L-365,260 reversed effect of sincalide against morphine on electrical and mechanical activities of rat duodenum in vitro.
OBJECTIVE
To study the antagonism of sincalide (CCK-8) to the effect of morphine and its mechanism.


METHODS
The electrical and mechanical activities of rat duodenum in vitro were recorded simultaneously.


RESULTS
Acetylcholine (ACh, 300 nmol/L) increased the spike potential amplitude (SPA) and the number (SPN) of rat duodenum in vitro, followed by an increase of duodenal contraction amplitudes (CA). The SPA, SPN, and CA of duodenum in vitro were not obviously affected by injection of morphine (330 nmol/L), but it could selectively inhibit the potentiation of ACh. After administration of CCK-8 (0.7 nmol/L), the SPA, SPN, and CA of duodenal segment did not exhibit obvious changes. But CCK-8 could selectively antagonize the effects of morphine, ie, the SPA and SPN were increased again, followed by an increase of CA. CCK-B receptor antagonist L-365,260 (30 nmol/L) reversed the antagonism of CCK-8 to the effect of morphine.


CONCLUSIONS
CCK-8 could selectively antagonize the effect of morphine which inhibited the potentiation of ACh on duodenal activities in vitro. The antagonistic effect of CCK-8 on morphine was mainly mediated by CCK-B receptor.
Yang
Chun-Xiao
CX
Department of Neurology of 2nd Affiliated Hospital, Harbin Medical University, Harbin 150086, China.
Xu
Man-Ying
MY
Liu
Feng-Yu
FY
Yang
Dong-Xiao
DX
Wang
Shu-Zhen
SZ
D000109:Acetylcholine / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001570:Benzodiazepinones / Q000494:pharmacology*; D004386:Duodenum / Q000502:physiology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors*; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010671:Phenylurea Compounds / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D043887:Receptor, Cholecystokinin B / Q000037:antagonists & inhibitors*; D012844:Sincalide / Q000494:pharmacology*
D001570:Benzodiazepinones; D010671:Phenylurea Compounds; D043887:Receptor, Cholecystokinin B; C058121:L 365260; D009020:Morphine; D012844:Sincalide; D000109:Acetylcholine