Electrophysiological effect of resveratrol on pacemaker cells in sinoatrial node of rabbits

AI M In order toinvestigate whether resvera-trol can be used as a kind of antiarrhythmic drug,theelectrophysiological effect of resveratrol on pacemakercells in sinoatrial node was studied.METHODS Usingintracellular microelectrode technique to record the actionpotential of pacemaker cells in sinoatrial node of rabbits.RESULTS Resveratrol(30-120μmol.L-1) signifi-cantly decreased amplitude of action potential,maximalrate of depolarization(Vmax),velocity of diastolic(phase4) depolarization and rate of pacemaker firing,but didnot affect maximal diastolic potential and duration of 90 %repolarization of action potential.Pretreatment with L-typecalciumchannel agonist Bay-K-8644(0.5μmol.L-1) 10min antagonizedthe effect of resveratrol(60μmol.L-1).While applying cesiumchloride(2 mmol.L-1),a hyper-polarization-activated current blocker,adding tetraethy-lammoniumchloride(20 mmol.L-1),a potassiumchan-nel antagonist,or applyingL-NAME(0.5 mmol.L-1),a NOsynthase inhibitor,had nosignificantlyinfluence onthe electrophysiological effects of resveratrol.CONCLU-SION Resveratrol exerts inhibitory electrophysiologicaleffects on pacemaker cells in sinoatrial node of rabbits,which may be due to reduction in calciuminfluxviaaNO-independent manner.