Cholecystokinin octapeptide, proglumide, and conditioned taste avoidance in rats

Past research has shown that large (pharmacological) doses of cholecystokinin octapeptide (CCK-8) can influence conditioned behavior in rats. In the present study rats were allowed to locate and drink from a drinking tube that contained a sucrose solution. Following 30 sec exposure to the sucrose, intraperitoneal injections of NaCl or CCK-8 were given, with several variables measured 24 hr later. CCK-8 (100 micrograms/kg) was found to increase the latency to begin drinking the sucrose. It was also found that CCK-8 (10 micrograms/kg and 100 micrograms/kg) reduced the amount of sucrose consumption following the pairing of sucrose exposure and CCK-8. In addition, CCK-8 (100 micrograms/kg) reduced the amount of time rats spent in the area of the conditioning apparatus where the sucrose was located. These results are consistent with past research which found that CCK-8 can produce conditioned taste avoidance in rats. These results suggest that pharmacological doses of CCK-8 can act as an aversive stimulus during conditioning. Proglumide was found to block all of the effects produced by CCK-8 while producing little effect by itself.