Intraperitoneally injected cholecystokinin-octapeptide activates pica in rats

Cholecystokinin-octapeptide (CCK-8) was injected intraperitoneally into rats to see if it could cause them to eat kaolin (clay)--a pica behavior which has been shown to indicate gastric distress. In the first study, a single large dose of CCK-8 (20 micrograms/kg) failed to produce pica. In the second study, 4 smaller doses of CCK-8 (8 micrograms/kg), 30 min apart, produced significant ingestion of kaolin compared to the baseline condition of vehicle injections. The pica was comparable to that observed in another group of rats given a toxic dose of LiCl (127 mg/kg, IP). It is concluded that intraperitoneal injections of CCK-8 can induce a state of gastric distress in the rat.