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Cholecystokinin octapeptide (CCK-8) antagonized nalgesia mediated by mu and kappa opioid receptors

Wang Xiaohong, Wang Xiaojing, Han Jisheng

Department of Physiology, Beijing Medical University. Beijing, China

Abstract

CCK-8 has been shown to antagonize the analgesia produced by morphine or
endogenous opioid peptides. The present study was performed to clarify the interaction between CCK-8 and different opioid ligands. Analgesia produced by
intrathecal (I.T.) injection of the specific #mu# receptor agonist PL017 10ng or #kappa# receptor agonist NDAP 500 ng can be antagonized by I.T. injection CCK-8 at a dose as small as 4 ng. In contrast, analgesia produced by I.T. injection of the #delta# receptor agonist DPDPE (6.5,13 and 26 #mu#g) was not blocked by CCK-8 (4 ng or 40 ng, I.T.). The antagonistic effect of CCK-8 on PL017 and NDAP could be completely reversed by progiumide (3#mu#g, I.T.).I.T. injection of CCK-8 (4 or 40 ng single dose or cummulative dose of 0.1,0.2,0.5 and 1.0#mu#g at 10 min intervals) produced neither analgesia nor hyperalgesia. In conclusion, CCK-8 preferentially antagonizes opioid analgesia mediated by #mu# and #kappa# receptors, and this antagonistic effect is mediated by CCK receptors.

Key words: CCK-8;PL017;NDAP;Proglumide;Intrathecal injection

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Citing This Article：

Wang Xiaohong, Wang Xiaojing, Han Jisheng. Cholecystokinin octapeptide (CCK-8) antagonized nalgesia mediated by mu and kappa opioid receptors. Acta Physiol Sin 1990; 42 (3): (in Chinese with English abstract).