Cholecystokinin modulates voltage dependent K+ currents in cultured rat hippocampal neurones

Much interest has been focussed recently on neuroactive peptides originally found in the peripheral nervous system, but now, increasingly, being shown to be present in considerable amounts in the mammalian CNS. One of these peptides, cholecystokinin (CCK), is present in large amounts in higher brain areas. Immunoreactivity to CCK has been demonstrated in the mammalian hippocampus and dentate gyrus, localised in nerve terminals, and increasingly this peptide is being suggested as having a role as a transmitter in the CNS. Generally, CCK appears to produce depolarisations of neurones: e.g. mesenteric ganglion cells, and hippocampal neurones [5], although the mechanism by which it does so remains unclear, there being reports of either a decrease in input resistance, an increase, or both.