Accelerated expression of cholecystokinin gene in the brain of rats rendered tolerant to morphine.
Results from behavioural studies have shown that central cholecystokinin octapeptide (CCK-8) is a powerful antagonist against opioid effects and that an increased release of central CCK-8 plays an important role in the mechanisms of tolerance to morphine analgesia. No information is available concerning the rate of biosynthesis of CCK-8 in response to chronic morphine administration. Blot hybridization experiments made in the present study revealed a marked increase in preproCCK mRNA in the brain of rats receiving chronic morphine treatment for 1, 3 and 6 days, showing an increment of 52% (p < 0.05), 62% (p < 0.05) and 97% (p < 0.01) respectively. The results suggest that an acceleration of the expression of the CCK gene during long-term morphine treatment might constitute one of the mechanisms for morphine tolerance.
Zhou
Y
Y
Neuroscience Research Centre, Beijing Medical University, China.
Sun
Y H
YH
Zhang
Z W
ZW
Han
J S
JS
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D002766:Cholecystokinin / Q000235:genetics*; D003720:Densitometry; D004361:Drug Tolerance; D015870:Gene Expression / Q000187:drug effects*; D009020:Morphine / Q000494:pharmacology*; D009693:Nucleic Acid Hybridization; D012313:RNA / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D013268:Stimulation, Chemical; D014158:Transcription, Genetic / Q000187:drug effects
D012333:RNA, Messenger; D012313:RNA; D009020:Morphine; D002766:Cholecystokinin