BRAIN CHOLECYSTOKININ TETRAPEPTIDE LEVELS ARE INCREASED IN A RAT MODEL OF ANXIETY

RATS exposed to the smell of a predator adopted the freezing posture i ndicative of anxiety. Correlatively, the concentration of cholecystoki nin tetrapeptide (CCK-4) was increased in the olfactory bulb, frontal and central cortex, dorsal and ventral striatum, central amygdala and the nucleus of the solitary tract. The concentration of CCK-8 was incr eased only in the ventral striatum. Glutamate was increased in the cor tex and the striatum and dopamine was increased in the cortex. Intrape ritoneal injection of CCK-4 increased brain levels of CCK-4 and replic ated, in part, the behavioural effect of the smell of the predator. In jection of a CCK-B-receptor antagonist had the opposite behavioural ef fect. The results support a role for CCK-4 in anxiety.