Role of nitric oxide synthase in gastric mucosal lesion induced by psychological stress

Objective To explore the relationship between the changes of nitric oxide synthase in gastric mucosa induced by physical stress, psychological stress and related reagents as well as acute gastric mucosal lesion. Methods Animal model was constructed with impulsive stimulator of high voltage and stable currency, one hundred and twenty male SD rats were randomly divided into four groups: control, regular, irregular and reagent group. NOS activity was measured by spectrophotometry and index of injured gastric mucosa was measured by the method of Nils Lambecht. Immunohistochemistry and polyantibodies of NOSⅠ,NOSⅡ,NOSⅢ were employed to investigate the distribution sites of NOS. Results NOS activity was stable in normal rats but increased significantly in group of psychological stress( P 0.05); gastric mucosal injury was observed in the regular and irregular groups and the latter was more severe( P 0.05),proteins of NOSⅠ,NOSⅢ could be observed in rats' gastric mucosa under normal circumstance and stress,protein of NOSⅡ could be found only in both stresses and no difference noted. NOS activity decreased after any one of the three reagents administrated and L NAME showed most marked change( P 0.01), with increased injury index; whereas decreased injury index was present in the other subgroups ( P 0.05). Conclusions The degree of increase of the NOS activity and gastric mucosal injury are positively correlated to the severity of psychological stress,the sites of NOS under stress were not relevant to the degree of stress; AG and L Arg have protective effect on the gastric mucosa while L NAME aggravates the mucosal damage.