Cholecystokinin modulation of apomorphine- or amphetamine-induced stereotypy in rats: opposite effects

Stereotyped behavior can be induced by the dopamine agonist apomorphine or by the releasing agent amphetamine. Cholecystokinin influence on dopamine-m ediated behaviors has been extensively studied but a real controversy remai ns. Our purpose was to further characterize the dopamine-cholecystokinin in teraction in apomorphine- and amphetamine-induced stereotyped behavior usin g sulphated cholecystokinin octapeptide (CCK8) and cholecystokinin tetrapep tide (CCK4) treatments. The results showed that CCK8 decreases apomorphine- induced stereotyped behavior and CCK4 has no effect. CCK4 and CCK8 increase d the amphetamine-induced stereotyped behavior; CCK4 was more effective. Th e results confirm the opposite modulation of apomorphine or amphetamine-ind uced stereotyped behavior by CCK. These data suggest that this modulation i s mediated by both CCK receptors on apomorphine-induced and only by CCK, re ceptors on amphetamine-induced stereotyped behavior. (C) 2001 Elsevier Scie nce Inc. All rights reserved.