Involvement of a Ca2+/calmodulin-dependent protein kinase II-associated mechanism in the induction of an outward potassium current by quisqualate.
The inhibitory action of a glutamate agonist, quisqualate, in association with the intracellular signal transduction, was electrophysiologically examined in identified Euhadra neurons. Quisqualate dose-dependently induced a slow outward current (Quis current) which was blocked by tetraethylammonium. This current was suppressed by intracellular injection of Ca2+/calmodulin-dependent protein kinase II (CaMKII), and was enhanced by a CaMKII inhibitor, KN-62. However, no significant changes in the Quis current were observed when the catalytic subunit of protein kinase A (PKA) or the protein kinase C (PKC) fragment (530-558) was intracellularly applied; or using a PKA inhibitor, H-8, or a PKC inhibitor, staurosporine. These results suggest a novel mechanism linked to CaMKII, by which quisqualate induces an outward potassium current.
Department of Anatomy (2nd Division), Gifu University School of Medicine, Japan.
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M
Onozuka
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Watanabe
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K
Nagata
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S
Imai
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives*; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D004558:Electric Stimulation; D004594:Electrophysiology; D007546:Isoquinolines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D016318:Quisqualic Acid / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D012908:Snails / Q000502:physiology*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D007546:Isoquinolines; D010879:Piperazines; D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D016318:Quisqualic Acid; D017871:Calcium-Calmodulin-Dependent Protein Kinases