Investigation of relaxant effects of new agents affecting nitric oxide/cyclic guanosine monophosphate pathway on sheep oddi sphincter

Comparative Relaxant Effects of Ataciguat and Zaprinast on Sheep Sphincter of Oddi

BACKGROUND

Relaxing the sphincter of Oddi (SO) is an important process during endoscopic retrograde cholangiopancreatography (ERCP) procedures. This issue suggests that the easier the sphincterotomy and cannulation, the more post-ERCP complications decrease.

AIMS

To compare the relaxant effects of ataciguat (a novel soluble guanylyl cyclase activator) and zaprinast (an inhibitor of phosphodiesterase 5) on sheep SO in vitro, thus testing whether they can be used during ERCP.

STUDY DESIGN

Animal experimentation.

METHODS

Sheep SO rings were placed in tissue baths and their isometric tension to ataciguat and zaprinast were tested. We also tested their isometric tension against ataciguat in the presence of 1H-(1,2,4) oxadiazole (4,3-a) quinoxalin-1-one (ODQ) which is a soluble guanylyl cyclase inhibitor.

RESULTS

Ataciguat and zaprinast both triggered concentration addicted relaxation on sheep SO rings (p=0.0018, p=0.0025 respectively) but the relaxation of the ataciguat was significantly greater than that of zaprinast at all concentrations (p=0.0024). It was observed that decreased relaxation responses were initiated by ataciguat in the presence of ODQ (p=0.0012).

CONCLUSION

Ataciguat and zaprinast both have relaxing effects on sphincter of Oddi, although that of zaprinast is lower. We believe that ataciguat and zaprinast can be used in ERCP procedures in order to relax the sphincter of Oddi and thus can be used locally in order to decrease complications.

Effects of cholecystectomy on the changes of motility of Beagle dogs' sphincter of Oddi

PURPOSE

To observe the effect of cholecystectomy on the changes of motion pattern of Beagle dogs' sphincter of Oddi (SO), and investigate the modulatory role of nitric oxide (NO) and cholecystokinin (CCK) in the regulation of SO.

METHODS

Pressure of common bile duct, SO motility, response to bolus injections of cholecystokinin (CCK, 20 ng/kg and 100 ng/kg), basal pressure (BP) and phasic contraction amplitude (PCA) were measured respectively by manometry in six Beagle dogs before and after cholecystectomy.

RESULTS

After cholecystectomy, the pressure and diameter of common bile ducts (CBD) was significantly increased (p<0.01); BP and phasic contraction frequency (PCF) were also increased, however, no significant differences were found between the two groups; the SO motilities was not significantly changed. The relaxation responded to physiological dose of CCK (20ng/kg) was decreased, while bolus-dose of CCK (100ng/kg) induced rapid contractions and decreased PCA after cholecystectomy. The regulation pattern of SO pressure modulated by NO and its inhibitor had changed after cholecystectomy.

CONCLUSION

After cholecystectomy in Beagle dogs, no obviously change of motion pattern of SO was observed through self-compensation, but these compensations may lead to some changes of regulation pattern of CCK and NO on SO.

Pretreatment with gabexate mesilate alters expression of vasoactive intestinal peptide and neuronal nitric oxide synthase in the duodenal mucosa of patients undergoing ERCP

AIM: To explore the effect of pretreatment with gabexate mesilate on the expression of vasoactive intestinal peptide (VIP) and neuronal nitric oxide synthase (nNOS) in the duodenal mucosa of patients undergoing endoscopic retrograde cholangiopancreatography (ERCP).

METHODS: A total of thirty patients with unexplained abdominal pain and jaundice were recruited to the study from September 2009 to July 2010 and divided into two groups: patients intravenously infused with gabexate mesilate and those with saline before ERCP. Three minutes after infusion, specimens were taken to detect the levels of VIP and nNOS by means of double-antibody sandwich ELISA.

RESULTS: The level of VIP (ng/L) in the papillary mucosa of patients pretreated with gabexate mesilate was significantly higher than that of controls (0.032 ± 0.004 vs 0.031 ± 0.002, P < 0.05), while that of nNOS showed no statistical difference between the two groups of patients. The mean content of nNOS (μmol/L) in the sphincter of Oddi of patients pretreated with gabexate mesilate was significantly higher than that of controls (9.55 ± 1.10 vs 8.29 ± 0.56, P < 0.01), while there was no marked difference in the level of nNOS in the sphincter of Oddi between the two groups of patients.

CONCLUSION: Pretreatment with gabexate mesilate up-regulates the expression of VIP in the papillary mucosa and nNOS in the sphincter of Oddi in patients undergoing ERCP.