Fast and Slow Steps in the Activation of Sodium ... - BioMedSearch
Fast and Slow Steps in the Activation of Sodium Channels CLAY M. A R M S T R O N G and Wu. F. GILLY From the Department of Physiology,G4, School of Medicine, Universityof Pennsylvania, Philadelphia, Pennsylvania 19104
Kinetic features of sodium conductance (gNa) and associated gating current (Ig) were studied in voltage-clamped, internally perfused squid axons. Following a step depolarization Ig ON has several kinetic components: (a) a rapid, early phase largely precedinggsa turn-on; (b) a delayed intermediate component developing as gsa increases; and (c) a slow component continuing after gN, is fully activated. With small depolarizations the early phase shows a quick rise (
Kinetic features of sodium conductance (gNa) and associated gating current (Ig) were studied in voltage-clamped, internally perfused squid axons. Following a step depolarization Ig ON has several kinetic components: (a) a rapid, early phase largely precedinggsa turn-on; (b) a delayed intermediate component developing as gsa increases; and (c) a slow component continuing after gN, is fully activated. With small depolarizations the early phase shows a quick rise (
