Published online Dec 15, 1998. doi: 10.3748/wjg.v4.i6.524
Revised: September 20, 1998
Accepted: November 14, 1998
Published online: December 15, 1998
AIM: To study the antagonism of cholecystokinin octapeptide (CCK-8) against the effect of morphine and its mechanism.
METHODS: The method and mechanical activities of rat duodenum in vitro were recorded simultaneously.
RESULTS: Acetylcholine (ACh) could increase the amplitude and the number of the spike potential (SPA and SPN) of rat duodenum in vitro, followed by the increase of the duodenal contraction amplitudes (CA), showing a positive correlation. Morphine, on the contrary, inhibited the potentiation of ACh, showing a negative correlation. CCK-8 could antagonize the effects of morphine, i.e. the SPA and SPN were increased again, followed by the increase of CA. CCK-A receptor antagonist Devazepide could reverse the antagonism of CCK-8 to the effect of morphine.
CONCLUSION: CCK-8 could antagonize the effect of morphine which inhibited the potentiation of ACh on the duodenal activities in vitro. The antagonistic effect of CCK-8 on morphine was mainly mediated by CCK-A receptor.