Role of calcium activated potassium channel in cardioprotection induced by anoxic postconditioning in isolated rat heart / 中国病理生理杂志

ABSTRACT

AIM: To investigate whether calcium activated potassium channel(KCa) and mitochondrial permeability transition pore(mPTP) contribute to cardioprotective effect elicited by anoxic postconditioning.METHODS: The isolated perfused hearts of male Sprague-Dawley rats were subjected to 30 min global anoxic followed by 120 min reoxygenation.Formazan content of myocardium was measured at 490 nm spectrophotometrically,and the level of lactate dehydrogenase(LDH) in the coronary effluent was detected.The absorbance of isolated heart mitochondria at 520 nm was determined.RESULTS: Anoxic postconditioning increased formazan content,reduced LDH release,improved the hemodynamic parameters of the left ventricular developed pressure,maximal rise/fall rate of left ventricular pressure,left ventricular end-diastolic pressure and rate pressure product and attenuated the decrease of coronary flow during reperfusion.Pretreatment with paxilline(1 ?mol/L) inhibited the effect of anoxic postconditioning.The opening of mPTP was suppressed in the mitochondria isolated from A/R hearts treated with anoxic postconditioning.CONCLUSION: The findings indicate that in the isolated rat heart,anoxic postconditioning protects myocardium against anoxic/reoxygenation injury via inhibiting KCa and the mPTP opening.