1 5051 155 PHARMACOLOGICAL RESCUE OF NOCICEPTIVE HYPERSENSITIVITY AND OXYTOCIN ANALGESIA IMPAIRMENT IN A RAT MODEL OF NEONATAL MATERNAL SEPARATION. OXYTOCIN (OT), KNOWN FOR ITS NEUROHORMONAL EFFECTS AROUND BIRTH, HAS RECENTLY BEEN SUGGESTED FOR BEING A CRITICAL DETERMINANT IN NEURODEVELOPMENTAL DISORDERS. THIS HYPOTHALAMIC NEUROPEPTIDE EXERTS A POTENT ANALGESIC EFFECT THROUGH AN ACTION ON THE NOCICEPTIVE SYSTEM. THIS ENDOGENOUS CONTROL OF PAIN HAS AN IMPORTANT ADAPTIVE VALUE BUT MIGHT BE ALTERED BY EARLY LIFE STRESS, POSSIBLY CONTRIBUTING TO ITS LONG-TERM CONSEQUENCES ON PAIN RESPONSES AND ASSOCIATED COMORBIDITIES. WE TESTED THIS HYPOTHESIS USING A RAT MODEL OF NEONATAL MATERNAL SEPARATION (NMS) KNOWN TO INDUCE LONG-TERM CONSEQUENCES ON SEVERAL BRAIN FUNCTIONS INCLUDING CHRONIC STRESS, ANXIETY, ALTERED SOCIAL BEHAVIOR, AND VISCERAL HYPERSENSITIVITY. WE FOUND THAT ADULT RATS WITH A HISTORY OF NMS WERE HYPERSENSITIVE TO NOXIOUS MECHANICAL/THERMAL HOT STIMULI AND TO INFLAMMATORY PAIN. WE FAILED TO OBSERVE OT RECEPTOR-MEDIATED STRESS-INDUCED ANALGESIA AND OT ANTIHYPERALGESIA AFTER CARRAGEENAN INFLAMMATION. THESE ALTERATIONS WERE PARTIALLY RESCUED IF NMS PUPS WERE TREATED BY INTRAPERITONEAL DAILY INJECTION DURING NMS WITH OT OR ITS DOWNSTREAM SECOND MESSENGER ALLOPREGNANOLONE. THE INVOLVEMENT OF EPIGENETIC CHANGES IN THESE ALTERATIONS WAS CONFIRMED SINCE NEONATAL TREATMENT WITH THE HISTONE DEACETYLASE INHIBITOR SAHA, NOT ONLY NORMALIZED NOCICEPTIVE SENSITIVITIES BUT ALSO RESTORED OT RECEPTOR-MEDIATED STRESS-INDUCED ANALGESIA AND THE ENDOGENOUS ANTIHYPERALGESIA IN INFLAMED NMS RATS. THERE IS GROWING EVIDENCE IN THE LITERATURE THAT EARLY LIFE STRESS MIGHT IMPAIR THE NOCICEPTIVE SYSTEM ONTOGENY AND FUNCTION. THIS STUDY SUGGESTS THAT THESE ALTERATIONS MIGHT BE RESTORED WHILE STIMULATING OT RECEPTOR SIGNALING OR HISTONE DEACETYLASE INHIBITORS, USING MOLECULES THAT ARE CURRENTLY AVAILABLE OR PART OF CLINICAL TRIALS FOR OTHER PATHOLOGIES. 2018 2 2105 37 EPIGENETIC EVIDENCE FOR INVOLVEMENT OF THE OXYTOCIN RECEPTOR GENE IN OBSESSIVE-COMPULSIVE DISORDER. BACKGROUND: OBSESSIVE-COMPULSIVE DISORDER (OCD) IS A CHRONIC NEURODEVELOPMENTAL DISORDER THAT AFFECTS UP TO 3% OF THE GENERAL POPULATION. ALTHOUGH EPIGENETIC MECHANISMS PLAY A ROLE IN NEURODEVELOPMENT DISORDERS, EPIGENETIC PATHWAYS ASSOCIATED WITH OCD HAVE RARELY BEEN INVESTIGATED. OXYTOCIN IS A NEUROPEPTIDE INVOLVED IN NEUROBEHAVIORAL FUNCTIONS. OXYTOCIN HAS BEEN SHOWN TO BE ASSOCIATED WITH THE REGULATION OF COMPLEX SOCIO-COGNITIVE PROCESSES SUCH AS ATTACHMENT, SOCIAL EXPLORATION, AND SOCIAL RECOGNITION, AS WELL AS ANXIETY AND OTHER STRESS-RELATED BEHAVIORS. OXYTOCIN HAS ALSO BEEN LINKED TO THE PATHOPHYSIOLOGY OF OCD, ALBEIT INCONSISTENTLY. THE AIM OF THIS STUDY WAS TO INVESTIGATE METHYLATION IN TWO TARGETS SEQUENCES LOCATED IN THE EXON III OF THE OXYTOCIN RECEPTOR GENE (OXTR), IN OCD PATIENTS AND HEALTHY CONTROLS. WE USED BISULFITE SEQUENCING TO QUANTIFY DNA METHYLATION IN PERIPHERAL BLOOD SAMPLES COLLECTED FROM 42 OCD PATIENTS AND 31 HEALTHY CONTROLS. RESULTS: WE FOUND THAT THE LEVEL OF METHYLATION OF THE CYTOSINE-PHOSPHATE-GUANINE SITES IN TWO TARGETS SEQUENCES ANALYZED WAS GREATER IN THE OCD PATIENTS THAN IN THE CONTROLS. THE HIGHER METHYLATION IN THE OCD PATIENTS CORRELATED WITH OCD SEVERITY. WE MEASURED DNA METHYLATION IN THE PERIPHERAL BLOOD, WHICH PREVENTED US FROM DRAWING ANY CONCLUSIONS ABOUT PROCESSES IN THE CENTRAL NERVOUS SYSTEM. CONCLUSION: TO OUR KNOWLEDGE, THIS IS THE FIRST STUDY INVESTIGATING DNA METHYLATION OF THE OXTR IN OCD. FURTHER STUDIES ARE NEEDED TO EVALUATE THE ROLES THAT DNA METHYLATION AND OXYTOCIN PLAY IN OCD. 2016 3 1677 34 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 4 4061 33 MATERNAL ADVERSITIES DURING PREGNANCY AND CORD BLOOD OXYTOCIN RECEPTOR (OXTR) DNA METHYLATION. THE AIM OF THIS STUDY WAS TO INVESTIGATE WHETHER MATERNAL ADVERSITIES AND CORTISOL LEVELS DURING PREGNANCY PREDICT CORD BLOOD DNA METHYLATION OF THE OXYTOCIN RECEPTOR (OXTR). WE COLLECTED CORD BLOOD OF 39 BABIES BORN TO MOTHERS PARTICIPATING IN A CROSS-SECTIONAL STUDY (N = 100) CONDUCTED IN BASEL, SWITZERLAND (2007-10). MOTHERS COMPLETED THE INVENTORY OF LIFE EVENTS (SECOND TRIMESTER: T2), THE EDINBURGH POSTNATAL DEPRESSION SCALE (EPDS, THIRD TRIMESTER: T3), THE TRIER INVENTORY OF CHRONIC STRESS (TICS-K, 1-3 WEEKS POSTPARTUM) AND PROVIDED SALIVA SAMPLES (T2, T3) FOR MATERNAL CORTISOL PROFILES, AS COMPUTED BY THE AREA UNDER THE CURVE WITH RESPECT TO GROUND (AUCG) OR INCREASE (AUCI) FOR THE CORTISOL AWAKENING RESPONSE (CAR) AND FOR DIURNAL CORTISOL PROFILES (DAY). OXTR DNA METHYLATION WAS QUANTIFIED USING SEQUENOM EPITYPER. THE NUMBER OF STRESSFUL LIFE EVENTS (P = 0.032), EPDS SCORE (P = 0.007) AND CORTISOL AUCGS AT T2 (CAR: P = 0.020; DAY: P = 0.024) WERE NEGATIVELY ASSOCIATED WITH OXTR DNA METHYLATION. OUR FINDINGS SUGGEST THAT DISTINCT PRENATAL ADVERSITIES PREDICT DECREASED DNA METHYLATION IN A GENE THAT IS RELEVANT FOR CHILDBIRTH, MATERNAL BEHAVIOR AND WELLBEING OF MOTHER AND OFFSPRING. IF A REDUCED OXTR METHYLATION INCREASES OXTR EXPRESSION, OUR FINDINGS COULD SUGGEST AN EPIGENETIC ADAPTATION TO AN ADVERSE EARLY ENVIRONMENT. 2016 5 4402 37 MODULATION OF NOCICEPTION BY SOCIAL FACTORS IN RODENTS: CONTRIBUTION OF THE OPIOID SYSTEM. RATIONALE: THE OPIOID SYSTEM IS INVOLVED IN THE REGULATION OF SEVERAL BEHAVIORAL AND PHYSIOLOGICAL RESPONSES, CONTROLLING PAIN, REWARD, AND ADDICTIVE BEHAVIORS. OPIOID ADMINISTRATION, DEPENDING ON DRUGS AND DOSES, USUALLY AFFECTS SOCIABILITY REDUCING INTERACTIONS BETWEEN CONSPECIFICS, WHEREAS SOME AFFILIATIVE BEHAVIORS SUCH AS SEXUAL ACTIVITY, SOCIAL GROOMING, AND PLAY BEHAVIOR INCREASE THE ENDOGENOUS OPIOID ACTIVITY. OBJECTIVES: THE POSSIBLE INTERACTION BETWEEN ENDOGENOUS OPIOIDS RELEASED DURING SOCIO/SEXUAL BEHAVIOR AND THEIR ANALGESIC EFFECT ON PAIN RESPONSE IS REVIEWED IN THE RODENT LITERATURE. RESULTS: DIRECT EVIDENCE FOR SOCIALLY MEDIATED OPIOID CHANGES RESULTING IN INCREASE IN NOCICEPTIVE THRESHOLD DERIVES FROM STUDIES EXPLORING THE EFFECTS OF DEFEAT EXPERIENCES, SOCIAL ISOLATION, MATERNAL, SEXUAL BEHAVIOR, AND SOCIAL REUNION AMONG KIN OR FAMILIAR ANIMALS IN LABORATORY RODENTS. INDIRECT EVIDENCE FOR ENDOGENOUS ACTIVATION OF THE OPIOID SYSTEM, POSSIBLY AFFECTING PAIN SENSITIVITY, DERIVES FROM STUDIES INVESTIGATING THE RELEVANCE OF NATURAL SOCIAL REWARD USING THE CONDITIONED PLACE PREFERENCE PROTOCOLS OR ANALYZING ULTRASONIC VOCALIZATIONS ASSOCIATED TO POSITIVE AFFECTIVE CONTEXTS. FINALLY, GENETIC AND EPIGENETIC FACTORS THAT AFFECT THE OPIOID SYSTEM DURING DEVELOPMENT ARE REPORTED TO BE INVOLVED IN MODULATING THE RESPONSE TO SOCIAL STIMULI AS WELL AS NOCICEPTION. CONCLUSIONS: ALL STUDIES HIGHLIGHT THE RELEVANCE OF AFFILIATIVE CONTACT BEHAVIOR BETWEEN CONSPECIFICS THAT IS RESPONSIBLE FOR THE ACTIVATION OF THE ENDOGENOUS MU-OPIOID SYSTEM, INDUCING NOCICEPTIVE THRESHOLD INCREASE. 2012 6 4848 34 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 7 6627 44 UNDERSTANDING RESILIENCE: NEW APPROACHES FOR PREVENTING AND TREATING PTSD. ALL INDIVIDUALS EXPERIENCE STRESSFUL LIFE EVENTS, AND UP TO 84% OF THE GENERAL POPULATION WILL EXPERIENCE AT LEAST ONE POTENTIALLY TRAUMATIC EVENT. IN SOME CASES, ACUTE OR CHRONIC STRESSORS LEAD TO THE DEVELOPMENT OF POSTTRAUMATIC STRESS DISORDER (PTSD) OR OTHER PSYCHOPATHOLOGY; HOWEVER, THE MAJORITY OF PEOPLE ARE RESILIENT TO SUCH EFFECTS. RESILIENCE IS THE ABILITY TO ADAPT SUCCESSFULLY IN THE FACE OF STRESS AND ADVERSITY. A WEALTH OF RESEARCH HAS BEGUN TO IDENTIFY THE GENETIC, EPIGENETIC, NEURAL, AND ENVIRONMENTAL UNDERPINNINGS OF RESILIENCE, AND HAS INDICATED THAT RESILIENCE IS MEDIATED BY ADAPTIVE CHANGES ENCOMPASSING SEVERAL ENVIRONMENTAL FACTORS, NEURAL CIRCUITS, NUMEROUS NEUROTRANSMITTERS, AND MOLECULAR PATHWAYS. THE FIRST PART OF THIS REVIEW FOCUSES ON RECENT FINDINGS REGARDING THE GENETIC, EPIGENETIC, DEVELOPMENTAL, PSYCHOSOCIAL, AND NEUROCHEMICAL FACTORS AS WELL AS NEURAL CIRCUITS AND MOLECULAR PATHWAYS THAT UNDERLIE THE DEVELOPMENT OF RESILIENCE. EMERGING AND EXCITING AREAS OF RESEARCH AND NOVEL METHODOLOGICAL APPROACHES, INCLUDING GENOME-WIDE GENE EXPRESSION STUDIES, IMMUNE, ENDOCANNABINOID, OXYTOCIN, AND GLUTAMATERGIC SYSTEMS, ARE EXPLORED TO HELP DELINEATE INNOVATIVE MECHANISMS THAT MAY CONTRIBUTE TO RESILIENCE. THE SECOND PART REVIEWS SEVERAL INTERVENTIONS AND PREVENTATIVE APPROACHES DESIGNED TO ENHANCE RESILIENCE IN BOTH DEVELOPMENTAL AND ADULT POPULATIONS. SPECIFICALLY, THE REVIEW WILL DELINEATE APPROACHES AIMED TO BOLSTER RESILIENCE IN INDIVIDUALS WITH PTSD. FURTHERMORE, WE DISCUSS NOVEL PHARMACOLOGIC APPROACHES, INCLUDING THE N-METHYL-D-ASPARTATE (NMDA) RECEPTOR KETAMINE AND NEUROPEPTIDE Y (NPY), AS EXCITING NEW PROSPECTS FOR NOT ONLY THE TREATMENT OF PTSD BUT AS NEW TARGETS TO ENHANCE RESILIENCE. OUR GROWING UNDERSTANDING OF RESILIENCE AND INTERVENTIONS WILL HOPEFULLY LEAD TO THE DEVELOPMENT OF NEW STRATEGIES FOR NOT JUST TREATING PTSD BUT ALSO SCREENING AND EARLY IDENTIFICATION OF AT-RISK YOUTH AND ADULTS. TAKEN TOGETHER, EFFORTS AIMED AT DISSEMINATION AND IMPLEMENTATION OF NOVEL INTERVENTIONS TO ENHANCE RESILIENCE WILL HAVE TO KEEP PACE WITH THE GROWTH OF NEW PREVENTIVE AND TREATMENT STRATEGIES. 2016 8 1750 31 EARLY LIFE STRESS AND PEDIATRIC POSTTRAUMATIC STRESS DISORDER. TRAUMATIC STRESS EXPOSURE DURING CRITICAL PERIODS OF DEVELOPMENT MAY HAVE ESSENTIAL AND LONG-LASTING EFFECTS ON THE PHYSICAL AND MENTAL HEALTH OF INDIVIDUALS. TWO THIRDS OF YOUTH ARE EXPOSED TO POTENTIALLY TRAUMATIC EXPERIENCES BY THE AGE OF 17, AND APPROXIMATELY 5% OF ADOLESCENTS MEET LIFETIME CRITERIA FOR POSTTRAUMATIC STRESS DISORDER (PTSD). THE ROLE OF THE STRESS SYSTEM IS THE MAINTENANCE OF HOMEOSTASIS IN THE PRESENCE OF REAL/PERCEIVED AND ACUTE/CHRONIC STRESSORS. EARLY-LIFE STRESS (ELS) HAS AN IMPACT ON NEURONAL BRAIN NETWORKS INVOLVED IN STRESS REACTIONS, AND COULD EXERT A PROGRAMMING EFFECT ON GLUCOCORTICOID SIGNALING. STUDIES ON PEDIATRIC PTSD REVEAL DIVERSE NEUROENDOCRINE RESPONSES TO ADVERSE EVENTS AND RELATED LONG-TERM NEUROENDOCRINE AND EPIGENETIC ALTERATIONS. NEUROENDOCRINE, NEUROIMAGING, AND GENETIC STUDIES IN CHILDREN WITH PTSD AND ELS EXPERIENCES ARE CRUCIAL IN UNDERSTANDING RISK AND RESILIENCE FACTORS, AND ALSO THE NATURAL HISTORY OF PTSD. 2020 9 6478 27 TOPICAL REVIEW: THE EMERGING FIELD OF EPIGENETICS: INFORMING MODELS OF PEDIATRIC TRAUMA AND PHYSICAL HEALTH. OBJECTIVE: TRAUMA EXPERIENCED DURING CHILDHOOD AND ADOLESCENCE HAS BEEN LINKED TO A NUMBER OF CHRONIC MEDICAL CONCERNS. WE HIGHLIGHT MAJOR FINDINGS FROM THE PEDIATRIC TRAUMA LITERATURE TO PROVIDE A MODEL FOR UNDERSTANDING THIS ASSOCIATION. METHODS: STUDIES EXAMINING THE EFFECTS OF TRAUMA WERE SYSTEMATICALLY REVIEWED AND SYNTHESIZED INTO A MODEL PROPOSING A CENTRAL ROLE FOR EPIGENETICS IN THE WAYS THAT CHILDHOOD EXPERIENCES CAN AFFECT HEALTH. RESULTS: EARLY HYPOTHALAMIC PITUITARY ADRENAL (HPA) AXIS RESPONSE MAY IMPACT INITIAL TRAUMA EXPERIENCE, WITH DOWNSTREAM EFFECTS ON POSTTRAUMA ADJUSTMENT REFLECTED IN POSTTRAUMA NEUROBIOLOGY, PSYCHOLOGICAL HEALTH, AND PHYSICAL HEALTH. CONCLUSIONS: PROSPECTIVE RESEARCH WITH CHILDREN AND ADOLESCENTS EXPOSED TO TRAUMA IS NEEDED TO BETTER CHARACTERIZE THE GENETIC AND EPIGENETIC INFLUENCES ON THE COURSE OF HPA AND IMMUNE PROCESSES AS RELATED TO POSTTRAUMA PSYCHOLOGICAL AND PHYSICAL HEALTH OUTCOMES. 2016 10 5200 37 PRENATAL MATERNAL STRESS PREDICTS METHYLATION OF GENES REGULATING THE HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL SYSTEM IN MOTHERS AND NEWBORNS IN THE DEMOCRATIC REPUBLIC OF CONGO. EXPOSURE TO STRESS EARLY IN LIFE PERMANENTLY SHAPES ACTIVITY OF THE HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL (HPA) AXIS AND THE BRAIN. PRENATALLY, GLUCOCORTICOIDS PASS THROUGH THE PLACENTA TO THE FETUS WITH POSTNATAL IMPACTS ON BRAIN DEVELOPMENT, BIRTH WEIGHT (BW), AND HPA AXIS FUNCTIONING. LITTLE IS KNOWN ABOUT THE BIOLOGICAL MECHANISMS BY WHICH PRENATAL STRESS AFFECTS POSTNATAL FUNCTIONING. THIS STUDY ADDRESSES THIS GAP BY EXAMINING THE EFFECT OF CHRONIC STRESS AND TRAUMATIC WAR-RELATED STRESS ON EPIGENETIC CHANGES IN FOUR KEY GENES REGULATING THE HPA AXIS IN NEONATAL CORD BLOOD, PLACENTA, AND MATERNAL BLOOD: CRH, CRHBP, NR3C1, AND FKBP5. PARTICIPANTS WERE 24 MOTHER-NEWBORN DYADS IN THE CONFLICT-RIDDEN REGION OF THE EASTERN DEMOCRATIC REPUBLIC OF CONGO. BW DATA WERE COLLECTED AT DELIVERY AND MATERNAL INTERVIEWS WERE CONDUCTED TO ASSESS CULTURALLY RELEVANT CHRONIC AND WAR-RELATED STRESSORS. CHRONIC STRESS AND WAR TRAUMA HAD WIDESPREAD EFFECTS ON HPA AXIS GENE METHYLATION, WITH SIGNIFICANT EFFECTS OBSERVED AT TRANSCRIPTION FACTOR BINDING (TFB) SITES IN ALL TARGET GENES TESTED. SOME CHANGES IN METHYLATION WERE UNIQUE TO CHRONIC OR WAR STRESS, WHEREAS OTHERS WERE OBSERVED ACROSS BOTH STRESSOR TYPES. MOREOVER, STRESS EXPOSURES IMPACTED MATERNAL AND FETAL TISSUES DIFFERENTLY, SUPPORTING THEORETICAL MODELS THAT STRESS IMPACTS VARY ACCORDING TO LIFE PHASE. METHYLATION IN SEVERAL NR3C1 AND CRH CPG SITES, ALL LOCATED AT TFB SITES, WAS ASSOCIATED WITH BW. THESE FINDINGS SUGGEST THAT PRENATAL STRESS EXPOSURE IMPACTS DEVELOPMENT VIA EPIGENETIC CHANGES IN HPA AXIS GENES. 2016 11 632 38 BIOLOGICAL CORRELATES OF EARLY LIFE STRESSFUL EVENTS IN MAJOR DEPRESSIVE DISORDER. MAJOR DEPRESSIVE DISORDER (MDD) IS THE MOST COMMON PSYCHIATRIC DISORDER AND RESPONDS FOR IMPORTANT PSYCHOSOCIAL CONSEQUENCES. STRESSFUL LIFE EVENTS, ESPECIALLY EARLY LIFE STRESS (ELS), CONTRIBUTE TO AN INCREASED PROBABILITY TO DEVELOP MDD, LEADING IN PARTICULAR TO SEVERE AND CHRONIC MANIFESTATION AND UNFAVORABLE TREATMENT OUTCOME. THE ASSOCIATION BETWEEN ELS AND MDD SEEMS TO HAVE BIOLOGICAL BASES, CONSISTING IN DYSREGULATIONS OCCURRING AT DIFFERENT LEVELS. THE AIM OF THIS NARRATIVE REVIEW IS TO PROPOSE AN OVERVIEW OF THE LITERATURE RANGING FROM GENETIC, EPIGENETIC, EXPRESSION AND PROTEIN TO NEUROIMAGING CORRELATES UNDERLYING THIS RELATIONSHIP. A SEARCH ON PUBMED OF STUDIES ASSESSING BIOLOGICAL CORRELATES OF ELS IN MDD DEVELOPMENT, FOCUSING ON HUMAN STUDIES CONDUCTED IN BOTH PERIPHERAL AND BRAIN TISSUES, WAS PERFORMED. EVIDENCE INDICATED THAT THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND THE SEROTONERGIC, DOPAMINERGIC, NEUROTROPHIN AND OXYTOCIN SYSTEMS MIGHT PLAY A ROLE IN THE MEDIATION BETWEEN ELS AND MDD. THE MOST CONSISTENT RESULTS WERE FOUND FOR GENETIC AND EPIGENETIC STUDIES AND INDICATED A JOINT INVOLVEMENT OF THE SYSTEMS MENTIONED. EXPRESSION STUDIES ARE LESS NUMEROUS AND POINT TO AN INVOLVEMENT OF STRESS-RELATED SYSTEMS. CONCERNING PROTEIN STUDIES, THE MAIN MEDIATORS ARE MARKERS RELATED TO THE INFLAMMATORY AND IMMUNE SYSTEMS. NEUROIMAGING STUDIES AIMING AT EVALUATING BRAIN ALTERATIONS CONNECTING ELS AND MDD IN RELATION TO BIOMARKERS INDICATED THE HIPPOCAMPUS, THE AMYGDALA AND THE FRONTAL CORTEX AS IMPORTANT ANATOMICAL MEDIATORS. THESE FINDINGS CAN BUILD THE BASES FOR FUTURE RESEARCH AND CLINICAL INTERVENTIONS; INDEED, THE CLARIFICATION OF BIOLOGICAL MECHANISMS MEDIATING THE RELATIONSHIP BETWEEN ELS AND MDD CAN LEAD TO NEW AND INDIVIDUALIZED PREVENTIVE AND THERAPEUTIC POSSIBILITIES. 2021 12 4632 31 NEUROIMAGING GENETIC APPROACHES TO POSTTRAUMATIC STRESS DISORDER. NEUROIMAGING GENETIC STUDIES THAT ASSOCIATE GENETIC AND EPIGENETIC VARIATION WITH NEURAL ACTIVITY OR STRUCTURE PROVIDE AN OPPORTUNITY TO LINK GENES TO PSYCHIATRIC DISORDERS, OFTEN BEFORE PSYCHOPATHOLOGY IS DISCERNABLE IN BEHAVIOR. HERE WE REVIEW NEUROIMAGING GENETICS STUDIES WITH PARTICIPANTS WHO HAVE POSTTRAUMATIC STRESS DISORDER (PTSD). RESULTS SHOW THAT GENES RELATED TO THE PHYSIOLOGICAL STRESS RESPONSE (E.G., GLUCOCORTICOID RECEPTOR AND ACTIVITY, NEUROENDOCRINE RELEASE), LEARNING AND MEMORY (E.G., PLASTICITY), MOOD, AND PAIN PERCEPTION ARE TIED TO NEURAL INTERMEDIATE PHENOTYPES ASSOCIATED WITH PTSD. THESE GENES ARE ASSOCIATED WITH AND SOMETIMES PREDICT NEURAL STRUCTURE AND FUNCTION IN AREAS INVOLVED IN ATTENTION, EXECUTIVE FUNCTION, MEMORY, DECISION-MAKING, EMOTION REGULATION, SALIENCE OF POTENTIAL THREATS, AND PAIN PERCEPTION. EVIDENCE SUGGESTS THESE RISK POLYMORPHISMS AND NEURAL INTERMEDIATE PHENOTYPES ARE VULNERABILITIES TOWARD DEVELOPING PTSD IN THE AFTERMATH OF TRAUMA, OR VULNERABILITIES TOWARD PARTICULAR SYMPTOMS ONCE PTSD HAS DEVELOPED. WORK DISTINGUISHING BETWEEN THE RE-EXPERIENCING AND DISSOCIATIVE SUB-TYPES OF PTSD, AND EXAMINING OTHER PTSD SYMPTOM CLUSTERS IN ADDITION TO THE RE-EXPERIENCING AND HYPERAROUSAL SYMPTOMS, WILL FURTHER CLARIFY NEUROBIOLOGICAL MECHANISMS AND INCONSISTENT FINDINGS. FURTHERMORE, AN EXCITING POSSIBILITY IS THAT GENETIC ASSOCIATIONS WITH PTSD MAY EVENTUALLY BE UNDERSTOOD THROUGH DIFFERENTIAL INTERMEDIATE PHENOTYPES OF NEURAL CIRCUIT STRUCTURE AND FUNCTION, POSSIBLY UNDERLYING THE DIFFERENT SYMPTOM CLUSTERS SEEN WITHIN PTSD. 2016 13 6266 29 THE NEUROBIOLOGY OF SUICIDE. THE STRESS-DIATHESIS MODEL POSITS THAT SUICIDE IS THE RESULT OF AN INTERACTION BETWEEN STATE-DEPENDENT (ENVIRONMENTAL) STRESSORS AND A TRAIT-LIKE DIATHESIS OR SUSCEPTIBILITY TO SUICIDAL BEHAVIOUR, INDEPENDENT OF PSYCHIATRIC DISORDERS. FINDINGS FROM POST-MORTEM STUDIES OF THE BRAIN AND FROM GENOMIC AND IN-VIVO NEUROIMAGING STUDIES INDICATE A BIOLOGICAL BASIS FOR THIS DIATHESIS, INDICATING THE IMPORTANCE OF NEUROBIOLOGICAL SCREENING AND INTERVENTIONS, IN ADDITION TO COGNITIVE AND MOOD INTERVENTIONS, IN THE PREVENTION OF SUICIDE. EARLY-LIFE ADVERSITY AND EPIGENETIC MECHANISMS MIGHT EXPLAIN SOME OF THE LINK BETWEEN SUICIDE RISK AND BRAIN CIRCUITRY AND NEUROCHEMISTRY ABNORMALITIES. RESULTS FROM A RANGE OF STUDIES USING DIVERSE DESIGNS AND POST-MORTEM AND IN-VIVO TECHNIQUES SHOW IMPAIRMENTS OF THE SEROTONIN NEUROTRANSMITTER SYSTEM AND THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS STRESS-RESPONSE SYSTEM IN THE DIATHESIS FOR SUICIDAL BEHAVIOUR. THESE IMPAIRMENTS MANIFEST AS IMPAIRED COGNITIVE CONTROL OF MOOD, PESSIMISM, REACTIVE AGGRESSIVE TRAITS, IMPAIRED PROBLEM SOLVING, OVER-REACTIVITY TO NEGATIVE SOCIAL SIGNS, EXCESSIVE EMOTIONAL PAIN, AND SUICIDAL IDEATION, LEADING TO SUICIDAL BEHAVIOUR. BIOMARKERS RELATED TO THE DIATHESIS MIGHT HELP TO INFORM RISK-ASSESSMENT PROCEDURES AND TREATMENT CHOICE IN THE PREVENTION OF SUICIDE. 2014 14 4622 24 NEUROBIOLOGICAL DEVELOPMENT IN THE CONTEXT OF CHILDHOOD TRAUMA. NEUROBIOLOGICAL SYSTEMS MAY BE PARTICULARLY SUSCEPTIBLE TO DELETERIOUS IMPACT OF CHILDHOOD TRAUMA, AND THE IMPACT OF CHILDHOOD TRAUMA ON DEVELOPMENT AND SUBSEQUENT FUNCTIONAL OUTCOMES ACROSS THE LIFESPAN HAS BEEN WELL-DOCUMENTED. THE CURRENT REVIEW ADDRESSES THE NEUROBIOLOGICAL IMPACT OF EXPOSURE TO INTERPERSONAL TRAUMA IN CHILDHOOD IN THE CONTEXT OF EXECUTIVE FUNCTION, EMOTION REGULATION, AND DISSOCIATION/INTEROCEPTIVE AWARENESS. SUBSEQUENT RISK FOR PTSD AND DEPRESSION IS ALSO DISCUSSED. THE PATHWAY OF RISK FROM CHILDHOOD TRAUMA TO THESE COGNITIVE, EMOTIONAL, AND PSYCHIATRIC OUTCOMES IS ADDRESSED IN TERMS OF POTENTIAL STRUCTURAL AND FUNCTIONAL ALTERATIONS WITHIN THE HIPPOCAMPUS, PREFRONTAL CORTEX, AND AMYGDALA RESULTING FROM CHRONIC OR REPEATED ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND ITS INTERACTION WITH AND INFLUENCE ON GENETIC AND EPIGENETIC PROCESSES DURING SENSITIVE PERIODS OF DEVELOPMENT. IMPLICATIONS FOR PRACTICE ARE DISCUSSED. 2017 15 1821 41 EFFECTS OF CHRONIC SOCIAL DEFEAT ON BEHAVIORAL AND NEURAL CORRELATES OF SOCIALITY: VASOPRESSIN, OXYTOCIN AND THE VASOPRESSINERGIC V1B RECEPTOR. CHRONIC SOCIAL STRESS IN RODENTS PRODUCES BEHAVIORAL AND NEUROENDOCRINE PATTERNS ANALOGOUS TO SYMPTOMS ASSOCIATED WITH PSYCHOPATHOLOGIES IN HUMANS. CHRONIC SOCIAL DEFEAT IN MICE HAS BEEN USED TO STUDY THE GENETIC AND EPIGENETIC PRECURSORS OF STRESS-RELATED SOCIAL DISORDERS. THE NEUROPEPTIDES ARGININE VASOPRESSIN (AVP) AND OXYTOCIN (OT) ARE RELEASED IN CENTRAL TARGETS TO MODULATE ANTI- AND PRO-SOCIAL BEHAVIORS, RESPECTIVELY. AVP BINDS TO V1A AND V1B RECEPTORS (V1BRS) IN DISCRETE BRAIN REGIONS RELATED TO ANXIETY, DEPRESSION AND AFFILIATIVE BEHAVIORS. RECENT EVIDENCE SUGGESTS THAT V1BRS ARE INVOLVED IN STRESS AND ANXIETY AND MAY BE AN ATTRACTIVE TARGET FOR THE TREATMENT OF ASSOCIATED DISORDERS. IN THE PRESENT SERIES OF EXPERIMENTS, WE AIMED TO EVALUATE THE EFFECTS OF CHRONIC SOCIAL DEFEAT STRESS ON: 1) ANXIETY-RELATED BEHAVIORS IN A SOCIAL INVESTIGATION PARADIGM AND THEIR POTENTIAL MODULATION BY AN ACUTE DOSE OF SSR149415, A V1BR ANTAGONIST; 2) AVP AND FOS PROTEIN LEVELS IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS (PVN) AND; 3) AVP- AND OT-RECEPTOR (OTR) MRNA LEVELS IN BRAIN REGIONS ASSOCIATED WITH SOCIALITY. WHEN COMPARED TO UNDEFEATED ANIMALS, SOCIALLY DEFEATED MICE EXHIBITED AN ANXIOGENIC BEHAVIORAL PROFILE TOWARDS A NOVEL MALE CONSPECIFIC, WITH SSR149415 PARTLY ATTENUATING THESE EFFECTS. HISTOCHEMISTRY USING IMMUNOFLUORESCENCE SHOWED DEFEAT PRODUCED SIGNIFICANT ELEVATIONS OF FOS AND DOUBLE LABELING OF AVP AND FOS PROTEINS IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS (PVN). SSR149415 ATTENUATED THE EFFECTS OF DEFEAT ON FOS AND AVP/FOS DOUBLE LABELING, CONSISTENT WITH AN ANXIOLYTIC EFFECT. DEFEATED MICE SHOWED ELEVATED LEVELS OF OTR MRNA LEVELS IN THE LATERAL SEPTUM (LS) IN ADDITION TO INCREASED V1BR AND OTR MRNA IN THE MEDIAL AMYGDALA (MEA). WE SUGGEST THE INVOLVEMENT OF V1BRS AND OTRS IN A CIRCUIT INVOLVING THE PVN, MEA AND LS IN THE EFFECTS OF DEFEAT ON SOCIALITY. SSR149415 ATTENUATED ANXIOGENESIS IN THE SOCIAL INVESTIGATION MODEL AND BOTH FOS AND AVP/FOS LABELING, SUGGESTING V1BRS ARE AN ATTRACTIVE TARGET FOR THE TREATMENT OF ANXIETY IN GENERAL AND DISORDERS OF SOCIALITY IN PARTICULAR. 2011 16 5310 29 PSYCHOBIOLOGY AND MOLECULAR GENETICS OF RESILIENCE. EVERY INDIVIDUAL EXPERIENCES STRESSFUL LIFE EVENTS. IN SOME CASES ACUTE OR CHRONIC STRESS LEADS TO DEPRESSION AND OTHER PSYCHIATRIC DISORDERS, BUT MOST PEOPLE ARE RESILIENT TO SUCH EFFECTS. RECENT RESEARCH HAS BEGUN TO IDENTIFY THE ENVIRONMENTAL, GENETIC, EPIGENETIC AND NEURAL MECHANISMS THAT UNDERLIE RESILIENCE, AND HAS SHOWN THAT RESILIENCE IS MEDIATED BY ADAPTIVE CHANGES IN SEVERAL NEURAL CIRCUITS INVOLVING NUMEROUS NEUROTRANSMITTER AND MOLECULAR PATHWAYS. THESE CHANGES SHAPE THE FUNCTIONING OF THE NEURAL CIRCUITS THAT REGULATE REWARD, FEAR, EMOTION REACTIVITY AND SOCIAL BEHAVIOUR, WHICH TOGETHER ARE THOUGHT TO MEDIATE SUCCESSFUL COPING WITH STRESS. 2009 17 6626 31 UNDERSTANDING RESILIENCE. RESILIENCE IS THE ABILITY TO ADAPT SUCCESSFULLY IN THE FACE OF STRESS AND ADVERSITY. STRESSFUL LIFE EVENTS, TRAUMA, AND CHRONIC ADVERSITY CAN HAVE A SUBSTANTIAL IMPACT ON BRAIN FUNCTION AND STRUCTURE, AND CAN RESULT IN THE DEVELOPMENT OF POSTTRAUMATIC STRESS DISORDER (PTSD), DEPRESSION AND OTHER PSYCHIATRIC DISORDERS. HOWEVER, MOST INDIVIDUALS DO NOT DEVELOP SUCH ILLNESSES AFTER EXPERIENCING STRESSFUL LIFE EVENTS, AND ARE THUS THOUGHT TO BE RESILIENT. RESILIENCE AS SUCCESSFUL ADAPTATION RELIES ON EFFECTIVE RESPONSES TO ENVIRONMENTAL CHALLENGES AND ULTIMATE RESISTANCE TO THE DELETERIOUS EFFECTS OF STRESS, THEREFORE A GREATER UNDERSTANDING OF THE FACTORS THAT PROMOTE SUCH EFFECTS IS OF GREAT RELEVANCE. THIS REVIEW FOCUSES ON RECENT FINDINGS REGARDING GENETIC, EPIGENETIC, DEVELOPMENTAL, PSYCHOSOCIAL, AND NEUROCHEMICAL FACTORS THAT ARE CONSIDERED ESSENTIAL CONTRIBUTORS TO THE DEVELOPMENT OF RESILIENCE. NEURAL CIRCUITS AND PATHWAYS INVOLVED IN MEDIATING RESILIENCE ARE ALSO DISCUSSED. THE GROWING UNDERSTANDING OF RESILIENCE FACTORS WILL HOPEFULLY LEAD TO THE DEVELOPMENT OF NEW PHARMACOLOGICAL AND PSYCHOLOGICAL INTERVENTIONS FOR ENHANCING RESILIENCE AND MITIGATING THE UNTOWARD CONSEQUENCES. 2013 18 3001 33 GENETIC, EPIGENETIC AND ENVIRONMENTAL IMPACT ON SEX DIFFERENCES IN SOCIAL BEHAVIOR. THE FIELD OF BEHAVIORAL NEUROENDOCRINOLOGY HAS GENERATED THOUSANDS OF STUDIES THAT INDICATE DIFFERENCES IN BRAIN STRUCTURE AND REACTIVITY TO GONADAL STEROIDS THAT PRODUCE SEX-SPECIFIC PATTERNS OF SOCIAL BEHAVIOR. HOWEVER, RAPIDLY EMERGING EVIDENCE SHOWS THAT GENETIC POLYMORPHISMS AND RESULTING DIFFERENCES IN THE EXPRESSION OF NEUROACTIVE PEPTIDES AND RECEPTORS AS WELL AS EARLY-LIFE EXPERIENCE AND EPIGENETIC CHANGES ARE IMPORTANT MODIFIERS OF SOCIAL BEHAVIOR. FURTHERMORE, DUE TO ITS INHERENT COMPLEXITY, THE NEUROCHEMICAL MECHANISMS UNDERLYING SEX DIFFERENCES IN SOCIAL BEHAVIOR ARE USUALLY STUDIED IN A TIGHTLY REGULATED LABORATORY SETTING RATHER THAN IN COMPLEX ENVIRONMENTS. IMPORTANTLY, SPECIFIC HORMONES MAY ELICIT A RANGE OF DIFFERENT BEHAVIORS DEPENDING ON THE CUES PRESENT IN THESE ENVIRONMENTS. FOR EXAMPLE, INDIVIDUALS EXPOSED TO A PSYCHOSOCIAL STRESSOR MAY RESPOND DIFFERENTLY TO THE EFFECTS OF A GONADAL STEROID THAN THOSE NOT EXPOSED TO CHRONIC STRESS. THE OBJECTIVE OF THIS REVIEW IS NOT TO RE-EXAMINE THE ACTIVATIONAL EFFECTS OF HORMONES ON SEX DIFFERENCES IN SOCIAL BEHAVIOR BUT RATHER TO CONSIDER HOW GENETIC AND ENVIRONMENTAL FACTORS MODIFY THE EFFECTS OF HORMONES ON BEHAVIOR. WE WILL FOCUS ON ESTROGEN AND ITS RECEPTORS BUT CONSIDERATION IS ALSO GIVEN TO THE ROLE OF ANDROGENS. FURTHERMORE, WE HAVE LIMITED OUR DISCUSSIONS TO THE IMPORTANCE OF OXYTOCIN AND VASOPRESSIN AS TARGETS OF GONADAL STEROIDS AND HOW THESE EFFECTS ARE MODIFIED BY GENETIC AND EXPERIENTIAL SITUATIONS. TAKEN TOGETHER, THE DATA CLEARLY UNDERSCORE THE NEED TO EXPAND RESEARCH INITIATIVES TO CONSIDER GENE-ENVIRONMENT INTERACTIONS FOR BETTER UNDERSTANDING OF THE NEUROBIOLOGY OF SEX DIFFERENCES IN SOCIAL BEHAVIOR. 2009 19 3463 34 HYPOTHALAMIC-PITUITARY-ADRENAL AND HYPOTHALAMIC-PITUITARY-GONADAL AXES: SEX DIFFERENCES IN REGULATION OF STRESS RESPONSIVITY. GONADAL HORMONES PLAY A KEY ROLE IN THE ESTABLISHMENT, ACTIVATION, AND REGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS. BY INFLUENCING THE RESPONSE AND SENSITIVITY TO RELEASING FACTORS, NEUROTRANSMITTERS, AND HORMONES, GONADAL STEROIDS HELP ORCHESTRATE THE GAIN OF THE HPA AXIS TO FINE-TUNE THE LEVELS OF STRESS HORMONES IN THE GENERAL CIRCULATION. FROM EARLY LIFE TO ADULTHOOD, GONADAL STEROIDS CAN DIFFERENTIALLY AFFECT THE HPA AXIS, RESULTING IN SEX DIFFERENCES IN THE RESPONSIVITY OF THIS AXIS. THE HPA AXIS INFLUENCES MANY PHYSIOLOGICAL FUNCTIONS MAKING AN ORGANISM'S RESPONSE TO CHANGES IN THE ENVIRONMENT APPROPRIATE FOR ITS REPRODUCTIVE STATUS. ALTHOUGH THE ACUTE HPA RESPONSE TO STRESSORS IS A BENEFICIAL RESPONSE, CONSTANT ACTIVATION OF THIS CIRCUITRY BY CHRONIC OR TRAUMATIC STRESSFUL EPISODES MAY LEAD TO A DYSREGULATION OF THE HPA AXIS AND CAUSE PATHOLOGY. COMPARED TO MALES, FEMALE MICE AND RATS SHOW A MORE ROBUST HPA AXIS RESPONSE, AS A RESULT OF CIRCULATING ESTRADIOL LEVELS WHICH ELEVATE STRESS HORMONE LEVELS DURING NON-THREATENING SITUATIONS, AND DURING AND AFTER STRESSORS. FLUCTUATING LEVELS OF GONADAL STEROIDS IN FEMALES ACROSS THE ESTROUS CYCLE ARE A MAJOR FACTOR CONTRIBUTING TO SEX DIFFERENCES IN THE ROBUSTNESS OF HPA ACTIVITY IN FEMALES COMPARED TO MALES. MOREOVER, GONADAL STEROIDS MAY ALSO CONTRIBUTE TO EPIGENETIC AND ORGANIZATIONAL INFLUENCES ON THE HPA AXIS EVEN BEFORE PUBERTY. CORRESPONDINGLY, CROSSTALK BETWEEN THE HYPOTHALAMIC-PITUITARY-GONADAL (HPG) AND HPA AXES COULD LEAD TO ABNORMALITIES OF STRESS RESPONSES. IN HUMANS, A DYSREGULATED STRESS RESPONSE IS ONE OF THE MOST COMMON SYMPTOMS SEEN ACROSS MANY NEUROPSYCHIATRIC DISORDERS, AND AS A RESULT, SUCH INTERACTIONS MAY EXACERBATE PERIPHERAL PATHOLOGIES. IN THIS REVIEW, WE DISCUSS THE HPA AND HPG AXES AND REVIEW HOW GONADAL STEROIDS INTERACT WITH THE HPA AXIS TO REGULATE THE STRESS CIRCUITRY DURING ALL STAGES IN LIFE. 2017 20 1754 32 EARLY LIFE STRESS, THE DEVELOPMENT OF AGGRESSION AND NEUROENDOCRINE AND NEUROBIOLOGICAL CORRELATES: WHAT CAN WE LEARN FROM ANIMAL MODELS? EARLY LIFE STRESS (CHILD AND ADOLESCENT ABUSE, NEGLECT AND TRAUMA) INDUCES ROBUST ALTERATIONS IN EMOTIONAL AND SOCIAL FUNCTIONING RESULTING IN ENHANCED RISK FOR THE DEVELOPMENT OF PSYCHOPATHOLOGIES SUCH AS MOOD AND AGGRESSIVE DISORDERS. HERE, AN OVERVIEW IS GIVEN ON RECENT FINDINGS IN PRIMATE AND RODENT MODELS OF EARLY LIFE STRESS, DEMONSTRATING THAT CHRONIC DEPRIVATION OF EARLY MATERNAL CARE AS WELL AS CHRONIC DEPRIVATION OF EARLY PHYSICAL INTERACTIONS WITH PEERS ARE PROFOUND RISK FACTORS FOR THE DEVELOPMENT OF INAPPROPRIATE AGGRESSIVE BEHAVIORS. ALTERATIONS IN THE HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL (HPA), VASOPRESSIN AND SEROTONIN SYSTEMS AND THEIR RELEVANCE FOR THE REGULATION OF AGGRESSION ARE DISCUSSED. DATA SUGGEST THAT SOCIAL DEPRIVATION-INDUCED INAPPROPRIATE FORMS OF AGGRESSION ARE ASSOCIATED WITH HIGH OR LOW HPA AXIS (RE)ACTIVITY AND A GENERALLY LOWER FUNCTIONING OF THE SEROTONIN SYSTEM IN ADULTHOOD. MOREOVER, GENETIC AND EPIGENETIC MODIFICATIONS IN HPA AND SEROTONIN SYSTEMS INFLUENCE THE OUTCOME OF EARLY LIFE STRESS AND MAY EVEN MODERATE ADVERSE EFFECTS OF EARLY SOCIAL DEPRIVATION ON AGGRESSION. A MORE COMPREHENSIVE STUDY OF AGGRESSION, NEUROENDOCRINE, NEUROBIOLOGICAL AND (EPI)GENETIC CORRELATES OF EARLY LIFE STRESS USING ANIMAL MODELS IS NECESSARY TO PROVIDE A BETTER UNDERSTANDING OF THE INVASIVE AGGRESSIVE DEFICITS OBSERVED IN HUMANS EXPOSED TO CHILD MALTREATMENT. 2009