CCK4-induced panic in healthy subjects II: neurochemical correlates

Cholecystokinin tetrapeptide (CCK4) induces symptoms similar to those of pa nic attack. The present study investigated the effects of CCK4 administrati on on catecholaminergic system. In this double blind, randomised, crossover experiment, 16 healthy subjects received injections of either 25 mu g of C CK4 or placebo on two separate occasions. Platelet and plasma catecholamine concentrations were assessed before the administration and compared to pos t-injection values. The results clearly show that both plasma and platelet concentrations of catecholamines are significantly affected by CCK4. Plasma norepinephrine (NE) and epinephrine (EPI) raised significantly above basel ine in the immediate post-CCK4 period, while in plasma dopamine (DA), the s ignificant increases were delayed. In the platelets, significant post-CCK4 increases of NE and EPI concentrations were observed with a delay of severa l minutes. In summary, we have demonstrated that, in healthy subjects, CCK4 increases peripheral concentrations of catecholamines in both plasma and p latelets, with the most consistent changes occurring in platelet NE and pla sma EPI concentrations. (C) 1999 Elsevier Science B.V./ECNP. All rights res erved.