Nitroester drug's effects and their antagonistic effects against morphine on human sphincter of Oddi motility

Abstract

Aim: To evaluate the effects of nitroester drugs on human sphincter of Oddi (SO) motility and their antagonistic effects against morphine which shows excitatory effect on Oddi's sphincter motility.

Methods: The effects of these drugs on SO were evaluated by means of choledochofiberoscopy manometry. A total of 67 patients having T-tubes after cholecystectomy and choledochotomy were involved in the study, they were randomly divided into glyceryl trinitrate (GTN) group, isosorbide dinitrate (ISDN) group, pentaerythritol tetranitrate (PTN) group, morphine associated with GTN group, morphine associated with ISDN group and morphine associated with PTN group. Basal pressure of Oddi's sphincter (BPOS), amplitude of phasic contractions (SOCA), frequency of phasic contractions (SOF), duration of phasic contractions (SOD), duodenal pressure (DP) and common bile duct pressure (CBDP) were scored and analyzed. Morphine was given intramuscularly while nitroester drugs were applied sublingually.

Results: BPOS and SOCA decreased significantly after administration of ISDN and GTN, BPOS reduced from 10.95+/-7.49 mmHg to 5.92+/-4.04 mmHg (P<0.05) evidently after application of PTN. BPOS increased from 7.37+/-5.58 mmHg to 16.60+/-13.87 mmHg, SOCA increased from 54.09+/-38.37 mmHg to 100.70+/-43.51 mmHg, SOF increased from 7.15+/-3.20 mmHg to 10.38+/-2.93 mmHg and CBDP increased 3.75+/-1.95 mmHg to 10.49+/-8.21 mmHg (P<0.01) evidently after injection of morphine. After associated application of ISDN and GTN, the four indications above decreased obviously. As for application associated with PTN, SOCA and SOF decreased separately from 100.64+/-44.99 mmHg to 66.17+/-35.88 mmHg and from 10.70+/-2.76 mmHg to 9.04+/-1.71 mmHg (P<0.05) markedly.

Conclusion: The regular dose of GTN, ISDN and PTN showed inhibitory effect on SO motility, morphine showed excitatory effect on SO while GTN, ISDN and PTN could antagonize the effect of morphine. Among the three nitroester drugs, the effect of ISDN on SO was most significant.