1 5328 160 PULSED RADIOFREQUENCY ATTENUATES COMPLETE FREUND'S ADJUVANT-INDUCED EPIGENETIC SUPPRESSION OF POTASSIUM CHLORIDE COTRANSPORTER 2 EXPRESSION. BACKGROUND: PULSED RADIOFREQUENCY (PRF) TREATMENT OFFERS PAIN RELIEF FOR PATIENTS SUFFERING FROM CHRONIC PAIN WHO DO NOT RESPOND WELL TO CONVENTIONAL TREATMENTS. WE TESTED WHETHER PRF TREATMENT ATTENUATED COMPLETE FREUND'S ADJUVANT (CFA)-INDUCED INFLAMMATORY PAIN. EPIGENETIC MODIFICATION OF POTASSIUM-CHLORIDE COTRANSPORTER 2 (KCC2) GENE EXPRESSION WAS EXAMINED TO ELUCIDATE THE POTENTIAL CONTRIBUTING MECHANISM. METHODS: MALE SPRAGUE-DAWLEY RATS WERE INJECTED WITH CFA INTO THE PLANTAR SURFACE OF THE LEFT HIND PAW TO INDUCE INFLAMMATION. PRF (20 MINUTES OF 500-KHZ RF PULSES, DELIVERED AT A RATE OF 2 HZ, MAXIMUM TEMPERATURE 42 MASCULINEC) WAS DELIVERED TO THE L5 AND L6 ANTERIOR PRIMARY RAMUS JUST DISTAL TO THE INTERVERTEBRAL FORAMEN OF ADULT CFA OR SALINE RATS. THE HIND PAW WITHDRAWAL THRESHOLD TO VON FREY FILAMENT STIMULI AND WITHDRAWAL LATENCY TO RADIANT HEAT WERE DETERMINED BEFORE AND AFTER CFA. ACETYL-HISTONE H3 AND H4 WAS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION IN SPINAL DORSAL HORN. KCC2 EXPRESSION WAS DETERMINED BY WESTERN BLOT. INHIBITORY SYNAPTIC FUNCTION WAS EVALUATED BY PATCH CLAMP IN LAMINA II NEURONS. RESULTS: KCC2 GENE EXPRESSION WAS SUPPRESSED THROUGH HISTONE HYPOACETYLATION, RESULTING IN DECREASED EFFICACY OF GABAERGIC SIGNALING IN CFA RATS. PRF INCREASED HISTONE ACETYLATION AND KCC2 EXPRESSION, PARTIALLY RESTORED THE GABA SYNAPTIC FUNCTION, AND RELIEVED SENSITIZED PAIN BEHAVIOR. CONCLUSION: THESE FINDINGS SUGGEST THAT PRF MIGHT BE AN ALTERNATIVE THERAPY FOR INFLAMMATORY PAIN. ONE OF THE UNDERLYING MECHANISMS IS THROUGH MODIFICATION OF KCC2, WHICH IS AN IMPORTANT DETERMINANT FOR THE EFFICACY OF INHIBITORY NEUROTRANSMISSION IN THE SPINAL CORD, AND ITS EXPRESSION LEVELS ARE REGULATED BY HISTONE ACETYLATION EPIGENETICALLY FOLLOWING INFLAMMATION. 2017 2 5075 28 PHYSIOLOGICAL ADAPTATION OF THE GROWTH-RESTRICTED FETUS. THE GROWTH-RESTRICTED FETUS IN UTERO IS EXPOSED TO A HOSTILE ENVIRONMENT AND SUFFERS UNDERNUTRITION AND HYPOXIA. TO COPE WITH THE STRESS, THE FETUS CHANGES ITS PHYSIOLOGICAL FUNCTIONS. THESE ADAPTIVE CHANGES AID INTRAUTERINE SURVIVAL; HOWEVER, THEY CAN LEAD TO PERMANENT FUNCTIONAL AND STRUCTURAL CHANGES THAT CAN CONTRIBUTE TO THE DEVELOPMENT OF SERIOUS CHRONIC DISEASES LATER IN LIFE. EPIGENETIC MECHANISMS ARE AN IMPORTANT PART OF THE PATHOPHYSIOLOGICAL PROCESSES BEHIND THIS "DEVELOPMENTAL ORIGIN OF ADULT DISEASES." THE DOMINANT CARDIOVASCULAR ADAPTIVE CHANGE IS THE REDISTRIBUTION OF BLOOD FLOW IN HYPOXIC FETUSES, WITH PREFERENTIAL SUPPLY OF BLOOD TO THE FETAL BRAIN, MYOCARDIUM, AND ADRENAL GLANDS. THE PROPORTION OF BLOOD FROM THE UMBILICAL VEIN TO THE DUCTUS VENOSUS AND FORAMEN OVALE INCREASES, WHICH INCREASES THE CARDIAC OUTPUT OF THE LEFT HEART VENTRICLE. THE INCREASED PERFUSION OF FETAL BRAIN CAN BE FOLLOWED WITH DOPPLER ULTRASOUND AS INCREASED DIASTOLIC VELOCITIES AND DECREASED PULSATILITY INDEX IN THE MIDDLE CEREBRAL ARTERY. 2018 3 2452 74 EPIGENETIC SUPPRESSION OF POTASSIUM-CHLORIDE CO-TRANSPORTER 2 EXPRESSION IN INFLAMMATORY PAIN INDUCED BY COMPLETE FREUND'S ADJUVANT (CFA). BACKGROUND: MULTIPLE MECHANISMS CONTRIBUTE TO THE STIMULUS-EVOKED PAIN HYPERSENSITIVITY THAT MAY BE EXPERIENCED AFTER PERIPHERAL INFLAMMATION. PERSISTENT PATHOLOGICAL STIMULI IN MANY PAIN CONDITIONS AFFECT THE EXPRESSION OF CERTAIN GENES THROUGH EPIGENETIC ALTERNATIONS. THE MAIN PURPOSE OF OUR STUDY WAS TO INVESTIGATE THE ROLE OF EPIGENETIC MODIFICATION ON POTASSIUM-CHLORIDE CO-TRANSPORTER 2 (KCC2) GENE EXPRESSION IN THE PERSISTENCE OF INFLAMMATORY PAIN. METHODS: PERSISTENT INFLAMMATORY PAIN WAS INDUCED THROUGH THE INJECTION OF COMPLETE FREUND'S ADJUVANT (CFA) IN THE LEFT HIND PAW OF RATS. ACETYL-HISTONE H3 AND H4 LEVEL WAS DETERMINED BY CHROMATIN IMMUNOPRECIPITATION IN THE SPINAL DORSAL HORN. PAIN BEHAVIOUR AND INHIBITORY SYNAPTIC FUNCTION OF SPINAL CORD WERE DETERMINED BEFORE AND AFTER CFA INJECTION. KCC2 EXPRESSION WAS DETERMINED BY REAL TIME RT-PCR AND WESTERN BLOT. INTRATHECAL KCC2 SIRNA (2 MUG PER 10 MUL PER RAT) OR HDAC INHIBITOR (10 MUG PER 10 MUL PER RAT) WAS INJECTED ONCE DAILY FOR 3 DAYS BEFORE CFA INJECTION. RESULTS: PERSISTENT INFLAMMATORY PAIN EPIGENETICALLY SUPPRESSED KCC2 EXPRESSION THROUGH HISTONE DEACETYLASE (HDAC)-MEDIATED HISTONE HYPOACETYLATION, RESULTING IN DECREASED INHIBITORY SIGNALLING EFFICACY. KCC2 KNOCK-DOWN CAUSED BY INTRATHECAL ADMINISTRATION OF KCC2 SIRNA IN NAIVE RATS REDUCED KCC2 EXPRESSION IN THE SPINAL CORD, LEADING TO SENSITIZED PAIN BEHAVIOURS AND IMPAIRED INHIBITORY SYNAPTIC TRANSMISSION IN THEIR SPINAL CORDS. MOREOVER, INTRATHECAL HDAC INHIBITOR INJECTION IN CFA RATS INCREASED KCC2 EXPRESSION, PARTIALLY RESTORING THE SPINAL INHIBITORY SYNAPTIC TRANSMISSION AND RELIEVING THE SENSITIZED PAIN BEHAVIOUR. CONCLUSION: THESE FINDINGS SUGGEST THAT THE TRANSCRIPTION OF SPINAL KCC2 IS REGULATED BY HISTONE ACETYLATION EPIGENETICALLY FOLLOWING CFA. SIGNIFICANCE: PERSISTENT PAIN SUPPRESSES KCC2 EXPRESSION THROUGH HDAC-MEDIATED HISTONE HYPOACETYLATION AND CONSEQUENTLY IMPAIRS THE INHIBITORY FUNCTION OF INHIBITORY INTERNEURONS. DRUGS SUCH AS HDAC INHIBITORS THAT SUPPRESS THE INFLUENCES OF PERSISTENT PAIN ON THE EXPRESSION OF KCC2 MAY SERVE AS A NOVEL ANALGESIC. 2017 4 3955 36 LONG MARCH TOWARD SAFE AND EFFECTIVE ANALGESIA BY ENHANCING GENE EXPRESSION OF KCC2: FIRST STEPS TAKEN. LOW INTRANEURONAL CHLORIDE IN SPINAL CORD DORSAL HORN PAIN RELAY NEURONS IS CRITICAL FOR PHYSIOLOGIC TRANSMISSION OF PRIMARY PAIN AFFERENTS BECAUSE LOW INTRANEURONAL CHLORIDE DICTATES WHETHER GABA-ERGIC AND GLYCIN-ERGIC NEUROTRANSMISSION IS INHIBITORY. IF THE NEURONAL CHLORIDE ELEVATES TO PATHOLOGIC LEVELS, THEN SPINAL CORD PRIMARY PAIN RELAY BECOMES LEAKY AND EXHIBITS THE BEHAVIORAL HALLMARKS OF PATHOLOGIC PAIN, NAMELY HYPERSENSITIVITY AND ALLODYNIA. LOW CHLORIDE IN SPINAL CORD DORSAL HORN NEURONS IS MAINTAINED BY PROPER GENE EXPRESSION OF KCC2 AND SUSTAINED PHYSIOLOGIC FUNCTION OF THE KCC2 CHLORIDE EXTRUDING ELECTRONEUTRAL TRANSPORTER. PERIPHERAL NERVE INJURY AND OTHER FORMS OF NEURAL INJURY EVOKE GREATLY DIMINISHED KCC2 GENE EXPRESSION AND SUBSEQUENT CORRUPTION OF INHIBITORY NEUROTRANSMISSION IN THE SPINAL CORD DORSAL HORN, THUS CAUSING DERAILMENT OF THE GATE FUNCTION FOR PAIN. HERE I REVIEW KEY DISCOVERIES THAT HAVE HELPED US UNDERSTAND THESE FUNDAMENTALS, AND FOCUS ON RECENT INSIGHTS RELATING TO THE DISCOVERY OF KCC2 GENE EXPRESSION ENHANCING COMPOUNDS VIA COMPOUND SCREENS IN NEURONS. ONE SUCH STUDY CHARACTERIZED THE KINASE INHIBITOR, KENPAULLONE, MORE IN-DEPTH, REVEALING ITS FUNCTION AS A ROBUST AND LONG-LASTING ANALGESIC IN PRECLINICAL MODELS OF NERVE INJURY AND CANCER BONE PAIN, ALSO ELUCIDATING ITS MECHANISM OF ACTION VIA GSK3BETA INHIBITION, DIMINISHING DELTA-CATENIN PHOSPHORYLATION, AND FACILITATING ITS NUCLEAR TRANSFER AND SUBSEQUENT ENHANCEMENT OF KCC2 GENE EXPRESSION BY DE-REPRESSING KAISO EPIGENETIC TRANSCRIPTIONAL REGULATOR. FUTURE DIRECTIONS RE KCC2 GENE EXPRESSION ENHANCEMENT ARE DISCUSSED, NAMELY COMBINATION WITH OTHER ANALGESICS AND ANALGESIC METHODS, SUCH AS SPINAL CORD STIMULATION AND ELECTROACUPUNCTURE, GENE THERAPY, AND LEVERAGING KCC2 GENE EXPRESSION-ENHANCING NANOMATERIALS. 2022 5 2448 44 EPIGENETIC SUPPRESSION OF GAD65 EXPRESSION MEDIATES PERSISTENT PAIN. CHRONIC PAIN IS A COMMON NEUROLOGICAL DISEASE INVOLVING LASTING, MULTIFACETED MALADAPTATIONS RANGING FROM GENE MODULATION TO SYNAPTIC DYSFUNCTION AND EMOTIONAL DISORDERS. SUSTAINED PATHOLOGICAL STIMULI IN MANY DISEASES ALTER THE OUTPUT ACTIVITIES OF CERTAIN GENES THROUGH EPIGENETIC MODIFICATIONS, BUT IT IS UNCLEAR HOW EPIGENETIC MECHANISMS OPERATE IN THE DEVELOPMENT OF CHRONIC PAIN. WE SHOW HERE THAT IN THE RAT BRAINSTEM NUCLEUS RAPHE MAGNUS, WHICH IS IMPORTANT FOR CENTRAL MECHANISMS OF CHRONIC PAIN, PERSISTENT INFLAMMATORY AND NEUROPATHIC PAIN EPIGENETICALLY SUPPRESSES GAD2 (ENCODING GLUTAMIC ACID DECARBOXYLASE 65 (GAD65)) TRANSCRIPTION THROUGH HISTONE DEACETYLASE (HDAC)-MEDIATED HISTONE HYPOACETYLATION, RESULTING IN IMPAIRED GAMMA-AMINOBUTYRIC ACID (GABA) SYNAPTIC INHIBITION. GAD2 KNOCKOUT MICE SHOWED SENSITIZED PAIN BEHAVIOR AND IMPAIRED GABA SYNAPTIC FUNCTION IN THEIR BRAINSTEM NEURONS. IN WILD-TYPE BUT NOT GAD2 KNOCKOUT MICE, HDAC INHIBITORS STRONGLY INCREASED GAD65 ACTIVITY, RESTORED GABA SYNAPTIC FUNCTION AND RELIEVED SENSITIZED PAIN BEHAVIOR. THESE FINDINGS SUGGEST GAD65 AND HDACS AS POTENTIAL THERAPEUTIC TARGETS IN AN EPIGENETIC APPROACH TO THE TREATMENT OF CHRONIC PAIN. 2011 6 2751 47 EXPRESSION OF ACETYL-HISTONE H3 AND ACETYL-HISTONE H4 IN DORSAL ROOT GANGLION AND SPINAL DORSAL HORN IN RAT CHRONIC PAIN MODELS. AIMS: HISTONE ACETYLATION AND DEACETYLATION ARE TWO HISTONE POSTTRANSLATIONAL MODIFICATIONS THAT ARE USUALLY CONTROLLED BY HISTONE ACETYLTRANSFERASES (HATS) AND HISTONE DEACETYLASES (HDACS). ALTHOUGH HATS OR HDACS INHIBITORS COULD RELIEVE PAIN HYPERSENSITIVITIES IN CHRONIC PAIN ANIMAL MODELS, IT IS NOT CLEAR ON THE EXPRESSION OF GLOBAL HISTONE ACETYLATION IN THE DORSAL ROOT GANGLION (DRG) OR SPINAL DORSAL HORN IN CHRONIC PAIN CONDITIONS. MAIN METHODS: A SPINAL NERVE LIGATION (SNL)-INDUCED NEUROPATHIC PAIN MODEL AND A COMPLETE FREUND'S ADJUVANT (CFA)-INDUCED INFLAMMATORY PAIN MODEL IN RATS WERE USED TO EXAMINE THE EXPRESSION OF TOTAL ACETYL-HISTONE H3 (ACH3) AND TOTAL ACETYL-HISTONE H4 (ACH4) BY IMMUNOFLUORESCENCE OR WESTERN BLOT. KEY FINDINGS: ACH3 AND ACH4 NOT ONLY LOCALIZED IN NEURONAL NUCLEI, BUT ALSO IN NUCLEI OF GLIAL CELLS IN THE DRG. UNILATERAL SNL INDUCED THE INCREASE OF ACH3 AND ACH4 EXPRESSION IN THE INJURED LUMBAR 5 (L5) DRG, BUT NOT IN THE UNINJURED L5 DRG OR THE SPINAL DORSAL HORN, WHILE UNILATERAL INTRAPLANTAR INJECTION OF CFA INCREASED ACH3 AND ACH4 EXPRESSION IN THE IPSILATERAL L4/5 SPINAL DORSAL HORN, BUT NOT IN THE L4/5 DRG. SIGNIFICANCE: THESE RESULTS PROVIDE MORPHOLOGICAL EVIDENCE FOR GLOBAL HISTONE ACETYLATION EXPRESSION IN THE DRG AND SPINAL CORD AND INDICATE THE DIFFERENTIAL EXPRESSION IN THE DRG AND SPINAL DORSAL HORN IN DIFFERENT CHRONIC PAIN MODELS. MORE PRECISE EPIGENETIC MECHANISMS OF HISTONE ACETYLATION ON THE TARGET GENES NEED TO BE REVEALED. 2018 7 5018 42 PERSISTENT INFLAMMATION-INDUCED UP-REGULATION OF BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) PROMOTES SYNAPTIC DELIVERY OF ALPHA-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLEPROPIONIC ACID RECEPTOR GLUA1 SUBUNITS IN DESCENDING PAIN MODULATORY CIRCUITS. THE ENHANCED AMPA RECEPTOR PHOSPHORYLATION AT GLUA1 SERINE 831 SITES IN THE CENTRAL PAIN-MODULATING SYSTEM PLAYS A PIVOTAL ROLE IN DESCENDING PAIN FACILITATION AFTER INFLAMMATION, BUT THE UNDERLYING MECHANISMS REMAIN UNCLEAR. WE SHOW HERE THAT, IN THE RAT BRAIN STEM, IN THE NUCLEUS RAPHE MAGNUS, WHICH IS A CRITICAL RELAY IN THE DESCENDING PAIN-MODULATING SYSTEM OF THE BRAIN, PERSISTENT INFLAMMATORY PAIN INDUCED BY COMPLETE FREUND ADJUVANT (CFA) CAN ENHANCE AMPA RECEPTOR-MEDIATED EXCITATORY POSTSYNAPTIC CURRENTS AND THE GLUA2-LACKING AMPA RECEPTOR-MEDIATED RECTIFICATION INDEX. WESTERN BLOT ANALYSIS SHOWED AN INCREASE IN GLUA1 PHOSPHORYLATION AT SER-831 BUT NOT AT SER-845. THIS WAS ACCOMPANIED BY AN INCREASE IN DISTRIBUTION OF THE SYNAPTIC GLUA1 SUBUNIT. IN PARALLEL, THE LEVEL OF HISTONE H3 ACETYLATION AT BDNF GENE PROMOTER REGIONS WAS REDUCED SIGNIFICANTLY 3 DAYS AFTER CFA INJECTION, AS INDICATED BY CHIP ASSAYS. THIS WAS CORRELATED WITH AN INCREASE IN BDNF MRNA LEVELS AND BDNF PROTEIN LEVELS. SEQUESTERING ENDOGENOUS EXTRACELLULAR BDNF WITH TRKB-IGG IN THE NUCLEUS RAPHE MAGNUS DECREASED AMPA RECEPTOR-MEDIATED SYNAPTIC TRANSMISSION AND GLUA1 PHOSPHORYLATION AT SER-831 3 DAYS AFTER CFA INJECTION. UNDER THE SAME CONDITIONS, BLOCKADE OF TRKB RECEPTOR FUNCTIONS, PHOSPHOLIPASE C, OR PKC IMPAIRED GLUA1 PHOSPHORYLATION AT SER-831 AND DECREASED EXCITATORY POSTSYNAPTIC CURRENTS MEDIATED BY GLUA2-LACKING AMPA RECEPTORS. TAKEN TOGETHER, THESE RESULTS SUGGEST THAT EPIGENETIC UP-REGULATION OF BDNF BY PERIPHERAL INFLAMMATION INDUCES GLUR1 PHOSPHORYLATION AT SER-831 SITES THROUGH ACTIVATION OF THE PHOSPHOLIPASE C-PKC SIGNALING CASCADE, LEADING TO THE TRAFFICKING OF GLUA1 TO PAIN-MODULATING NEURONAL SYNAPSES. 2014 8 6612 35 ULTRA-LOW-DOSE NALOXONE ENHANCES THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN PTX-TREATED RATS: REGULATION ON GLOBAL HISTONE METHYLATION. OBJECTIVE: EPIGENETIC REPROGRAMMING MAY HAVE A POSSIBLE ROLE IN NEUROPATHIC PAIN DEVELOPMENT; THE PRESENT STUDY EXAMINED THE GLOBAL PATTERNS OF LYSINE HISTONE MODIFICATION. IN THIS SERIAL STUDY WE ANALYZED THE LEVELS OF HISTONE 3 LYSINE 4 MONOMETHYLATION, HISTONE 3 LYSINE 4 DIMETHYLATION, AND HISTONE 3 LYSINE 9 TRIMETHYLATION IN PERTUSSIS TOXIN (PTX)-INDUCED THERMAL HYPERALGESIC RAT SPINAL CORDS. METHODS: MALE WISTAR RATS IMPLANTED WITH AN INTRATHECAL CATHETER RECEIVED A SINGLE INTRATHECAL PTX (1 MUG IN 5 MUL SALINE) INJECTION. FOUR DAYS LATER, THEY WERE RANDOMLY ASSIGNED TO RECEIVE EITHER A SINGLE INJECTION OF SALINE, OR ULTRA-LOW-DOSE NALOXONE (15 NG IN 5 MUL SALINE), FOLLOWED BY MORPHINE (10 MUG IN 5 MUL SALINE) INJECTION 30 MINUTES LATER. RESULTS: THE RESULTS SHOWED THAT PTX INJECTION INDUCED THERMAL HYPERALGESIA AND SIGNIFICANT INCREASE OF GLOBAL HISTONE METHYLATION IN THE SPINAL CORDS. INTRATHECAL MORPHINE ALONE DID NOT AFFECT THE THERMAL HYPERALGESIA AND GLOBAL HISTONE METHYLATION. IN CONTRAST, INTRATHECAL ADMINISTRATION OF ULTRA-LOW-DOSE NALOXONE PLUS MORPHINE SIGNIFICANTLY ATTENUATED THE PTX-INDUCED THERMAL HYPERALGESIA AND DOWN-REGULATED THE GLOBAL HISTONE METHYLATION. CONCLUSION: THE RESULTS SUGGEST THAT ULTRA-LOW-DOSE NALOXONE MIGHT BE CLINICAL VALUABLE FOR NEUROPATHIC PAIN MANAGEMENT VIA REGULATING GLOBAL HISTONE MODIFICATION. 2012 9 2680 34 EVALUATION OF EPIGENETIC (HDAC, DNMT) AND PAIN (GAD65, TGF) FACTORS FOLLOWING PHOTOBIOMODULATION THERAPY IN A NEUROPATHIC PAIN MODEL. PHOTOBIOMODULATION THERAPY (PBMT) IS CONVERTED TO THE MOST COMMON ANALGESIC TREATMENT BEFORE THE WHOLE MECHANISM IS YET TO BE DISCOVERED. THIS STUDY FOR THE FIRST TIME WAS DESIGNED TO INVESTIGATE ALTERNATIONS OF EPIGENETIC FACTORS AFTER PAIN AND PBMT. THE CCI MODEL WAS CHOSEN TO INDUCE PAIN. PAIN EVALUATION TESTS INCLUDING PLANTAR, ACETONE, VON FREY, AND PINCH WERE DONE WEEKLY. THEN SPINAL CORD TISSUE WAS ISOLATED FOR EVALUATING MRNA EXPRESSION OF DNMT3A, HDAC1, AND NRSF USING RT-QPCR METHOD, AND PROTEIN EXPRESSION FACTORS OF HDAC2 AND DNMT3A USING WESTERN BLOTTING. GAD65 AND TGF-BETA PROTEINS WERE ASSESSED BY THE IHC METHOD. PBMT INCREASED THE PAIN THRESHOLD UP TO THE POINT WHERE IT ROUGHLY MET THE PAIN THRESHOLD OF THE CONTROL GROUP. AFTER THREE WEEKS OF TREATMENT, BOTH PBMT PROTOCOLS DEMONSTRATED A REDUCTION IN ALLODYNIA AND HYPERALGESIA. WHILE SOME MOLECULES, SUCH AS TGF-BETA AND GAD65, INCREASED FOLLOWING PBMT, WE OBSERVED NO INHIBITION OF NRSF, HDAC1, AND DNMT3A EXPRESSION DESPITE IMPLEMENTING TWO DIFFERENT PROTOCOLS. 2023 10 687 45 BRAINSTEM BRAIN-DERIVED NEUROTROPHIC FACTOR SIGNALING IS REQUIRED FOR HISTONE DEACETYLASE INHIBITOR-INDUCED PAIN RELIEF. OUR PREVIOUS STUDY DEMONSTRATED THAT PERSISTENT PAIN CAN EPIGENETICALLY SUPPRESS THE TRANSCRIPTION OF GAD2 [ENCODING GLUTAMIC ACID DECARBOXYLASE 65 (GAD65)] AND CONSEQUENTLY IMPAIR THE INHIBITORY FUNCTION OF GABAERGIC SYNAPSES IN CENTRAL PAIN-MODULATING NEURONS. THIS CONTRIBUTES TO THE DEVELOPMENT OF PERSISTENT PAIN SENSITIZATION. HISTONE DEACETYLASE (HDAC) INHIBITORS INCREASED GAD65 ACTIVITY CONSIDERABLY, RESTORED GABA SYNAPTIC FUNCTION, AND RENDERED SENSITIZED PAIN BEHAVIOR LESS PRONOUNCED. HOWEVER, THE MOLECULAR MECHANISMS BY WHICH HDAC REGULATES GABAERGIC TRANSMISSION THROUGH GAD65 UNDER PAIN CONDITIONS ARE UNKNOWN. THIS WORK SHOWED THAT HDAC INHIBITOR-INDUCED INCREASES IN COLOCALIZATION OF GAD65 AND SYNAPTIC PROTEIN SYNAPSIN I ON THE PRESYNAPTIC AXON TERMINALS OF THE NUCLEUS RAPHE MAGNUS (NRM) WERE BLOCKED BY A TRKB RECEPTOR ANTAGONIST K252A [(9S,10R,12R)-2,3,9,10,11,12-HEXAHYDRO-10-HYDROXY-9-METHYL-1-OXO-9,12-EPOXY-1H-DIINDOLO[1,2,3-FG:3',2',1'-KL]PYRROLO[3,4-I][1,6]BENZODIAZOCINE-10-CARBOXYLIC ACID METHYL ESTER], INDICATING THAT BDNF-TRKB SIGNALING MAY BE REQUIRED IN GAD65 MODULATION OF GABA SYNAPTIC FUNCTION. AT THE BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) PROMOTER, HDAC INHIBITORS INDUCED SIGNIFICANT INCREASES IN H3 HYPERACETYLATION, CONSISTENT WITH THE INCREASE IN BDNF MRNA AND TOTAL PROTEINS. ALTHOUGH EXOGENOUS BDNF FACILITATED GABA MINIATURE INHIBITORY POSTSYNAPTIC CURRENTS AND GAD65 ACCUMULATION IN NRM NEURONAL SYNAPSES IN NORMAL RATS, IT FAILED TO DO SO IN ANIMALS SUBJECTED TO PERSISTENT INFLAMMATION. IN ADDITION, BLOCKADE OF THE TRKB RECEPTOR WITH K252A HAS NO EFFECT ON MINIATURE INHIBITORY POSTSYNAPTIC CURRENTS AND SYNAPTIC GAD65 ACCUMULATION UNDER NORMAL CONDITIONS. IN ADDITION, THE ANALGESIC EFFECTS OF HDAC INHIBITORS ON BEHAVIOR WERE BLOCKED BY NRM INFUSION OF K252A. THESE FINDINGS SUGGEST THAT BDNF-TRKB SIGNALING IS REQUIRED FOR DRUGS THAT REVERSE THE EPIGENETIC EFFECTS OF CHRONIC PAIN AT THE GENE LEVEL, SUCH AS HDAC INHIBITORS. 2015 11 1800 39 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 12 369 33 AN ANDROGEN-DEPENDENT SEXUAL DIMORPHISM VISIBLE AT PUBERTY IN THE RAT HYPOTHALAMUS. MORPHOLOGICAL STUDIES IN RODENTS HAVE WELL DOCUMENTED THE MASCULINIZATION OF THE PERINATAL BRAIN BY ESTRADIOL DERIVED FROM AROMATIZED TESTOSTERONE, AND THE RESULTING IRREVERSIBLE QUANTITATIVE SEX-DIFFERENCES GENERATED IN CELL NUMBERS OR EXPRESSION OF CHEMICAL PHENOTYPES. HERE, USING IMMUNOHISTOCHEMISTRY, WE EXPLORED HOW THIS APPLIES TO THE POSTNATAL DEVELOPMENT AND MASCULINIZATION OF THE NEUROKININ B (NKB)-CONTAINING SYSTEM OF THE ARCUATE NUCLEUS/MEDIAN EMINENCE COMPLEX (ARC/ME). IN ADULT RATS, NKB-IMMUNOREACTIVE NEURONS EXHIBIT AN UNUSUAL, QUALITATIVE SEXUAL DIMORPHISM OF THEIR VENTRAL AXONAL PROJECTIONS: TO THE NEUROPIL IN FEMALES, TO CAPILLARY VESSELS IN MALES. IN ADULTS, THERE WAS NO SEX-DIFFERENCE IN THE NUMBERS OF NKB-IMMUNOREACTIVE PERIKARYA OR CAPILLARY VESSELS IN THE ARC/ME, SUGGESTING THAT THIS SEXUAL DIMORPHISM CANNOT BE EXPLAINED BY THE EXISTENCE OF SUPERNUMERARY STRUCTURES. AT BIRTH (DAY 0) THE NKB SYSTEM WAS IMMATURE IN BOTH SEXES, AND WHILE ITS ADULT FEATURES EMERGED PROGRESSIVELY UNTIL PUBERTY IN FEMALES, THEY DID NOT DEVELOP BEFORE PUBERTY (DAY 40) IN MALES, REVEALING A SEXUAL DIMORPHISM ONLY LATE POSTNATALLY. WHEN MALES WERE ORCHIDECTOMIZED AT DAY 30, THE MASCULINE DISTRIBUTION OF NKB-IMMUNOREACTIVE AXONS EXPECTED AT DAY 40 WAS NOT SEEN, WHILE IT WAS APPARENT AFTER CHRONIC TREATMENT WITH TESTOSTERONE OR DIHYDROTESTOSTERONE, SUGGESTING A TESTICULAR MASCULINIZING ACTION VIA ANDROGEN RECEPTORS AT PUBERTY. MOREOVER IN THESE PREPUBERTAL-ORCHIDECTOMIZED MALES, THE DISTRIBUTION OF NKB-IMMUNOREACTIVE AXONS WAS SURPRISINGLY FEMINIZED BY CHRONIC ESTRADIOL ALONE, SUGGESTING THAT NKB NEURONS ARE NOT IRREVERSIBLY PROGRAMMED BEFORE PUBERTY. LAST, IN ADULT FEMALES, THE DISTRIBUTION OF NKB-IMMUNOREACTIVE AXONS WAS FEMININE 30 DAYS AFTER OVARIECTOMY, AND IT WAS MASCULINIZED AFTER CONCURRENT CHRONIC DIHYDROTESTOSTERONE, SUGGESTING THAT NKB NEURONS REMAIN RESPONSIVE TO ANDROGENS LATE IN REPRODUCTIVE LIFE. THUS, THE SEXUAL DIFFERENTIATION OF THE HYPOTHALAMUS PROCEEDS WELL BEYOND THE PERINATAL PERIOD AND INCLUDES THE EPIGENETIC ACTION OF NON-AROMATIZABLE ANDROGENS UPON SUBSETS OF NEURONS THAT HAVE RETAINED BIPOTENT FEATURES. 2007 13 5480 46 RESVERATROL REVERSES MORPHINE-INDUCED NEUROINFLAMMATION IN MORPHINE-TOLERANT RATS BY REVERSAL HDAC1 EXPRESSION. BACKGROUND/PURPOSE: WE PREVIOUSLY SHOWED THAT SUBSEQUENT INTRATHECAL (I.T.) INJECTION OF RESVERATROL (30 MUG) SIGNIFICANTLY REVERSES MORPHINE-EVOKED NEUROINFLAMMATION IN MORPHINE-TOLERANT RATS. THE PRESENT STUDY EXAMINED THE UNDERLYING MECHANISM. METHODS: MALE WISTAR RATS WERE IMPLANTED WITH TWO I.T. CATHETERS, ONE OF WHICH WAS CONNECTED TO A MINIOSMOTIC PUMP AND USED FOR MORPHINE (15 MUG/H) OR SALINE INFUSION FOR 120 HOURS. TO EXAMINE THE EFFECTS ON SPINAL CORD EXPRESSION OF HISTONE DEACETYLASE 1 (HDAC1), THE INFLAMMATORY CYTOKINE TUMOR NECROSIS FACTOR-ALPHA (TNF-ALPHA), AND TNF RECEPTOR (TNFR) 1 AND TNFR2 DURING TOLERANCE INDUCTION, A TAIL-FLICK TEST WAS PERFORMED PRIOR TO INFUSION AND AFTER 24 HOURS, 48 HOURS, 72 HOURS, 96 HOURS, AND 120 HOURS OF INFUSION. RESULTS: RESVERATROL TREATMENT PRIOR TO MORPHINE CHALLENGE RESTORED THE ANTINOCICEPTIVE EFFECT OF MORPHINE IN MORPHINE-TOLERANT RATS AND REVERSED THE MORPHINE INFUSION-INDUCED INCREASE IN HDAC1, TNF-ALPHA, AND TNFR1 EXPRESSION. MOREOVER, CHRONIC MORPHINE INFUSION INCREASED TNFR1-SPECIFIC EXPRESSION IN NEURON IN MORPHINE-TOLERANT RAT SPINAL CORDS, AND THIS EFFECT WAS ALMOST COMPLETELY INHIBITED BY RESVERATROL TREATMENT PRIOR TO MORPHINE CHALLENGE. CONCLUSION: RESVERATROL RESTORES THE ANTINOCICEPTIVE EFFECT OF MORPHINE BY REVERSING MORPHINE INFUSION-INDUCED SPINAL CORD NEUROINFLAMMATION AND INCREASE IN TNFR1 EXPRESSION. THE REVERSAL OF THE MORPHINE-INDUCED INCREASE IN TNFR1 EXPRESSION BY RESVERATROL IS PARTIALLY DUE TO REVERSAL OF THE MORPHINE INFUSION-INDUCED INCREASE IN HDAC1 EXPRESSION. RESVERATROL PRETREATMENT CAN BE USED AS AN ADJUVANT IN CLINICAL PAIN MANAGEMENT FOR PATIENTS WHO NEED LONG-TERM MORPHINE TREATMENT OR WITH NEUROPATHIC PAIN. 2016 14 204 43 ACTIVATION OF HDAC4 AND GR SIGNALING CONTRIBUTES TO STRESS-INDUCED HYPERALGESIA IN THE MEDIAL PREFRONTAL CORTEX OF RATS. "STRESS-INDUCED HYPERALGESIA (SIH)" IS A PHENOMENON THAT STRESS CAN LEAD TO AN INCREASE IN PAIN SENSITIVITY. EPIGENETIC MECHANISMS HAVE BEEN KNOWN TO PLAY FUNDAMENTAL ROLES IN STRESS AND PAIN. HISTONE ACETYLATION IS AN EPIGENETIC FEATURE THAT IS CHANGED IN NUMEROUS STRESS-RELATED DISEASE SITUATIONS. HOWEVER, EPIGENETIC MECHANISM FOR SIH IS NOT WELL KNOWN. WE INVESTIGATED THE EFFECT OF HISTONE ACETYLATION ON PAIN HYPERSENSITIVITY USING SPS (SINGLE-PROLONGED STRESS) + CFA (COMPLETE FREUND'S ADJUVANT) MODEL. WE SHOWED THAT THE GLUCOCORTICOID RECEPTOR (GR)-PERK-PCREB-FOS SIGNALING PATHWAY WAS UPREGULATED ON STRESS-INDUCED HYPERALGESIA AND THE PAW WITHDRAWAL THRESHOLD IN THE SPS + CFA GROUP DROPPED SIGNIFICANTLY COMPARED WITH THE SPS OR CFA GROUP. HISTONE DEACETYLASES 4 (HDAC4)-EXPRESSING NEURONS IN THE MEDIAL PREFRONTAL CORTEX (MPFC) WERE INCREASED IN THE SPS + CFA-EXPOSED GROUP COMPARED WITH CFA-EXPOSED OR SPS-EXPOSED GROUP. AND WE SHOWED THAT THE EFFECTS OF STRESS-INDUCED HYPERALGESIA WERE CRITICALLY REGULATED VIA REVERSIBLE ACETYLATION (HDAC4) OF THE GR. INHIBITING HDAC4 BY MICROINJECTION OF SODIUM BUTYRATE INTO THE MPFC COULD DISRUPT GLUCOCORTICOID RECEPTOR (GR) SIGNALING PATHWAY, WHICH LOWERED SPS + CFA-CAUSED MECHANICAL ALLODYNIA AND ALLEVIATED ANXIETY-LIKE BEHAVIOR. TOGETHER, OUR STUDIES SUGGEST THAT HDAC INHIBITORS MIGHT INVOLVE IN THE PROCESS OF STRESS-INDUCED HYPERALGESIA. 2020 15 5865 37 SUPPRESSION OF HDAC2 IN SPINAL CORD ALLEVIATES MECHANICAL HYPERALGESIA AND RESTORES KCC2 EXPRESSION IN A RAT MODEL OF BONE CANCER PAIN. EPIGENETIC MODULATION PARTICIPATES IN THE MECHANISM OF MULTIPLE TYPES OF PATHOLOGICAL PAIN, SO TARGETING THE INVOLVED REGULATORS MAY BE A PROMISING STRATEGY FOR PAIN TREATMENT. OUR PREVIOUS RESEARCH IDENTIFIED THE ANALGESIC EFFECT OF THE HISTONE DEACETYLASE (HDAC) INHIBITOR TRICHOSTATIN A (TSA) ON MECHANICAL HYPERALGESIA IN A RAT MODEL OF BONE CANCER PAIN (BCP) VIA RESTORATION OF MU-OPIOID RECEPTOR (MOR) EXPRESSION. HOWEVER, THE SPECIFIC TYPES OF HDACS CONTRIBUTING TO BCP HAVE NOT BEEN EXPLORED. THE PRESENT STUDY INVESTIGATED THE EXPRESSION PATTERN OF SOME COMMON HDACS AND FOUND THAT HDAC2 WAS UP-REGULATED IN A TIME-DEPENDENT MANNER IN THE LUMBAR SPINAL CORD OF BCP RATS. TSA APPLICATION SUPPRESSED HDAC2 EXPRESSION IN CULTURED PC12 CELLS AND REVERSED THE AUGMENTED HDAC2 IN BCP RATS. AN RNA-INTERFERING STRATEGY CONFIRMED THE ESSENTIAL ROLE OF HDAC2 IN THE MODULATION OF MECHANICAL HYPERALGESIA FOLLOWING TUMOR CELL INOCULATION, AND WE FURTHER EXAMINED ITS POSSIBLE DOWNSTREAM TARGETS. NOTABLY, HDAC2 KNOCK-DOWN DID NOT RESTORE MOR EXPRESSION, BUT IT ROBUSTLY REVERSED THE DOWN-REGULATION OF POTASSIUM-CHLORIDE COTRANSPORTER 2 (KCC2). THE IMPAIRED KCC2 EXPRESSION IS A VITAL MECHANISM OF MANY TYPES OF PATHOLOGICAL PAIN. THEREFORE, OUR RESULTS DEMONSTRATED THAT HDAC2 IN SPINAL CORD CONTRIBUTED TO THE MECHANICAL HYPERALGESIA IN BCP RATS, AND THIS EFFECT MAY BE ASSOCIATED WITH KCC2 MODULATION. 2018 16 2667 40 ESTROGEN AND SEROTONIN ENHANCE STRESS-INDUCED VISCERAL HYPERSENSITIVITY IN FEMALE RATS BY UP-REGULATING BRAIN-DERIVED NEUROTROPHIC FACTOR IN SPINAL CORD. BACKGROUND: WE PREVIOUSLY REPORTED THAT FEMALE OFFSPRING OF DAMS SUBJECTED TO CHRONIC PRENATAL STRESS (CPS) DEVELOP ENHANCED VISCERAL HYPERSENSITIVITY (VHS) FOLLOWING EXPOSURE TO CHRONIC STRESS IN ADULT LIFE THAT IS MEDIATED BY UP-REGULATION OF SPINAL CORD BDNF. THE AIMS OF THIS STUDY WERE TO EXAMINE THE ROLES OF ESTROGEN RECEPTOR ALPHA (ERALPHA) AND AN INCREASE IN SPINAL SEROTONIN SIGNALING IN PROMOTING THIS ENHANCED VHS IN FEMALE RATS AND UP-REGULATION OF SPINAL CORD BDNF TRANSCRIPTION. METHODS: PREGNANT DAMS WERE EXPOSED TO CHRONIC STRESS FROM E11 UNTIL DELIVERY. AT 8 WEEKS, A CHRONIC ADULT STRESS (CAS) PROTOCOL WAS APPLIED FOR NINE DAYS. KEY RESULTS: OVARIECTOMY BEFORE CAS OR TREATMENT WITH LETROZOLE BEFORE AND DURING CAS SIGNIFICANTLY PREVENTED THE DEVELOPMENT OF ENHANCED VHS IN FEMALE CPS+CAS RATS. INTRATHECAL APPLICATION OF ERALPHA SIRNA SIGNIFICANTLY REDUCED VHS, DECREASED LUMBAR-SACRAL SPINAL CORD EXPRESSION OF BOTH ERALPHA AND BDNF, AND REVERSED PRO-TRANSCRIPTIONAL EPIGENETIC MODIFICATIONS AT BDNF PROMOTER LX. CEREBROSPINAL FLUID SEROTONIN LEVELS AND 5HT3A RECEPTOR EXPRESSION IN THE LS SPINAL CORD WERE BOTH SIGNIFICANTLY INCREASED IN FEMALE CPS+CAS RATS. DURING CAS, INTRATHECAL INFUSION OF ALOSETRON SIGNIFICANTLY DECREASED VHS, REDUCED BDNF AND ERALPHA EXPRESSION IN THE LS SPINAL CORD, AND ATTENUATED RNA POL II AND ERALPHA BINDING TO THE BNDF CORE PROMOTER IX. CONCLUSIONS & INFERENCES: SEROTONIN-MEDIATED ACTIVATION OF 5HT3A RECEPTORS IN THE SPINAL CORD DRIVES THE DEVELOPMENT OF ENHANCED FEMALE-SPECIFIC VHS IN OUR TWO HIT CPS+CAS THROUGH UP-REGULATION OF SPINAL CORD ERALPHA. 2021 17 2365 47 EPIGENETIC REGULATION OF SPINAL CXCR2 SIGNALING IN INCISIONAL HYPERSENSITIVITY IN MICE. BACKGROUND: THE REGULATION OF GENE EXPRESSION IN NOCICEPTIVE PATHWAYS CONTRIBUTES TO THE INDUCTION AND MAINTENANCE OF PAIN SENSITIZATION. HISTONE ACETYLATION IS A KEY EPIGENETIC MECHANISM CONTROLLING CHROMATIN STRUCTURE AND GENE EXPRESSION. CHEMOKINE CC MOTIF RECEPTOR 2 (CXCR2) IS A PROINFLAMMATORY RECEPTOR IMPLICATED IN NEUROPATHIC AND INFLAMMATORY PAIN AND IS KNOWN TO BE REGULATED BY HISTONE ACETYLATION IN SOME SETTINGS. THE AUTHORS SOUGHT TO INVESTIGATE THE ROLE OF HISTONE ACETYLATION ON SPINAL CXCR2 SIGNALING AFTER INCISION. METHODS: GROUPS OF 5-8 MICE UNDERWENT HIND PAW INCISION. SUBEROYLANILIDE HYDROXAMIC ACID AND ANACARDIC ACID WERE USED TO INHIBIT HISTONE DEACETYLASE AND HISTONE ACETYLTRANSFERASE, RESPECTIVELY. BEHAVIORAL MEASURES OF THERMAL AND MECHANICAL SENSITIZATION AS WELL AS HYPERALGESIC PRIMING WERE USED. BOTH MESSAGE RNA QUANTIFICATION AND CHROMATIN IMMUNOPRECIPITATION ANALYSIS WERE USED TO STUDY THE REGULATION OF CXCR2 AND LIGAND EXPRESSION. FINALLY, THE SELECTIVE CXCR2 ANTAGONIST SB225002 WAS ADMINISTERED INTRATHECALLY TO REVEAL THE FUNCTION OF SPINAL CXCR2 RECEPTORS AFTER HIND PAW INCISION. RESULTS: SUBEROYLANILIDE HYDROXAMIC ACID SIGNIFICANTLY EXACERBATED MECHANICAL SENSITIZATION AFTER INCISION. CONVERSELY, ANACARDIC ACID REDUCED INCISIONAL SENSITIZATION AND ALSO ATTENUATED INCISION-INDUCED HYPERALGESIC PRIMING. OVERALL, ACETYLATED HISTONE H3 AT LYSINE 9 WAS INCREASED IN SPINAL CORD TISSUES AFTER INCISION, AND ENHANCED ASSOCIATION OF ACETYLATED HISTONE H3 AT LYSINE 9 WITH THE PROMOTER REGIONS OF CXCR2 AND KERATINOCYTE-DERIVED CHEMOKINE (CXCL1) WAS OBSERVED AS WELL. BLOCKING CXCR2 REVERSED MECHANICAL HYPERSENSITIVITY AFTER HIND PAW INCISION. CONCLUSIONS: HISTONE MODIFICATION IS AN IMPORTANT EPIGENETIC MECHANISM REGULATING INCISION-INDUCED NOCICEPTIVE SENSITIZATION. THE SPINAL CXCR2 SIGNALING PATHWAY IS ONE EPIGENETICALLY REGULATED PATHWAY CONTROLLING EARLY AND LATENT SENSITIZATION AFTER INCISION. 2013 18 5201 34 PRENATAL MORPHINE EXPOSURE INCREASES GAMMA OSCILLATION AND THETA COHERENCE IN THE RAT REWARD SYSTEM. PREVIOUS STUDIES HAVE FOUND THAT PRENATAL MORPHINE (PNM) EXPOSURE LEADS TO BOTH INCREASED AND DECREASED RISK OF SUBSTANCE ABUSE IN OFFSPRING. UNDERSTANDING MORE ABOUT THE NEUROBIOLOGICAL CHANGES AFTER THE PNM EXPOSURE WOULD HELP TO UNDERSTAND MORE ABOUT THIS ISSUE. SIGNALING FROM DOPAMINE NEURONS OF THE VENTRAL TEGMENTAL AREA (VTA) IN THE MESOACCUMBAL AND MESOCORTICAL PATHWAYS PLAYS A VITAL ROLE IN DRUG DEPENDENCY. TO PROVIDE FURTHER KNOWLEDGE ABOUT THE EFFECTS OF PNM ON DRUG SEEKING BEHAVIOR AND THE DOPAMINE SYSTEM. WE RECORDED LOCAL FIELD POTENTIALS (LFP) SIMULTANEOUSLY IN THE VTA, NAC (NUCLEUS ACCUMBENS), BLA (BASOLATERAL AMYGDALA) AND MPFC (MEDIAL PREFRONTAL CORTEX) IN MALE ADULT RATS PRENATALLY TREATED WITH SALINE OR MORPHINE. MORPHINE (10 MG/KG) INDUCED CONDITIONED PLACE PREFERENCE (CPP) ESTABLISHMENT, EXTINCTION AND PRIMING WERE TESTED TO INVESTIGATE THE EFFECTS OF PNM ON ADDICTIVE-LIKE BEHAVIOR. IN ADDITION, THE EXPRESSION OF NUCLEAR HISTONE DEACETYLASES (HDAC4, HDAC5), WHICH PLAYS ESSENTIAL EPIGENETIC ROLES IN NEUROPLASTICITY AFTER DRUG USE WERE ALSO TESTED IN VTA AND NAC. THE RESULTS SHOWED THAT PNM DID NOT CHANGE THE ACQUISITION OF MORPHINE CPP IN MALE RATS, BUT IMPAIRED CPP EXTINCTION AND MORPHINE (5 MG/KG) - PRIMED REINSTATEMENT OF CPP AFTER EXTINCTION. PNM INCREASED THE LOW GAMMA (30-60 HZ) AND HIGH (60-90 HZ) GAMMA LFP POWERS IN NAC AND BLA. PNM ALSO LEADS TO INCREASED THETA (4-9 HZ) COHERENCE BETWEEN VTA AND NAC, AND INCREASED HDAC5 EXPRESSION IN VTA. AFTER CHRONIC MORPHINE ADMINISTRATION, COHERENCE BETWEEN VTA-NAC, MPFC-NAC AND MPFC-BLA INCREASED SIGNIFICANTLY IN PNS RATS, BUT NO CHANGES WERE FIND IN PNM RATS, INDICATING IMPAIRED PLASTICITY IN BRAIN CIRCUITS. ALL THESE RESULTS SUGGEST THAT PNM EXPOSURE INCREASED REWARD PROCESSING IN ADULT MALE RATS, BUT IMPAIRED MORPHINE CPP EXTINCTION AND REINSTATEMENT, WHICH RELATE TO DECREASES NETWORK PLASTICITY AND INCREASED HDAC5 EXPRESSION IN THE REWARD SYSTEM. 2022 19 3154 43 GLUN2B/CAMKII MEDIATES CFA-INDUCED HYPERALGESIA VIA HDAC4-MODIFIED SPINAL COX2 TRANSCRIPTION. HISTONE DEACETYLASE 4 (HDAC4), WHICH ACTIVELY SHUTTLES BETWEEN THE NUCLEUS AND CYTOPLASM, IS AN ATTRACTIVE CANDIDATE FOR A REPRESSOR MECHANISM IN EPIGENETIC MODIFICATION. HOWEVER, THE POTENTIAL ROLE OF HDAC4-DEPENDENT EPIGENETICS IN THE NEURAL PLASTICITY UNDERLYING THE DEVELOPMENT OF INFLAMMATORY PAIN HAS NOT BEEN WELL ESTABLISHED. BY INJECTING COMPLETE FREUND'S ADJUVANT (CFA) INTO THE HIND-PAW OF SPRAGUE-DAWLEY RATS (200-250 G), WE FOUND ANIMALS DISPLAYED BEHAVIORAL HYPERALGESIA WAS ACCOMPANIED WITH HDAC4 PHOSPHORYLATION AND CYTOPLASMIC REDISTRIBUTION IN THE DORSAL HORN NEURONS. CYTOPLASMIC HDAC4 RETENTION LED TO ITS UNCOUPLING WITH THE COX2 PROMOTER, HENCE PROMPTING SPINAL COX2 TRANSCRIPTION AND EXPRESSION IN THE DORSAL HORN. MOREOVER, THE GLUN2B-BEARING N-METHYL-D-ASPARTATE RECEPTOR (GLUN2B-NMDAR)/CALMODULIN-DEPENDENT PROTEIN KINASE II (CAMKII) ACTED AS AN UPSTREAM CASCADE TO FACILITATE HDAC4 PHOSPHORYLATION/REDISTRIBUTION-ASSOCIATED SPINAL COX2 EXPRESSION AFTER INFLAMMATORY INSULTS. THE RESULTS OF THIS PILOT STUDY DEMONSTRATED THAT THE DEVELOPMENT AND/OR MAINTENANCE OF INFLAMMATORY PAIN INVOLVED THE SPINAL HDAC4-DEPENDENT EPIGENETIC MECHANISMS. OUR FINDINGS OPEN UP A NEW AVENUE FOR THE DEVELOPMENT OF A NOVEL MEDICAL STRATEGY FOR THE RELIEF OF INFLAMMATORY PAIN. 2018 20 73 31 A MULTI-GENERATIONAL STUDY ON LOW-DOSE BPA EXPOSURE IN WISTAR RATS: EFFECTS ON MATERNAL BEHAVIOR, FLAVOR INTAKE AND DEVELOPMENT. BISPHENOL A (BPA) IS A COMMON ENDOCRINE DISRUPTOR FOUND AS AN ENVIRONMENTAL AND FOOD CONTAMINANT. IT EXERTS BOTH DEVELOPMENTAL AND BEHAVIORAL EFFECTS, MAINLY WHEN EXPOSURE OCCURS IN EARLY LIFE. THE AIM OF THIS STUDY WAS TO DETERMINE THE MULTI-GENERATIONAL EFFECTS OF CHRONIC, HUMAN-RELEVANT LOW-DOSE EXPOSURE TO BPA ON DEVELOPMENT, MATERNAL BEHAVIOR AND FLAVOR PREFERENCE IN WISTAR RATS. BPA WAS ORALLY ADMINISTERED AT A DAILY DOSE OF 5 MUG/KG BODY WEIGHT TO F0 PREGNANT DAMS FROM THE FIRST DAY OF GESTATION (GD 1) UNTIL THE LAST DAY OF LACTATION (LD 21), AND THEN TO F1 OFFSPRING FROM WEANING (PND 21) TO ADULTHOOD (PND 100). F2 OFFSPRING WERE NOT EXPOSED. DEVELOPMENT AND CLINICAL SIGNS OF TOXICITY WERE ASSESSED DAILY. MATERNAL BEHAVIOR WAS EVALUATED BY OBSERVING NURSING AND PUP-CARING ACTIONS, AS WELL AS "NON-MATERNAL" BEHAVIORS IN F0 AND F1 DAMS FROM PARTURITION UNTIL LD 8. THE FLAVOR PREFERENCES OF F1 AND F2 OFFSPRING WERE EVALUATED BASED ON THE INTAKE OF SWEET, SALT AND FAT SOLUTIONS USING THE TWO-BOTTLE CHOICE TEST ON PND 21-34 AND PND 86-99. BPA EXPOSURE: 1) DECREASED MATERNAL BEHAVIOR IN F1 DAMS, 2) CAUSED DEVELOPMENTAL DEFECTS IN BOTH F1 AND F2 OFFSPRING, WITH A NOTICEABLE DECREASE IN ANOGENITAL DISTANCE IN MALE RATS, AND 3) DID NOT AFFECT FLAVORED SOLUTION INTAKE IN F1, BUT INDUCED CHANGES IN SWEET PREFERENCE IN F2 JUVENILES AND IN SALT AND FAT SOLUTION INTAKES IN F2 ADULTS, AND 4) INDUCED A BODY WEIGHT INCREASE IN THE F2 GENERATION ONLY, WHEREAS FOOD INTAKE AND WATER CONSUMPTION DID NOT CHANGE. TAKEN AS A WHOLE, OUR FINDINGS SHOWED THAT BOTH GESTATIONAL (F0) AND LIFELONG (F1) EXPOSURES TO A HUMAN-RELEVANT DOSE OF BPA COULD INDUCE MULTI-GENERATIONAL EFFECTS ON BOTH DEVELOPMENT AND BEHAVIOR. THESE RESULTS SUGGEST POSSIBLE SELECTIVE NEUROENDOCRINE DEFECTS AND/OR EPIGENETIC CHANGES CAUSED BY BPA EXPOSURE. 2014