Cholecystokinin reduces body temperature in vehicle- but not capsaicin-pretreated rats.
Systemic administration of cholecystokinin C-terminal octapeptide (CCK-8) decreases body temperature. However, it remains unclear whether reduction of body temperature is concomitant with suppression of food intake at CCK-8 doses that approach physiological levels. We examined rectal temperature after intraperitoneal CCK-8, 4 micrograms/kg, both in the presence and absence of a preferred food. We found that rectal temperature was significantly reduced by CCK-8 in both conditions and that the reduction of temperature coincided with the time of maximal suppression of food intake by CCK-8. In rats pretreated systemically with 25 or 175 mg/kg of the sensory neurotoxin capsaicin, both suppression of food intake and reduction of body temperature were significantly attenuated or abolished. The 25 mg/kg capsaicin treatment did not alter corneal chemosensitivity or the ability of rats to maintain normothermia at elevated ambient temperature, suggesting that capsaicin damage to neural substrates mediating CCK-8-induced reduction of body temperature 1) did not generalize to cephalic or peripheral warm-sensitive structures, and 2) was limited to fine sensory fibers accessible to intraperitoneal capsaicin application.
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Department of Food Science and Toxicology, Holm Research Center, University of Idaho, Moscow 83843.
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology*; D003315:Cornea / Q000187:drug effects; D004435:Eating; D005518:Food Preferences; D007274:Injections, Intraperitoneal; D008297:Male; D014677:Pharmaceutical Vehicles; D051381:Rats; D017207:Rats, Sprague-Dawley; D012007:Rectum; D012844:Sincalide / Q000494:pharmacology*
D014677:Pharmaceutical Vehicles; D012844:Sincalide; D002211:Capsaicin