Role of opioid receptors in cardioprotection of cold-restraint stress and morphine.
Since cold exposure confers cardioprotection, the present study attempted to determine the role of opioid receptors (OR). Stress with cold exposure and restraint for 3 h, shown previously to induce peptic ulcer in a synergistic manner, attenuated infarct size induced by myocardial ischemia and reperfusion in the isolated perfused rat heart from 36.64 +/- 1.8 to 22.85 +/- 2.6%. This is similar to protecting the rat with morphine at 8 mg/kg, which also attenuated the infarct size from 36.26 +/- 1.6 to 20.30 +/- 2.1%. The effects of cold-restraint or morphine were abolished by naloxone, a non-selective OR antagonist; nor-binaltorphimine, a selective kappa-OR antagonist; naltrindole, a selective delta-OR antagonist, or CTOP, a selective mu-OR antagonist. The effects were also attenuated by blockade of protein kinase C or the mitochondrial K(ATP) channel. The finding is first evidence that all three OR subtypes mediate cardioprotection of cold-restraint stress in the rat.
Wu
S
S
Department of Physiology, Faculty of Medicine, University of Hong Kong, Hong Kong SAR, China.
Wong
M C Y
MC
Chen
M
M
Cho
C H
CH
Wong
T M
TM
D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D003080:Cold Temperature; D006321:Heart / Q000187:drug effects* / Q000502:physiology*; D009020:Morphine / Q000737:chemistry / Q000494:pharmacology*; D009203:Myocardial Infarction / Q000517:prevention & control*; D017202:Myocardial Ischemia; D009206:Myocardium / Q000378:metabolism*; D009270:Naloxone / Q000494:pharmacology; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists; D010477:Perfusion; D011188:Potassium / Q000737:chemistry; D015221:Potassium Channels / Q000737:chemistry*; D011493:Protein Kinase C / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D011957:Receptors, Opioid / Q000502:physiology*; D017473:Receptors, Opioid, kappa / Q000737:chemistry; D015427:Reperfusion Injury; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000494:pharmacology; D013312:Stress, Physiological; D013997:Time Factors
D009292:Narcotic Antagonists; D015221:Potassium Channels; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; C049352:phenylalanyl-cyclo(cysteinyltyrosyl-tryptophyl-ornithyl-threonyl-penicillamine)threoninamide; C051843:binaltorphimine; D009270:Naloxone; D013004:Somatostatin; D009271:Naltrexone; D009020:Morphine; D000255:Adenosine Triphosphate; D011493:Protein Kinase C; C055382:naltrindole; D011188:Potassium