K-ATP channels mediate the beneficial effects of chronic ethanol ingestion

Chronic ingestion of low doses of ethanol protects the myocardium from isch emic injury by activating adenosine receptors and protein kinase C. We test ed the hypothesis that ATP-dependent potassium (K-ATP) channels mediate the se beneficial effects. Dogs were fed with ethanol (1.5 g/kg) or water mixed with dry food twice per day for 12 wk. After they were acutely instrumente d for measurement of hemodynamics, dogs received saline (vehicle) or glybur ide (0.1 mg/kg iv) and were subjected to 60 min of coronary artery occlusio n followed by 3 h of reperfusion. Infarct size (through triphenyltetrazoliu m chloride staining) was significantly (P < 0.05) reduced to 14 <plus/minus > 1% of the left ventricular area at risk in ethanol-pretreated dogs compar ed with controls (25 +/- 2%). Glyburide alone did not affect infarct size ( 25 +/- 3%) but abolished the protective effects of ethanol pretreatment (28 +/- 3%). No differences in hemodynamics or coronary collateral blood flow (through radioactive microspheres) were observed among groups. The results indicate that K-ATP channels mediate the protective effects of chronic cons umption of ethanol.