OPIOID RECEPTORS AGONISTS MIMIC PRECONDITIONING OF THE HEART: THE ROLE OF CYCLIC NUCLEOTIDES AND CA2+-ATP-ASE OF SARCOPLASMIC RETICULUM
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
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Issue: 3, 2010
Series of issue: Issue 3
Rubric: Biology
Pages: 64 — 69
Downloads: 1220