1 5970 85 TESTOSTERONE ACTS WITHIN THE MEDIAL AMYGDALA OF RATS TO REDUCE INNATE FEAR TO PREDATOR ODOR AKIN TO THE EFFECTS OF TOXOPLASMA GONDII INFECTION. RATS INFECTED WITH THE PROTOZOAN TOXOPLASMA GONDII EXHIBIT A REDUCED AVERSION TO CAT ODOR. THIS BEHAVIORAL CHANGE IS THOUGHT TO INCREASE TROPHIC TRANSMISSION OF THE PARASITE. INFECTED MALE RATS ALSO SHOW A GREATER TESTICULAR SYNTHESIS OF TESTOSTERONE AND EPIGENETIC CHANGE IN ARGININE VASOPRESSIN WITHIN THE MEDIAL AMYGDALA. HERE, WE SHOW THAT EXOGENOUS SUPPLY OF TESTOSTERONE WITHIN MEA OF UNINFECTED CASTRATES RECAPITULATES REDUCTION IN INNATE FEAR AKIN TO BEHAVIORAL CHANGE ATTRIBUTED TO THE PARASITE. WE ALSO SHOW THAT CASTRATION POST ESTABLISHMENT OF CHRONIC INFECTION PRECLUDES CHANGES IN FEAR AND MEDIAL AMYGDALA ARGININE VASOPRESSIN IN THE INFECTED MALE RATS. THESE OBSERVATIONS SUPPORT THE ROLE OF GONADAL HORMONES AND PURSUANT NEUROENDOCRINE CHANGES IN MEDIATING THE LOSS OF FEAR IN THE INFECTED RATS. THIS WORK ALSO DEMONSTRATES THAT TESTOSTERONE ACTING SPECIFICALLY WITHIN THE MEDIAL AMYGDALA SUFFICIENTLY EXPLAINS REDUCED DEFENSIVE BEHAVIORS OFTEN OBSERVED DURING THE APPETITIVE COMPONENT OF REPRODUCTIVE BEHAVIORS. 2020 2 6267 22 THE NEUROENDOCRINOLOGY OF STRESS: A NEVER ENDING STORY. EVOLUTIONARY SUCCESS DEPENDS ON OUR ABILITY TO ADAPT TO CHANGING CIRCUMSTANCES. THE NEUROENDOCRINE RESPONSE TO STRESS IS AN EXCELLENT EXAMPLE OF A PLASTIC SYSTEM THAT RESPONDS TO THREATS TO HOMEOSTASIS AND ALTERS ITS OUTPUT TO MEET CURRENT AND EXPECTED FUTURE DEMANDS. AT THE LEVEL OF THE HYPOTHALAMUS, THE CORTICOTROPH SECRETAGOGUES CORTICOTROPHIN-RELEASING HORMONE (CRH) AND ARGININE VASOPRESSIN (AVP) RESPOND RAPIDLY TO AN ACUTE STRESSOR BUT, FOLLOWING CHRONIC STRESS, THEY ADAPT WITH A REDUCTION OF CRH BUT A MAJOR INCREASE IN AVP. THE RELEASE OF CRH AND AVP ACTIVATES PRO-OPIOMELANOCORTIN IN ANTERIOR PITUITARY CORTICOTROPH CELLS AND THE RELEASE OF ADRENOCORTICOTROPHIC HORMONE INTO PERIPHERAL BLOOD FROM WHERE IT TARGETS RECEPTORS IN THE ADRENAL CORTEX TO RELEASE GLUCOCORTICOID HORMONES. THESE HORMONES (I.E. CORTICOSTERONE IN THE RAT AND CORTISOL IN MAN) ARE RELEASED IN A PULSATILE ULTRADIAN PATTERN WHICH DEFINES THE NORMAL CIRCADIAN RHYTHM. THE FREQUENCY OF THE PULSES IS INCREASED UNDER STATES OF CHRONIC STRESS, AND IN RATS WITH GENETICALLY DETERMINED HYPER-RESPONSIVENESS OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS. INTERESTINGLY, NEONATAL INFLUENCES CAN ALSO PROGRAMME ALTERATIONS IN ULTRADIAN RHYTHMICITY, IMPLICATING EPIGENETIC FACTORS IN ITS REGULATION. AT THE LEVEL OF TISSUE RECEPTORS, THE ALTERATION IN PATTERN OF GLUCOCORTICOID ULTRADIAN RHYTHM HAS DIFFERENTIAL EFFECTS ON MINERALOCORTICOID RECEPTOR AND GLUCOCORTICOID RECEPTOR (GR) BINDING TO DNA AND OFFERS A MECHANISM FOR TISSUE SPECIFIC RESPONSES TO ALTERED GLUCOCORTICOID DYNAMICS. THE EFFECTS OF NEONATAL EXPERIENCE ARE NOT ONLY SEEN AT THE LEVEL OF CRH AND GR REGULATION, BUT ALSO ARE EVIDENT IN BEHAVIOURAL RESPONSES TO STRESS AND IN THE RESPONSIVENESS OF BRAIN STEM SEROTONERGIC PATHWAYS, AS MEASURED BY TRYPTOPHAN HYDROXYLASE MRNA IN THE BRAIN STEM. 2008 3 1821 21 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 4 2251 17 EPIGENETIC MODULATION OF VASOPRESSIN EXPRESSION IN HEALTH AND DISEASE. VASOPRESSIN IS A UBIQUITOUS MOLECULE PLAYING AN IMPORTANT ROLE IN A WIDE RANGE OF PHYSIOLOGICAL PROCESSES THEREBY IMPLICATED IN THE PATHOMECHANISM OF MANY DISORDERS. ITS EFFECT IS WELL CHARACTERIZED THROUGH V2 RECEPTORS, WHICH REGULATES THE WATER RESORPTION IN KIDNEY, WHILE ITS VASOCONSTRICTORY EFFECT THROUGH V1A RECEPTOR ALSO RECEIVED A LOT OF ATTENTION IN THE MAINTENANCE OF BLOOD PRESSURE DURING SHOCK. HOWEVER, THE MOST STRIKING IS ITS CENTRAL EFFECT BOTH THROUGH THE V1B RECEPTORS IN STRESS-AXIS REGULATION AS WELL AS THROUGH V1A RECEPTORS REGULATING MANY ASPECTS OF OUR BEHAVIOR (E.G., SOCIAL BEHAVIOR, LEARNING AND MEMORY). VASOPRESSIN HAS BEEN IMPLICATED IN THE DEVELOPMENT OF DEPRESSION, DUE TO ITS CONNECTION WITH CHRONIC STRESS, AS WELL AS SCHIZOPHRENIA BECAUSE OF ITS INVOLVEMENT IN SOCIAL INTERACTIONS AND MEMORY PROCESSES. EPIGENETIC CHANGES MAY ALSO PLAY A ROLE IN THE DEVELOPMENT OF THESE DISORDERS. THE POSSIBLE MECHANISM INCLUDES DNA METHYLATION, HISTONE MODIFICATION AND/OR MICRO RNAS, AND THESE POSSIBLE REGULATIONS WILL BE IN THE FOCUS OF OUR PRESENT REVIEW. 2021 5 4649 19 NEUROPEPTIDES AND NEUROPEPTIDE RECEPTORS: DRUG TARGETS, AND PEPTIDE AND NON-PEPTIDE LIGANDS: A TRIBUTE TO PROF. DIETER SEEBACH. THE NUMBER OF NEUROPEPTIDES AND THEIR CORRESPONDING RECEPTORS HAS INCREASED STEADILY OVER THE LAST FOURTY YEARS: INITIALLY, PEPTIDES WERE ISOLATED FROM GUT OR BRAIN (E.G., SUBSTANCE P, SOMATOSTATIN), THEN BY TARGETED MINING IN SPECIFIC REGIONS (E.G., CORTISTATIN, OREXIN IN THE BRAIN), OR BY DEORPHANIZATION OF G-PROTEIN-COUPLED RECEPTORS (GPCRS; OREXIN, GHRELIN RECEPTORS) AND THROUGH THE COMPLETION THE HUMAN GENOME PROJECT. NEUROPEPTIDES (AND THEIR RECEPTORS) HAVE REGIONALLY RESTRICTED DISTRIBUTIONS IN THE CENTRAL AND PERIPHERAL NERVOUS SYSTEM. THE NEUROPEPTIDE SIGNALING IS SOMEWHAT MORE DISTINCT SPATIALLY THAN SIGNALING WITH CLASSICAL, LOW-MOLECULAR-WEIGHT NEUROTRANSMITTERS THAT ARE MORE WIDELY EXPRESSED, AND, THEREFORE, ONE ASSUMES THAT DRUGS ACTING AT NEUROPEPTIDE RECEPTORS MAY HAVE MORE SELECTIVE PHARMACOLOGICAL ACTIONS WITH POSSIBLY FEWER SIDE EFFECTS THAN DRUGS ACTING ON GLUTAMATERGIC, GABAERGIC, MONOAMINERGIC, OR CHOLINERGIC SYSTEMS. NEUROPEPTIDE RECEPTORS, WHICH MAY HAVE A FEW OR MULTIPLE SUBTYPES AND SPLICE VARIANTS, BELONG ALMOST EXCLUSIVELY TO THE GPCR FAMILY ALSO KNOWN AS SEVEN-TRANSMEMBRANE RECEPTORS (7TM), A FAVORITE CLASS OF DRUG TARGETS IN THE PHARMACEUTICAL INDUSTRY. MOST NEUROPEPTIDES ARE CO-STORED AND CO-RELEASED WITH CLASSIC NEUROTRANSMITTERS, ALBEIT OFTEN ONLY AT HIGHER FREQUENCIES OF STIMULATION OR AT BURSTING ACTIVITY, THUS RESTRICTING THE NEUROPEPTIDE SIGNALING TO SPECIFIC CIRCUMSTANCES, ANOTHER REASON TO ASSUME THAT NEUROPEPTIDE DRUG MIMICS MAY HAVE LESS SIDE EFFECTS. NEUROPEPTIDES POSSESS A WIDE SPECTRUM OF FUNCTIONS FROM NEUROHORMONE, NEUROTRANSMITTER TO GROWTH FACTOR, BUT ALSO AS KEY INFLAMMATORY MEDIATORS. NEUROPEPTIDES BECOME 'ACTIVE' WHEN THE NERVOUS SYSTEM IS CHALLENGED, E.G., BY STRESS, INJURY, DRUG ABUSE, OR NEUROPSYCHIATRIC DISORDERS WITH GENETIC, EPIGENETIC, AND/OR ENVIRONMENTAL COMPONENTS. THE UNSUSPECTED NUMBER OF TRUE NEUROPEPTIDES AND THEIR COGNATE RECEPTORS PROVIDES OPPORTUNITIES TO IDENTIFY NOVEL TARGETS FOR THE TREATMENT OF BOTH CENTRAL AND PERIPHERAL NERVOUS SYSTEM DISORDERS. BOTH, RECEPTOR SUBTYPE-SELECTIVE ANTAGONISTS AND AGONISTS ARE BEING DEVELOPED, AS ILLUSTRATED BY THE SUCCESS OF SOMATOSTATIN AGONISTS, ANGIOTENSIN, AND ENDOTHELIN ANTAGONISTS, AND THE EXPECTED CLINICAL APPLICATIONS OF NK-1/2/3 (SUBSTANCE P) RECEPTOR ANTAGONISTS, CRF, VASOPRESSIN, NPY, NEUROTENSIN, OREXIN ANTAGONISTS, OR NEUROPEPTIDE RECEPTOR MODULATORS; SUCH LIGANDS HAVE EFFICACY IN PRECLINICAL OR CLINICAL MODELS OF PAIN AND NEUROPSYCHIATRIC DISEASES, SUCH AS MIGRAINE, CHRONIC/NEUROPATHIC PAIN, ANXIETY, SLEEP DISORDERS, DEPRESSION, AND SCHIZOPHRENIA. IN ADDITION, BOTH POSITIVE AND NEGATIVE ALLOSTERIC MODULATORS HAVE BEEN DESCRIBED WITH INTERESTING IN VIVO ACTIVITIES (E.G., AT GALANIN RECEPTORS). THE FIELD HAS BECOME MORE COMPLEX NOW THAT AN INCREASING NUMBER OF HETEROMERIC NEUROPEPTIDE RECEPTORS ARE DESCRIBED, E.G., GHRELIN RECEPTORS WITH 5-HT(2C) OR DOPAMINE D(1), D(2) RECEPTORS. AT LONG LAST, STRUCTURE-BASED DRUG DISCOVERY CAN NOW BE ENVISAGED WITH CONFIDENCE, SINCE CRYSTAL OR SOLUTION STRUCTURE OF GPCRS AND GPCR-LIGAND COMPLEXES, INCLUDING PEPTIDE RECEPTORS, ARE PUBLISHED ALMOST ON A MONTHLY BASIS. FINALLY, ALTHOUGH MOST COMPOUNDS ACTING AT PEPTIDE RECEPTORS ARE STILL PEPTIDOMIMETICS, THE LAST DECADE HAS SEEN THE EMERGENCE OF LOW-MOLECULAR-WEIGHT NONPEPTIDE LIGANDS (E.G., FOR OREXIN, GHRELIN, OR NEUROKININ RECEPTORS), AND SURPRISING PROGRESS HAS BEEN MADE WITH BETA- AND GAMMA-PEPTIDES AS VERY STABLE AND POTENT MIMETICS OF, E.G., SOMATOSTATIN (SRIF), WHERE THE NATIVE SRIF HAS A HALF-LIFE LIMITED TO 2-3 MIN. THIS LAST POINT WILL BE ILLUSTRATED MORE SPECIFICALLY, AS WE HAVE HAD A LONG-STANDING COLLABORATION WITH PROF. D. SEEBACH TO WHOM THIS REVIEW IS DEDICATED AT THE OCCASION OF HIS 75TH BIRTHDAY. 2012 6 5051 20 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 7 1754 19 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 8 3463 22 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 9 3001 22 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 10 4402 13 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 11 4647 20 NEUROPEPTIDE AND SMALL TRANSMITTER COEXISTENCE: FUNDAMENTAL STUDIES AND RELEVANCE TO MENTAL ILLNESS. NEUROPEPTIDES ARE AUXILIARY MESSENGER MOLECULES THAT ALWAYS CO-EXIST IN NERVE CELLS WITH ONE OR MORE SMALL MOLECULE (CLASSIC) NEUROTRANSMITTERS. NEUROPEPTIDES ACT BOTH AS TRANSMITTERS AND TROPHIC FACTORS, AND PLAY A ROLE PARTICULARLY WHEN THE NERVOUS SYSTEM IS CHALLENGED, AS BY INJURY, PAIN OR STRESS. HERE NEUROPEPTIDES AND COEXISTENCE IN MAMMALS ARE REVIEWED, BUT WITH SPECIAL FOCUS ON THE 29/30 AMINO ACID GALANIN AND ITS THREE RECEPTORS GALR1, -R2 AND -R3. IN PARTICULAR, GALANIN'S ROLE AS A CO-TRANSMITTER IN BOTH RODENT AND HUMAN NORADRENERGIC LOCUS COERULEUS (LC) NEURONS IS ADDRESSED. EXTENSIVE EXPERIMENTAL ANIMAL DATA STRONGLY SUGGEST A ROLE FOR THE GALANIN SYSTEM IN DEPRESSION-LIKE BEHAVIOR. THE TRANSLATIONAL POTENTIAL OF THESE RESULTS WAS TESTED BY STUDYING THE GALANIN SYSTEM IN POSTMORTEM HUMAN BRAINS, FIRST IN NORMAL BRAINS, AND THEN IN A COMPARISON OF FIVE REGIONS OF BRAINS OBTAINED FROM DEPRESSED PEOPLE WHO COMMITTED SUICIDE, AND FROM MATCHED CONTROLS. THE DISTRIBUTION OF GALANIN AND THE FOUR GALANIN SYSTEM TRANSCRIPTS IN THE NORMAL HUMAN BRAIN WAS DETERMINED, AND SELECTIVE AND PARALLEL CHANGES IN LEVELS OF TRANSCRIPTS AND DNA METHYLATION FOR GALANIN AND ITS THREE RECEPTORS WERE ASSESSED IN DEPRESSED PATIENTS WHO COMMITTED SUICIDE: UPREGULATION OF TRANSCRIPTS, E.G., FOR GALANIN AND GALR3 IN LC, PARALLELED BY A DECREASE IN DNA METHYLATION, SUGGESTING INVOLVEMENT OF EPIGENETIC MECHANISMS. IT IS HYPOTHESIZED THAT, WHEN EXPOSED TO SEVERE STRESS, THE NORADRENERGIC LC NEURONS FIRE IN BURSTS AND RELEASE GALANIN FROM THEIR SOMA/DENDRITES. GALANIN THEN ACTS ON SOMATO-DENDRITIC, INHIBITORY GALANIN AUTORECEPTORS, OPENING POTASSIUM CHANNELS AND INHIBITING FIRING. THE PURPOSE OF THESE AUTORECEPTORS IS TO ACT AS A 'BRAKE' TO PREVENT OVEREXCITATION, A BRAKE THAT IS ALSO PART OF RESILIENCE TO STRESS THAT PROTECTS AGAINST DEPRESSION. DEPRESSION THEN ARISES WHEN THE INHIBITION IS TOO STRONG AND LONG LASTING - A MALADAPTION, ALLOSTATIC LOAD, LEADING TO DEPLETION OF NA LEVELS IN THE FOREBRAIN. IT IS SUGGESTED THAT DISINHIBITION BY A GALANIN ANTAGONIST MAY HAVE ANTIDEPRESSANT ACTIVITY BY RESTORING FOREBRAIN NA LEVELS. A ROLE OF GALANIN IN DEPRESSION IS ALSO SUPPORTED BY A RECENT CANDIDATE GENE STUDY, SHOWING THAT VARIANTS IN GENES FOR GALANIN AND ITS THREE RECEPTORS CONFER INCREASED RISK OF DEPRESSION AND ANXIETY IN PEOPLE WHO EXPERIENCED CHILDHOOD ADVERSITY OR RECENT NEGATIVE LIFE EVENTS. IN SUMMARY, GALANIN, A NEUROPEPTIDE COEXISTING IN LC NEURONS, MAY PARTICIPATE IN THE MECHANISM UNDERLYING RESILIENCE AGAINST A SERIOUS AND COMMON DISORDER, MDD. EXISTING AND FURTHER RESULTS MAY LEAD TO AN INCREASED UNDERSTANDING OF HOW THIS ILLNESS DEVELOPS, WHICH IN TURN COULD PROVIDE A BASIS FOR ITS TREATMENT. 2018 12 3092 16 GENOMIC AND EPIGENOMIC MECHANISMS OF GLUCOCORTICOIDS IN THE BRAIN. FOLLOWING THE DISCOVERY OF GLUCOCORTICOID RECEPTORS IN THE HIPPOCAMPUS AND OTHER BRAIN REGIONS, RESEARCH HAS FOCUSED ON UNDERSTANDING THE EFFECTS OF GLUCOCORTICOIDS IN THE BRAIN AND THEIR ROLE IN REGULATING EMOTION AND COGNITION. GLUCOCORTICOIDS ARE ESSENTIAL FOR ADAPTATION TO STRESSORS (ALLOSTASIS) AND IN MALADAPTATION RESULTING FROM ALLOSTATIC LOAD AND OVERLOAD. ALLOSTATIC OVERLOAD, WHICH CAN OCCUR DURING CHRONIC STRESS, CAN RESHAPE THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS THROUGH EPIGENETIC MODIFICATION OF GENES IN THE HIPPOCAMPUS, HYPOTHALAMUS AND OTHER STRESS-RESPONSIVE BRAIN REGIONS. GLUCOCORTICOIDS EXERT THEIR EFFECTS ON THE BRAIN THROUGH GENOMIC MECHANISMS THAT INVOLVE BOTH GLUCOCORTICOID RECEPTORS AND MINERALOCORTICOID RECEPTORS DIRECTLY BINDING TO DNA, AS WELL AS BY NON-GENOMIC MECHANISMS. FURTHERMORE, GLUCOCORTICOIDS SYNERGIZE BOTH GENOMICALLY AND NON-GENOMICALLY WITH NEUROTRANSMITTERS, NEUROTROPHIC FACTORS, SEX HORMONES AND OTHER STRESS MEDIATORS TO SHAPE AN ORGANISM'S PRESENT AND FUTURE RESPONSES TO A STRESSFUL ENVIRONMENT. HERE, WE DISCUSS THE MECHANISMS OF GLUCOCORTICOID ACTION IN THE BRAIN AND REVIEW HOW GLUCOCORTICOIDS INTERACT WITH STRESS MEDIATORS IN THE CONTEXT OF ALLOSTASIS, ALLOSTATIC LOAD AND STRESS-INDUCED NEUROPLASTICITY. 2017 13 4860 25 OREXIN SIGNALING MEDIATES THE ANTIDEPRESSANT-LIKE EFFECT OF CALORIE RESTRICTION. DURING PERIODS OF REDUCED FOOD AVAILABILITY, ANIMALS MUST RESPOND WITH BEHAVIORAL ADAPTATIONS THAT PROMOTE SURVIVAL. DESPITE THE FACT THAT MANY PSYCHIATRIC SYNDROMES INCLUDE DISORDERED EATING PATTERNS AS A COMPONENT OF THE ILLNESS, LITTLE IS KNOWN ABOUT THE NEUROBIOLOGY UNDERLYING BEHAVIORAL CHANGES INDUCED BY SHORT-TERM CALORIE RESTRICTION. PRESENTLY, WE DEMONSTRATE THAT 10 D OF CALORIE RESTRICTION, CORRESPONDING TO A 20-25% WEIGHT LOSS, CAUSES A MARKED ANTIDEPRESSANT-LIKE RESPONSE IN TWO RODENT MODELS OF DEPRESSION AND THAT THIS RESPONSE IS DEPENDENT ON THE HYPOTHALAMIC NEUROPEPTIDE OREXIN (HYPOCRETIN). WILD-TYPE MICE, BUT NOT MICE LACKING OREXIN, SHOW LONGER LATENCY TO IMMOBILITY AND LESS TOTAL IMMOBILITY IN THE FORCED SWIM TEST AFTER CALORIE RESTRICTION. IN THE SOCIAL DEFEAT MODEL OF CHRONIC STRESS, CALORIE RESTRICTION REVERSES THE BEHAVIORAL DEFICITS SEEN IN WILD-TYPE MICE BUT NOT IN OREXIN KNOCK-OUT MICE. ADDITIONALLY, CHRONIC SOCIAL DEFEAT STRESS INDUCES A PROLONGED REDUCTION IN THE EXPRESSION OF PREPRO-OREXIN MRNA VIA EPIGENETIC MODIFICATION OF THE OREXIN GENE PROMOTER, WHEREAS CALORIE RESTRICTION ENHANCES THE ACTIVATION OF OREXIN CELLS AFTER SOCIAL DEFEAT. TOGETHER, THESE DATA INDICATE THAT OREXIN PLAYS AN ESSENTIAL ROLE IN MEDIATING REDUCED DEPRESSION-LIKE SYMPTOMS INDUCED BY CALORIE RESTRICTION. 2008 14 5310 16 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 15 5815 16 STRESS AND GLUCOCORTICOID RECEPTOR TRANSCRIPTIONAL PROGRAMMING IN TIME AND SPACE: IMPLICATIONS FOR THE BRAIN-GUT AXIS. BACKGROUND: CHRONIC PSYCHOLOGICAL STRESS IS ASSOCIATED WITH ENHANCED ABDOMINAL PAIN AND ALTERED INTESTINAL BARRIER FUNCTION THAT MAY RESULT FROM A PERTURBATION IN THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS. THE GLUCOCORTICOID RECEPTOR (GR) EXPLOITS DIVERSE MECHANISMS TO ACTIVATE OR SUPPRESS CONGENERIC GENE EXPRESSION, WITH REGULATORY VARIATION ASSOCIATED WITH STRESS-RELATED DISORDERS IN PSYCHIATRY AND GASTROENTEROLOGY. PURPOSE: DURING ACUTE AND CHRONIC STRESS, CORTICOTROPIN-RELEASING HORMONE DRIVES SECRETION OF ADRENOCORTICOTROPIC HORMONE FROM THE PITUITARY, ULTIMATELY LEADING TO THE RELEASE OF CORTISOL (HUMAN) AND CORTICOSTERONE (RODENT) FROM THE ADRENAL GLANDS. CORTISOL BINDS WITH THE GR IN THE CYTOSOL, TRANSLOCATES TO THE NUCLEUS, AND ACTIVATES THE NR3C1 (NUCLEAR RECEPTOR SUBFAMILY 3, GROUP C, MEMBER 1 [GR]) GENE. THIS REVIEW FOCUSES ON THE RAPIDLY DEVELOPING OBSERVATIONS THAT CORTISOL IS RESPONSIBLE FOR DRIVING CIRCADIAN AND ULTRADIAN BURSTS OF TRANSCRIPTIONAL ACTIVITY IN THE CLOCK (CLOCK CIRCADIAN REGULATOR) AND PER (PERIOD CIRCADIAN CLOCK 1) GENE FAMILIES, AND THIS RHYTHM IS DISRUPTED IN MAJOR DEPRESSIVE DISORDER, BIPOLAR DISORDER, AND STRESS-RELATED GASTROINTESTINAL AND IMMUNE DISORDERS. GLUCOCORTICOID RECEPTOR REGULATES DIFFERENT SETS OF TRANSCRIPTS IN A TISSUE-SPECIFIC MANNER, THROUGH PULSATILE WAVES OF GENE EXPRESSION THAT INCLUDES OCCUPANCY OF GLUCOCORTICOID RESPONSE ELEMENTS LOCATED WITHIN CONSTITUTIVELY OPEN SPATIAL DOMAINS IN CHROMATIN. EMERGING EVIDENCE SUPPORTS A POTENTIALLY PIVOTAL ROLE FOR EPIGENETIC REGULATION OF HOW GR INTERACTS WITH OTHER CHROMATIN REGULATORS TO CONTROL THE EXPRESSION OF ITS TARGET GENES. DYSREGULATION OF THE CENTRAL AND PERIPHERAL GR REGULOME HAS POTENTIALLY SIGNIFICANT CONSEQUENCES FOR STRESS-RELATED DISORDERS AFFECTING THE BRAIN-GUT AXIS. 2016 16 1750 14 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 17 3774 18 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 18 3313 16 HIPPOCAMPAL BDNF IN PHYSIOLOGICAL CONDITIONS AND SOCIAL ISOLATION. EXPOSURE OF AN ORGANISM TO CHRONIC PSYCHOSOCIAL STRESS MAY AFFECT BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION THAT HAS BEEN IMPLICATED IN THE ETIOLOGY OF PSYCHIATRIC DISORDERS, SUCH AS DEPRESSION. GIVEN THAT DEPRESSION IN HUMANS HAS BEEN LINKED WITH SOCIAL STRESS, THE CHRONIC SOCIAL STRESS PARADIGMS FOR MODELING PSYCHIATRIC DISORDERS IN ANIMALS HAVE THUS BEEN DEVELOPED. CHRONIC SOCIAL ISOLATION IN ANIMAL MODELS GENERALLY CAUSES CHANGES IN HYPOTHALAMIC-PITUITARY-ADRENAL AXIS FUNCTIONING, ASSOCIATED WITH ANXIETY- AND DEPRESSIVE-LIKE BEHAVIORS. ALSO, THIS CHRONIC STRESS CAUSES DOWNREGULATION OF BDNF PROTEIN AND MRNA IN THE HIPPOCAMPUS, A STRESS-SENSITIVE BRAIN REGION CLOSELY RELATED TO THE PATHOPHYSIOLOGY OF DEPRESSION. IN THIS REVIEW, WE DISCUSS THE CURRENT KNOWLEDGE REGARDING THE STRUCTURE, FUNCTION, INTRACELLULAR SIGNALING, INTER-INDIVIDUAL DIFFERENCES AND EPIGENETIC REGULATION OF BDNF IN BOTH PHYSIOLOGICAL CONDITIONS AND DEPRESSION AND CHANGES IN CORTICOSTERONE LEVELS, AS A MARKER OF STRESS RESPONSE. SINCE BDNF LEVELS ARE AGE DEPENDENT IN HUMANS AND RODENTS, THIS REVIEW WILL ALSO HIGHLIGHT THE EFFECTS OF ADOLESCENT AND ADULT CHRONIC SOCIAL ISOLATION MODELS OF BOTH GENDERS ON THE BDNF EXPRESSION. 2017 19 4632 18 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 20 23 17 60 YEARS OF NEUROENDOCRINOLOGY: REDEFINING NEUROENDOCRINOLOGY: STRESS, SEX AND COGNITIVE AND EMOTIONAL REGULATION. THE DISCOVERY OF STEROID HORMONE RECEPTORS IN BRAIN REGIONS THAT MEDIATE EVERY ASPECT OF BRAIN FUNCTION HAS BROADENED THE DEFINITION OF 'NEUROENDOCRINOLOGY' TO INCLUDE THE RECIPROCAL COMMUNICATION BETWEEN THE BRAIN AND THE BODY VIA HORMONAL AND NEURAL PATHWAYS. THE BRAIN IS THE CENTRAL ORGAN OF STRESS AND ADAPTATION TO STRESS BECAUSE IT PERCEIVES AND DETERMINES WHAT IS THREATENING, AS WELL AS THE BEHAVIORAL AND PHYSIOLOGICAL RESPONSES TO THE STRESSOR. THE ADULT AND DEVELOPING BRAIN POSSESS REMARKABLE STRUCTURAL AND FUNCTIONAL PLASTICITY IN RESPONSE TO STRESS, INCLUDING NEURONAL REPLACEMENT, DENDRITIC REMODELING, AND SYNAPSE TURNOVER. STRESS CAUSES AN IMBALANCE OF NEURAL CIRCUITRY SUBSERVING COGNITION, DECISION-MAKING, ANXIETY AND MOOD THAT CAN ALTER EXPRESSION OF THOSE BEHAVIORS AND BEHAVIORAL STATES. THIS IMBALANCE, IN TURN, AFFECTS SYSTEMIC PHYSIOLOGY VIA NEUROENDOCRINE, AUTONOMIC, IMMUNE AND METABOLIC MEDIATORS. IN THE SHORT TERM, AS FOR INCREASED FEARFUL VIGILANCE AND ANXIETY IN A THREATENING ENVIRONMENT, THESE CHANGES MAY BE ADAPTIVE. BUT, IF THE DANGER PASSES AND THE BEHAVIORAL STATE PERSISTS ALONG WITH THE CHANGES IN NEURAL CIRCUITRY, SUCH MALADAPTATION MAY NEED INTERVENTION WITH A COMBINATION OF PHARMACOLOGICAL AND BEHAVIORAL THERAPIES, AS IS THE CASE FOR CHRONIC ANXIETY AND DEPRESSION. THERE ARE IMPORTANT SEX DIFFERENCES IN THE BRAIN RESPONSES TO STRESSORS THAT ARE IN URGENT NEED OF FURTHER EXPLORATION. MOREOVER, ADVERSE EARLY-LIFE EXPERIENCE, INTERACTING WITH ALLELES OF CERTAIN GENES, PRODUCE LASTING EFFECTS ON BRAIN AND BODY OVER THE LIFE-COURSE VIA EPIGENETIC MECHANISMS. WHILE PREVENTION IS MOST IMPORTANT, THE PLASTICITY OF THE BRAIN GIVES HOPE FOR THERAPIES THAT TAKE INTO CONSIDERATION BRAIN-BODY INTERACTIONS. 2015