title: Expression of heat shock protein 27 and troponin T and troponin I after naloxone-precipitated morphine withdrawal.
abstract: Heat shock protein (Hsp27) renders cardioprotection from stress situations but little is known about its role in myofilaments. In this study we have evaluated the relationship between Hsp27 and troponin response after naloxone-induced morphine withdrawal. Rats were treated with two morphine (75 mg) pellets during six days. Precipitated withdrawal was induced by naloxone on day seven. Hsp27 expression, Hsp27 phosphorylated at serine 82 (Ser82), cardiac troponin T (cTnT), cardiac troponin I (cTnI) and µ-calpain were evaluated by immunoblotting in left ventricle. Hsp, cTnT and cTnI was also evaluated by immunofluorescence procedure. Our results show that enhancement in Hsp27 expression and phosphorylation induced by naloxone-precipitated morphine withdrawal occurs with concomitant increases of cTnT and µ-calpain expression, whereas cTnI was decreased. We also observed co-localization of Hsp27 with cTnT in cardiac tissues. These findings provide new information into the possible role of Hsp27 in the protection of cTnT degradation by µ-calpain (a protease mediating proteolysis of cTnT and cTnI) after morphine withdrawal.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Murcia, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Martínez-Laorden
authors.affiliation: Department of Pharmacology, School of Medicine, University of Murcia, Spain. Electronic address: palmela@um.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: Almela
authors.affiliation: Department of Pharmacology, School of Medicine, University of Murcia, Spain.
authors.forename: María-Victoria
authors.initials: MV
authors.lastname: Milanés
authors.affiliation: Department of Pharmacology, School of Medicine, University of Murcia, Spain.
authors.forename: María-Luisa
authors.initials: ML
authors.lastname: Laorden
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects; D002154:Calpain / Q000378:metabolism; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009021:Morphine Dependence / Q000378:metabolism* / Q000503:physiopathology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D013375:Substance Withdrawal Syndrome / Q000378:metabolism* / Q000503:physiopathology; D019210:Troponin I / Q000378:metabolism*; D020107:Troponin T / Q000378:metabolism*
chemical_list: D000701:Analgesics, Opioid; D055551:HSP27 Heat-Shock Proteins; D009292:Narcotic Antagonists; D019210:Troponin I; D020107:Troponin T; D009270:Naloxone; D009020:Morphine; D002154:Calpain
keywords: Hsp 27; Morphine withdrawal; Troponins.; left ventricle; µ-calpain