Effect of Exogenous Extracellular Nicotinamide Adenine Dinucleotide (NAD(+)) on Bioelectric Activity of the Pacemaker and Conduction System of the Heart

摘要

In rat sinoatrial node, NAD(+) (10 mu M) reduced the rate of spontaneous action potentials, duration of action potentials, and the velocity of slow diastolic depolarization, but the rate of action potential front propagation increases. In passed rabbit Purkinje fi bers, NAD(+) (10 mu M) reduced the duration of action potentials. Under conditions of spontaneous activity of Purkinje fi bers, NAD(+) reduced the fi ring rate and the rate of slow diastolic depolarization. The effects of extracellular NAD(+) on bioelectric activity of the pacemaker (sinoatrial node) and conduction system of the heart (Purkinje fi bers) are probably related to activation of P1 and P2 purinoceptors.