Effects of cholecystokinin and caerulein on gastric emptying.

The effect of exogenous cholecystokinin (CCK) on the gastric emptying of liquid and solid diets, as well as the action of oxethazaine, a topical anesthetic, on the satiety effect of endogenous CCK, were investigated in adult rats. Intraperitoneal (i.p.) injections of the synthetic octapeptide of CCK (CCK-OP) and caerulein slowed the gastric emptying of both solid and liquid diets. The suppression of feeding produced by L-phenylalanine, which is known to release endogenous CCK, was abolished when the rats were pretreated with oxethazaine. The dose of CCK-OP and caerulein administered in the present work (80 Ivy dog units or 2.7 micrograms/kg i.p. for CCK-OP; 2 micrograms/kg i.p. for caerulein), had significantly depressed the intake of fasted rats in previous experiments. There seems to be a relationship between gastric emptying and the effectiveness of CCK in inducing satiety in rats. It is further concluded that the release of CCK from the duodenal mucosa is neural in character.