Effects of nitric oxide in the path of relaxation caused by cholecystokinin on the sphincter of Oddi of dogs

Objective To investigate whether cholecystokinin(CCK) could contribute to the relaxation of sphincter of Oddi(SO) through nitric oxide(NO).Methods The beagle dog's experiment was established with manometry catheter inserted into the common bile duct and sphincter of Oddi retrogradely through the opened duodenum,measuring the SO motility and its response to drugs respectively by manometry.Results Compared with physiological dose of CCK(20 ng/kg) used separately,the effect of SO's relaxation was more intensive when using NO together with CCK(20 ng/kg).However,there's no difference between using the admixture and NO.Although sodium nitroprusside(SNP) dripped with injection of CCK(100 ng/kg) could reduce SO's motility relatively,but the trend of rapid contraction of SO caused by large dose of CCK did not change.Conclusion The results suggest that NO relaxes beagle dog's SO as a transmitter of non-adrenergic non-cholinergic nerve,which probably plays an important role in the path of CCK's relaxation.