Effects of Salusin‐β on action potential and ionic currents in ventricular myocytes of rats

AIM: Salusin-β is a regulatory peptide that exerts negative inotropic effect on ventricular muscle, but its electrophysiological effects on ventricular myocytes are still unknown. METHODS: Action potential and channel currents such as sodium current (I(N) (a) ), transient outward potassium current (I(to) ), steady-state potassium current (I(sus) ), sodium-calcium exchange current (I(N) (aCa) ) and inward rectifier potassium current (I(K) (1) ) were measured in ventricular myocytes isolated from 12 to 16 weeks rats by whole-cell voltage-clamp techniques. RESULTS: Salusin-β dose-dependently shortened the duration of action potential in rat ventricular myocytes. Furthermore, salusin-β significantly inhibited I(N) (aCa) and increased I(to) , but did not affect I(N) (a) , I(sus) and I(K) (1) . CONCLUSION: These results suggest that the effect of salusin-β on action potential may be partly attributed to a decrease in inward currents and an increase in outward currents.