Cholecystokinin depolarizes neurons of cat pancreatic ganglion

The effect of cholecystokinin octapeptide (CCK-8) on membrane potential and conductance of cat pancreatic ganglion neurons was studied in vitro by means of intracellular microelectrode recording methods. Microejection of S-CCK-8 and NS-CCK-8 evoked, by direct action, a slow, reversible membrane depolarization. The majority of neurons tested were more sensitive to S-CCK-8. The depolarizing response to S-CCK-8 and NS-CCK-8 was accompanied in different neurons by a variable change in membrane permeability to Na⁺ and/or K⁺. The effects of S-CCK-8 and NS-CCK-8 were mediated by the CCK(B) receptor. The results suggest that S-CCK-8 and NS-CCK-8 increase the excitability of pancreatic ganglion neurons by acting on postsynaptic CCK(B) receptors.