The role of Nitrergic system on the isolated gastric fundus smooth muscles of rats with experimentally induced gastric ulcers

NO is now recognized as a mediator of mucosal defense that exhibits many of the same actions as PGs in the gastrointestinal tract. In this study, the effects of the nitrergic systems on alterations related to neurotransmitter release obtained by the electrical field stimulation (EFS) have been investigated in the gastric ulcer and 48 hours of starvation groups formed by experimental indomethacin in the isolated rat gastric fundus smooth muscles.L-NAME, control and starvation for 48 hours significantly increased neurogenic contractions induced by EFS in the rat isolated gastric fundus; nevertheless, the increase in the ulcer groups was not significant. This situation indicates that NO synthesis increases in order to prevent the damage in the gastric mucosa related to starvation.Sildenafil reduced the neurogenic contractions induced by EFS in all three groups as well. This could be accepted as another finding that shows may be related to increasing endojen NO effect, in the control, 48 hours starvation and ulcer groups.L-Arjinin reduced the responses of neurogenic contraction induced by EFS in all of the three groups. It was observed that the reduction among groups was not statistically significant. This effect may be related to the non-specific effect of L-Arjinin.It was observed that SNP as consantration-dependent caused relaxation responses in karbakol, the responses did not cause any differences among groups. That ekzojen NO did not change the relaxation responses indicates that seconder messenger system does not change due to ulcer and 48 hours of starvation.Papaverin has caused relaxation as consantration ?dependent in all groups. That the response of relaxation has not showed difference leads us to think that starvation and ulcer could not have an effect on the smooth muscle functions.These findings show that 48 hours of starvation increased NO in rats and the increased NO is protective of the tissue damage because of starvation but the ulcer progress has not changed NO activity; besides, neither starvation nor ulcer effected smooth muscle functions. We are in the thought that the reason of that endojen and ekzojen NO have not showed too much difference might be due to the mediators except for NO; such as PG, GH, TXA2, LT CGRP; and the interaction among these mediators.