A Tight-Seal Whole Cell Study of the Voltage-Dependent Gating Mechanism of K-Channels of Protoplasmic Droplets of Chara corallina.
The biophysical properties of voltage-dependent K(+)-channels of protoplasmic droplets of Chara corallina Klein ex Willd., em, R.D.W. were investigated using the tight-seal whole cell method. Two potassium currents were observed in voltage-clamp mode and they can be used to explain the transient membrane potential time course observed in current-clamp mode. The K(+)-channels are identified by the effect of tetraethylammonium chloride which blocks both currents. A two-state, constant dipole moment model is used to fit the voltage-conductance curve. From this model the minimum equivalent gating charge involved in the gating mechanism of K(+)-channels of Chara can be estimated.
Homblé
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Department of Botany, University of Toronto, Toronto, Ontario M5S 1A1, Canada.