Receptor-mediated modulation of rat KV1.2 in Xenopus oocytes.
To investigate mechanisms for the receptor-mediated inhibition of a rat cardiac K+ channel clone (KV1.2), we coexpressed KV1.2 with a subtype of endothelin receptors (ETA) in Xenopus oocytes. Effects of endothelin ETA receptor stimulation were mimicked by application of PMA (4-beta-phorbol 12-myristate 13-acetate; 0.1 microM) or intracellular injection of CaCl2 (estimated concentration of 1 microM). These effects diminished in the presence of staurosporine (1 microM) or EGTA (estimated concentration of 5 mM). These results suggest that both activation of protein kinase C and an increase in intracellular Ca2+ contribute to the suppression.
Murakoshi
H
H
Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan.
Ishii
K
K
Nunoki
K
K
Taira
N
N
D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009865:Oocytes / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010716:Phosphatidylinositols / Q000378:metabolism; D010957:Plasmids / Q000502:physiology; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D018075:RNA, Complementary / Q000096:biosynthesis; D051381:Rats; D017466:Receptors, Endothelin / Q000235:genetics / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014981:Xenopus
D000470:Alkaloids; D010716:Phosphatidylinositols; D015221:Potassium Channels; D018075:RNA, Complementary; D017466:Receptors, Endothelin; D011493:Protein Kinase C; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium