Recently gastric mucosal nitric oxide(NO) synthase has been found in the rat. Evidence from many reports suggests that endogenous NO plays a role in maintaining gastric mucosal integrity and in protecting the mucosa against injury. NO seems to
suppress
stimulated and secretion in vivo. This study was conducted suing isolated rabbit gastric glands to investigate: firstly, the effect of NO on acid secretion in relation to cAMP and cGMP; secondly, the effect of acid secretagogues on NO synthase
activity.
Acid secretion from isolated gastric glands was measured by [14C]-aminopyrine accumulation ratio.
@ES The results were as follows;
@EN 1) Nitric oxide increased cGMP by histamine plus isobutylmethyl xanthine stimulation, but did not increase cAMP.
2) Nitric oxide synthase activity was not affected by increased acid secretion with histamine, dibutyryl cAMP, or histamine plus isobutylmethyl xanthine.
3) Endogenous nitric oxide from gastric mucosal nitric oxide synthase did not influence the basal acid secretion, but it did suppress the acid secretion under histamine plus isobutylmethyl xanthine stimulation.
4) Nitric oxide synthase inhibitor increased the acid secretion in stimulated gastric glands, which was suppressed by a nitric oxide substrate, L-arginine.
It is concluded that nitric oxide inhibits the stimulation of acid secretion via a cGMP pathway.
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