Effects of polaprezinc (Z-103) on ammonia-induced gastric mucosal lesions and potential difference reductions in rats

In order to clarify the effects of polaprezinc (Z-103) on Helicobacter pylori (H. pylori) related gastric mucosal lesions, we examined the effects of Z-103 on ammonia-induced gastric mucosal lesions and the potential difference (PD) reduction in rats. The development of gastric lesions were caused by the administration of 1% ammonia (1 ml/rat). The pretreatment of Z-103 (0.3 ~ 3 mg/kg) significantly inhibited the development of gastric lesions with ammonia in a dose-dependent manner. Sucralfate (30 ~ 300 mg/kg), cetraxate hydrochloride (10 ~ 100 mg/kg) and teprenone (10 ~ 100 mg/kg), but not cimetidine, also inhibited the gastric lesions induced by ammonia. Exposure of the gastric mucosa to 0.1% ammonia produced a transmucosal PD reduction. Pretreatment of Z-103 (1 ~ 10 mg/kg) significantly inhibited the PD reduction in a dose-dependent manner. However, sucralfate (300 mg/kg), teprenone (100 mg/kg), cetraxate hydrochloride (100 mg/kg) had no effect on the PD reduction. On the other hand, cimetidine (100 mg/kg) significantly aggravated the PD reduction with ammonia. These results suggest that Z-103 protects the gastric mucosa and enhances cellular resistance to ammonia. Moreover, Z-103 may be useful for the treatment of H. pylori related gastric lesions in clinical use.