Objective: To evaluate the effects of morphine on the human sphincter of Oddi pressure and the antagonism of anticholinergic agents against morphine.
Methods: The action of these drugs on the sphincter of Oddi (SO) was evaluated by means of choledochofiberscopy manometry in 40 operated patients with T-tube. The patients were divided randomly into 4 groups: anisodamine, atropine, buscopan, and control. The following data were recorded: duodenal pressure (DP), basal pressure of the sphincter of Oddi (BPSO), contractive amplitude of the sphincter of Oddi (CASO), contractive frequency of the sphincter of Oddi (CFSO), contractive duration of the sphincter of Oddi (CDSO), and pressure of the common bile duct (PCBD). Both morphine and anticholinergic agents were given intramuscularly.
Results: After injection of 10 mg morphine, BPSO, CASO, CFSO, and PCBD increased significantly. After injection of 15 mg anisodamine or 0.75 mg atropine, CASO, BPSO declined obviously, and after injection of 20 mg buscopan, CASO, BPSO, CFSO declined obviously, but in anisodamine, atropine and buscopan groups, they differed insignificantly.
Conclusions: The results illustrate that SO manometry via choledochofiberscopy is a new method for SO dynamic study. Morphine can increase DP, BPSO, CASO, PCBD, but anisodamine atropine and buscopan can antagonize the effect of morphine.