamate transmission. The proposed work will extend these previous findings by investigating brain sites where glutamate plays a role in nicotine reinforcement and dependence. Specific Aim 1 will explore brain sites involved in glutamatergic regulation of intravenous nicotine self-administration in rats, by administering mGluR5, NMDA or AMPA/kainate receptor antagonists into the nucleus accumbens shell, the ventral tegmental area, the central nucleus of the amygdala or the prefrontal cortex. Specific Aim 2 will explore brain sites (same as in Aim 1) where adaptations in glutamate system function occur with the development of nicotine dependence, that affect the regulation of brain reward function in nicotine-dependent rats. Brain reward function will be assessed with the intracranial self-stimulation procedure. The focus will be on mGluR2/3 and AMPA/kainate receptors. Finally, Specific Aim 3 will study intravenous nicotine self-administration in mGluR2/3 and mGluR7 knockout mice to further explore the role of these glutamate receptors in nicotine reinforcement. This work will provide information about the role of glutamate transmission in specific brain sites in nicotine reinforcement, and reveal adaptations that occur in glutamate function in specific brain sites during nicotine dependence;these adaptations are likely to contribute to the affective aspects of nicotine withdrawal and lead to relapse. Such studies will identify novel therapeutic targets for the treatment of nicotine dependence and habitual tobacco smoking in humans.

DESCRIPTION (provided by applicant): This is the second re-submission (A2) of competing renewal application 2R01MH062527. This application focuses on the neurobiology of cognitive symptoms of schizophrenia that are not well treated by available medications. Administration of the NMDA receptor antagonist phencyclidine (PCP) to humans evokes several schizophrenia-like effects, including cognitive deficits, observed only during PCP intoxication. In the proposed rat studies, the inducing condition will be a repeated PCP administration regimen that induces deficits in various cognitive functions that are relevant to schizophrenia (attention/vigilance, working memory, reasoning/problem solving, speed of processing, as identified by the NIMH-FDA collaborative MATRICS program), and alterations in glutamate and GABA system function implicated in schizophrenia neuropathology. Specifically, the effects of the repeated PCP administration regimen will be assessed in: a) the 5-choice serial reaction time task (5-CSRTT) that assesses attention and inhibition of inappropriate responding, corresponding to the attention and reasoning/problem solving domains, respectively;b) the discrete paired-trial variable-delay alternation task that assesses the working memory domain;and c) the cued-location reversal learning task that assesses cognitive flexibility, an aspect of the reasoning/problem solving domain. All tasks also assess the speed of processing domain. Specific Aim 1 will examine how three atypical antipsychotics, with different receptor affinity profiles and differential effects on cognitive measures in humans, alter PCP-induced deficits in the proposed cognitive tasks. Our extensive Preliminary Studies showed that clozapine, but not quetiapine, partially attenuated repeated PCP-induced deficits in attention and response inhibition in the 5-CSRTT, demonstrating that the study of the effects of antipsychotics with variable receptor profiles on cognitive tasks may provide information about neurotransmitters/receptors involved in some, but not other, cognitive deficits. Specific Aim 2 will investigate neurochemical correlates of PCP-induced cognitive deficits and their potential reversal by these atypical antipsychotics by using in vivo microdialysis to measure monoamine, glutamate, and GABA levels in the prefrontal cortex and the nucleus accumbens. These brain sites are implicated in schizophrenia pathology and performance in the proposed cognitive tasks. Finally, Specific Aim 3 will explore whether experimental pharmacological treatments probing specific neurotransmitter and receptor systems, including serotonin, norepinephrine, glutamate, and GABA, may reverse PCP-induced cognitive deficits. These treatments will be guided by the results of the dialysis studies. In summary, a multidisciplinary integrated experimental approach using behavioral, neurochemical, and pharmacological techniques will investigate the neuromechanisms underlying the cognitive deficits of schizophrenia, and specific transmitter actions of atypical antipsychotics that may mediate their differential effects on various cognitive domains. This work will aid in the discovery of novel therapeutic targets for these cognitive deficits. Schizophrenia is a chronic mental illness that results in tremendous human suffering and monetary costs to society. Cognitive impairments are core symptoms of schizophrenia that are not adequately treated by available medications and greatly contribute to profound functional impairment. The results of the proposed studies will promote our understanding of the neurobiology of cognitive deficits in schizophrenia, will elucidate specific neurotransmitter actions of atypical antipsychotics that may mediate their differential effects on various cognitive domains, and finally aid in the discovery of novel therapeutic targets for these poorly treated cognitive deficits.

DESCRIPTION (provided by applicant): This application is in response to RFA MH-03-008 to form a National Cooperative Drug Discovery Group for the Treatment of Mood Disorders or Nicotine Addiction (NCDDG-MD/NA) to work or innovative drug discovery for these two disorders, and the development and validation of a putative new animal model of antidepressant activity. This project will involve an academic partner, The Scripps Research Institute, La Jolla, California, and an industrial partner, Novartis Pharma AG, Basel Switzerland. The pharmacological approach proposed is the development of gamma-aminobutyric acid B (GABAB) receptor positive modulators as antidepressants and/or aids to smoking cessation. Specific Aim 1 will involve the synthesis and refinement of GABAB receptor positive modulators with good selectivity for the GABAB receptor. Specific Aim 2 will involve experiments characterizing these (GABAB positive modulators biochemically in human, rat and mouse GABAB receptor assays. Pharmacokinetics, brain penetration, and binding affinities for other receptors and channels will also be evaluated. Specific Aim 3 will assess the effects of these compounds in nicotine self-administration using both fixed-ratio and progressive ratio schedules of reinforcement in nicotine-dependent rats. Specific Aim 4 will assess the effects of the compounds in vivo and in animal models of depression. Initial studies will evaluate the potential side-effect profile of these compounds. Subsequent work will evaluate the effects of the compounds in 6 models of antidepressant activity: the forced swim test ill mice and rats, the tail suspension test in mice, the olfactory bulbectomy test in rats, and nicotine and amphetamine withdrawal in rats. The latter test will also provide information about potential therapeutic effects of the compounds on drug withdrawal hypothesized to contribute to relapse. Finally, Specific Aim 5 will attempt to develop and validate a new animal model of depression (7th model) involving olfactory bulbectomy as the inducing condition and brain reward thresholds as the dependent variable, and test putative antidepressant drugs. This integrated multidisciplinary research program focusing on both depression and smoking cessation and capitalizing on the expertise of both Scripps and Novartis scientists will be an innovative approach to the development of new therapeutics for these disorders. |

This application is in response to RFA MH-03-008 to form a National Cooperative Drug Discovery] Group for the Treatment of Mood Disorders or Nicotine Addiction (NCDDG-MD/NA) to work on] innovative drug discovery for these two disorders, and the development and validation of a putative new animal model of antidepressant activity. This project will involve an academic partner, The Scripps] Research Institute, La Jolla, California, and an industrial partner, Novartis Pharma AG, Basel, Switzerland. The pharmacological approach proposed is the development of gamma-aminobutyric acid B (GABAB) receptor positive modulators as antidepressants and/or aids to smoking cessation. Specific Aim 1 will involve the synthesis and refinement of GABAB receptor positive modulators with good selectivity for the GABAB receptor. Specific Aim 2 will involve experiments characterizing these GABAB positive modulators biochemically in human, rat and mouse GABAB receptor assays. Pharmacokinetics, brain penetration, and binding affinities for other receptors and channels will also be evaluated. Specific Aim 3 will assess the effects of these compounds in nicotine self-administration using both fixed-ratio and progressive ratio schedules of reinforcement in nicotine-dependent rats. Specific Aim 4 will assess the effects of the compounds in vivo and in animal models of depression. Initial studies will evaluate the potential side-effect profile of these compounds. Subsequent work will evaluate the effects of the compounds in 6 models of antidepressant activity: the forced swim test in mice and rats, the tail suspension test in mice, the olfactory bulbectomy test in rats, and nicotine and amphetamine withdrawal in rats. The latter test will also provide information about potential therapeutic effects of the compounds on drug withdrawal hypothesized to contribute to relapse. Finally, Specific Aim 5 will attempt to develop and validate a new animal model of depression (7th model) involving olfactory bulbectomy as the inducing condition and brain reward thresholds as the dependent variable, and test putative antidepressant drugs. This integrated multidisciplinary research program focusing on both depression and smoking cessation and capitalizing on the expertise of both Scripps and Novartis scientists will be an innovative approach to the development of new therapeutics for these disorders.

DESCRIPTION (provided by applicant): It is thought that nicotine is one of the main psychoactive ingredients in tobacco smoke that leads to habitual tobacco smoking in humans. Nicotine induces pleasurable euphoric-like effects and also enhances the effects of other rewarding stimuli (i.e., reward facilitation). Further, adaptations induced by chronic nicotine administration result in deficits in brain reward function and somatic signs during nicotine withdrawal. These three effects associated with nicotine consumption (i.e., pleasurable effects of acute nicotine, nicotine- induced facilitation of other rewards, and the aversive nicotine withdrawal syndrome) are all hypothesized to provide important sources of motivation that perpetuate the deadly tobacco smoking habit. The goals of the proposed project are threefold. Specific Aim 1 will attempt to identify specific nicotinic acetylcholine receptor (nAChR) subunits critically involved in the primary reinforcing effects of nicotine. Specific Aim 2 will attempt to identify nAchR subunits critically involved in the reward enhancing effects of acute nicotine. Finally, Specific Aim 3 will attempt to identify specific nAChR subunits which are critically involved in the brain reward function deficits and somatic signs associated with nicotine withdrawal. The proposed studies will be carried out in wildtype mice and genetically modified mice in which a7 or [unreadable]4 nAChR subunits have been null mutated or in which a 4 nAChR subunits have been rendered hypersensitive to nicotine (a7-/-, [unreadable]4-/-, and Leu9'Ala mice, respectively). These subunits have been selected because their localization implicates them in the effects of nicotine investigated in the proposed studies. To identify nAChR subunits critical to the various aspects of nicotine dependence, intravenous nicotine self-administration and intracranial self-stimulation (ICSS) procedures will be utilized. Nicotine self-administration and nicotine- induced lowering of ICSS thresholds will serve as measures of the reinforcing effects of nicotine and nicotine-induced facilitation of reward, respectively. Elevations of ICSS thresholds (i.e., reward deficits) and increased somatic signs of withdrawal during spontaneous nicotine withdrawal will serve as measures of the affective and somatic components of nicotine withdrawal, respectively. These studies will determine whether nAchRs containing the a7, [unreadable]4 and/or a4 subunits are critically involved in mediating effects of nicotine that are hypothesized to be crucial motivating factors in maintaining the tobacco smoking habit. Full nicotine dose-response functions will be generated. Future work will use additional mutant mice to investigate the potential role of other nAchR subunits in the same phenomena. Relevance: Improved understanding of the neurobiological substrates that underlie the rewarding effects of nicotine, the reward-enhancing effects of nicotine and the aversive effects of nicotine abstinence will provide insights into the sources of motivation that result in persistent use of tobacco in humans, and is likely to lead to new and improved behavioral and pharmacological treatments to assist smokers in quitting.

The primary objective of the Administrative Core is to provide the required administrative support to ensure the integrated, coherent and effective scientific operations of the three projects by alleviating Project Leaders from administrative duties. Another important function of the Administrative Core will be to coordinate consulting services to the grant. Specifically, the Core Objectives are: 1) To provide overall scientific and programmatic leadership (e.g., strategic planning, monitoring and evaluation) to the individual Projects in service of the overall scientific theme of this grant. 2) To oversee and coordinate month-to-month activities of the three Projects in order to facilitate reliable exchange of information, collaborative interactions, synergy and cohesiveness of the Projects' research efforts. 3) Preparation and co-ordination of all progress reports to NIH. 4) Preparation and co-ordination of manuscript preparation and submission. 5) Budget projections to assist the Program Director in overseeing the grant. 6) Organization of all aspects of the formal biannual and other informal meetings of the Group, including teleconferencing. 7) Travel arrangements for the Project Leaders to attend the Group meetings. 8) Preparation and distribution of minutes of the Executive Committee meetings. 9) Co-ordination of all consultant activities, including selection and invitation of consultants, and travel arrangements. 10) Facilitate and implement email and telephone consulting activities. 11) Assist with Invention Disclosures and interactions with the offices of Technology Development of UCSD and Scripps.

DESCRIPTION (provided by applicant): This is competing renewal application of grant 1 U01 MH69062 in response to Program Announcement PAR-08-238 (NCDDDG). The main objectives of this project are now focused on the synthesis, and in vitro and in vivo characterization of novel y-aminobutyric acid (GABA) B receptor positive modulators for the treatment of nicotine dependence. The proposed program consists of three Scientific Projects and an Administrative Core (U19) (PD: A. Markou). Project 1 (PI: M.G. Finn, The Scripps Research Institute, La Jolla, California) will design, synthesize, and refine new GABAB receptor positive modulators, using both combinatorial and click chemistry. Project 2 (PI: P. Griffin, The Scripps Research Institute, Jupiter, Florida), will profile the in vitro pharmacology of candidate GABAB receptor positive modulators using cell-based functional G-protein coupled receptor (GPCR) assays for GABAB receptors. Project 2 will also assess the in vitro metabolism, and in vivo brain penetration and pharmacokinetic characteristics of selected compounds. Compounds with the desired combination of properties will be tested in Project 3 (PI: A. Markou, Univ of California San Diego, La Jolla, California) in well validated rat models of nicotine dependence. These in vivo models will include nicotine self-administration, reward-enhancing effects of nicotine in the intracranial self-stimulation procedure, cue-induced reinstatement of nicotine-seeking and anxiety-like behavior during nicotine withdrawal. Extensive work during the previously funded period resulted in the first highly selective positive modulators for GABAB receptors with the desired behavioral effects in rat models of nicotine dependence. Thus, strong preclinical proof-of-concept has been established for the unique and novel strategy of GABAB receptor positive modulation in the treatment of nicotine dependence, and potentially dependence on other drugs of abuse. With this application, we seek funding to build on our previous results by: (a) expanding the pipeline of drug-like active agents;(b) understanding the factors that promote selective positive modulation of GABAB receptors;and (c) assessing how the newly synthesized compounds affect behaviors in rat models of nicotine dependence. This multidisciplinary research program integrates the complementary expertise of the participating scientists to provide innovative potential therapeutics for nicotine dependence in humans.

Abstract Project 3: Assessment of the effects of GABA{B} receptor compounds in animal models of nicotine dependence. Preclinical work conducted during the previous funding period suggests that activation of GABA{B} receptors may be a useful therapeutic strategy for nicotine dependence, with positive modulators exhibiting a better side-effect profile than agonists. Specifically, in rats GABA{B} agonists or positive modulators decreased: i) conditioned and unconditioned reinforcing effects of nicotine that contribute to nicotine dependence; ii) nicotine-induced molecular effects in the nucleus accumbens; iii) the reward enhancing effects of nicotine hypothesized to also contribute to nicotine dependence; and iv) cue-induced increases in nicotine-seeking with putative relevance to relapse in humans. The improved side-effect profile of GABA{B} positive modulators compared to agonists is suggested by the fact that modulators were more likely than agonists to block nicotine-induced behaviors at doses that did not alter responding for food. Thus, our data provide preclinical proof of concept for GABA{B} positive modulators as treatments for nicotine dependence. The main aim of Project 3 is to continue to provide in vivo behavioral characterization of GABA{B} compounds already available to us, and compounds generated by Project 1 and characterized in Project 2 for their GABA{B} properties and selectivity, and their metabolic and pharmacokinetic properties. Specifically, the Specific Aims of Project 3 will be the assessment of the effects of GABA{B} compounds on the: (1) reinforcing and motivational effects of intravenously self-administering nicotine, using fixed- and progressive-ratio schedules of reinforcement; (2) reward enhancing effects of nicotine assessed in the intracranial self-stimulation procedure; (3) cue-induced reinstatement of nicotine-seeking; and (4) increased reactivity to an anxiogenic situation during early nicotine withdrawal. Behavioral results will provide feedback to Projects 1 and 2, and inform future chemistry efforts. Complementary experiments will compare the effects of compounds that have positive effects on nicotine-related behaviors with their effects on food motivated behaviors, providing an important side-effect-related aspect of drug screening for potential anti-addiction medications. In summary. Project 3 will provide the behavioral preclinical characterization of novel GABA{B} receptor compounds as treatments for nicotine dependence in well validated behavioral rat models.

DESCRIPTION (provided by applicant): Depression is a serious psychiatric disorder that remains a major public health problem. Approximately 21% of the general population suffers from depression sometime in their lifetime, while the incidence of depression is 30-37% in drug abusers. There has not been development of new antidepressants with novel pharmacological mechanisms of action for several decades. Recent publications and preliminary data reviewed in this application suggest that antagonists or negative allosteric modulators at metabotropic glutamate receptors (mGluR) Group II (mGluR2 and mGluR3) may have antidepressant properties. Thus, mGluR2/3 are novel targets for antidepressant treatment. This new revised R01 application is in response to PAR-07-048 entitled "Drug Discovery for Nervous System Disorders" that encourages the synthesis and "preclinical testing of novel compounds for the prevention and treatment of nervous system disorders". A multidisciplinary research team comprised of chemists (Burnham Institute), in vitro pharmacologists (Vanderbilt University) and behavioral pharmacologists (University of California, San Diego) will focus on the synthesis and testing of new mGluR2/3 orthosteric antagonists and negative allosteric modulators as treatments for depression. Specific Aim 1 will involve the design and synthesis of novel mGluR2/3 orthosteric antagonists and negative allosteric modulators with optimized potency, selectivity, and in vivo activity. Specific Aim 2 will: i) evaluate and characterize the newly synthesized compounds for potency and efficacy at mGluR2, mGluR3, other mGluRs and various other central nervous system molecular targets, and ii) perform absorption, distribution, metabolism and excretion analyses, as well as evaluate blood brain barrier permeation and pharmacokinetics using in vitro and in vivo assays. Once the optimal mGluR2/3 compounds are identified (see Research Plan for criteria used to select compounds), Specific Aim 3 will investigate the effects of these selected compounds in animal models of: i) stress-induced anhedonia involving assessment of elevations in intracranial self-stimulation (ICSS) reward thresholds after chronic social defeat in rats;and ii) antidepressant-like activity in the forced swim test in rats. Anhedonia is defined as diminished interest or pleasure in rewarding stimuli and is considered a core behavioral phenotype of depression. Thus, compounds with demonstrated anti-anhedonic activity in the stress- induced anhedonia model or antidepressant-like activity in the forced swim test and which also exhibit drug-like properties will be considered putative drug candidates for future drug discovery and development efforts. Potential side-effects will be assessed in later years of the project, once drug-like candidates are identified. The proposed multidisciplinary research program is highly significant as it addresses an important public health problem, innovative as it focuses on Group II mGluRs as targets for novel antidepressants, and timely as it is in response to a Program Announcement by NIH. Therefore, this research program has the potential for a significant scientific and medical impact by contributing to the discovery of new medications for depression. PUBLIC HEALTH RELEVANCE: Depression is a serious psychiatric disorder that affects a large percentage of the USA population. The proposed project will synthesize new compounds that will target metabotropic glutamate receptors in the brain and evaluate them for their putative antidepressant activity in animal models of depression. This project is very innovative and promises to have a highly significant overall impact by promoting the discovery of new treatments for this devastating disorder.

DESCRIPTION (provided by applicant): This grant application is in response to NIAAA announcement RFA-AA-10-006 entitled Neurobiology of adolescent drinking in adulthood (NADIA), and is a part of a Consortium of researchers investigating broad spectrum behavioral and neuropathological changes during adulthood after adolescent ethanol (EtOH) exposure. There is high prevalence of binge drinking among adolescents. Adolescence is a critical period for brain development that is particularly vulnerable to the neurotoxic effects of EtOH. Although some adolescent and adult alcoholics show deficits in attention and increased impulsivity, it is not known whether these behavioral alterations preceded or are the result of alcohol abuse. Increased impulsivity during adolescence in general may partially be attributed to hypersensitivity of the reward system in the adolescent brain, a system whose functioning may be altered by excessive alcohol drinking in adolescence. In addition, considering that the reward circuitry also regulates responses to stress, underage drinking may also alter responses to stressors. Finally, underage drinking is likely to alter dopaminergic (DA) and serotonergic (5- HT) transmitter systems involved in impulsivity, reward processes, and stress responsivity. Adolescent intermittent ethanol (AIE) exposure in rats models several aspects of underage binge drinking in humans. The long-term effects of adolescent EtOH exposure on attention, impulsivity, brain reward function and responses to stress, as well as the effects of alcohol challenges on these behaviors during adulthood remain largely unknown. The proposed studies will fill this gap in knowledge by investigating the long-term impact of AIE on attention and impulsivity (Aim 1), impulsive and risky decision-making (Aim 2), brain reward function and stress responsiveness (Aim 3), and the neurochemical changes in DA and 5-HT transmission likely to be involved in these behavioral alterations (Aim 4) in rats. It is hypothesized that AIE will result in a neuropathology of the DA and 5-HT corticolimbic and striatal brain areas that will manifest itself as impaired attention, increased impulsivity, poor decision-making, reward deficits, and altered responses to stressors during adulthood. These findings may lead to the discovery of behavioral and neurochemical targets for the discovery of treatments to assist people affected by underage drinking who exhibit poor decision-making, highly impulsive behaviors, mental health problems, such as depression/anhedonia, and/or excessive alcohol drinking in adulthood. PUBLIC HEALTH RELEVANCE: Adolescent exposure to alcohol may induce severe long-term brain damage that may result in profound behavioral and cognitive deficits that impair day-to-day function in adulthood. Further, such abnormalities may lead to alcoholism and exacerbate responses to stressors. This project will identify potential behavioral and neuropathological mechanisms in adulthood resulting from alcohol exposure in adolescence, and thus lead to the design.