Effects of GS-386 on the calcium current in rabbit atrial myocytes

Park, Choon-ok; Chang, Kyeong-jae; Kim, Yang-mi; Haan, Jae-hee; Hong, Seong-geun

Korean Journal of Veterinary Research 1994;34(1):37-47.

Choon-ok Park, Kyeong-jae Chang, Yang-mi Kim, Jae-hee Haan, Seong-geun Hong

Department of Physiology and the Institute of Cardiovascular Research, College of Medicine, Gyeongsang National University

GS-386이 단일 심근 세포의 Ca²⁺ 전류에 미치는 효과

박춘옥, 장경재, 김양미, 한재희, 홍성근

경상대학교 의과대학 생리학교실, 심혈관연구소

Abstract

The effects of the novel compound GS-386 on the calcium current were investigated in rabbit atrial myocytes. The calcium current was recorded during various depolarizations of 200 ms duration from a holding potential of -40 mV using the whole cell patch clamp technique. The calcium current was activated from -30 mV, reached maximum amplitude at +10 mV and almost disappeared at +50 mV. Superfusion of GS-386 led to a reduction of the calcium current amplitude dose-dependently and $ED_{50}$ was $2.5{ imes}10^{-7}M$. But the dependence of the calcium current on the membrane potential was not altered by GS-386. The inactivation of the calcium currents showed single exponential curves in both before and after application of GS-386. The inactivation time constants before and after application of GS-386 were almost the same(35 ms and 32.5 ms). The steady-state inactivation curve of the calcium current was not shifted by GS-386. The calcium currents both before and after application of GS-386 recovered completely in 1 sec and the recovery time constants were about 200 ms in both cases. From the above results it is concluded that the novel compound GS-386 has calcium antagonistic property decreasing the calcium current.

Key Words: calcium current, whole cell patch clamp, rabbit atrial myocytes, calcium channel blocker