Inhibition of L-type calcium currents by salusin-β in rat cardiac ventricular myocytes

Salusin-beta is a new regulatory peptide relevant to the cardiovascular system and exerts negative inotropic effect on ventricular muscle. The purpose of the present study was to determine whether salusin-beta can inhibit cardiac L-type calcium channel current (I-Ca,I-L). Using whole-cell voltage-clamp techniques, I-Ca,I-L was measured in ventricular myocytes isolated from 12 to 16 weeks rats. Salusin-beta dose-dependently and reversibly reduced the magnitude of I-Ca,I-L in rat ventricular myocytes. Neither threshold potential nor the peak potential of current-voltage relationship was affected. Salusin-beta increased the rate of I-Ca,I-L inactivation without altering its gating properties. These results suggest salusin-beta inhibited I-Ca,I-L by increasing the rate of I-Ca,I-L inactivation and the inhibition of L-type Ca2+ channels induced by salusin-beta may contribute to its negative inotropic effect on ventricular muscle. (C) 2010 Elsevier Inc. All rights reserved.