title: Voltage activation and hysteresis of the non-selective voltage-dependent channel in the intact human red cell.
abstract: Suspension of intact human red cells in media with low chloride and sodium concentrations (isotonic sucrose substitution) results in strongly inside positive membrane potentials, which activate the voltage-dependent non-selective cation (NSVDC) channel. By systematic variation of the initial Nernst potentials for chloride (degree of ion substitution) as well as the chloride conductance (block by NS1652), and by exploiting the interplay between the Ca(2+)-permeable NSVDC channel, the Ca(2+)-activated K+ channel (the Gárdos channel) and the Ca(2+)-pump, a graded activation of the NSVDC channel was achieved. Under these conditions, it was shown that the NSVDC channels exist in two states of activation depending on the initial conditions for the activation. The hysteretic behaviour, which in patch clamp experiments has been found for the individual channel unit, is thus retained at the cellular level and can be demonstrated with red cells in suspension.
authors.affiliation: The August Krogh Institute, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen, Denmark. pbennekou@aki.ku.dk
authors.forename: Poul
authors.initials: P
authors.lastname: Bennekou
authors.forename: Trine L
authors.initials: TL
authors.lastname: Barksmann
authors.forename: Lars R
authors.initials: LR
authors.lastname: Jensen
authors.forename: Berit I
authors.initials: BI
authors.lastname: Kristensen
authors.forename: Palle
authors.initials: P
authors.lastname: Christophersen
mesh_terms: D015220:Calcium Channels / Q000378:metabolism / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000378:metabolism / Q000502:physiology; D004594:Electrophysiology; D004912:Erythrocytes / Q000502:physiology*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism / Q000502:physiology*; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000378:metabolism / Q000502:physiology
chemical_list: D015220:Calcium Channels; D007473:Ion Channels; D024681:Potassium Channels, Calcium-Activated; D000252:Calcium-Transporting ATPases