Suppression by calmodulin of glutamate-induced potassium current in identified snail neurons

Abstract Using the voltage-clamp technique combined with pressure injection, we examined the inhibitory action of glutamate (Glu) in identified snail neurons. Calimidazolium and N -(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7), calmodulin inhibitors, enhanced a slow outward current (Glu current) induced by Glu in a dose-dependent manner. This Glu current was suppressed by intracellular injection of calmodulin. However, no significant change in the Glu current was observed when either CaCl 2 or EGTA was intracellularly applied. These results suggest a novel calmodulin-mediated process, through which Glu induces an outward current.