Depression of rat feeding in familiar and novel environment by sulfated and nonsulfated cholecystokinin octapeptide.
The effects of cholecystokinin octapeptide sulfate ester (CCK-8-SE) and nonsulfated cholecystokinin octapeptide (CCK-8-NS) were tested on feeding by rats in familiar and novel environment. In a familiar environment only intraperitoneally (IP) administered CCK-8-SE (0.8-24 nmole/kg) could inhibit 30 min food intake of 24 hr food-deprived rats, while the same doses of CCK-8-NS IP and both octapeptides (0.8-8000 pmole/rat) intracerebroventricularly (ICV) were totally ineffective. The effects of CCK-8-SE and CCK-8-NS on feeding were also tested in a novel environment, i.e., in an open field. The parameters of exploratory activity and food intake of 24-hr food-deprived rats were recorded simultaneously during a 15-min session. After IP injection, CCK-8-SE dose-dependently depressed the food intake, and the higher doses (8.0 or 24 nmole/kg) also decreased the open field parameters, including number of approaches to food. In the novel environment, 8.0 or 24 nmole/kg IP injected CCK-8-NS also depressed the food intake, whereas the incidence of grooming was enhanced after 8.0 nmole/kg CCK-8-NS. The most effective doses of both octapeptides increased the latency to first bite. For the open field test ICV treatment was also carried out with 8, 80 or 800 pmole doses of the octapeptides, and after 80 pmole CCK-8-SE ICV the food intake was decreased, and after 80 or 800 pmole CCK-8-SE and 800 pmole CCK-8-NS the food intake/approach parameter was depressed.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D003864:Depression, Chemical; D004777:Environment; D005106:Exploratory Behavior / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D012844:Sincalide / Q000494:pharmacology*
D012844:Sincalide