An analysis of the change in K-permeability on depolarization in terms of affinity and numbers of total channels

摘要: A theoretical relation between permeability and ionic concentrations in a bathing solution has been derived by assuming that only channels unoccupied competing non-permeable ion can transport ions specific for channel. The affinities of the channel to competitor are expressed dissociation constants ion-site competitor-site complexes channel. Analyses K [K]o obtained from myelinated nerve fibres Nitella cells revealed affinity sites was independent membrane potential, whereas conductivity increased with depolarization. value constant K+-site complex, K1, estimated as 1244 mm nerve, K1 exp(ψ0FRT) 17.5 (ψ0 is surface potential at outer membrane). dependence on voltage total number conductance = [K]1 (obtained magnitude current computed using described above). It should be noted when partially saturated K+, neither chord nor “permeability coefficient”, defined Goldman Hodgkin-Katz formulation, correctly represents channels.