Nonlinear relationship between V+max and h infinity in frog skeletal muscle.
The relationship between the maximum velocity of action potential upstroke (V+max) and steady-state Na+ channel inactivation (h infinity) was studied in frog skeletal muscle during repetitive discharges evoked in the presence of cevadine (1 mumol/l). Conventional microelectrodes and vaseline-gap voltage-clamp techniques were used. A severe degree of nonlinearity was found between (h infinity) and (V+max) especially when the Na+ conductance (gNa) was small. The observed nonlinearity could be explained as a property of the normal Na+ channel gating in skeletal muscle rather than that of cevadine-modified channels. Part of this work has been published in abstract form in Biophys. J. 57: 105A, 1990.
Nánási
P P
PP
Department of Physiology, University Medical School of Debrecen, Hungary.
Dankó
M
M
Varró
A
A
Lathrop
D A
DA
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D009132:Muscles / Q000187:drug effects / Q000502:physiology*; D011893:Rana esculenta; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology*; D014702:Veratrine / Q000494:pharmacology
D015222:Sodium Channels; D014702:Veratrine