Effects And Mechanism Of Changes Of Local Neurotransmitters In Rats' Pylorus And Bile Reflux To The Stomach With Stress Ulcer

Background and Aims Stress ulcer occurs primarily in severe conditions such as severe burn, trauma, hemorrhagic shock etc with high incidence and mortality in intensive care units. However, the studies on the association between stress ulcer and bile reflux to the stomach with stress ulcer are still inconclusive. Therefore, this research aimed to confirm the existence of bile reflux during stress ulcer and then to investigate the effects and mechanism of changes of local neurotransmitters in rats' pylorus and bile reflux to the stomach under stress ulcer and the protective mechanism of Talcid on gastric mucosa under this severe circumstance.Methods Cold water immersing was used to copy stress ulcer model of rats. Eighty-five SD rats were randomly divided into four groups: the normal control group(n=10); the stress group(n=30); the antagonist group (n=25) and the Talcid group (n=20). The gastric ulcer index, pH and bile acid of gastric juice were measured before and after stress. The local contents of CGRP in rats' pylorus could be measured by the Radioimmunoassay Detection Kit. The local contents of nitric oxide in rats' pylorus could be measured by the Biochemic Detection Kit.Results The local contents of nitric oxide in rats' pylorus went up to the maximum at 1 hr after stress. The bile acid and pH of gastric juice peaked at 2 hrs after stress and the ulcer index peaked at 4 hrs after stress. But the local contents of CGRP in rats' pylorus decreased to the minimum at 4 hrs after stress. The bile acid and ulcer index in the L-NAME group were significantly lower than in the antagonist control group. However, the bile acid in the hCGRP8-37 group was less than in the antagonist control group. Compared with hCGRP8-37 group, there was a significant reduction in the bile acid of the L-NAME group. There was a significant reduction in the ulcer index of the hCGRP8-37 group compared with the L-NAME group and the antagonist control group. The bile acid and ulcer index in the stomach treated with Talcid decreased significantly compared with the normal saline group. But pH of gastric juice in Talcid group increased obviously.Conclusions There was a certain kind of positive correlation between the nitric oxide in rats' pylorus and bile acid to the stomach. For nitric oxide could loosen the pyloric sphincter and increase the bile acid to the stomach. L-NAME might reduce local contents of the nitric oxide in rats' pylorus so that the bile acid to the stomach might be decreased obviously with less tight pyloric sphincter. Meanwhile, the local contents ofCGRP in rats' pylorus was negatively associated with ulcer index, hence CGRP might protect gastric mucosa under stress circumstances. As a new combined drug, Talcid can effectively reduce the concentration of bile acid as well as ulcer index so as to protect gastric mucosa and prevent the occurrence of stress ulcer.