[Change in the selectivity of the sodium channels of a nerve fiber membrane under the action of veratrine].
The ionic currents of the nodal membrane were measured under voltage clamp conditions. The membrane being +40 mv. The replacing of the external Na+-ions to K+- and NH4+-ions have showed that the relative pearmeabilities of the veratrine-modified channels calculated from the constant field theory are arranged in the following row: PNa:PK:PNH4 = 1:0.29:0.61, which differs from the same row for the normal channels. The decreasing of the slope of current-voltage relations of the modified channels with the replacing of Na+-ions to K+- and NH4+-ions is the evidence of a more strong binding of these ions to external mouth of the modified channel compared to the binding of Na+-ions.
D000818:Animals; D001001:Anura; D002463:Cell Membrane Permeability / Q000187:drug effects; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D009441:Neurilemma / Q000187:drug effects*; D011898:Ranidae; D011901:Ranvier's Nodes / Q000187:drug effects; D012964:Sodium / Q000378:metabolism*; D014702:Veratrine / Q000494:pharmacology*
D007473:Ion Channels; D012964:Sodium; D014702:Veratrine
Izmenenie selektivnosti natrievykh kanalov membrany nervnogo volokna pri deĭstvii veratrina.