Time course of Ca and Ca-dependent K currents during molluscan nerve cell action potentials.
The time courses of Ca and Ca-dependent K currents during Ca-dependent action potentials were obtained by recording the membrane currents produced in response to spike-like voltage clamp pulses before and after selective blockade of channels. The Ca current had a biphasic waveform with a first surge and a late, large entry. The Ca-dependent K(Ca) current onset was relatively fast with a peak occurring at half spike repolarization. The fast activation of the K(Ca) current was consecutive to the first Ca entry. It is concluded that K(Ca) currents constitute a powerful spike repolarization mechanism in addition to the voltage-dependent K currents.
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006372:Helix, Snails; D007473:Ion Channels / Q000502:physiology*; D009431:Neural Conduction; D009474:Neurons / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*
D007473:Ion Channels; D011188:Potassium; D002118:Calcium