Suppression by calmodulin of glutamate-induced potassium current in identified snail neurons.
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 CaCl2 or EGTA was intracellularly applied. These results suggest a novel calmodulin-mediated process, through which Glu induces an outward current.
Onozuka
M
M
Department of Anatomy, Gifu University School of Medicine, Japan.
Watanabe
K
K
D000818:Animals; D002118:Calcium / Q000502:physiology; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000502:physiology; D018698:Glutamic Acid / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D012908:Snails / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D002147:Calmodulin; D004791:Enzyme Inhibitors; D018691:Excitatory Amino Acid Antagonists; D007093:Imidazoles; D015221:Potassium Channels; D013449:Sulfonamides; D013757:Tetraethylammonium Compounds; D018698:Glutamic Acid; C031938:calmidazolium; C017967:W 7; D019789:Tetraethylammonium; D002118:Calcium