1 5019 163 PERSISTENT INFLAMMATORY PAIN IS LINKED WITH ANXIETY-LIKE BEHAVIORS, INCREASED BLOOD CORTICOSTERONE, AND REDUCED GLOBAL DNA METHYLATION IN THE RAT AMYGDALA. CHRONIC PAIN INCREASES THE RISK OF DEVELOPING ANXIETY, WITH LIMBIC AREAS BEING LIKELY NEUROLOGICAL SUBSTRATES. DESPITE HIGH CLINICAL RELEVANCE, LITTLE IS KNOWN ABOUT THE PRECISE BEHAVIORAL, HORMONAL, AND BRAIN NEUROPLASTIC CORRELATES OF ANXIETY IN THE CONTEXT OF PERSISTENT PAIN. PREVIOUS STUDIES HAVE SHOWN THAT DECREASED NOCICEPTIVE THRESHOLDS IN CHRONIC PAIN MODELS ARE PARALLELED BY ANXIETY-LIKE BEHAVIOR IN RATS, BUT THERE ARE CONFLICTING IDEAS REGARDING ITS EFFECTS ON THE STRESS RESPONSE AND CIRCULATING CORTICOSTERONE LEVELS. EVEN LESS IS KNOWN ABOUT THE MOLECULAR MECHANISMS THROUGH WHICH THE BRAIN ENCODES PAIN-RELATED ANXIETY. THIS STUDY EXAMINES HOW PERSISTENT INFLAMMATORY PAIN IN A RAT MODEL WOULD IMPACT ANXIETY-LIKE BEHAVIORS AND CORTICOSTERONE RELEASE, AND WHETHER THESE CHANGES WOULD BE REFLECTED IN LEVELS OF GLOBAL DNA METHYLATION IN BRAIN AREAS INVOLVED IN STRESS REGULATION. COMPLETE FREUND'S ADJUVANT (CFA) OR SALINE WAS ADMINISTERED IN THE RIGHT HINDPAW OF ADULT MALE WISTAR RATS. BEHAVIORAL TESTING INCLUDED THE MEASUREMENT OF NOCICEPTIVE THRESHOLDS (DIGITAL ANESTHESIOMETER), MOTOR FUNCTION (OPEN FIELD TEST), AND ANXIETY-LIKE BEHAVIORS (ELEVATED PLUS MAZE AND THE DARK-LIGHT BOX TEST). CORTICOSTERONE WAS MEASURED VIA RADIOIMMUNOASSAY. GLOBAL DNA METHYLATION (ENZYME IMMUNOASSAY) AS WELL AS DNMT3A LEVELS (WESTERN BLOTTING) WERE QUANTIFIED IN THE AMYGDALA, PREFRONTAL CORTEX, AND VENTRAL HIPPOCAMPUS. CFA ADMINISTRATION RESULTED IN PERSISTENT REDUCTION IN NOCICEPTIVE THRESHOLD IN THE ABSENCE OF LOCOMOTOR ABNORMALITIES. INCREASED ANXIETY-LIKE BEHAVIORS WERE OBSERVED IN THE ELEVATED PLUS MAZE AND WERE ACCOMPANIED BY INCREASED BLOOD CORTICOSTERONE LEVELS 10 DAYS AFTER PAIN INDUCTION. GLOBAL DNA METHYLATION WAS DECREASED IN THE AMYGDALA, WITH NO CHANGES IN DNMT3A ABUNDANCE IN ANY OF THE REGIONS EXAMINED. PERSISTENT INFLAMMATORY PAIN PROMOTES ANXIETY -LIKE BEHAVIORS, HPA AXIS ACTIVATION, AND EPIGENETIC REGULATION THROUGH DNA METHYLATION IN THE AMYGDALA. THESE FINDINGS DESCRIBE A MOLECULAR MECHANISM THAT LINKS PAIN AND STRESS IN A WELL-CHARACTERIZED RODENT MODEL. 2022 2 1920 45 ENVIRONMENTAL ENRICHMENT PREVENTS STRESS-INDUCED EPIGENETIC CHANGES IN THE EXPRESSION OF GLUCOCORTICOID RECEPTOR AND CORTICOTROPHIN RELEASING HORMONE IN THE CENTRAL NUCLEUS OF THE AMYGDALA TO INHIBIT VISCERAL HYPERSENSITIVITY. INTRODUCTION: STRESS IS A KNOWN TRIGGER FOR THE SYMPTOMS OF IRRITABLE BOWEL SYNDROME (IBS), A GASTROINTESTINAL (GI) DISORDER THAT PRESENTS WITH ABNORMAL BOWEL HABITS AND ABDOMINAL PAIN DUE TO VISCERAL HYPERSENSITIVITY. WHILE BEHAVIORAL THERAPIES HAVE BEEN USED TO ATTENUATE IBS SYMPTOMS, THE UNDERLYING MECHANISMS BY WHICH THESE THERAPIES INTERACT WITH STRESS-INDUCED PATHOLOGY REMAINS TO BE DELINEATED. HERE WE USE A RAT MODEL TO TEST THE HYPOTHESIS THAT EXPOSURE TO ENVIRONMENTAL ENRICHMENT (EE) INHIBITS STRESS-INDUCED CHANGES WITHIN THE BRAIN-GUT AXIS TO PREVENT VISCERAL AND SOMATIC HYPERSENSITIVITY AND COLONIC HYPERPERMEABILITY. METHODS: FEMALE RATS (N = 8/GROUP) WERE HOUSED IN EE ONE WEEK BEFORE AND ONE WEEK DURING EXPOSURE TO WATER AVOIDANCE STRESS (WAS) WHILE CONTROLS WERE HOUSED IN STANDARD CAGES (SH). ONE DAY AFTER THE FINAL WAS EXPOSURE, COLONIC AND SOMATIC SENSITIVITY WERE ASSESSED BY THE VISCEROMOTOR RESPONSE (VMR) TO COLORECTAL DISTENSION (CRD) AND WITHDRAWAL THRESHOLD ELICITED BY AN ELECTRONIC VON FREY ON THE HIND PAW OF THE RATS RESPECTIVELY. ALL RATS WERE RETURNED TO SH FOR 3 WEEKS BEFORE COLONIC AND SOMATIC SENSITIVITY WERE REASSESSED ON DAY 28. THE RATS WERE THEN IMMEDIATELY EUTHANIZED AND THE SPINAL CORD WAS COLLECTED TO ASSESS CHANGES IN NEURONAL ACTIVATION (ASSESSED VIA ERK PHOSPHORYLATION) IN RESPONSE TO NOXIOUS CRD. A SEPARATE COHORT OF ANIMALS (N = 8/GROUP) THAT DID NOT UNDERGO BEHAVIORAL ASSESSMENTS WAS EUTHANIZED THE DAY AFTER THE FINAL WAS EXPOSURE AND THE CENTRAL NUCLEUS OF THE AMYGDALA (CEA) WAS COLLECTED TO INVESTIGATE WAS AND EE INDUCED EPIGENETIC CHANGES AT THE GLUCOCORTICOID RECEPTOR (GR) AND CORTICOTROPHIN RELEASING HORMONE (CRH) PROMOTER. THE COLON FROM THESE RATS WAS ALSO COLLECTED TO ASSESS COLONIC PERMEABILITY VIA CHANGES IN TRANSEPITHELIAL ELECTRICAL RESISTANCE (TEER) IN VITRO. RESULTS: EXPOSURE TO STRESS PERSISTENTLY INCREASED VMR TO CRD (P < 0.01) AND DECREASED THE HIND PAW WITHDRAWAL THRESHOLD (P < 0.001) IN FEMALE RATS. WAS ALSO DECREASED TEER IN THE COLON TISSUE OF FEMALE RATS (P = 0.05). IN THE CEA, WAS INDUCED A DECREASE IN HISTONE ACETYLATION AT THE GR PROMOTER BUT INCREASED HISTONE ACETYLATION AT THE CRH PROMOTER AND REDUCED GR-CRH INTERACTIONS IN THE CEA. ANALYSIS OF THE SPINAL CORD SHOWED THAT WAS INCREASED CRD-EVOKED ERK PHOSPHORYLATION IN THE DORSAL HORN. EXPOSURE TO EE PREVENTED WAS-INDUCED CHANGES IN THE CEA, DORSAL HORN AND COLON RESPECTIVELY TO PREVENT VISCERAL AND SOMATIC HYPERSENSITIVITY. CONCLUSION: OUR DATA REVEALS THAT BEHAVIORAL THERAPIES CAN PRODUCE LONG LASTING MOLECULAR AND EPIGENETIC CHANGES THAT CAN PREVENT STRESS-INDUCED PATHOLOGIES EVEN AFTER COMPLETION OF THE THERAPY. THESE RESULTS HIGHLIGHT THE POTENTIAL MECHANISMS BY WHICH BEHAVIORAL THERAPIES MAY AMELIORATE VISCERAL PAIN ASSOCIATED STRESS-RELATED PATHOLOGIES SUCH AS THE IRRITABLE BOWEL SYNDROME. 2021 3 849 41 CHILDHOOD TRAUMATIZATION IS ASSOCIATED WITH DIFFERENCES IN TRPA1 PROMOTER METHYLATION IN FEMALE PATIENTS WITH MULTISOMATOFORM DISORDER WITH PAIN AS THE LEADING BODILY SYMPTOM. BACKGROUND: THE CONSTRUCT OF MULTISOMATOFORM DISORDER (MSD) IS A COMMON POINT OF REFERENCE FOR PATIENTS IN DIFFERENT SOMATIC AND PSYCHOSOMATIC SPECIALTIES AND THEREFORE USEFUL IN STUDYING LARGE WELL-CHARACTERIZED COHORTS OF A PROTOTYPE OF A SOMATOFORM DISORDER AND IN PARALLEL AS A FUNCTIONAL SOMATIC SYNDROME (FSS). THIS DISORDER IS CHARACTERIZED BY DISTRESSING AND FUNCTIONALLY DISABLING SOMATIC SYMPTOMS WITH CHRONIC PAIN AS THE MOST FREQUENT AND CLINICALLY RELEVANT COMPLAINT. PAIN IS PERCEIVED BY NOCICEPTIVE NERVE FIBERS AND TRANSFERRED THROUGH THE GENERATION OF ACTION POTENTIALS BY DIFFERENT RECEPTOR MOLECULES KNOWN TO DETERMINE PAIN SENSITIVITY IN PATHOPHYSIOLOGICAL PROCESSES. PREVIOUS STUDIES HAVE SHOWN THAT FOR THE TRANSIENT RECEPTOR POTENTIAL ANKYRIN 1 (TRPA1), RECEPTOR METHYLATION OF A PARTICULAR CPG DINUCLEOTIDE IN THE PROMOTER REGION IS INVERSELY ASSOCIATED WITH BOTH HEAT PAIN AND PRESSURE PAIN THRESHOLDS. IN THIS STUDY, WE HYPOTHESIZED THAT TRPA1 PROMOTER METHYLATION REGULATES PAIN SENSITIVITY OF PATIENTS WITH MULTISOMATOFORM DISORDER (MSD). A COHORT OF 151 PATIENTS WITH MSD AND 149 MATCHED HEALTHY VOLUNTEERS WERE EVALUATED USING QUANTITATIVE SENSORY TESTING, CLINICAL AND PSYCHOMETRIC ASSESSMENT, AND METHYLATION ANALYSIS USING DNA ISOLATED FROM WHOLE BLOOD. RESULTS: WE FOUND CPG -628 TO BE CORRELATED WITH MECHANICAL PAIN THRESHOLD AND CPG -411 TO BE CORRELATED WITH MECHANICAL PAIN THRESHOLD IN FEMALE VOLUNTEERS, I.E., HIGHER METHYLATION LEVELS LEAD TO HIGHER PAIN THRESHOLDS. A NOVEL FINDING IS THAT METHYLATION LEVELS WERE SIGNIFICANTLY DIFFERENT BETWEEN PATIENTS WITH NO AND SEVERE LEVELS OF CHILDHOOD TRAUMA. CPG METHYLATION ALSO CORRELATED WITH PSYCHOMETRIC ASSESSMENT OF PAIN AND PAIN LEVELS RATED ON A VISUAL ANALOG SCALE. CONCLUSION: OUR FINDINGS SUPPORT THE HYPOTHESIS THAT EPIGENETIC REGULATION OF TRPA1 PLAYS A ROLE IN MECHANICAL PAIN SENSITIVITIES IN HEALTHY VOLUNTEERS. THEY FURTHER PROVIDE EVIDENCE FOR THE POSSIBLE INFLUENCE OF CHILDHOOD TRAUMATIC EXPERIENCES ON THE EPIGENETIC REGULATION OF TRPA1 IN PATIENTS WITH MSD. 2019 4 4579 26 N(6)-METHYLADENOSINE METHYLASE METTL3 CONTRIBUTES TO NEUROPATHIC PAIN BY EPIGENETIC SILENCING OF MU OPIOID RECEPTOR. WE AIMED AT EXPLORING THE ROLE AND MECHANISM OF METTL3-MEDIATED M(6)A MODIFICATION IN NEUROPATHIC PAIN. MALE SPRAGUE-DAWLEY RATS WERE RANDOMLY DIVIDED INTO FOUR GROUPS: SHAM OPERATION GROUP (SHAM GROUP), CHRONIC CONSTRICTION INJURY (CCI) OF THE SCIATIC NERVE MODEL GROUP (NPP GROUP), INTRATHECAL INJECTION OF VIRUS DOWN-REGULATED METTL3 + CCI MODEL GROUP (M3 + NPP GROUP) AND INTRATHECAL INJECTION OF NEGATIVE CONTROL VIRUS + CCI MODEL GROUP (SCR + NPP GROUP). THE M3 + NPP GROUP AND THE SCR + NPP GROUP WERE INTRATHECALLY INJECTED WITH VIRUS NINETEEN DAYS BEFORE OPERATION. THE PAW WITHDRAWAL MECHANICAL THRESHOLDS AND PAW WITHDRAWAL LATENCY WERE RESPECTIVELY RECORDED ONE DAY BEFORE OPERATION, THREE DAYS, FIVE DAYS AND SEVEN DAYS AFTER OPERATION. THE RATS WERE SACRIFICED ON THE SEVENTH DAY AFTER OPERATION, AND THEIR SPINAL CORD TISSUES WERE TAKEN. THE FROZEN SECTIONS OF RATS WERE PERFORMED TO OBSERVE THE EXPRESSION OF GREEN FLUORESCENT PROTEIN OF THE VIRUS. THE METHYLATION LEVEL OF RNA, THE PROTEIN EXPRESSION OF M(6)A-RELATED ENZYME (METTL3) AND MU OPIOID RECEPTOR (MOR) IN SPINAL CORD TISSUES OF THE FOUR GROUPS WERE MEASURED. DOWNREGULATION OF METTL3 HAD NO EFFECT ON THE OVERALL METHYLATION LEVEL OF THE SPINAL CORD, BUT IT COULD REGULATE THE METHYLATION LEVEL OF THE OPRM1 GENE RNA ENCODING MOR, PARTIALLY RESTORE THE EXPRESSION OF MOR, AND RELIEVE PAIN IN RATS. IN THE PROCESS OF NPP, METTL3 MAY INHIBIT THE EXPRESSION OF MOR BY REGULATING THE METHYLATION LEVEL OF OPRM1 GENE RNA ENCODING MOR, AND ULTIMATELY PROMOTE THE OCCURRENCE AND DEVELOPMENT OF NPP. 2023 5 6418 30 THE TEMPORAL EXPRESSION OF CIRCULATING MICRORNAS AFTER ACUTE EXPERIMENTAL PAIN IN HUMANS. BACKGROUND: MICRORNAS (MIRNAS) CAN MODULATE SEVERAL BIOLOGICAL SYSTEMS, INCLUDING THE PAIN SYSTEM. THIS STUDY AIMED TO EVALUATE THE TEMPORAL EXPRESSION OF CIRCULATING MIRNAS IN THE PLASMA OF HEALTHY VOLUNTEERS AS A MARKER FOR EPIGENETIC CHANGES BEFORE AND AFTER AN ACUTE, EXPERIMENTAL, PAIN PROVOCATION BY INTRAMUSCULAR HYPERTONIC SALINE INJECTION. METHODS: TWENTY VOLUNTEERS WERE RANDOMLY ALLOCATED INTO TWO GROUPS AND RECEIVED EITHER HYPERTONIC (PAIN) OR ISOTONIC (CONTROL) SALINE INJECTION IN THE FIRST DORSAL INTEROSSEOUS MUSCLE OF THEIR DOMINANT HAND. PAIN INTENSITY WAS CONTINUOUSLY RECORDED FOR 20 MINUTES AFTER INJECTION ON A VAS SCALE FROM 0 TO 100 (0 INDICATES NO PAIN AND 100 THE WORST IMAGINABLE PAIN). BLOOD SAMPLES WERE TAKEN AT BASELINE, 30 MINUTES, 3 HOURS, AND 24 HOURS POST-INJECTION, AND PLASMA WAS SEPARATED. MIRNA EXTRACTS WERE USED FOR RNA SEQUENCING WITH THE ILLUMINA NEXTSEQ PLATFORM. MIRNA TRANSCRIPTS WERE COMPARED BETWEEN THE PAIN AND THE NO-PAIN, CONTROL GROUP AT EVERY TIME POINT. SIGNIFICANT DIFFERENCES WERE CONSIDERED WHEN FOLDS WERE >2 AND THE FALSE DISCOVERY RATE WAS P < 0.05. RESULTS: AFTER 30 MINUTES, 4 MIRNAS WERE SIGNIFICANTLY ALTERED IN THE PAIN GROUP COMPARED TO CONTROLS, WHICH INCREASED TO 24 AFTER 3 HOURS AND TO 42 AFTER 24 HOURS FROM BASELINE (P < 0.0001). TWO MIRNAS WERE CONSISTENTLY UPREGULATED THROUGHOUT THE EXPERIMENT. ENRICHMENT ANALYSIS SHOWED SIGNIFICANT MIRNAS INVOLVED IN BRAIN PERCEPTION OF PAIN, BRAIN SIGNALLING AND RESPONSE TO STIMULI. CONCLUSIONS: THIS EXPLORATORY STUDY IS THE FIRST TO REPORT ON THE TEMPORAL EXPRESSION OF CIRCULATING MIRNAS AFTER AN ACUTE, HUMAN EXPERIMENTAL MUSCLE PAIN MODEL. SIGNIFICANCE: THIS EXPLORATORY STUDY EVALUATED THE TEMPORAL PROFILE OF CIRCULATING MIRNAS IN THE PLASMA OF HEALTHY SUBJECTS AFTER ACUTE EXPERIMENTAL PAIN. SEVERAL MIRNAS WERE ALTERED IN SUBJECTS AT THE TIMES OF FOLLOW-UP AFTER THE ACUTE PAIN MODEL WHEN COMPARED TO CONTROLS. MIRNAS PREVIOUSLY ASSOCIATED WITH PAIN PROCESSES WERE ALTERED IN THE PAIN GROUP. OUR RESULTS, BY SHOWING THE FAST AND PROLONGED MODIFICATIONS OF MIRNA ELICITED BY THE ACUTE EXPERIMENTAL PAIN MODEL, ADD NEW PERSPECTIVES TO THE TOPIC OF EPIGENETICS AND PAIN. 2023 6 1833 33 EFFECTS OF METHYL DONOR DIETS ON INCISIONAL PAIN IN MICE. BACKGROUND: DIETARY SUPPLEMENTATION WITH METHYL DONORS CAN INFLUENCE THE PROGRAMMING OF EPIGENETIC PATTERNS RESULTING IN PERSISTENT ALTERATIONS IN DISEASE SUSCEPTIBILITY AND BEHAVIOR. HOWEVER, THE DIETARY EFFECTS OF METHYL DONORS ON PAIN HAVE NOT BEEN EXPLORED. IN THIS STUDY, WE EVALUATED THE EFFECTS OF DIETARY METHYL DONOR CONTENT ON PAIN RESPONSES IN MICE. METHODS: MALE AND FEMALE C57BL/6J MICE WERE TREATED WITH HIGH OR LOW METHYL DONOR DIETS EITHER IN THE PERINATAL PERIOD OR AFTER WEANING. MECHANICAL AND THERMAL NOCICEPTIVE SENSITIVITY WERE MEASURED BEFORE AND AFTER INCISION. RESULTS: MICE FED HIGH OR LOW METHYL DONOR DIETS DISPLAYED EQUAL WEIGHT GAIN OVER THE COURSE OF THE EXPERIMENTS. WHEN EXPOSED TO THESE DIETARY MANIPULATIONS IN THE PERINATAL PERIOD, ONLY MALE OFFSPRING OF DAMS FED A HIGH METHYL DONOR DIET DISPLAYED INCREASED MECHANICAL ALLODYNIA. HINDPAW INCISION IN THESE ANIMALS CAUSED ENHANCED NOCICEPTIVE SENSITIZATION, BUT DIETARY HISTORY DID NOT AFFECT THE DURATION OF SENSITIZATION. FOR MICE EXPOSED TO HIGH OR LOW METHYL DONOR DIETS AFTER WEANING, NO SIGNIFICANT DIFFERENCES WERE OBSERVED IN MECHANICAL OR THERMAL NOCICEPTIVE SENSITIVITY EITHER AT BASELINE OR IN RESPONSE TO HINDPAW INCISION. CONCLUSIONS: PERINATAL DIETARY FACTORS SUCH AS METHYL DONOR CONTENT MAY IMPACT PAIN EXPERIENCES IN LATER LIFE. THESE EFFECTS, HOWEVER, MAY BE SPECIFIC TO SEX AND PAIN MODALITY. 2013 7 2078 36 EPIGENETIC DIVERGENCE IN THE TRPA1 PROMOTER CORRELATES WITH PRESSURE PAIN THRESHOLDS IN HEALTHY INDIVIDUALS. THE EXPRESSION PATTERN OF IMPORTANT TRANSDUCTION MOLECULES IN NOCICEPTIVE SENSORY NEURONS IS LIKELY TO DICTATE PAIN SENSITIVITY. WHILE THIS NOTION IS WELL ESTABLISHED FOR INCREASED PAIN SENSITIVITIES UNDER CONDITIONS LIKE INFLAMMATION AND NEUROPATHY, LESS IS KNOWN AS TO WHICH MOLECULES ARE DEFINING INTERINDIVIDUAL DIFFERENCES IN PAIN SENSITIVITY IN HEALTHY SUBJECTS. A GENOME-WIDE METHYLATION ANALYSIS ON MONOZYGOTIC TWINS FOUND THAT METHYLATION OF A CPG DINUCLEOTIDE IN THE PROMOTER OF TRANSIENT RECEPTOR POTENTIAL ANKYRIN 1 (TRPA1) IS INVERSELY ASSOCIATED WITH THE THRESHOLD FOR HEAT-INDUCED PAIN. SEVERAL IN VITRO STUDIES ALSO SUGGEST THAT TRPA1 MEDIATES MECHANICAL SENSITIVITY OF SENSORY AFFERENTS, THUS POTENTIALLY MEDIATING PRESSURE-EVOKED PAIN. IN THE PRESENT STUDY, WE THEREFORE INVESTIGATED THE EPIGENETIC PREDISPOSITION FOR PRESSURE PAIN BY ANALYZING THE METHYLATION STATUS OF 47 CPG SITES IN THE PROMOTER REGION OF TRPA1. USING DNA FROM WHOLE-BLOOD SAMPLES OF 75 HEALTHY VOLUNTEERS, WE FOUND THAT THE SAME CPG SITE PREVIOUSLY FOUND TO AFFECT THE THRESHOLD FOR HEAT-EVOKED PAIN IS HYPERMETHYLATED IN SUBJECTS WITH A LOW THRESHOLD FOR PRESSURE PAIN. WE ALSO FOUND GENDER DIFFERENCES, WITH FEMALES DISPLAYING HIGHER METHYLATION RATES COMBINED WITH HIGHER PRESSURE PAIN SENSITIVITIES AS COMPARED WITH MALES. IN CONCLUSION, OUR FINDINGS SUPPORT THE NOTION THAT EPIGENETIC REGULATION OF TRPA1 SEEMS TO REGULATE THERMAL AND MECHANICAL PAIN SENSITIVITIES. 2017 8 1800 28 EFFECT OF HISTONE DEACETYLASE INHIBITOR ON ETHANOL WITHDRAWAL-INDUCED HYPERALGESIA IN RATS. BACKGROUND: INCREASED PAIN SENSITIVITY IS OBSERVED FOLLOWING ALCOHOL WITHDRAWAL, AND ATTEMPTS TO ALLEVIATE THIS HYPERALGESIA CAN CONTRIBUTE TO THE CYCLE OF ADDICTION. THE AIM OF THIS STUDY WAS TO DETERMINE IF ALCOHOL WITHDRAWAL-INDUCED HYPERALGESIA WAS OBSERVED IN A CHRONIC ETHANOL EXPOSURE MODEL AND IF THIS PAIN WAS AFFECTED BY HISTONE DEACETYLASE INHIBITORS, THUS REVEALING AN EPIGENETIC MECHANISM. METHODS: ADULT MALE SPRAGUE DAWLEY RATS RECEIVED LIEBER-DECARLI LIQUID CONTROL OR ETHANOL (9% V/V) DIET FOR 15 DAYS. MECHANICAL SENSITIVITY WAS MEASURED WITH VON FREY HAIR STIMULATION OF THE HINDPAW DURING ETHANOL ADMINISTRATION AND 24- AND 72-HOUR WITHDRAWAL. RESULTS: ETHANOL WITHDRAWAL PRODUCED SEVERE AND SUSTAINED MECHANICAL HYPERALGESIA, AN EFFECT NOT OBSERVED IN THE CONTROL OR ETHANOL-MAINTAINED GROUPS. FURTHERMORE, THIS HYPERALGESIA WAS ATTENUATED BY THE HISTONE DEACETYLASE INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID TREATMENT. CONCLUSIONS: HEIGHTENED PAIN SENSITIVITY WAS OBSERVED FOLLOWING WITHDRAWAL FROM CHRONIC ETHANOL EXPOSURE, AND HISTONE DEACETYLASE INHIBITORS COULD BE NOVEL TREATMENTS FOR THIS ALCOHOL WITHDRAWAL-INDUCED HYPERALGESIA. 2019 9 5129 35 POSTOPERATIVE PAIN AND ANALGESIA: IS THERE A GENETIC BASIS TO THE OPIOID CRISIS? BACKGROUND: MULTIPLE FACTORS HAVE BEEN IMPLICATED IN DETERMINING WHY CERTAIN PATIENTS HAVE INCREASED POSTOPERATIVE PAIN, WITH THE POTENTIAL TO DEVELOP CHRONIC PAIN. THE PURPOSE OF THIS STUDY WAS TO: 1) IDENTIFY AND DESCRIBE GENES THAT AFFECT POSTOPERATIVE PAIN PERCEPTION AND CONTROL; 2) ADDRESS MODIFIABLE RISK FACTORS THAT RESULT IN EPIGENETIC ALTERED RESPONSES TO PAIN; AND 3) CHARACTERIZE DIFFERENCES IN PAIN SENSITIVITY AND THRESHOLDS BETWEEN OPIOID-NAIVE AND OPIOID-DEPENDENT PATIENTS. MATERIALS AND METHODS: THREE ELECTRONIC DATABASES WERE USED TO CONDUCT THE LITERATURE SEARCH: PUBMED, EBSCO HOST, AND SCOPUS. A TOTAL OF 372 ABSTRACTS WERE REVIEWED, OF WHICH 46 STUDIES WERE DEEMED RELEVANT AND ARE INCLUDED IN THIS REVIEW. RESULTS: SPECIFIC GENE ALTERATIONS THAT WERE SHOWN TO AFFECT POSTOPERATIVE PAIN CONTROL INCLUDED SINGLE NUCLEOTIDE POLYMORPHISMS IN THE MU, KAPPA, AND DELTA OPIOID RECEPTORS, ION CHANNEL GENES, CYTOTOXIC T-CELLS, GLUTAMATE RECEPTORS AND CYTOKINE GENES, AMONG OTHERS. ALCOHOLISM, OBESITY, AND SMOKING WERE ALL LINKED WITH GENETIC POLYMORPHISMS THAT ALTERED PAIN SENSITIVITY. OPIOID ABUSE WAS FOUND TO BE ASSOCIATED WITH A POORER RESPONSE TO ANALGESICS POSTOPERATIVELY, AS WELL AS A RISK FOR PRESCRIPTION OVERDOSE. CONCLUSION: ALTHOUGH PAIN PERCEPTION HAS MULTIPLE COMPLEX INFLUENCES, THE GREATEST VARIABILITY SEEN IN RESPONSE TO OPIOIDS AMONG POSTOPERATIVE PATIENTS KNOWN TO DATE CAN BE TRACED TO GENETIC DIFFERENCES IN OPIOID METABOLISM. FURTHER STUDY IS NEEDED TO DETERMINE THE CLINICAL SIGNIFICANCE OF THESE GENETIC ASSOCIATIONS. 2018 10 404 38 ANALYSIS OF EPIGENETIC AGE PREDICTORS IN PAIN-RELATED CONDITIONS. CHRONIC PAIN PREVALENCE IS HIGH WORLDWIDE AND INCREASES AT OLDER AGES. SIGNS OF PREMATURE AGING HAVE BEEN ASSOCIATED WITH CHRONIC PAIN, BUT FEW STUDIES HAVE INVESTIGATED AGING BIOMARKERS IN PAIN-RELATED CONDITIONS. A SET OF DNA METHYLATION (DNAM)-BASED ESTIMATES OF AGE, CALLED "EPIGENETIC CLOCKS," HAS BEEN PROPOSED AS BIOLOGICAL MEASURES OF AGE-RELATED ADVERSE PROCESSES, MORBIDITY, AND MORTALITY. THE AIM OF THIS STUDY IS TO ASSESS IF DIFFERENT PAIN-RELATED PHENOTYPES SHOW ALTERATIONS IN DNAM AGE. IN OUR ANALYSIS, WE CONSIDERED THREE COHORTS FOR WHICH WHOLE-BLOOD DNAM DATA WERE AVAILABLE: HEAT PAIN SENSITIVITY (HPS), INCLUDING 20 MONOZYGOTIC TWIN PAIRS DISCORDANT FOR HEAT PAIN TEMPERATURE THRESHOLD; FIBROMYALGIA (FM), INCLUDING 24 CASES AND 20 CONTROLS; AND HEADACHE, INCLUDING 22 CHRONIC MIGRAINE AND MEDICATION OVERUSE HEADACHE PATIENTS (MOH), 18 EPISODIC MIGRAINEURS (EM), AND 13 HEALTHY SUBJECTS. WE USED THE HORVATH'S EPIGENETIC AGE CALCULATOR TO OBTAIN DNAM-BASED ESTIMATES OF EPIGENETIC AGE, TELOMERE LENGTH, LEVELS OF 7 PROTEINS IN PLASMA, NUMBER OF SMOKED PACKS OF CIGARETTES PER YEAR, AND BLOOD CELL COUNTS. WE DID NOT FIND DIFFERENCES IN EPIGENETIC AGE ACCELERATION, CALCULATED USING FIVE DIFFERENT EPIGENETIC CLOCKS, BETWEEN SUBJECTS DISCORDANT FOR PAIN-RELATED PHENOTYPES. TWINS WITH HIGH HPS HAD INCREASED CD8+ T CELL COUNTS (NOMINAL P = 0.028). HPS THRESHOLDS WERE NEGATIVELY ASSOCIATED WITH ESTIMATED LEVELS OF GDF15 (NOMINAL P = 0.008). FM PATIENTS SHOWED DECREASED NAIVE CD4+ T CELL COUNTS COMPARED WITH CONTROLS (NOMINAL P = 0.015). THE SEVERITY OF FM MANIFESTATIONS EXPRESSED THROUGH VARIOUS EVALUATION TESTS WAS ASSOCIATED WITH DECREASED LEVELS OF LEPTIN, SHORTER LENGTH OF TELOMERES, AND REDUCED CD8+ T AND NATURAL KILLER CELL COUNTS (NOMINAL P < 0.05), WHILE THE DURATION OF PAINFUL SYMPTOMS WAS POSITIVELY ASSOCIATED WITH TELOMERE LENGTH (NOMINAL P = 0.034). NO DIFFERENCES IN DNAM-BASED ESTIMATES WERE DETECTED FOR MOH OR EM COMPARED WITH CONTROLS. IN SUMMARY, OUR STUDY SUGGESTS THAT HPS, FM, AND MOH/EM DO NOT SHOW SIGNS OF EPIGENETIC AGE ACCELERATION IN WHOLE BLOOD, WHILE HPS AND FM ARE ASSOCIATED WITH DNAM-BASED ESTIMATES OF IMMUNOLOGICAL PARAMETERS, PLASMA PROTEINS, AND TELOMERE LENGTH. FUTURE STUDIES SHOULD EXTEND THESE OBSERVATIONS IN LARGER COHORTS. 2020 11 2353 38 EPIGENETIC REGULATION OF OPIOID-INDUCED HYPERALGESIA, DEPENDENCE, AND TOLERANCE IN MICE. REPEATED ADMINISTRATION OF OPIOIDS SUCH AS MORPHINE INDUCES PERSISTENT BEHAVIORAL CHANGES INCLUDING OPIOID-INDUCED HYPERALGESIA (OIH), TOLERANCE, AND PHYSICAL DEPENDENCE. IN THE CURRENT WORK WE EXPLORED HOW THE BALANCE OF HISTONE ACETYLTRANSFERASE (HAT) VERSUS HISTONE DEACETYLASE (HDAC) MIGHT REGULATE THESE MORPHINE-INDUCED CHANGES. NOCICEPTIVE THRESHOLDS, ANALGESIA, AND PHYSICAL DEPENDENCE WERE ASSESSED DURING AND FOR A PERIOD OF SEVERAL WEEKS AFTER MORPHINE EXPOSURE. TO PROBE THE ROLES OF HISTONE ACETYLATION, THE HAT INHIBITOR CURCUMIN OR A SELECTIVE HDAC INHIBITOR SUBEROYLANILIDE HYDROXAMIC ACID (SAHA) WAS ADMINISTERED DAILY TO GROUPS OF ANIMALS. HISTONE ACETYLATION IN SPINAL CORD WAS ASSESSED BY WESTERN BLOT AND IMMUNOHISTOCHEMISTRY. CONCURRENT ADMINISTRATION OF CURCUMIN WITH MORPHINE FOR 4 DAYS SIGNIFICANTLY REDUCED DEVELOPMENT OF OPIOID-INDUCED MECHANICAL ALLODYNIA, THERMAL HYPERALGESIA, TOLERANCE, AND PHYSICAL DEPENDENCE. CONVERSELY, THE HDAC INHIBITOR SAHA ENHANCED THESE RESPONSES. INTERESTINGLY, SAHA TREATMENT AFTER THE TERMINATION OF OPIOID ADMINISTRATION SUSTAINED THESE BEHAVIORAL CHANGES FOR AT LEAST 4 WEEKS. HISTONE H3 ACETYLATION IN THE DORSAL HORN OF THE SPINAL CORD WAS INCREASED AFTER CHRONIC MORPHINE TREATMENT, BUT H4 ACETYLATION WAS UNCHANGED. MOREOVER, WE OBSERVED A DECREASE IN HDAC ACTIVITY IN THE SPINAL CORDS OF MORPHINE-TREATED MICE WHILE OVERALL HAT ACTIVITY WAS UNCHANGED, SUGGESTING A SHIFT TOWARD A STATE OF ENHANCED HISTONE ACETYLATION. PERSPECTIVE: THE CURRENT STUDY INDICATES THAT EPIGENETIC MECHANISMS PLAY A CRUCIAL ROLE IN OPIOID-INDUCED LONG-LASTING NEUROPLASTICITY. THESE RESULTS PROVIDE NEW SIGHT INTO UNDERSTANDING THE MECHANISMS OF OPIOID-INDUCED NEUROPLASTICITY AND SUGGEST NEW STRATEGIES TO LIMIT OPIOID ABUSE POTENTIAL AND INCREASE THE VALUE OF THESE DRUGS AS ANALGESICS. 2013 12 6559 26 TRANSGENERATIONAL INFLUENCE OF PARENTAL MORPHINE EXPOSURE ON PAIN PERCEPTION, ANXIETY-LIKE BEHAVIOR AND PASSIVE AVOIDANCE MEMORY AMONG MALE AND FEMALE OFFSPRING OF WISTAR RATS. ACCUMULATING EVIDENCE SUGGESTS THAT EPIGENETIC MECHANISMS PLAY AN IMPORTANT ROLE IN THE FORMATION AND MAINTENANCE OF MEMORY WITHIN THE BRAIN. MOREOVER, THE EFFECT OF PARENTAL DRUG-EXPOSURE BEFORE GESTATION ON BEHAVIORAL STATE OF OFFSPRING HAS BEEN LITTLE STUDIED. THE MAIN OBJECTIVE OF THE CURRENT STUDY IS TO EVALUATE THE EFFECT OF PARENTAL MORPHINE EXPOSURE ON AVOIDANCE MEMORY, MORPHINE PREFERENCE AND ANXIETY-LIKE BEHAVIOR OF OFFSPRING. THE TOTAL OF 32 MALES AND 32 FEMALES WERE USED FOR MATING. THE ANIMALS WERE TREATED WITH MORPHINE. THE OFFSPRING ACCORDING TO THEIR PARENTAL MORPHINE TREATMENT WAS DIVIDED INTO FOUR GROUPS (N=16) INCLUDING PATERNALLY TREATED, MATERNALLY TREATED, BOTH OF PARENTS TREATED AND NAIVE ANIMALS. THE PAIN PERCEPTION, ANXIETY-LIKE BEHAVIOR, AND AVOIDANCE MEMORY WERE EVALUATED IN THE OFFSPRING. IN THE CURRENT STUDY, THE TOTAL OF 256 OFFSPRING WAS USED FOR THE EXPERIMENTS (4 TASKS X 4 GROUPS OF OFFSPRING X 8 FEMALE OFFSPRING X 8 MALE OFFSPRING). THE FINDING REVEALED THAT THE AVOIDANCE MEMORY AND VISCERAL PAIN WERE REDUCED SIGNIFICANTLY IN MALE AND FEMALE OFFSPRING WITH AT LEAST ONE MORPHINE-TREATED PARENT. MOREOVER, ANXIETY-LIKE BEHAVIOR WAS REDUCED SIGNIFICANTLY IN THE MALE OFFSPRING WITH AT LEAST ONE MORPHINE-TREATED PARENT. WHILE ANXIETY-LIKE BEHAVIOR WAS INCREASED SIGNIFICANTLY IN FEMALE OFFSPRING THAT WERE TREATED BY MORPHINE EITHER MATERNALLY OR BOTH OF PARENTS. THE DATA REVEALED THAT THE ENDOGENOUS OPIOID SYSTEM MAY BE ALTERED IN THE OFFSPRING OF MORPHINE-TREATED PARENT(S), AND EPIGENETIC ROLE COULD BE IMPORTANT. HOWEVER, ANALYSIS OF VARIANCE SIGNIFIED THE IMPORTANT ROLE OF MATERNAL INHERITANCE. 2019 13 2300 30 EPIGENETIC REGULATION OF BDNF EXPRESSION IN THE PRIMARY SENSORY NEURONS AFTER PERIPHERAL NERVE INJURY: IMPLICATIONS IN THE DEVELOPMENT OF NEUROPATHIC PAIN. BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) IS KNOWN TO BE UP-REGULATED IN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY, AND TO CONTRIBUTE TO NEUROPATHIC PAIN. HERE, WE FOUND THAT THERMAL HYPERALGESIA AND MECHANICAL ALLODYNIA AT DAY 7 POST-INJURY WERE INHIBITED ONLY WHEN ANTI-BDNF ANTIBODY WAS INTRATHECALLY ADMINISTRATED AT DAY 2 POST-INJURY. CONSISTENT WITH BEHAVIORAL RESULTS, WESTERN BLOT ANALYSIS SHOWED THAT THE EXPRESSION LEVELS OF BDNF PROTEIN IN THE SPINAL DORSAL HORN WERE MARKEDLY INDUCED DURING EARLY STAGE POST-INJURY. MOREOVER, THE MAXIMAL INCREASE IN BDNF MRNA EXPRESSION IN THE DRG WAS OBSERVED AT DAY 1 POST-INJURY, AND SIGNIFICANTLY ELEVATED LEVELS WERE SUSTAINED FOR AT LEAST 14 DAYS. FOUR OF FIVE BDNF MRNA TRANSCRIPTS WERE UP-REGULATED AFTER NERVE INJURY, AND THE MOST INDUCIBLE TRANSCRIPT WAS EXON I. USING A CHROMATIN IMMUNOPRECIPITATION (CHIP) ASSAY, WE FOUND THAT NERVE INJURY PROMOTES HISTONE H3 AND H4 ACETYLATION, TRANSCRIPTIONALLY ACTIVE MODIFICATIONS, AT BDNF PROMOTER I AT DAY 1 POST-INJURY, AND THE LEVELS OF HISTONE ACETYLATION REMAIN ELEVATED FOR AT LEAST 7 DAYS. TAKEN TOGETHER, OUR FINDINGS SUGGEST THAT AN INITIAL INCREASE IN BDNF EXON I EXPRESSION CONTROLLED BY EPIGENETIC MECHANISMS MIGHT HAVE A CRUCIAL ROLE IN THE DEVELOPMENT OF NEUROPATHIC PAIN. 2013 14 1803 21 EFFECT OF PROLONGED EMOTIONAL AND PAIN STRESS ON THE CONTENT OF METHYLCYTOSINE-BINDING PROTEIN MECP2 IN NUCLEI OF HIPPOCAMPAL NEURONS IN RATS WITH DIFFERENT EXCITABILITY OF THE NERVOUS SYSTEM. IN RATS WITH LOW EXCITABILITY THRESHOLD OF THE NERVOUS SYSTEM DEMONSTRATING SIGNIFICANT AND PERSISTENT BEHAVIORAL DISORDERS UNDER STRESS CONDITIONS, THE CONTENT OF METHYLCYTOSINE-BINDING PROTEIN MECP2 IN NEURONAL NUCLEI OF HIPPOCAMPAL FIELD CA3 DECREASED OVER 2 WEEKS AFTER LONG-TERM EMOTIONAL AND PAIN STRESS. IT WAS HYPOTHESIZED THAT PROTEIN MECP2 TRIGGERS EPIGENETIC CHANGES IN DNA THAT UNDERLIE "STRESS MEMORY". 2006 15 219 32 ACUTE IMMOBILIZATION STRESS FOLLOWING CONTEXTUAL FEAR CONDITIONING REDUCES FEAR MEMORY: TIMING IS ESSENTIAL. BACKGROUND: HISTONE ACETYLATION IS REGULATED IN RESPONSE TO STRESS AND PLAYS AN IMPORTANT ROLE IN LEARNING AND MEMORY. CHRONIC STRESS IS KNOWN TO DETERIORATE COGNITION, WHEREAS ACUTE STRESS FACILITATES MEMORY FORMATION. HOWEVER, WHETHER ACUTE STRESS FACILITATES MEMORY FORMATION WHEN IT IS APPLIED AFTER FEAR STIMULATION IS NOT YET KNOWN. THEREFORE, THIS STUDY AIMED TO INVESTIGATE THE EFFECT OF ACUTE STRESS APPLIED AFTER FEAR TRAINING ON MEMORY FORMATION, MRNA EXPRESSION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), EPIGENETIC REGULATION OF BDNF EXPRESSION, AND CORTICOSTERONE LEVEL IN MICE IN VIVO. METHODS: MICE WERE SUBJECTED TO ACUTE IMMOBILIZATION STRESS FOR 30 MIN AT 60 OR 90 MIN AFTER CONTEXTUAL FEAR CONDITIONING TRAINING, AND ACETYLATION OF HISTONE 3 AT LYSINE 14 (H3K14) AND LEVEL OF CORTICOSTERONE WERE MEASURED USING WESTERN BLOT ANALYSIS AND ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA), RESPECTIVELY. A FREEZING BEHAVIOR TEST WAS PERFORMED 24 H AFTER TRAINING, AND MRNA EXPRESSION OF BDNF WAS MEASURED USING REAL-TIME POLYMERASE CHAIN REACTIONS. DIFFERENT GROUPS OF MICE WERE USED FOR EACH TEST. RESULTS: FREEZING BEHAVIOR SIGNIFICANTLY DECREASED WITH THE DOWN-REGULATION OF BDNF MRNA EXPRESSION CAUSED BY ACUTE IMMOBILIZATION STRESS AT 60 MIN AFTER FEAR CONDITIONING TRAINING OWING TO THE REDUCTION OF H3K14 ACETYLATION. HOWEVER, BDNF MRNA EXPRESSION AND H3K14 ACETYLATION WERE NOT REDUCED IN ANIMALS SUBJECTED TO IMMOBILIZATION STRESS AT 90 MIN AFTER THE TRAINING. FURTHER, THE CORTICOSTERONE LEVEL WAS SIGNIFICANTLY HIGH IN MICE SUBJECTED TO IMMOBILIZATION STRESS AT 60 MIN AFTER THE TRAINING. CONCLUSION: ACUTE IMMOBILIZATION STRESS FOR 30 MIN AT 60 MIN AFTER FEAR CONDITIONING TRAINING IMPAIRED MEMORY FORMATION AND REDUCED BDNF MRNA EXPRESSION AND H3K14 ACETYLATION IN THE HIPPOCAMPUS OF MICE OWING TO THE HIGH LEVEL OF CORTICOSTERONE. 2016 16 119 33 A SYSTEMATIC EXAMINATION OF BRAIN VOLUMETRIC ABNORMALITIES IN RECENT-ONSET SCHIZOPHRENIA USING VOXEL-BASED, SURFACE-BASED AND REGION-OF-INTEREST-BASED MORPHOMETRIC ANALYSES. BACKGROUND: BRAIN MORPHOMETRIC ABNORMALITIES IN SCHIZOPHRENIA HAVE BEEN EXTENSIVELY REPORTED IN THE LITERATURE. WHOLE-BRAIN VOLUMETRIC REDUCTIONS ARE ALMOST UNIVERSALLY REPORTED BY MOST STUDIES IRRESPECTIVE OF THE CHARACTERISTICS OF THE SAMPLES STUDIED (E.G., CHRONIC/RECENT-ONSET; MEDICATED/NEUROLEPTIC-NAIVE ETC.). HOWEVER, THE SAME CANNOT BE SAID OF THE REPORTED REGIONAL MORPHOMETRIC ABNORMALITIES IN SCHIZOPHRENIA. WHILE CERTAIN REGIONAL MORPHOMETRIC ABNORMALITIES ARE MORE FREQUENTLY REPORTED THAN OTHERS, THERE ARE NO SUCH ABNORMALITIES THAT ARE UNIVERSALLY REPORTED ACROSS STUDIES. VARIABILITY OF SOCIO-DEMOGRAPHIC AND CLINICAL CHARACTERISTICS ACROSS STUDY SAMPLES AS WELL AS TECHNICAL AND METHODOLOGICAL ISSUES RELATED TO ACQUISITION AND ANALYSES OF BRAIN STRUCTURAL IMAGES MAY CONTRIBUTE TO INCONSISTENCY OF BRAIN MORPHOMETRIC FINDINGS IN SCHIZOPHRENIA. THE OBJECTIVE OF THE PRESENT STUDY THEREFORE WAS TO SYSTEMATICALLY EXAMINE BRAIN MORPHOMETRY IN PATIENTS WITH RECENT-ONSET SCHIZOPHRENIA TO FIND OUT IF THERE ARE SIGNIFICANT WHOLE-BRAIN OR REGIONAL VOLUMETRIC DIFFERENCES DETECTABLE AT THE APPROPRIATE SIGNIFICANCE THRESHOLD, AFTER ATTEMPTING TO CONTROL FOR VARIOUS CONFOUNDING FACTORS THAT COULD IMPACT BRAIN VOLUMES. METHODS: STRUCTURAL MAGNETIC RESONANCE IMAGES OF 90 SUBJECTS (SCHIZOPHRENIA = 45; HEALTHY SUBJECTS = 45) WERE ACQUIRED USING A 3 TESLA MAGNET. MORPHOMETRIC ANALYSES WERE CARRIED OUT FOLLOWING STANDARD ANALYSES PIPELINES OF THREE MOST COMMONLY USED STRATEGIES, VIZ., WHOLE-BRAIN VOXEL-BASED MORPHOMETRY, WHOLE-BRAIN SURFACE-BASED MORPHOMETRY, AND BETWEEN-GROUP COMPARISONS OF REGIONAL VOLUMES GENERATED BY AUTOMATED SEGMENTATION AND PARCELLATION. RESULTS: IN OUR SAMPLE OF PATIENTS HAVING RECENT-ONSET SCHIZOPHRENIA WITH LIMITED NEUROLEPTIC EXPOSURE, THERE WERE NO SIGNIFICANT WHOLE BRAIN OR REGIONAL BRAIN MORPHOMETRIC ABNORMALITIES NOTED AT THE APPROPRIATE STATISTICAL SIGNIFICANCE THRESHOLDS WITH OR WITHOUT INCLUDING AGE, GENDER AND INTRACRANIAL VOLUME OR TOTAL BRAIN VOLUME IN THE STATISTICAL ANALYSES. CONCLUSIONS: IN THE BACKGROUND OF THE CONFLICTING FINDINGS IN THE LITERATURE, OUR FINDINGS INDICATE THAT BRAIN MORPHOMETRIC ABNORMALITIES MAY NOT BE DIRECTLY RELATED TO THE SCHIZOPHRENIA PHENOTYPE. ANALYSIS OF THE REASONS FOR THE INCONSISTENT RESULTS ACROSS STUDIES AS WELL AS CONSIDERATION OF ALTERNATE SOURCES OF VARIABILITY OF BRAIN MORPHOLOGY IN SCHIZOPHRENIA SUCH AS EPISTATIC AND EPIGENETIC MECHANISMS COULD PERHAPS ADVANCE OUR UNDERSTANDING OF STRUCTURAL BRAIN ALTERATIONS IN SCHIZOPHRENIA. 2015 17 4913 34 PAIN MODULATION IN WAG/RIJ EPILEPTIC RATS (A GENETIC MODEL OF ABSENCE EPILEPSY): EFFECTS OF BIOLOGICAL AND PHARMACOLOGICAL HISTONE DEACETYLASE INHIBITORS. EPIGENETIC MECHANISMS ARE INVOLVED IN EPILEPSY AND CHRONIC PAIN DEVELOPMENT. ABOUT THAT, WE STUDIED THE EFFECTS OF THE NATURAL HISTONE DEACETYLASE (HDAC) INHIBITOR SODIUM BUTYRATE (BUT) IN COMPARISON WITH VALPROIC ACID (VPA) IN A VALIDATED GENETIC MODEL OF GENERALIZED ABSENCE EPILEPSY AND EPILEPTOGENESIS. WAG/RIJ RATS WERE TREATED WITH BUT (30 MG/KG), VPA (300 MG/KG), AND THEIR COMBINATION (BUT + VPA) DAILY PER OS FOR 6 MONTHS. RATS WERE SUBJECTED AT RANDALL-SELITTO, VON FREY, HOT PLATE, AND TAIL FLICK TESTS AFTER 1, 3, AND 6 MONTHS OF TREATMENT TO EVALUATE HYPERSENSITIVITY TO NOXIOUS AND NON-NOXIUOUS STIMULI. MOREOVER, PPAR-GAMMA (G3335 1 MG/KG), GABA-B (CGP35348 80 MG/KG), AND OPIOID (NALOXONE 1 MG/KG) RECEPTOR ANTAGONISTS WERE ADMINISTRATED TO INVESTIGATE THE POSSIBLE MECHANISMS INVOLVED IN ANALGESIC ACTIVITY. THE EXPRESSION OF NFKB, GLUTATHIONE REDUCTASE, AND PROTEIN OXIDATION (CARBONYLATION) WAS ALSO EVALUATED BY WESTERN BLOT ANALYSIS. WAG/RIJ RATS SHOWED AN ALTERED PAIN THRESHOLD THROUGHOUT THE STUDY (P < 0.001). BUT AND BUT + VPA TREATMENT REDUCED HYPERSENSITIVITY (P < 0.01). VPA WAS SIGNIFICANTLY EFFECTIVE ONLY AFTER 1 MONTH (P < 0.01). ALL THE THREE RECEPTORS ARE INVOLVED IN BUT + VPA EFFECTS (P < 0.001). BUT AND BUT + VPA DECREASED THE EXPRESSION OF NFKB AND ENHANCED GLUTATHIONE REDUCTASE (P < 0.01); PROTEIN OXIDATION (CARBONYLATION) WAS REDUCED (P < 0.01). NO EFFECT WAS REPORTED WITH VPA. IN CONCLUSION BUT, ALONE OR IN COADMINISTRATION WITH VPA, IS A VALUABLE CANDIDATE FOR MANAGING THE EPILEPSY-RELATED PERSISTENT PAIN. 2020 18 3600 45 IMPORTANCE OF EPIGENETIC MECHANISMS IN VISCERAL PAIN INDUCED BY CHRONIC WATER AVOIDANCE STRESS. EPIGENETIC MOLECULAR MECHANISMS, WHICH INCLUDE DNA METHYLATION AND HISTONE DEACETYLATION, ARE IMPLICATED IN THE DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS. PREVIOUSLY, WE DEMONSTRATED THAT REPEATED WATER AVOIDANCE STRESS (WAS), A VALIDATED MODEL OF CHRONIC PSYCHOLOGICAL STRESS, INDUCES HEIGHTENED VISCERAL PAIN BEHAVIORS IN RODENTS THAT RESEMBLE IRRITABLE BOWEL SYNDROME (IBS) SEQUELAE. HOWEVER, THE INVOLVEMENT OF EPIGENETIC MOLECULAR MECHANISMS IN THE PATHOPHYSIOLOGY OF STRESS-INDUCED VISCERAL PAIN HAS NOT BEEN EXPLORED. OUR HYPOTHESIS IS THAT EPIGENETIC MECHANISMS WITHIN THE CENTRAL NERVOUS SYSTEM (CNS) ARE IMPORTANT TO CHRONIC STRESS-INDUCED VISCERAL HYPERSENSITIVITY. ADULT MALE F-344 RATS WITH INTRACEREBROVENTRICULAR (I.C.V.) CANNULAE WERE EXPOSED TO 7 DAYS OF REPEATED WAS. CONTROLS RECEIVED A SHAM STRESS. FOLLOWING THE DAILY 1H STRESSOR, TRICHOSTATIN A (TSA; 100 NG/ML), A POTENT HISTONE DEACETYLASE INHIBITOR, OR VEHICLE (VEH; 0.1% DMSO/SALINE,) AS CONTROL WAS ADMINISTERED VIA THE I.C.V. CANNULA. VISCERAL SENSITIVITY WAS ASSESSED 24H AFTER THE FINAL WAS AND QUANTIFIED THE VISCEROMOTOR RESPONSE (VMR) BY RECORDING THE NUMBER OF ABDOMINAL CONTRACTIONS IN RESPONSE TO GRADED PRESSURES (20-60 MMHG) OF COLORECTAL DISTENSIONS (CRD). FROM A SEPARATE GROUP OF RATS THAT WERE EXPOSED TO REPEATED WAS OR SHAM STRESS, THE AMYGDALA WAS ISOLATED TO ASSESS THE METHYLATION STATUS OF GLUCOCORTICOID RECEPTOR (GR) AND CORTICOTROPIN RELEASING-FACTOR (CRF) GENES VIA BISULFITE SEQUENCING AND VERIFIED BY PYROSEQUENCING. GR AND CRF GENE EXPRESSION WAS QUANTIFIED VIA QRT-PCR. STRESSED RATS EXHIBITED VISCERAL HYPERSENSITIVITY THAT WAS SIGNIFICANTLY ATTENUATED BY TSA. COMPARED TO SHAM CONTROLS, METHYLATION OF THE GR GENE WAS INCREASED FOLLOWING WAS WHILE EXPRESSION OF THE GR GENE WAS DECREASED. METHYLATION OF THE CRF PROMOTER WAS DECREASED WITH WAS WITH A CONCOMITANT INCREASE IN CRF EXPRESSION. THIS STUDY DEMONSTRATES THE INVOLVEMENT OF CENTRAL EPIGENETIC MECHANISMS IN REGULATING STRESS-INDUCED VISCERAL HYPERSENSITIVITY AND PROVIDES A FOUNDATION FOR EXPLORING THE EPIGENETIC MECHANISMS THAT MAY CONTRIBUTE TO IBS-LIKE SYMPTOMATOLOGY. 2013 19 4402 29 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 20 1818 37 EFFECTS OF CHRONIC METHAMPHETAMINE EXPOSURE ON REWARDING BEHAVIOR AND NEURODEGENERATION MARKERS IN ADULT MICE. RECREATIONAL AND MEDICAL USE OF STIMULANTS AMONG YOUNG ADULTS HAVE GAINED POPULARITY IN THE UNITED STATES OVER THE LAST DECADE AND THEIR USE MAY INCREASE VULNERABILITY TO BRAIN BIOCHEMICAL CHANGES AND ADDICTIVE BEHAVIORS. THE LONG-TERM EFFECTS OF CHRONIC STIMULANT EXPOSURE IN LATER ADULTHOOD HAVE NOT BEEN FULLY ELUCIDATED.OUR STUDY INVESTIGATED WHETHER CHRONIC EXPOSURE TO METHAMPHETAMINE (METH), AT A DOSE DESIGNED TO EMULATE HUMAN THERAPEUTIC DOSING FOR ADHD, WOULD PROMOTE BIOCHEMICAL ALTERATIONS AND AFFECT SENSITIVITY TO THE REWARDING EFFECTS OF SUBSEQUENT METH DOSING.GROUPS OF 3.5-MONTH-OLD MALE AND FEMALE C57BL/6J MICE WERE ADMINISTERED NON-CONTINGENT INTRAPERITONEAL INJECTIONS OF EITHER SALINE OR METH (1.4 MG/KG) TWICE A DAY FOR 1 MONTH (5 DAYS/WEEK). METH (0.5 MG/KG)-INDUCED CONDITIONED PLACE PREFERENCE (CPP) WAS TESTED IN MICE TO DETERMINE THE EFFECTS OF PREVIOUS METH EXPOSURE ON REWARD-RELATED BEHAVIOR. MICE WERE RANDOMLY ASSIGNED TO EXPERIMENT I (MALES AND FEMALES) OR EXPERIMENT II (FEMALES ONLY) IN WHICH CPP TESTING WAS RESPECTIVELY PERFORMED EITHER 0.5 OR 5 MONTHS AFTER THE END OF METH INJECTIONS, AT ~5 OR 10 MONTHS OLD RESPECTIVELY. THE MIDBRAIN AND STRIATUM, REGIONS INVOLVED IN REWARD CIRCUIT, WERE ASSESSED FOR MARKERS ASSOCIATED WITH NEUROTOXICITY, DOPAMINERGIC FUNCTION, NEUROINFLAMMATION AND EPIGENETIC CHANGES AFTER BEHAVIORAL TESTING.PREVIOUS EXPOSURE TO CHRONIC METH DID NOT HAVE SIGNIFICANT SHORT-TERM EFFECTS ON CPP RESPONSE BUT LED TO A DECREASED CPP RESPONSE IN 10-MONTH-OLD FEMALES. PREVIOUS EXPOSURE TO METH INDUCED SOME SHORT-TERM CHANGES TO BIOCHEMICAL MARKERS MEASURED IN A BRAIN REGION AND SEX-DEPENDENT MANNER, WHILE LONG-TERM CHANGES WERE ONLY OBSERVED WITH GFAP AND KDM5C.IN CONCLUSION, OUR DATA SUGGEST SEX- AND POST-EXPOSURE DURATION-DEPENDENT OUTCOMES AND WARRANT FURTHER EXPLORATION OF THE LONG-TERM NEUROBEHAVIORAL CONSEQUENCES OF PSYCHOSTIMULANT USE IN BOTH SEXES. 2023