Modulation of vertebrate brain Na+ and K+ channels by subtypes of protein kinase C.
Effects of purified subtypes I, II and III of protein kinase C (PKC) on voltage-dependent transient K+ (A) and Na+ channels were studied in Xenopus oocytes injected with chick brain RNA. The experiments were performed in the constant presence of 10 nM beta-phorbol 12-myristate-13-acetate (PMA). Intracellular injection of subtype I (tau) reduced the A-current (IA), with no effect on Na+ current (INa). PKC subtype II (beta 1 + beta 2) and III (alpha) reduced both currents. PKC did not affect the response to kainate. Inactivated (heated) or unactivated (injected in the absence of PMA) enzyme and vehicle alone had no effect. Our results strongly suggest that INa and IA in vertebrate neurons are modulated by PKC; all PKC subtypes exert a similar effect on the A-channel while only subtypes II and III modulate the Na+ channel.
Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel.
I
I
Lotan
N
N
Dascal
Z
Z
Naor
R
R
Boton
D000818:Animals; D001693:Biological Transport, Active; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002642:Chick Embryo; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*; D011493:Protein Kinase C / Q000494:pharmacology*; D015222:Sodium Channels / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014981:Xenopus
D007473:Ion Channels; D015221:Potassium Channels; D015222:Sodium Channels; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate