1 4848 117 OPIOID-INDUCED STRUCTURAL AND FUNCTIONAL PLASTICITY OF MEDIUM-SPINY NEURONS IN THE NUCLEUS ACCUMBENS. OPIOID USE DISORDER (OUD) IS A CHRONIC RELAPSING CLINICAL CONDITION WITH TREMENDOUS MORBIDITY AND MORTALITY THAT FREQUENTLY PERSISTS, DESPITE TREATMENT, DUE TO AN INDIVIDUAL'S UNDERLYING PSYCHOLOGICAL, NEUROBIOLOGICAL, AND GENETIC VULNERABILITIES. EVIDENCE SUGGESTS THAT THESE VULNERABILITIES MAY HAVE NEUROCHEMICAL, CELLULAR, AND MOLECULAR BASES. KEY NEUROPLASTIC EVENTS WITHIN THE MESOCORTICOLIMBIC SYSTEM THAT EMERGE THROUGH CHRONIC EXPOSURE TO OPIOIDS MAY HAVE A DETERMINATIVE INFLUENCE ON BEHAVIORAL SYMPTOMS ASSOCIATED WITH OUD. IN PARTICULAR, STRUCTURAL AND FUNCTIONAL ALTERATIONS IN THE DENDRITIC SPINES OF MEDIUM SPINY NEURONS (MSNS) WITHIN THE NUCLEUS ACCUMBENS (NAC) AND ITS DOPAMINERGIC PROJECTIONS FROM THE VENTRAL TEGMENTAL AREA (VTA) ARE BELIEVED TO FACILITATE THESE BEHAVIORAL SEQUELAE. ADDITIONALLY, GLUTAMATERGIC NEURONS FROM THE PREFRONTAL CORTEX, THE BASOLATERAL AMYGDALA, THE HIPPOCAMPUS, AND THE THALAMUS PROJECT TO THESE SAME MSNS, PROVIDING AN ENRICHED TARGET FOR SYNAPTIC PLASTICITY. HERE, WE REVIEW LITERATURE RELATED TO NEUROADAPTATIONS IN NAC MSNS FROM DOPAMINERGIC AND GLUTAMATERGIC PATHWAYS IN OUD. WE ALSO DESCRIBE NEW FINDINGS RELATED TO TRANSCRIPTIONAL, EPIGENETIC, AND MOLECULAR MECHANISMS IN MSN PLASTICITY IN THE DIFFERENT STAGES OF OUD. 2021 2 747 27 CANNABIS-INDUCED HYPODOPAMINERGIC ANHEDONIA AND COGNITIVE DECLINE IN HUMANS: EMBRACING PUTATIVE INDUCTION OF DOPAMINE HOMEOSTASIS. OVER YEARS, THE REGULAR USE OF CANNABIS HAS SUBSTANTIALLY INCREASED AMONG YOUNG ADULTS, AS INDICATED BY THE RISE IN CANNABIS USE DISORDER (CUD), WITH AN ESTIMATED PREVALENCE OF 8. 3% IN THE UNITED STATES. RESEARCH SHOWS THAT EXPOSURE TO CANNABIS IS ASSOCIATED WITH HYPODOPAMINERGIC ANHEDONIA (DEPRESSION), COGNITIVE DECLINE, POOR MEMORY, INATTENTION, IMPAIRED LEARNING PERFORMANCE, REDUCED DOPAMINE BRAIN RESPONSE-ASSOCIATED EMOTIONALITY, AND INCREASED ADDICTION SEVERITY IN YOUNG ADULTS. THE ADDICTION MEDICINE COMMUNITY IS INCREASING CONCERN BECAUSE OF THE HIGH CONTENT OF DELTA-9-TETRAHYDROCANNABINOL (THC) CURRENTLY FOUND IN ORAL AND VAPING CANNABIS PRODUCTS, THE COGNITIVE EFFECTS OF CANNABIS MAY BECOME MORE PRONOUNCED IN YOUNG ADULTS WHO USE THESE CANNABIS PRODUCTS. PRELIMINARY RESEARCH SUGGESTS THAT IT IS POSSIBLE TO INDUCE 'DOPAMINE HOMEOSTASIS,' THAT IS, RESTORE DOPAMINE FUNCTION WITH DOPAMINE UPREGULATION WITH THE PROPOSED COMPOUND AND NORMALIZE BEHAVIOR IN CHRONIC CANNABIS USERS WITH CANNABIS-INDUCED HYPODOPAMINERGIC ANHEDONIA (DEPRESSION) AND COGNITIVE DECLINE. THIS PSYCHOLOGICAL, NEUROBIOLOGICAL, ANATOMICAL, GENETIC, AND EPIGENETIC RESEARCH ALSO COULD PROVIDE EVIDENCE TO USE FOR THE DEVELOPMENT OF AN APPROPRIATE POLICY REGARDING THE DECRIMINALIZATION OF CANNABIS FOR RECREATIONAL USE. 2021 3 2398 27 EPIGENETIC REPROGRAMMING OF CORTICAL NEURONS THROUGH ALTERATION OF DOPAMINERGIC CIRCUITS. ALTERATIONS OF THE DOPAMINERGIC SYSTEM ARE ASSOCIATED WITH THE COGNITIVE AND FUNCTIONAL DYSFUNCTIONS THAT CHARACTERIZE COMPLEX NEUROPSYCHIATRIC DISORDERS. WE MODELED A DYSFUNCTIONAL DOPAMINERGIC SYSTEM USING MICE WITH TARGETED ABLATION OF DOPAMINE (DA) D2 AUTORECEPTORS IN MESENCEPHALIC DOPAMINERGIC NEURONS. LOSS OF D2 AUTORECEPTORS ABOLISHES D2-MEDIATED CONTROL OF DA SYNTHESIS AND RELEASE. HERE, WE SHOW THAT THIS MUTATION LEADS TO A PROFOUND ALTERATION OF THE GENOMIC LANDSCAPE OF NEURONS RECEIVING DOPAMINERGIC AFFERENTS AT DISTAL SITES, SPECIFICALLY IN THE PREFRONTAL CORTEX. INDEED, WE OBSERVED A REMARKABLE DOWNREGULATION OF GENE EXPRESSION IN THIS AREA OF ~2000 GENES, WHICH INVOLVES A WIDESPREAD INCREASE IN THE HISTONE REPRESSIVE MARK H3K9ME2/3. THIS REPROGRAMMING PROCESS IS COUPLED TO PSYCHOTIC-LIKE BEHAVIORS IN THE MUTANT MICE. IMPORTANTLY, CHRONIC TREATMENT WITH A DA AGONIST CAN REVERT THE GENOMIC PHENOTYPE. THUS, CORTICAL NEURONS UNDERGO A PROFOUND EPIGENETIC REPROGRAMMING IN RESPONSE TO DYSFUNCTIONAL D2 AUTORECEPTOR SIGNALING LEADING TO ALTERED DA LEVELS, A PROCESS THAT MAY UNDERLIE A NUMBER OF NEUROPSYCHIATRIC DISORDERS. 2014 4 2934 28 GENETIC ADDICTION RISK SCORE (GARS) , A PREDICTOR OF VULNERABILITY TO OPIOID DEPENDENCE. THE INTERACTION OF NEUROTRANSMITTERS AND GENES THAT CONTROL THE RELEASE OF DOPAMINE IS THE BRAIN REWARD CASCADE (BRC). VARIATIONS WITHIN THE BRC, WHETHER GENETIC OR EPIGENETIC, MAY PREDISPOSE INDIVIDUALS TO ADDICTIVE BEHAVIORS AND ALTERED PAIN TOLERANCE. THIS DISCUSSION AUTHORED BY A GROUP OF CONCERNED SCIENTISTS AND CLINICIANS EXAMINES THE GENETIC ADDICTION RISK SCORE (GARS), THE FIRST TEST TO ACCURATELY PREDICT VULNERABILITY TO PAIN, ADDICTION, AND OTHER COMPULSIVE BEHAVIORS, DEFINED AS REWARD DEFICIENCY SYNDROME (RDS). INNOVATIVE STRATEGIES TO COMBAT EPIDEMIC OPIOID, IATROGENIC PRESCRIPTION DRUG ABUSE AND DEATH, BASED ON THE ROLE OF DOPAMINERGIC TONE IN PAIN PATHWAYS, ARE PROPOSED. SENSITIVITY TO PAIN MAY RESIDE IN THE MESOLIMBIC PROJECTION SYSTEM, WHERE GENETIC POLYMORPHISMS ASSOCIATE WITH A PREDISPOSITION TO PAIN VULNERABILITY OR TOLERANCE. THEY PROVIDE UNIQUE THERAPEUTIC TARGETS THAT COULD ASSIST IN THE TREATMENT OF PAIN, AND IDENTIFY RISK FOR SUBSEQUENT ADDICTION. PHARMACOGENOMIC TESTING OF CANDIDATE GENES LIKE CB1, MU RECEPTORS, AND PENK MIGHT RESULT IN PHARMACOGENOMIC, PERSONALIZED SOLUTIONS, AND IMPROVED CLINICAL OUTCOMES. GENETICALLY IDENTIFYING RISK FOR ALL RDS BEHAVIORS, ESPECIALLY IN COMPROMISED POPULATIONS, MAY BE A FRONTLINE TOOL TO ASSIST MUNICIPALITIES TO PROVIDE BETTER RESOURCE ALLOCATION. 2018 5 3774 29 INTERACTION OF GONADAL HORMONES, DOPAMINERGIC SYSTEM, AND EPIGENETIC REGULATION IN THE GENERATION OF SEX DIFFERENCES IN SUBSTANCE USE DISORDERS: A SYSTEMATIC REVIEW. SUBSTANCE USE DISORDER (SUD) IS A CHRONIC CONDITION CHARACTERIZED BY PATHOLOGICAL DRUG-TAKING AND SEEKING BEHAVIORS. REMARKABLY DIFFERENT BETWEEN MALES AND FEMALES, SUGGESTING THAT DRUG ADDICTION IS A SEXUALLY DIFFERENTIATED DISORDER. THE NEUROBIOLOGICAL BASES OF SEX DIFFERENCES IN SUD INCLUDE SEX-SPECIFIC REWARD SYSTEM ACTIVATION, INFLUENCED BY INTERACTIONS BETWEEN GONADAL HORMONE LEVEL CHANGES, DOPAMINERGIC REWARD CIRCUITS, AND EPIGENETIC MODIFICATIONS OF KEY REWARD SYSTEM GENES. THIS SYSTEMATIC REVIEW, ADHERING TO PICOS AND PRISMA-P 2015 GUIDELINES, HIGHLIGHTS THE SEX-DEPENDENT ROLES OF ESTROGENS, PROGESTERONE, AND TESTOSTERONE IN SUD. IN PARTICULAR, ESTRADIOL ELEVATES AND PROGESTERONE REDUCES DOPAMINERGIC ACTIVITY IN SUD FEMALES, WHILST TESTOSTERONE AND PROGESTERONE AUGMENT SUD BEHAVIOR IN MALES. FINALLY, SUD IS ASSOCIATED WITH A SEX-SPECIFIC INCREASE IN THE RATE OF OPIOID AND MONOAMINERGIC GENE METHYLATION. THE STUDY REVEALS THE NEED FOR DETAILED RESEARCH ON GONADAL HORMONE LEVELS, DOPAMINERGIC OR REWARD SYSTEM ACTIVITY, AND EPIGENETIC LANDSCAPES IN BOTH SEXES FOR EFFICIENT SUD THERAPY DEVELOPMENT. 2023 6 1651 33 DOPAMINE AND GLUCOSE, OBESITY, AND REWARD DEFICIENCY SYNDROME. OBESITY AS A RESULT OF OVEREATING AS WELL AS A NUMBER OF WELL DESCRIBED EATING DISORDERS HAS BEEN ACCURATELY CONSIDERED TO BE A WORLD-WIDE EPIDEMIC. RECENTLY A NUMBER OF THEORIES BACKED BY A PLETHORA OF SCIENTIFICALLY SOUND NEUROCHEMICAL AND GENETIC STUDIES PROVIDE STRONG EVIDENCE THAT FOOD ADDICTION IS SIMILAR TO PSYCHOACTIVE DRUG ADDICTION. OUR LABORATORY HAS PUBLISHED ON THE CONCEPT KNOWN AS REWARD DEFICIENCY SYNDROME (RDS) WHICH IS A GENETIC AND EPIGENETIC PHENOMENA LEADING TO IMPAIRMENT OF THE BRAIN REWARD CIRCUITRY RESULTING IN A HYPO-DOPAMINERGIC FUNCTION. RDS INVOLVES THE INTERACTIONS OF POWERFUL NEUROTRANSMITTERS AND RESULTS IN ABNORMAL CRAVING BEHAVIOR. A NUMBER OF IMPORTANT FACTS WHICH COULD HELP TRANSLATE TO POTENTIAL THERAPEUTIC TARGETS ESPOUSED IN THIS FOCUSED REVIEW INCLUDE: (1) CONSUMPTION OF ALCOHOL IN LARGE QUANTITIES OR CARBOHYDRATES BINGING STIMULATES THE BRAIN'S PRODUCTION OF AND UTILIZATION OF DOPAMINE; (2) IN THE MESO-LIMBIC SYSTEM THE ENKEPHALINERGIC NEURONS ARE IN CLOSE PROXIMITY, TO GLUCOSE RECEPTORS; (3) HIGHLY CONCENTRATED GLUCOSE ACTIVATES THE CALCIUM CHANNEL TO STIMULATE DOPAMINE RELEASE FROM P12 CELLS; (4) A SIGNIFICANT CORRELATION BETWEEN BLOOD GLUCOSE AND CEREBROSPINAL FLUID CONCENTRATIONS OF HOMOVANILLIC ACID THE DOPAMINE METABOLITE; (5) 2-DEOXYGLUCOSE (2DG), THE GLUCOSE ANALOG, IN PHARMACOLOGICAL DOSES IS ASSOCIATED WITH ENHANCED DOPAMINE TURNOVER AND CAUSES ACUTE GLUCOPRIVATION. EVIDENCE FROM ANIMAL STUDIES AND FMRI IN HUMANS SUPPORT THE HYPOTHESIS THAT MULTIPLE, BUT SIMILAR BRAIN CIRCUITS ARE DISRUPTED IN OBESITY AND DRUG DEPENDENCE AND FOR THE MOST PART, IMPLICATE THE INVOLVEMENT OF DA-MODULATED REWARD CIRCUITS IN PATHOLOGIC EATING BEHAVIORS. BASED ON A CONSENSUS OF NEUROSCIENCE RESEARCH TREATMENT OF BOTH GLUCOSE AND DRUG LIKE COCAINE, OPIATES SHOULD INCORPORATE DOPAMINE AGONIST THERAPY IN CONTRAST TO CURRENT THEORIES AND PRACTICES THAT UTILIZES DOPAMINE ANTAGONISTIC THERAPY. CONSIDERING THAT UP UNTIL NOW CLINICAL UTILIZATION OF POWERFUL DOPAMINE D2 AGONISTS HAVE FAILED DUE TO CHRONIC DOWN REGULATION OF D2 RECEPTORS NEWER TARGETS BASED ON NOVEL LESS POWERFUL D2 AGONISTS THAT UP-REGULATE D2 RECEPTORS SEEMS PRUDENT. WE ENCOURAGE NEW STRATEGIES TARGETED AT IMPROVING DA FUNCTION IN THE TREATMENT AND PREVENTION OF OBESITY A SUBTYPE OF REWARD DEFICIENCY. 2014 7 6352 35 THE ROLE OF GABA(A) RECEPTORS IN THE DEVELOPMENT OF ALCOHOLISM. ALCOHOLISM IS A COMMON, HERITABLE, CHRONIC RELAPSING DISORDER. GABA(A) RECEPTORS UNDERGO ALLOSTERIC MODULATION BY ETHANOL, ANESTHETICS, BENZODIAZEPINES AND NEUROSTEROIDS AND HAVE BEEN IMPLICATED IN THE ACUTE AS WELL AS THE CHRONIC EFFECTS OF ETHANOL INCLUDING TOLERANCE, DEPENDENCE AND WITHDRAWAL. MEDICATIONS TARGETING GABA(A) RECEPTORS AMELIORATE THE SYMPTOMS OF ACUTE WITHDRAWAL. ETHANOL INDUCES PLASTICITY IN GABA(A) RECEPTORS: TOLERANCE IS ASSOCIATED WITH GENERALLY DECREASED GABA(A) RECEPTOR ACTIVATION AND DIFFERENTIALLY ALTERED SUBUNIT EXPRESSION. THE DOPAMINE (DA) MESOLIMBIC REWARD PATHWAY ORIGINATING IN THE VENTRAL TEGMENTAL AREA (VTA), AND INTERACTING STRESS CIRCUITRY PLAY AN IMPORTANT ROLE IN THE DEVELOPMENT OF ADDICTION. VTA GABAERGIC INTERNEURONS ARE THE PRIMARY INHIBITORY REGULATORS OF DA NEURONS AND A SUBSET OF VTA GABA(A) RECEPTORS MAY BE IMPLICATED IN THE SWITCH FROM HEAVY DRINKING TO DEPENDENCE. GABA(A) RECEPTORS MODULATE ANXIETY AND RESPONSE TO STRESS; IMPORTANT ELEMENTS OF SUSTAINED DRINKING AND RELAPSE. THE GABA(A) RECEPTOR SUBUNIT GENES CLUSTERED ON CHROMOSOME 4 ARE HIGHLY EXPRESSED IN THE REWARD PATHWAY. SEVERAL RECENT STUDIES HAVE PROVIDED STRONG EVIDENCE THAT ONE OF THESE GENES, GABRA2, IS IMPLICATED IN ALCOHOLISM IN HUMANS. THE INFLUENCE OF THE INTERACTION BETWEEN ETHANOL AND GABA(A) RECEPTORS IN THE REWARD PATHWAY ON THE DEVELOPMENT OF ALCOHOLISM TOGETHER WITH GENETIC AND EPIGENETIC VULNERABILITIES WILL BE EXPLORED IN THIS REVIEW. 2008 8 4828 27 OLANZAPINE INDUCED DNA METHYLATION CHANGES SUPPORT THE DOPAMINE HYPOTHESIS OF PSYCHOSIS. BACKGROUND: THE DOPAMINE (DA) HYPOTHESIS OF SCHIZOPHRENIA PROPOSES THE MENTAL ILLNESS IS CAUSED BY EXCESSIVE TRANSMISSION OF DOPAMINE IN SELECTED BRAIN REGIONS. MULTIPLE LINES OF EVIDENCE, INCLUDING BLOCKAGE OF DOPAMINE RECEPTORS BY ANTIPSYCHOTIC DRUGS THAT ARE USED TO TREAT SCHIZOPHRENIA, SUPPORT THE HYPOTHESIS. HOWEVER, THE DOPAMINE D2 RECEPTOR (DRD2) BLOCKADE CANNOT EXPLAIN SOME IMPORTANT ASPECTS OF THE THERAPEUTIC EFFECT OF ANTIPSYCHOTIC DRUGS. IN THIS STUDY, WE HYPOTHESIZED THAT ANTIPSYCHOTIC DRUGS COULD AFFECT THE TRANSCRIPTION OF GENES IN THE DA PATHWAY BY ALTERING THEIR EPIGENETIC PROFILE. METHODS: TO TEST THIS HYPOTHESIS, WE EXAMINED THE EFFECT OF OLANZAPINE, A COMMONLY USED ATYPICAL ANTIPSYCHOTIC DRUG, ON THE DNA METHYLATION STATUS OF GENES FROM DA NEUROTRANSMISSION IN THE BRAIN AND LIVER OF RATS. GENOMIC DNA ISOLATED FROM HIPPOCAMPUS, CEREBELLUM, AND LIVER OF OLANZAPINE TREATED (N = 2) AND CONTROL (N = 2) RATS WERE ANALYZED USING RAT SPECIFIC METHYLATION ARRAYS. RESULTS: OUR RESULTS SHOW THAT OLANZAPINE CAUSES METHYLATION CHANGES IN GENES ENCODING FOR DA RECEPTORS (DOPAMINE D1 RECEPTOR, DOPAMINE D2 RECEPTOR AND DOPAMINE D5 RECEPTOR), A DA TRANSPORTER (SOLUTE CARRIER FAMILY 18 MEMBER 2), A DA SYNTHESIS (DIFFERENTIAL DISPLAY CLONE 8), AND A DA METABOLISM (CATECHOL-O-METHYLTRANSFERASE). WE ASSESSED A TOTAL OF 40 GENES IN THE DA PATHWAY AND FOUND 19 TO BE DIFFERENTIALLY METHYLATED BETWEEN OLANZAPINE TREATED AND CONTROL RATS. MOST (17/19) GENES SHOWED AN INCREASE IN METHYLATION, IN THEIR PROMOTER REGIONS WITH IN SILICO ANALYSIS STRONGLY INDICATING A FUNCTIONAL POTENTIAL TO SUPPRESS TRANSCRIPTION IN THE BRAIN. CONCLUSION: OUR RESULTS SUGGEST THAT CHRONIC OLANZAPINE MAY REDUCE DA ACTIVITY BY ALTERING GENE METHYLATION. IT MAY ALSO EXPLAIN THE DELAYED THERAPEUTIC EFFECT OF ANTIPSYCHOTICS, WHICH OCCURS DESPITE RAPID DOPAMINE BLOCKADE. FURTHERMORE, GIVEN THE COMMON NATURE OF EPIGENETIC VARIATION, THIS LENDS INSIGHT INTO THE DIFFERENTIAL THERAPEUTIC RESPONSE OF PSYCHOTIC PATIENTS WHO DISPLAY ADEQUATE BLOCKAGE OF DOPAMINE RECEPTORS. 2013 9 1460 28 DISORDERS OF CONSCIOUSNESS AND PHARMACEUTICALS THAT ACT ON OXYGEN BASED AMINO ACID AND MONOAMINE NEUROTRANSMITTER PATHWAYS OF THE BRAIN. OXYGEN BASED NEUROTRANSMITTERS IN THE SYNAPSES OF THE BRAIN ARE PROPOSED TO PLAY AN IMPORTANT ROLE IN THE GENERATION OF CONSCIOUSNESS. THEY INCLUDE THE AMINO ACIDS GLUTAMATE AND GABA WHICH USE KREBS CYCLE PRECURSORS FOR THEIR SYNTHESIS, AND THE MONOAMINES DOPAMINE, NORADRENALIN, ADRENALIN AND SEROTONIN, WHICH ARE DERIVED FROM TYROSINE AND TRYPTOPHAN. DURING ISCHEMIA AFTER AN ACUTE BRAIN INJURY, A GABA SURGE OFTEN INITIATES BRAIN SUPPRESSION. IT HAS BEEN PROPOSED THAT WITH CHRONIC ISCHEMIA, A SECONDARY, POSSIBLY EPIGENETIC RESPONSE OCCURS WHEN NEUROTRANSMITTERS DEPLETE, A GLUCOSE AND OXYGEN SAVING MECHANISM TERMED NEURODORMANCY THAT MAY INVOKE ALTERNATIVE LONG TERM LOW ENERGY METABOLIC PATHWAYS IN THE BRAIN, ENCOUNTERED IN DISORDERS OF CONSCIOUSNESS. SOME MEDICATIONS CAN REVERSE DISORDERS OF CONSCIOUSNESS IN SOME PATIENTS. VIRTUALLY ALL OF THEM ACT ON NEUROTRANSMITTER SYSTEMS THAT USE OXYGEN AS A BUILDING BLOCK OR AS AN ENERGY SOURCE WITHIN THE BRAIN. PHARMACEUTICALS THAT ACT IN THE OXYGEN BASED AMINO ACID SYSTEMS OF THE BRAIN INCLUDE THE GABAERGIC MEDICATIONS ZOLPIDEM AND BACLOFEN, WHILE THOSE THAT ACT IN THE MONOAMINE AXES INCLUDE THE DOPAMINERGIC MEDICATIONS L DOPA, AMANTADINE, BROMOCRIPTINE, APOMORPHINE AND METHYLPHENIDATE, AND THE NORADRENERGIC AND SEROTONERGIC MEDICATIONS DESIPRAMINE, AMITRIPTYLINE, PROTRIPTYLINE AND FLUOXETINE. ANOTHER GROUP ARE THE CHOLINESTERASE INHIBITORS, RESPONSIBLE FOR INCREASING ACETYLCHOLINE, WHICH IS SYNTHESIZED FROM THE KREBS CYCLE INITIATOR, ACETYL COA. IT APPEARS THAT PHARMACEUTICALS THAT ARE ACTIVE IN THE OXYGEN BASED NEUROTRANSMITTER PATHWAYS OF THE BRAIN ARE SUCCESSFUL TO AROUSE TO CONSCIOUSNESS PATIENTS THAT SUFFER FROM ITS DISORDERS. RESEARCH NEEDS TO BE SUPPORTED AS FOUNDATION TO UNDERSTAND THE BIOCHEMICAL MECHANISMS THAT ARE INVOLVED IN CONSCIOUSNESS DISORDERS AND TO EXPLORE FURTHER THE PHARMACOLOGICAL TREATMENT POSSIBILITIES FOR THESE DEVASTATING NEUROLOGICAL CONDITIONS. 2014 10 1091 35 COGNITIVE ENHANCERS AS A TREATMENT FOR HEROIN RELAPSE AND ADDICTION. HEROIN ADDICTION IS A DISORDER THAT STEMS FROM MALADAPTIVE PLASTICITY WITHIN NEURAL CIRCUITS AND PRODUCES BROAD COGNITIVE DEFICITS. DESPITE CONSIDERABLE ADVANCES IN PSYCHOTHERAPY AND PHARMACOTHERAPY FOR HEROIN RELAPSE AND ADDICTION, EFFECTIVE TREATMENTS FOR HEROIN USE DISORDER ARE STILL LACKING. INCREASING PRECLINICAL EVIDENCE INDICATES THAT HEROIN SEEKING BEHAVIOR IS PERSISTENT AFTER WITHDRAWAL, WHILE COGNITIVE DYSFUNCTIONS ASSOCIATED WITH CHRONIC HEROIN USE ARE AN IMPORTANT CONTRIBUTING FACTOR TO RISK OF HEROIN RELAPSE AND ADDICTION. COGNITIVE ENHANCERS MAY BE USED TO STIMULATE TREATMENT SUCCESS AND ENHANCE TREATMENT EFFICACY. THE PURPOSE OF THIS REVIEW IS TO OUTLINE THE LITERATURE THAT DEMONSTRATES THE COGNITIVE DEFICITS DURING THE DEVELOPMENT OF HEROIN ADDICTION AND WITHDRAWAL PROCESS, AND SEVERAL FACTORS THAT UNDERLINE THE EFFICACY OF COGNITIVE ENHANCERS FOR HEROIN USE DISORDERS. THE REVIEW, THEN, EXAMINES THE POTENTIAL USE AND PHARMACOLOGICAL MECHANISMS OF COGNITIVE ENHANCERS THAT ACT ON CHOLINERGIC, GLUTAMATERGIC, DOPAMINERGIC OR ADRENERGIC PATHWAYS. IT ALSO EXAMINES THE EFFECTS OF COMPOUNDS THAT ALTER CREB SIGNALING AND EPIGENETIC MECHANISMS IN ANIMAL MODEL OF HEROIN RELAPSE. THE CURRENT BODY OF RESEARCH REVEALS THE NEW INSIGHTS INTO THE PHARMACOLOGICAL MECHANISMS UNDERLYING HEROIN ADDICTION AND HOLDS A SIGNIFICANT PROMISE FOR COGNITIVE ENHANCERS AS AN IMPROVED APPROACH TO TREAT HEROIN USE DISORDER IN A MORE EFFICIENT AND PERSISTENT WAY. 2019 11 3314 40 HIPPOCAMPAL CANNABINOID 1 RECEPTORS ARE MODULATED FOLLOWING COCAINE SELF-ADMINISTRATION IN MALE RATS. COCAINE ADDICTION IS A COMPLEX PATHOLOGY INDUCING LONG-TERM NEUROPLASTIC CHANGES THAT, IN TURN, CONTRIBUTE TO MALADAPTIVE BEHAVIORS. THIS BEHAVIORAL DYSREGULATION IS ASSOCIATED WITH TRANSCRIPTIONAL REPROGRAMMING IN BRAIN REWARD CIRCUITRY, ALTHOUGH THE MECHANISMS UNDERLYING THIS MODULATION REMAIN POORLY UNDERSTOOD. THE ENDOGENOUS CANNABINOID SYSTEM MAY PLAY A ROLE IN THIS PROCESS IN THAT CANNABINOID MECHANISMS MODULATE DRUG REWARD AND CONTRIBUTE TO COCAINE-INDUCED NEURAL ADAPTATIONS. IN THIS STUDY, WE INVESTIGATED WHETHER COCAINE SELF-ADMINISTRATION INDUCES LONG-TERM ADAPTATIONS, INCLUDING TRANSCRIPTIONAL MODIFICATIONS AND ASSOCIATED EPIGENETIC PROCESSES. WE FIRST EXAMINED ENDOCANNABINOID GENE EXPRESSION IN REWARD-RELATED BRAIN REGIONS OF THE RAT FOLLOWING SELF-ADMINISTERED (0.33 MG/KG INTRAVENOUS, FR1, 10 DAYS) COCAINE INJECTIONS. INTERESTINGLY, WE FOUND INCREASED CNR1 EXPRESSION IN SEVERAL STRUCTURES, INCLUDING PREFRONTAL CORTEX, NUCLEUS ACCUMBENS, DORSAL STRIATUM, HIPPOCAMPUS, HABENULA, AMYGDALA, LATERAL HYPOTHALAMUS, VENTRAL TEGMENTAL AREA, AND ROSTROMEDIAL TEGMENTAL NUCLEUS, WITH MOST PRONOUNCED EFFECTS IN THE HIPPOCAMPUS. ENDOCANNABINOID LEVELS, MEASURED BY MASS SPECTROMETRY, WERE ALSO ALTERED IN THIS STRUCTURE. CHROMATIN IMMUNOPRECIPITATION FOLLOWED BY QPCR IN THE HIPPOCAMPUS REVEALED THAT TWO ACTIVATING HISTONE MARKS, H3K4ME3 AND H3K27AC, WERE ENRICHED AT SPECIFIC ENDOCANNABINOID GENES FOLLOWING COCAINE INTAKE. TARGETING CB1 RECEPTORS USING CHROMOSOME CONFORMATION CAPTURE, WE HIGHLIGHTED SPATIAL CHROMATIN RE-ORGANIZATION IN THE HIPPOCAMPUS, AS WELL AS IN THE NUCLEUS ACCUMBENS, SUGGESTING THAT DESTABILIZATION OF THE CHROMATIN MAY CONTRIBUTE TO NEURONAL RESPONSES TO COCAINE. OVERALL, OUR RESULTS HIGHLIGHT A KEY ROLE FOR THE HIPPOCAMPUS IN COCAINE-INDUCED PLASTICITY AND BROADEN THE UNDERSTANDING OF NEURONAL ALTERATIONS ASSOCIATED WITH ENDOCANNABINOID SIGNALING. THE LATTER SUGGESTS THAT EPIGENETIC MODIFICATIONS CONTRIBUTE TO MALADAPTIVE BEHAVIORS ASSOCIATED WITH CHRONIC DRUG USE. 2022 12 3315 25 HIPPOCAMPAL MU OPIOID RECEPTORS ARE MODULATED FOLLOWING COCAINE SELF-ADMINISTRATION IN RAT. COCAINE ADDICTION IS A COMPLEX PATHOLOGY INDUCED BY LONG-TERM BRAIN CHANGES. UNDERSTANDING THE NEUROCHEMICAL CHANGES UNDERLYING THE REINFORCING EFFECTS OF THIS DRUG OF ABUSE IS CRITICAL FOR REDUCING THE SOCIETAL BURDEN OF DRUG ADDICTION. THE MU OPIOID RECEPTOR PLAYS A MAJOR ROLE IN DRUG REWARD. THIS RECEPTOR IS MODULATED BY CHRONIC COCAINE TREATMENT IN SPECIFIC BRAIN STRUCTURES, BUT FEW STUDIES INVESTIGATED NEUROCHEMICAL ADAPTATIONS INDUCED BY VOLUNTARY COCAINE INTAKE. IN THIS STUDY, WE INVESTIGATED WHETHER INTRAVENOUS COCAINE-SELF ADMINISTRATION (0.33 MG/KG/INJECTION, FIXED-RATIO 1 [FR1], 10 DAYS) IN RATS INDUCES TRANSCRIPTIONAL AND FUNCTIONAL CHANGES OF THE MU OPIOID RECEPTOR IN REWARD-RELATED BRAIN REGIONS. EPIGENETIC PROCESSES WITH HISTONE MODIFICATIONS WERE EXAMINED FOR TWO ACTIVATING MARKS, H3K4ME3, AND H3K27AC. WE FOUND AN INCREASE OF MU OPIOID RECEPTOR GENE EXPRESSION ALONG WITH A POTENTIATION OF ITS FUNCTIONALITY IN HIPPOCAMPUS OF COCAINE SELF-ADMINISTERING ANIMALS COMPARED TO SALINE CONTROLS. CHROMATIN IMMUNOPRECIPITATION FOLLOWED BY QPCR REVEALED NO MODIFICATIONS OF THE HISTONE MARK H3K4ME3 AND H3K27AC LEVELS AT MU OPIOID RECEPTOR PROMOTER. OUR STUDY HIGHLIGHTS THE HIPPOCAMPUS AS AN IMPORTANT TARGET TO FURTHER INVESTIGATE NEUROADAPTIVE PROCESSES LEADING TO COCAINE ADDICTION. 2021 13 1677 32 DRUG ADDICTION: HYPERKATIFEIA/NEGATIVE REINFORCEMENT AS A FRAMEWORK FOR MEDICATIONS DEVELOPMENT. COMPULSIVE DRUG SEEKING THAT IS ASSOCIATED WITH ADDICTION IS HYPOTHESIZED TO FOLLOW A HEURISTIC FRAMEWORK THAT INVOLVES THREE STAGES (BINGE/INTOXICATION, WITHDRAWAL/NEGATIVE AFFECT, AND PREOCCUPATION/ANTICIPATION) AND THREE DOMAINS OF DYSFUNCTION (INCENTIVE SALIENCE/PATHOLOGIC HABITS, NEGATIVE EMOTIONAL STATES, AND EXECUTIVE FUNCTION, RESPECTIVELY) VIA CHANGES IN THE BASAL GANGLIA, EXTENDED AMYGDALA/HABENULA, AND FRONTAL CORTEX, RESPECTIVELY. THIS REVIEW FOCUSES ON NEUROCHEMICAL/NEUROCIRCUITRY DYSREGULATIONS THAT CONTRIBUTE TO HYPERKATIFEIA, DEFINED AS A GREATER INTENSITY OF NEGATIVE EMOTIONAL/MOTIVATIONAL SIGNS AND SYMPTOMS DURING WITHDRAWAL FROM DRUGS OF ABUSE IN THE WITHDRAWAL/NEGATIVE AFFECT STAGE OF THE ADDICTION CYCLE. HYPERKATIFEIA PROVIDES AN ADDITIONAL SOURCE OF MOTIVATION FOR COMPULSIVE DRUG SEEKING VIA NEGATIVE REINFORCEMENT. NEGATIVE REINFORCEMENT REFLECTS AN INCREASE IN THE PROBABILITY OF A RESPONSE TO REMOVE AN AVERSIVE STIMULUS OR DRUG SEEKING TO REMOVE HYPERKATIFEIA THAT IS AUGMENTED BY GENETIC/EPIGENETIC VULNERABILITY, ENVIRONMENTAL TRAUMA, AND PSYCHIATRIC COMORBIDITY. NEUROBIOLOGICAL TARGETS FOR HYPERKATIFEIA IN ADDICTION INVOLVE NEUROCIRCUITRY OF THE EXTENDED AMYGDALA AND ITS CONNECTIONS VIA WITHIN-SYSTEM NEUROADAPTATIONS IN DOPAMINE, ENKEPHALIN/ENDORPHIN OPIOID PEPTIDE, AND GAMMA-AMINOBUTYRIC ACID/GLUTAMATE SYSTEMS AND BETWEEN-SYSTEM NEUROADAPTATIONS IN PROSTRESS CORTICOTROPIN-RELEASING FACTOR, NOREPINEPHRINE, GLUCOCORTICOID, DYNORPHIN, HYPOCRETIN, AND NEUROIMMUNE SYSTEMS AND ANTISTRESS NEUROPEPTIDE Y, NOCICEPTIN, ENDOCANNABINOID, AND OXYTOCIN SYSTEMS. SUCH NEUROCHEMICAL/NEUROCIRCUITRY DYSREGULATIONS ARE HYPOTHESIZED TO MEDIATE A NEGATIVE HEDONIC SET POINT THAT GRADUALLY GAINS ALLOSTATIC LOAD AND SHIFTS FROM A HOMEOSTATIC HEDONIC STATE TO AN ALLOSTATIC HEDONIC STATE. BASED ON PRECLINICAL STUDIES AND TRANSLATIONAL STUDIES TO DATE, MEDICATIONS AND BEHAVIORAL THERAPIES THAT RESET BRAIN STRESS, ANTISTRESS, AND EMOTIONAL PAIN SYSTEMS AND RETURN THEM TO HOMEOSTASIS WOULD BE PROMISING NEW TARGETS FOR MEDICATION DEVELOPMENT. SIGNIFICANCE STATEMENT: THE FOCUS OF THIS REVIEW IS ON NEUROCHEMICAL/NEUROCIRCUITRY DYSREGULATIONS THAT CONTRIBUTE TO HYPERKATIFEIA, DEFINED AS A GREATER INTENSITY OF NEGATIVE EMOTIONAL/MOTIVATIONAL SIGNS AND SYMPTOMS DURING WITHDRAWAL FROM DRUGS OF ABUSE IN THE WITHDRAWAL/NEGATIVE AFFECT STAGE OF THE DRUG ADDICTION CYCLE AND A DRIVING FORCE FOR NEGATIVE REINFORCEMENT IN ADDICTION. MEDICATIONS AND BEHAVIORAL THERAPIES THAT REVERSE HYPERKATIFEIA BY RESETTING BRAIN STRESS, ANTISTRESS, AND EMOTIONAL PAIN SYSTEMS AND RETURNING THEM TO HOMEOSTASIS WOULD BE PROMISING NEW TARGETS FOR MEDICATION DEVELOPMENT. 2021 14 2092 21 EPIGENETIC EFFECT OF CHRONIC STRESS ON DOPAMINE SIGNALING AND DEPRESSION. BECAUSE OF THE COMPLEX CAUSAL FACTORS LEADING TO DEPRESSION, EPIGENETICS IS OF CONSIDERABLE INTEREST FOR THE UNDERSTANDING EFFECT OF STRESS IN DEPRESSION. DOPAMINE IS A KEY NEUROTRANSMITTER IMPORTANT IN MANY PHYSIOLOGICAL FUNCTIONS, INCLUDING MOTOR CONTROL, MOOD, AND THE REWARD PATHWAY. THESE FACTORS LEAD MANY DRUGS TO TARGET DOPAMINE RECEPTORS IN TREATING DEPRESSIVE DISORDERS. IN THIS REVIEW, WE TRY TO PORTRAY HOW CHRONIC STRESS AS AN EPIGENETIC FACTOR CHANGES THE GENE REGULATION PATTERN BY INTERRUPTING DOPAMINE SIGNALING MECHANISM. 2013 15 5712 31 SIRT1 MEDIATES DEPRESSION-LIKE BEHAVIORS IN THE NUCLEUS ACCUMBENS. DEPRESSION IS A RECURRING AND LIFE-THREATENING ILLNESS THAT AFFECTS UP TO 120 MILLION PEOPLE WORLDWIDE. IN THE PRESENT STUDY, WE SHOW THAT CHRONIC SOCIAL DEFEAT STRESS, AN ETHOLOGICALLY VALIDATED MODEL OF DEPRESSION IN MICE, INCREASES SIRT1 LEVELS IN THE NUCLEUS ACCUMBENS (NAC), A KEY BRAIN REWARD REGION. INCREASES IN SIRT1, A WELL CHARACTERIZED CLASS III HISTONE DEACETYLASE, AFTER CHRONIC SOCIAL DEFEAT SUGGEST A ROLE FOR THIS ENZYME IN MEDIATING DEPRESSION-LIKE BEHAVIORS. WHEN RESVERATROL, A PHARMACOLOGICAL ACTIVATOR OF SIRT1, WAS DIRECTLY INFUSED BILATERALLY INTO THE NAC, WE OBSERVED AN INCREASE IN DEPRESSION- AND ANXIETY-LIKE BEHAVIORS. CONVERSELY, INTRA-NAC INFUSIONS OF EX-527, A SIRT1 ANTAGONIST, REDUCED THESE BEHAVIORS; EX-527 ALSO REDUCED ACUTE STRESS RESPONSES IN STRESS-NAIVE MICE. NEXT, WE INCREASED SIRT1 LEVELS DIRECTLY IN NAC BY USE OF VIRAL-MEDIATED GENE TRANSFER AND OBSERVED AN INCREASE IN DEPRESSIVE- AND ANXIETY-LIKE BEHAVIORS WHEN MICE WERE ASSESSED IN THE OPEN-FIELD, ELEVATED-PLUS-MAZE, AND FORCED SWIM TESTS. USING A CRE-INDUCIBLE VIRAL VECTOR SYSTEM TO OVEREXPRESS SIRT1 SELECTIVELY IN DOPAMINE D1 OR D2 SUBPOPULATIONS OF MEDIUM SPINY NEURONS (MSNS) IN THE NAC, WE FOUND THAT SIRT1 PROMOTES DEPRESSIVE-LIKE BEHAVIORS ONLY WHEN OVEREXPRESSED IN D1 MSNS, WITH NO EFFECT SEEN IN D2 MSNS. CONVERSELY, SELECTIVE ABLATION OF SIRT1 IN THE NAC USING VIRAL-CRE IN FLOXED SIRT1 MICE RESULTED IN DECREASED DEPRESSION- AND ANXIETY-LIKE BEHAVIORS. TOGETHER, THESE RESULTS DEMONSTRATE THAT SIRT1 PLAYS AN ESSENTIAL ROLE IN THE NAC IN REGULATING MOOD-RELATED BEHAVIORAL ABNORMALITIES AND IDENTIFIES A NOVEL SIGNALING PATHWAY FOR THE DEVELOPMENT OF INNOVATIVE ANTIDEPRESSANTS TO TREAT MAJOR DEPRESSIVE DISORDERS. SIGNIFICANCE STATEMENT: IN THIS STUDY, WE DEMONSTRATE A PIVOTAL ROLE FOR SIRT1 IN ANXIETY- AND DEPRESSION-LIKE BEHAVIORS IN THE NUCLEUS ACCUMBENS (NAC), A KEY BRAIN REWARD REGION. WE SHOW THAT STRESS STABLY INDUCES SIRT1 EXPRESSION IN THIS BRAIN REGION AND THAT ALTERING SIRT1 ACTIVITY USING A PHARMACOLOGICAL OR GENETIC APPROACH REGULATES ANXIETY- AND DEPRESSION-LIKE BEHAVIORS. THESE RESULTS SUGGEST THAT SIRT1 PLAYS AN ESSENTIAL ROLE IN REGULATING MOOD-RELATED BEHAVIORS AND INTRODUCES A NOVEL SIGNALING PATHWAY FOR THE DEVELOPMENT OF INNOVATIVE ANTIDEPRESSANTS TO TREAT DEPRESSION AND OTHER STRESS-RELATED DISORDERS. A RECENT GROUNDBREAKING PUBLICATION BY THE CONVERGE CONSORTIUM (2015) IDENTIFIED A REPRODUCIBLE ASSOCIATION OF THE SIRT1 LOCUS WITH MAJOR DEPRESSION IN HUMANS. THEREFORE, OUR RESULTS ARE TIMELY AND HAVE SIGNIFICANT TRANSLATIONAL RELEVANCE. 2016 16 4469 39 MOLECULAR NEUROLOGICAL CORRELATES OF ENDORPHINERGIC/DOPAMINERGIC MECHANISMS IN REWARD CIRCUITRY LINKED TO ENDORPHINERGIC DEFICIENCY SYNDROME (EDS). THE CONSENSUS OF THE CURRENT LITERATURE STRONGLY SUPPORTS THE CONCEPT THAT BRAIN NEUROTRANSMITTERS, AND SECOND MESSENGERS INVOLVED IN THE NET RELEASE OF DOPAMINE IN THE MESOLIMBIC REGION, ESPECIALLY THE NUCLEUS ACCUMBENS (NAC), IS DIRECTLY LINKED TO MOTIVATION, ANTI-STRESS, INCENTIVE SALIENCE (WANTING), AND WELL-BEING. THE ROLE OF DOPAMINE IN TERMS OF ALCOHOL WITHDRAWAL SYMPTOMOLOGY, COCAINE CRAVING BEHAVIOR, DOPAMINE -CONDENSATION PRODUCTS (TIQS), AND MORE RECENTLY, THE GENETIC ASPECTS OF DRUG-SEEKING AND PRO-DOPAMINE REGULATION, PROVIDE COMPELLING EVIDENCE OF THE RELEVANT MOLECULAR NEUROLOGICAL CORRELATES OF DOPAMINERGIC /ENDORPHINERGIC MECHANISMS IN REWARD CIRCUITRY DUE TO GENETIC POLYMORPHISMS AND EPIGENETIC INSULTS. IN THE FACE OF AN AMERICANS OPIOID EPIDEMIC, THE CLINICAL CONSENSUS IS TO TREAT OPIOID USE DISORDER (OUD) WITH LIFE-LONG OPIOID SUBSTITUTION THERAPY. HOWEVER, THE AUTHORS SUGGEST A PARADIGM SHIFT INVOLVING NOVEL MODALITIES LIKE TARGETING THE ENDORPHINERGIC SYSTEM LINKED TO DOPAMINE RELEASE AT THE NAC, IN TERMS OF THE INDUCTION OF REQUIRED "DOPAMINE HOMEOSTASIS." UTILIZING THE KNOWN GENETIC - ENVIRONMENTAL INTERACTION THEOREM P = G +E, THE AUTHORS PROVIDE A CLEAR RATIONALE FOR THE ADOPTION OF GENETIC RISK TESTING COUPLED WITH ENDORPHINERGIC/DOPAMINE REGULATION TO ADDRESS DYSFUNCTION ACROSS THE BRAIN REWARD CIRCUITRY. THE GOAL OF ALTERING RESTING-STATE, FUNCTIONAL CONNECTIVITY MAY REQUIRE A GENTLE "NEUROTRANSMITTER FIX" VIS ENKEPHALINASE INHIBITION TO OVERCOME OR COMBAT - SELF-INDUCTION OF ACUTE DOPAMINE RELEASE VIA PSYCHOACTIVE SUBSTANCE MISUSE RESULTING IN CHRONIC DOPAMINE DOWN-REGULATION. AS SUBSETS OF REWARD DEFICIENCY, WE ARE POISED TO PROVIDE NOVEL, GENETICALLY GUIDED THERAPY FOR ENDORPHINERGIC, OPIOIDERGIC, AND DOPAMINERGIC DEFICIENCIES AND RELATED SYNDROMES, UTILIZING "PRECISION ADDICTION MANAGEMENT. 2020 17 1653 30 DOPAMINE TRANSPORTER KNOCKOUT RATS DISPLAY EPIGENETIC ALTERATIONS IN RESPONSE TO COCAINE EXPOSURE. (1) BACKGROUND: THERE IS AN URGENT NEED FOR EFFECTIVE TREATMENTS FOR COCAINE USE DISORDER (CUD), AND NEW PHARMACOLOGICAL APPROACHES TARGETING EPIGENETIC MECHANISMS APPEAR TO BE PROMISING OPTIONS FOR THE TREATMENT OF THIS DISEASE. DOPAMINE TRANSPORTER (DAT) TRANSGENIC RATS RECENTLY HAVE BEEN PROPOSED AS A NEW ANIMAL MODEL FOR STUDYING SUSCEPTIBILITY TO CUD. (2) METHODS: DAT TRANSGENIC RATS WERE TREATED CHRONICALLY WITH COCAINE (10 MG/KG) FOR 8 DAYS, AND THE EXPRESSION OF EPIGENETIC MODULATORS, LYSINE DEMETHYLASE 6B (KDM6B) AND BROMODOMAIN-CONTAINING PROTEIN 4 (BRD4), WAS EXAMINED IN THE PREFRONTAL CORTEX (PFC). (3) RESULTS: WE SHOW THAT ONLY FULL KNOCKOUT (KO) OF DAT IMPACTS BASAL LEVELS OF KDM6B IN FEMALES. ADDITIONALLY, COCAINE ALTERED THE EXPRESSION OF BOTH EPIGENETIC MARKERS IN A SEX- AND GENOTYPE-DEPENDENT MANNER. IN RESPONSE TO CHRONIC COCAINE, KDM6B EXPRESSION WAS DECREASED IN MALE RATS WITH PARTIAL DAT MUTATION (HET), WHILE NO CHANGES WERE OBSERVED IN WILD-TYPE (WT) OR KO RATS. INDEED, WHILE HET MALE RATS HAVE REDUCED KDM6B AND BRD4 EXPRESSION, HET FEMALE RATS SHOWED INCREASED KDM6B AND BRD4 EXPRESSION LEVELS, HIGHLIGHTING THE IMPACT OF SEX ON EPIGENETIC MECHANISMS IN RESPONSE TO COCAINE. FINALLY, BOTH MALE AND FEMALE KO RATS SHOWED INCREASED EXPRESSION OF BRD4, BUT ONLY KO FEMALES EXHIBITED SIGNIFICANTLY INCREASED KDM6B EXPRESSION IN RESPONSE TO COCAINE. ADDITIONALLY, THE MAGNITUDE OF THESE EFFECTS WAS BIGGER IN FEMALES WHEN COMPARED TO MALES FOR BOTH EPIGENETIC ENZYMES. (4) CONCLUSIONS: THIS PRELIMINARY STUDY PROVIDES ADDITIONAL SUPPORT THAT TARGETING KDM6B AND/OR BRD4 MAY POTENTIALLY BE THERAPEUTIC IN TREATING ADDICTION-RELATED BEHAVIORS IN A SEX-DEPENDENT MANNER. 2023 18 2773 40 EXTRACELLULAR SIGNAL-REGULATED PROTEIN KINASES 1 AND 2 ACTIVATION BY ADDICTIVE DRUGS: A SIGNAL TOWARD PATHOLOGICAL ADAPTATION. ADDICTION IS A CHRONIC AND RELAPSING PSYCHIATRIC DISORDER THAT IS THOUGHT TO OCCUR IN VULNERABLE INDIVIDUALS. SYNAPTIC PLASTICITY EVOKED BY DRUGS OF ABUSE IN THE SO-CALLED NEURONAL CIRCUITS OF REWARD HAS BEEN PROPOSED TO UNDERLIE BEHAVIORAL ADAPTATIONS THAT CHARACTERIZE ADDICTION. BY INCREASING DOPAMINE IN THE STRIATUM, ADDICTIVE DRUGS ALTER THE BALANCE OF DOPAMINE AND GLUTAMATE SIGNALS CONVERGING ONTO STRIATAL MEDIUM-SIZED SPINY NEURONS (MSNS) AND ACTIVATE INTRACELLULAR EVENTS INVOLVED IN LONG-TERM BEHAVIORAL ALTERATIONS. OUR LABORATORY CONTRIBUTED TO THE IDENTIFICATION OF SALIENT MOLECULAR CHANGES INDUCED BY ADMINISTRATION OF ADDICTIVE DRUGS TO RODENTS. WE PIONEERED THE OBSERVATION THAT A COMMON FEATURE OF ADDICTIVE DRUGS IS TO ACTIVATE, BY A DOUBLE TYROSINE/THREONINE PHOSPHORYLATION, THE EXTRACELLULAR SIGNAL-REGULATED KINASES 1 AND 2 (ERK1/2) IN THE STRIATUM, WHICH CONTROL A PLETHORA OF SUBSTRATES, SOME OF THEM BEING CRITICALLY INVOLVED IN COCAINE-MEDIATED MOLECULAR AND BEHAVIORAL ADAPTATIONS. HEREIN, WE REVIEW HOW THE INTERPLAY BETWEEN DOPAMINE AND GLUTAMATE SIGNALING CONTROLS COCAINE-INDUCED ERK1/2 ACTIVATION IN MSNS. WE EMPHASIZE THE KEY ROLE OF N-METHYL-D-ASPARTATE RECEPTOR POTENTIATION BY D1 RECEPTOR TO TRIGGER ERK1/2 ACTIVATION AND ITS SUBSEQUENT NUCLEAR TRANSLOCATION WHERE IT MODULATES BOTH EPIGENETIC AND GENETIC PROCESSES ENGAGED BY COCAINE. WE DISCUSS HOW COCAINE-INDUCED LONG-TERM SYNAPTIC AND STRUCTURAL PLASTICITY OF MSNS, AS WELL AS BEHAVIORAL ADAPTATIONS, ARE INFLUENCED BY ERK1/2-CONTROLLED TARGETS. WE CONCLUDE THAT A BETTER KNOWLEDGE OF MOLECULAR MECHANISMS UNDERLYING ERK1/2 ACTIVATION BY DRUGS OF ABUSE AND/OR ITS ROLE IN LONG-TERM NEURONAL PLASTICITY IN THE STRIATUM MAY PROVIDE A NEW ROUTE FOR THERAPEUTIC TREATMENT IN ADDICTION. 2014 19 76 30 A NEW ASPECT OF CHRONIC PAIN AS A LIFESTYLE-RELATED DISEASE. PHYSICAL EXERCISE HAS BEEN ESTABLISHED AS A LOW-COST, SAFE, AND EFFECTIVE WAY TO MANAGE CHRONIC INTRACTABLE PAIN. WE INVESTIGATED THE UNDERLYING MECHANISMS OF EXERCISE-INDUCED HYPOALGESIA (EIH) USING A MOUSE MODEL OF NEUROPATHIC PAIN (NPP). EPIGENETIC CHANGES IN ACTIVATED MICROGLIA AND MAINTAINED GABA SYNTHESIS IN THE SPINAL DORSAL HORN MAY CONTRIBUTE TO EIH. VOLUNTARY EXERCISE (VE), A STRONG REWARD FOR ANIMALS, ALSO INDUCED EIH, WHICH MAY BE DUE IN PART TO THE ACTIVATION OF DOPAMINE (DA) NEURONS IN THE VENTRAL TEGMENTAL AREA (VTA). VE INCREASES THE EXPRESSION OF PCREB IN DOPAMINERGIC NEURONS IN THE VTA, WHICH WOULD ENHANCE DOPAMINE PRODUCTION, AND THEREBY CONTRIBUTES TO THE ACTIVATION OF THE MESOLIMBIC REWARD SYSTEM IN NPP MODEL MICE. WE DEMONSTRATED THAT NEURONS IN THE LATERODORSAL TEGMENTAL AND PEDUNCULOPONTINE TEGMENTAL NUCLEI, A MAJOR INPUT SOURCE OF REWARDING STIMULI TO THE VTA, WERE ACTIVATED BY EXERCISE. CHRONIC PAIN IS AT LEAST PARTLY ATTRIBUTED TO SEDENTARY AND INACTIVE LIFESTYLE AS INDICATED BY THE FEAR-AVOIDANCE MODEL. THEREFORE, CHRONIC PAIN COULD BE RECOGNIZED AS A LIFESTYLE-RELATED DISEASE. PHYSICAL ACTIVITY/INACTIVITY MAY BE DETERMINED BY GENETIC/EPIGENETIC AND NEURAL FACTORS ENCODED IN OUR BRAIN. THE HYPOTHALAMUS AND REWARD SYSTEM IS CLOSELY RELATED IN THE AXIS OF FOOD INTAKE, ENERGY METABOLISM AND PHYSICAL ACTIVITY. UNDERSTANDING THE INTERACTIONS BETWEEN THE MESOLIMBIC DA SYSTEM AND THE HYPOTHALAMUS THAT SENSE AND REGULATE ENERGY BALANCE IS THUS OF SIGNIFICANT IMPORTANCE. FOR EXAMPLE, PROOPIOMELANOCORTIN NEURONS AND MELANOCORTIN 4 RECEPTORS MAY PLAY A ROLE IN CONNECTING THESE TWO SYSTEMS. THEREFORE, IN A CERTAIN SENSE, CHRONIC PAIN AND OBESITY MAY SHARE COMMON BEHAVIORAL AND NEURAL PATHOLOGY, I.E. PHYSICAL INACTIVITY, AS A RESULT OF INACTIVATION OF THE MESOLIMBIC DA SYSTEM. EXERCISE AND INCREASING PHYSICAL ACTIVITY IN DAILY LIFE MAY BE IMPORTANT IN TREATING AND PREVENTING CHRONIC PAIN, A LIFE-STYLE RELATED DISEASE. 2017 20 6108 28 THE ENRICHED ENVIRONMENT AMELIORATES CHRONIC UNPREDICTABLE MILD STRESS-INDUCED DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE IMPAIRMENT BY ACTIVATING THE SIRT1/MIR-134 SIGNALING PATHWAY IN HIPPOCAMPUS. BACKGROUND: CHRONIC UNPREDICTABLE MILD STRESS (CUMS) IS AN IMPORTANT RISK FACTOR FOR DEPRESSION AND COGNITIVE DEFICITS IN HUMANS. ENRICHED ENVIRONMENT (EE) SHOWED A BENEFICIAL EFFECT ON DEPRESSION AND COGNITION BY ENHANCING BRAIN DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION AND SYNAPTIC PLASTICITY. HOWEVER, IT IS STILL NOT CLEARLY UNDERSTOOD WHETHER AN EPIGENETIC MECHANISM IS INVOLVED IN THE BDNF MODULATION AND SYNAPTIC PLASTICITY THAT OCCURS AFTER EE TREATMENT FOR THE DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE DEFICITS ELICITED BY CUMS. IN THIS STUDY, WE INVESTIGATED THE POSSIBLE MECHANISM OF THE NEUROPROTECTIVE EFFECT OF EE. METHODS: ALL RATS WERE EXPOSED TO THE 5-WEEK CUMS PROCEDURE EXCEPT THE CONTROL GROUP. AFTER CUMS PROCEDURE, SOME RATS WERE STEREOTAXICALLY INJECTED WITH SIRT1 PHARMACOLOGIC INHIBITOR EX527 OR SIRT1 KNOCKING DOWN LENTIVIRUS (SH-SIRT1) IN THE HIPPOCAMPUS FOLLOWED BY EE TREATMENT FOR 3 WEEKS. OTHER RATS WERE DIRECTLY SUBJECTED TO EE TREATMENT WITHOUT STEREOTAXIC INJECTION. BEHAVIORAL TESTS WERE USED TO APPRAISE DEPRESSION AND COGNITION AFTER EE TREATMENT. THEN EPIGENETIC MOLECULES, SYNAPTIC PROTEINS, DENDRITIC SPINE DENSITY AND BRANCHES, AND SYNAPTIC MORPHOLOGY OF THE DORSAL HIPPOCAMPUS WERE DETERMINED. RESULTS: WE FOUND THAT CUMS INDUCED DEPRESSIVE-LIKE BEHAVIORS INCLUDING DECREASED SUCROSE PREFERENCE RATIO, PROLONGED IMMOBILITY AND REDUCED LOCOMOTOR AND EXPLORATORY ACTIVITY; COGNITIVE DEFICITS INCLUDING SPATIAL LEARNING AND MEMORY IMPAIRMENT; REDUCED DENDRITIC SPINE DENSITY AND NUMBER OF BRANCHES; THINNED POSTSYNAPTIC DENSITY; DOWNREGULATED SIRT1/MICRORNA-134 PATHWAY, DECREASED BDNF AND SYNAPTIC PROTEINS INCLUDING SYNAPTOPHYSIN (SYN) AND POSTSYNAPTIC DENSITY PROTEIN 95 (PSD95) EXPRESSION IN THE HIPPOCAMPUS. HOWEVER, THE CUMS-INDUCED DEPRESSIVE-LIKE BEHAVIORS, COGNITIVE DEFICITS, DENDRITIC SPINE DENSITY AND BRANCH NUMBER REDUCTION, POSTSYNAPTIC DENSITY THINNING, SIRT1/MICRORNA-134 PATHWAY DOWNREGULATION, BDNF AND SYNAPTIC PROTEINS REDUCTION, INCLUDING SYNAPTOPHYSIN (SYN) AND POSTSYNAPTIC DENSITY PROTEIN 95 (PSD95), WERE REVERSED BY EE TREATMENT. HOWEVER, DEPRESSIVE-LIKE BEHAVIORS AND COGNITIVE DEFICITS WERE OBSERVED AGAIN IN RATS SUBJECTED TO STEREOTAXIC INJECTION WITH EX527 OR SH-SIRT1. FURTHERMORE, THIS STUDY ALSO FOUND THAT SIRT1/MICRORNA-134 REGULATES THE DOWNSTREAM MOLECULES BDNF, AND THE SYNAPTIC PROTEINS SYN AND PSD95 IN PRIMARY CULTURED HIPPOCAMPAL NEURONS. CONCLUSIONS: THIS STUDY PROVIDES EVIDENCE FOR THE NEUROPROTECTIVE ROLE OF EE ON DEPRESSION AND COGNITIVE DEFICITS BY ACTIVATING THE SIRT1/MICRORNA-134 PATHWAY, WHICH ACCOUNTS FOR THE REGULATION OF SYNAPTIC PROTEINS, INCLUDING BDNF, PSD95 AND SYN, DENDRITIC REMODELING AND ULTRASTRUCTURE CHANGES OF SYNAPSES IN THE HIPPOCAMPUS. 2019