Cholecystokinin interferes with the thermoregulatory effect of exogenous and endogenous opioids

Neuropeptides. Aug-Sep 1989;14(2):85-92. doi: 10.1016/0143-4179(89)90063-2.


Intraperitoneal (ip) injection of cholecystokinin octapeptide sulfate ester (CCK; 5, 10 and 50 micrograms/kg) reduced the hypothermic response to 8 mg/kg and 32 mg/kg systemic morphine in restrained and freely moving rats, respectively. The hyperthermia elicited by a subcutaneous (sc) injection of 8 mg/kg morphine to freely moving rats was not diminished by CCK pretreatment. CCK (5 micrograms/kp ip) completely prevented the restraint stress-induced hyperthermia. Naloxone (1 mg/gk sc) was effective in antagonizing both the hyperthermic and the hypothermic effects of morphine and the stress-induced emotional hyperthermia. These results support the hypothesis that CCK may contribute to regulation of the endogenous opioid system.

MeSH terms

  • Animals
  • Body Temperature Regulation / drug effects*
  • Cholecystokinin / pharmacology*
  • Endorphins / physiology*
  • Hyperthermia, Induced
  • Hypothermia, Induced
  • Injections, Intraperitoneal
  • Male
  • Morphine / pharmacology*
  • Naloxone / pharmacology
  • Rats
  • Rats, Inbred Strains


  • Endorphins
  • Naloxone
  • Morphine
  • Cholecystokinin