title: Kinetics and distribution of voltage-gated Ca, Na and K channels on the somata of rat cerebellar Purkinje cells.
abstract: Voltage gated ion channels on the somatic membrane of rat cerebellar Purkinje cells were studied in dissociated cell culture with the combination of cell-attached and whole-cell variation of patch clamp technique. The method enables us to record local somatic membrane current under an improved space clamp condition. Transient (fast-inactivating) and steady (slow inactivating) Ca channel currents, Na current, transient (fast-inactivating) and steady (slow-inactivating) K currents, were observed. Transient and steady Ca channel currents were activated at test potentials more positive than -40 mV and -20 mV, respectively (in 50 mM external Ba). The transient current inactivated with a half-decay time of 10-30 ms during maintained depolarizing pulses, while the steady current showed relatively little inactivation. Na current was activated at more positive potentials than -60 mV, and inactivated with a half-decay time of less than 5 ms. Transient and steady K outward currents were recorded at more positive potential than -20 mV and -40 mV, respectively. The transient current inactivated with a half-decay time of 2-8 ms. Ca, Na and K channels showed different patterns of distribution on the somatic membrane. Steady Ca channels tended to cluster compared with Na or K channels.
authors.affiliation: Department of Physiology, School of Medicine, University of California, Los Angeles 90024.
authors.forename: T
authors.initials: T
authors.lastname: Hirano
authors.forename: S
authors.initials: S
authors.lastname: Hagiwara
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D002478:Cells, Cultured; D004553:Electric Conductivity; D007700:Kinetics; D008564:Membrane Potentials; D015221:Potassium Channels / Q000502:physiology*; D011689:Purkinje Cells / Q000502:physiology*; D051381:Rats; D015222:Sodium Channels / Q000502:physiology*
chemical_list: D015220:Calcium Channels; D015221:Potassium Channels; D015222:Sodium Channels