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1 | It was studied effect of activation of M-opioid receptor (OR) on the tolerance of isolated perfused rat heart to global 45 min ischemia and 30 min reperfusion. In vivo pretpeatment with selective M-opioid receptor agonist DAMGO (0,1mg/kg intravenously) increased tolerance of isolated perfused rat heart to ischemia and reperfusion. This effect was completely abolished by pretreatment with the M-antagonist CTAP. Addition of DAMGO and DALDA to the perfusion solution in a final concentration of 170 nМ before ischemia had no cardioprotective effect. However, addition of DALDA to the perfusion solution in a final concentration of 33 nM also decreased creatine kinase levels in the coronary sinus effluent. Keywords: M-оpioid receptors, isolated heart, ischemia, reperfusion | 1332 | ||||
2 | It has been found that occupancy of and ^-opioid receptors (ORs) by DPDPE and U-50488, respectively, prevents irreversible cardiac cell damage during global ischemia (45 min) and reperfusion (30 min) of the isolated perfused rat heart by the Langendorff technique. Activation of Kj-ORs decreased cAMP levels in the myocardium during reperfusion but stimulation of 8J-ORs had no effect on the cAMP levels. The occupancy of both types of receptors did not alter the cGMP levels before and after ischemia. Cardioprotective effect of DPDPE was completely abolished by pretreatment with cyclopiazonic acid, an inhibitor of Ca2+-ATPase of sarcoplasmic reticulum. Authors proposed that cardioprotective effect of U-50488 is mediated via a decrease in cAMP levels in the heart but cardioprotective effect of DPDPE is depended on the activity of Ca2+-ATPase of sarcoplasmic reticulum. Keywords: isolated perfused rat heart, ischemia, reperfusion, opioid receptors | 1190 |