Conductance fluctuations in Ranvier nodes.
Voltage fluctuations associated with the sodium system were measured upon elimination of the potassium current in the nodal membrane by internal application of cesium-ions. The intensity of this noise reaches a maximal value at a membrane potential in the vicinity of --40 mV. Here the power spectrum consists of two additive components: a 1/f component and a Lorentzian. The Lorentzian is associated with h-gate kinetics and is consistent with the binary state conduction model. On the basis of this model the sodium-channel conductance is calculated to be 2 to 5-10(-12) S. The analysis is complicated by the existence of an incomplete slow sodium inactivation process.
D000818:Animals; D001001:Anura; D002586:Cesium / Q000494:pharmacology; D008564:Membrane Potentials; D009431:Neural Conduction; D009622:Noise; D011188:Potassium; D011896:Rana temporaria; D011901:Ranvier's Nodes / Q000502:physiology*; D012584:Sciatic Nerve / Q000166:cytology; D012964:Sodium
D002586:Cesium; D012964:Sodium; D011188:Potassium