The Effect of Lambert-Eaton Syndrome IgG on Calcium Current in Rat Chromaffin Cells

J Korean Neurol Assoc > Volume 11(2); 1993 > Article

Journal of the Korean Neurological Association 1993;11(2): 209-221.

람버트-이튼 증후군 IgG가 rat chromaffin 세포에서 Ca-전류에 미치는 영향

서대원, 이광우,노재규,이상복,명호진,김상정,구용숙,김전

서울대학교 신경과, 생리학.

The Effect of Lambert-Eaton Syndrome IgG on Calcium Current in Rat Chromaffin Cells

D. W. Seo, M.D., K. W. Lee, M.D., J. K. Rho, M.D., S. B. Lee, M.D., H. J. Myung, M.D., S. J. Kim, M.D., Y. S. Goo, M.D., J. Kim, M.D.

Department of neurology and Physiology , College of medicine, Seoul National University

Abstract

In rat chromaffin cells persistent inward calcium currents which were evoked by depolarizing step pulses from holding potential of-80mV, increased to a maximum amplitude at around +lOmV, became smaller with progressively higher depolarizing pulses and reversed at aroung +60mV. Assuming this current is double exponential decaying current, the longer time constant was 1825+146msec and its amplitude (A1) 80.6+ 6.6pA. The shorter one and its ampltude(A2)were 60.9+5.4msec and 16.5+1.2pA respectively (the correlation coefficient=0.93, N=63, mean+S.E.). So we refer these component to L-type and N-type calcium current, respectively. When we added Cd2+ in the outer solution, the calcium current was blocked. Dihydropyridine(nicardipine) produced a concentration-dependent block of long lasting calcium currents of rat chromaffin cells. When 1uM dihydropyridine was added, the properties of the unblocked current was similar to N-type currer.t because the time constant was below 100msec. Lambert-Eaton syndrome IgG significantly blocked 72% of steady state calcium current(p< 0.05). Especially the L-type calcium current with long time constant was significantly blocked when compared to the current in normal control (p