ABSTRACT
<p><b>AIM</b>To investigate the effects of sodium sulfonate daidzein (SSD) on stress-induced gastric ulcer and explore its possible mechanism.</p><p><b>METHODS</b>Using exhausted swimming and counting the number of gastric ulcer to establish the model of stress-induced gastric ulcer. Mouse experience intraperitoneal injection of different doses of SSD and L-NAME, and NDP histochemical method was used to detect the changes of nitric oxide synthase (NOS) positive neurons in stomach.</p><p><b>RESULTS</b>SSD had dose-dependent protective effect on gastric mucosa. L-NAME could prevent stress induced gastric lesion. After combined injection of L-NAME and effective dose of SSD, the protective effect of SSD on gastric mucosa was reinforced. The number of NOS ganglion was constant, and effective dose of SSD had slight effect on NOS-positive neurons in normal mouse while it decreased NOS positive neurons in per area and in per ganglia after stress.</p><p><b>CONCLUSION</b>The increased nitric oxide (NO) leads to gastric ulcer during stress, SSD has protective effect on gastric mucosa and this effect may be mediated by inhibiting NOS and restricting the overproduction of NO during stress.</p>