Protective effect of carvedilol on abnormality of L-type calcium current induced by oxygen free radical in cardiomyocytes

Abstract

The protective effect of carvedilol on abnormality of L-type calcium current induced by oxygen free radical in single guinea pig ventricular myocytes was studied. Whole-cell patch clamp technique was used to study the effect of H₂O₂ (0.5 mmol/L) on L-type calcium current in single guinea pig ventricular myocytes and the action of pretreatment with carvedilol (0.5 μmol/L). 0.5 μmol/L carvedilol had no significant effect onI_Ca.L and its channel dynamics. In the presence of 0.5 mmol/L H₂O₂, peak current ofI_Ca.L was reduced significantly (P<0.001), theI-V curve ofI_Ca.L was shifted upward, steady-state activation curve and steady-state deactivation curve ofI_Ca.L were shifted left and recovery time ofI_Ca.L was delayed significantly (P<0.001). 0.5 μmol/L carvedilol significantly alleviated the inhibitory effect of H₂O₂ onI_Ca.L as compared with that in H₂O₂. It was concluded that carvedilol could alleviate the abnormality of L-type calcium current induced by oxygen free radical in cardiomyocytes. It shows partly the possible mechanism of the special availability of carvedilol in chronig heart failure.

Keywords

carvedilol / oxidative stress / calcium current / patch clamp

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