title: Opioid-induced cardioprotection against myocardial infarction and arrhythmias: mitochondrial versus sarcolemmal ATP-sensitive potassium channels.
abstract: We examined the role of the sarcolemmal and mitochondrial ATP-sensitive potassium (K(ATP)) channel in a rat model of myocardial infarction after stimulation with the selective delta(1)-opioid receptor agonist TAN-67. Hearts were subjected to 30 min of regional ischemia and 2 h of reperfusion. Infarct size was expressed as a percentage of the area at risk. TAN-67 significantly reduced infarct size/area at risk (29.6 +/- 3.3) versus control (63. 1 +/- 2.3). The sarcolemmal-selective K(ATP) channel antagonist HMR 1098, administered 10 min before TAN-67, did not significantly attenuate cardioprotection (26.0 +/- 7.3) at a dose (3 mg/kg) that had no effect in the absence of TAN-67 (56.3 +/- 4.3). Pretreatment with the mitochondrial selective antagonist 5-hydroxydecanoic acid (5-HD) 5 min before the 30-min occlusion completely abolished TAN-67-induced cardioprotection (54.3 +/- 2.7), but had no effect in the absence of TAN-67 (62.6 +/- 4.1), suggesting the involvement of the mitochondrial K(ATP) channel. Additionally, we examined the antiarrhythmic effects of TAN-67 in the presence or absence of 5-HD and HMR 1098 during 30 min of ischemia. Control animals had an average arrhythmia score of 10.40 +/- 2.41. TAN-67 significantly reduced the arrhythmia score during 30 min of ischemia (2.38 +/- 0. 85). 5-HD and HMR 1098 in the absence of TAN-67 produced an insignificant decrease in the arrhythmia score (8.80 +/- 2.56 and 4. 20 +/- 1.07, respectively). 5-HD administration before TAN-67 treatment abolished its antiarrhythmic effect (4.71 +/- 1.11). However, HMR 1098 did not abolish TAN-67-induced protection against arrhythmias (1.67 +/- 0.80). These data suggest that delta(1)-opioid receptor stimulation is cardioprotective against myocardial ischemia and sublethal arrhythmias and suggest a role for the mitochondrial K(ATP) channel in mediating these cardioprotective effects.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226-3548, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Fryer
authors.forename: A K
authors.initials: AK
authors.lastname: Hsu
authors.forename: H
authors.initials: H
authors.lastname: Nagase
authors.forename: G J
authors.initials: GJ
authors.lastname: Gross
mesh_terms: D000255:Adenosine Triphosphate / Q000502:physiology; D000701:Analgesics, Opioid / Q000037:antagonists & inhibitors / Q000627:therapeutic use*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001145:Arrhythmias, Cardiac / Q000517:prevention & control*; D001549:Benzamides / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D003652:Decanoic Acids / Q000494:pharmacology; D004347:Drug Interactions; D006339:Heart Rate / Q000187:drug effects; D006880:Hydroxy Acids / Q000494:pharmacology; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000502:physiology; D009203:Myocardial Infarction / Q000517:prevention & control*; D017202:Myocardial Ischemia / Q000150:complications; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D011804:Quinolines / Q000037:antagonists & inhibitors / Q000627:therapeutic use*; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000819:agonists; D012508:Sarcolemma / Q000187:drug effects* / Q000502:physiology; D014693:Ventricular Fibrillation / Q000517:prevention & control
chemical_list: D000701:Analgesics, Opioid; D000889:Anti-Arrhythmia Agents; D001549:Benzamides; D003652:Decanoic Acids; D006880:Hydroxy Acids; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D011804:Quinolines; D017465:Receptors, Opioid, delta; C094142:TAN 67; C052853:5-hydroxydecanoic acid; D000255:Adenosine Triphosphate; C410297:HMR 1098