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A major role for calcium-dependent potassium current in action potential repolarization in adrenal chromaffin cells
J J Pancrazio1, P A Johnson, C Lynch
1Department of Anesthesiology, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
Brain Research
|December 30, 1994
Abstract:
To determine the extent which Ca dependent K current (IKCa) contributes during an action potential (AP), bovine chromaffin cells were voltage-clamped using a pre-recorded AP as the command voltage waveform. Based on (1) differential sensitivity of IKCa and Ca-independent K current (IK) to tetraethylammonium; (2) measurements of AP currents under conditions where Ca activation of IKCa had been abolished; and (3) blockade by charybdotoxin, IKCa comprised 70-90% of the outward K current during AP repolarization. In addition, observations are made concerning the form of AP-evoked Ca current.