title: Molecular mechanism of protein kinase C modulation of sodium channel alpha-subunits expressed in Xenopus oocytes.
abstract: The mechanism of modulation of sodium channel alpha-subunits (Type IIA) by a protein kinase C (PKC) activator was studied on single channel level. It was found that: (i) time constants for channel activation were prolonged; (ii) inactivation remained virtually unchanged; (iii) peak sodium inward current was reduced as evidenced by calculation of average sodium currents; and (iv) time constants for current activation and decay were prolonged. (i), (iii) and (iv) were voltage dependent, being most prominent at threshold potentials. The data show that a voltage dependent action on the activation gate can account for the observed reduction of peak inward sodium current and prolongation of current decay in macroscopic experiments.
authors.affiliation: Institute of Medical Physics and Biophysics, Karl-Franzens University Graz, Austria.
authors.forename: W
authors.initials: W
authors.lastname: Schreibmayer
authors.forename: N
authors.initials: N
authors.lastname: Dascal
authors.forename: I
authors.initials: I
authors.lastname: Lotan
authors.forename: M
authors.initials: M
authors.lastname: Wallner
authors.forename: L
authors.initials: L
authors.lastname: Weigl
mesh_terms: D000818:Animals; D008564:Membrane Potentials; D009865:Oocytes / Q000378:metabolism*; D011493:Protein Kinase C / Q000096:biosynthesis / Q000502:physiology*; D015222:Sodium Channels / Q000187:drug effects / Q000201:enzymology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014982:Xenopus laevis / Q000378:metabolism*
chemical_list: D015222:Sodium Channels; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate