[Conduction of a nerve impulse along a myelineated fiber while varying the membrane properties of nodes of Ranvier].
The mathematical model of a frog myelinated axon [1, 3] has been used to study the dependence of the conduction velocity (theta) on the parameters of the nodal membrane: its capacity (CN), leakage conductance (gl), sodium and potassium maximum conductances (gNa, gK). Calculations have shown that theta practically does not depend on gK:theta raises only by 3% when gK is diminished to zero. The increase of theta with reducing of gl or CN can be described by formulae: theta (m/s) = 19-300.gl (muS) or theta = 16-1.87.CN(pF) (Fig 1,2). Theta depends strongly on gNa:theta approximately equal to (gNa)7/8 (Fig 3). Due to the capacity of Na channels (determined by the gating charge movement) there is a maximum in the relation between the number of Na channels per node and the theta (Fig 4). A clear-cut maximum does exist also in the curve relating theta to the nodal membrane area (Fig. 5a). The position of the maximum and the shape of this curve depend on gl and CN but not on gNa (Fig. 5b).
D000818:Animals; D001001:Anura; D003201:Computers; D007473:Ion Channels / Q000502:physiology; D008433:Mathematics; D008959:Models, Neurological; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009431:Neural Conduction; D011901:Ranvier's Nodes / Q000502:physiology*
D007473:Ion Channels
Provedenie nervnogo impul'sa po mielinizirovannomu voloknu pri var'irovanii svoĭstv membrany perekhvata Ranv'e.