title: Inactivation of the Na permeability in squid giant axons.
abstract: Inactivation of the Na permeability has been studied in intact and perfused squid giant axons with the voltage clamp method. The main results are: 1. Upon depolarization inactivation develops along an exponential time course; the upper limit for an initial delay in the development of inactivation is 50-100 musec. 2. Adding 20-40 mM KCl to K-free external solution accelerates the development of inactivation and slows its removal. 3. Scorpion venoms increase the maintained conductance, i.e. make inactivation less complete; the voltage dependence of the maintained conductance is different from that of the peak conductance.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002463:Cell Membrane Permeability; D049832:Decapodiformes; D004553:Electric Conductivity; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D012604:Scorpion Venoms / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*
chemical_list: D007473:Ion Channels; D012604:Scorpion Venoms; D011189:Potassium Chloride; D012964:Sodium