CHOLECYSTOKININ ENHANCES THE ACOUSTIC STARTLE RESPONSE IN RATS

THE present study examined the effects of the neuropeptide cholecystok inin (CCK) on neurones of the caudal pontine reticular nucleus (PnC), which mediates the acoustic startle response (ASR) in rats. Electrophy siological experiments revealed an excitatory effect of CCK on acousti cally responsive neurones in the PnC. On the behavioural level, CCK al so enhanced the ASR. Since the PnC is not only an obligatory relay sta tion of the brain circuit mediating the ASR, but also receives modulat ory input from brain areas involved in the expression of fear and anxi ety, the enhancement of the ASR by CCK could be interpreted as an anxi ogenic-like effect of this peptide.