[Intracerebroventricular administration of cholecystokinin inhibits the dopamine- and serotoninergic systems of the brain].

In male Wistar rats, intraventricular administration of cholecystokinin caused specific dose-dependent behavioral changes: low doses (0.1--0.25 U) depressed the exploratory activity whereas higher doses (0.5--8.0 U) caused head twitches, stereotyped gnawing and hyperreactivity. Cholecystokinin suppressing markedly dopamine and serotonin turnover in various brain structures, completely blocked the behavioral effects of amphetamine (2.5 mg/kg) and 5-hydroxytryptophan (150 mg/kg). The data obtained suggest that cholecystokinin suppresses presynaptic dopamine- and serotoninergic mechanisms but enhances the sensitivity of postsynaptic receptors of these systems.