title: Slow actions of hyperpolarization on sodium channels in the membrane of myelinated nerve.
abstract: The mean sodium current, I, and the variance of sodium current fluctuations, var, were measured in myelinated nerve during a depolarization to V = 40 mV applied from the resting potential (VH = 0) or from a hyperpolarizing holding potential VH = -28 mV. From I and var the relative variations in the number N and the conductance gamma of sodium channels following changes of the holding potential were calculated. Hyperpolarizing the membrane from VH = 0 to -28 mV increased N by a factor of 3.7, whereas gamma decreased by a factor of 0.53. These actions of holding potential on sodium channels develop slowly since 500 ms prepulses to 0 or -28 mV do not alter the values of N and gamma.
mesh_terms: D000818:Animals; D001001:Anura; D002462:Cell Membrane / Q000502:physiology; D007473:Ion Channels / Q000502:physiology*; D008433:Mathematics; D008564:Membrane Potentials; D009186:Myelin Sheath / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology*; D011893:Rana esculenta; D012964:Sodium / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D012964:Sodium