Modulation of the transient potassium current in rat hippocampal neurones by cholecystokinin.

Cholecystokinin (CCK) affects neuronal excitability in a variety of in vivo and in vitro preparations, apparently by modulating a resting potassium conductance. The data presented here show that CCK (applied as CCK8-S) also affects the transient potassium current in hippocampal neurones, by changing the voltage dependence of the inactivation and activation of the current. The way in which the voltage dependence is changed can lead to either an enhancement of the current or an attenuation, depending upon the voltage protocol used. This effect of CCK does not desensitise over a time period of minutes, and may therefore be important in controlling neuronal excitability in the CNS.