[Abolition of the inhibitory effect of antibodies against S-100 proteins on the calcium current of molluscan neurons after intracellular injection of EGTA]

Abstract

A two-electrode voltage clamp method was used to study Ca inward current (ICa) in unidentified isolated snail neurons. Extracellular administration of antibodies against S-100 proteins (AS-100) produces a reversible inhibition of ICa in a dose-dependent and time-dependent manner. Intracellular injection of EGTA with the help of 10nA 5-10 min microiontophoresis through a multibarrel microelectrode evoked a weak increase in the amplitude of the ICa before AS-100 application and a complete abolition of the inhibitory effect of AS-100 on the ICa. The data obtained suggest that AS-100 application results in an increase in the intracellular Ca concentration and Ca-dependent inactivation of Ca-channels.