Carbachol promotes Na+ entry and augments Na/Ca exchange current in guinea pig ventricular myocytes

A study was conducted on the effect of carbochol (CCh) on the Na/Ca exchange current in voltage-clamped ventricular myocytes isolated from guinea pig hearts and superfused with Tyrode solution at 35 degrees C. The results are consistent with the hypothesis that CCh, via muscarinic receptors, eventually promotes Na/Ca current exchange at the sarcolemma. Moreover, this action is responsible for the increased contractions.