Behavioral effects of cholecystokinin and its related peptides in rats

Behavioral effects of cholecystokinin (CCK) were observed in neofrontal decorticated and sham-operated rats. In the decorticated rats the cataleptic and analgesic effects of beta-endorphin were markedly enhanced. When CCK-antiserum was administered together with beta-endorphin, these effects were also enhanced. Sulfated CCK-8 decreased locomotion and rearing in open field test. Proglumide, a selective antagonist of CCK, blocked CCK-8-induced-hypomotility, but it had no influence on the actions of CCK-4. When general activity was monitored using an Automex, the activity counts markedly increased in the decorticated rats, while in the sham-operated rats such increase was not observed. Non-sulfated CCK-8 also stimulated the motility, particularly in the decorticated rats. On the other hand, CCK-4 was opposite to the results of CCK-8. In the decorticated rats rearing, sniffing and head stereotypy were increased by CCK-8, but grooming was not affected.