J Korean Neurol Assoc.  1993 Jun;11(2):209-221.

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

• Seo DW
• Lee KW
• Rho JK
• Lee SB
• Myung HJ
• Kim SJ
• Goo YS
• Kim J

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

MeSH Terms

Animals
Calcium Channels, L-Type
Calcium Channels, N-Type
Calcium*
Chromaffin Cells*
Immunoglobulin G*
Lambert-Eaton Myasthenic Syndrome*
Rats*
Calcium
Calcium Channels, L-Type
Calcium Channels, N-Type
Immunoglobulin G