[Effect of anxiolytic drugs on the development and healing process of stress ulcer: application of endoscopic observation].

The present study was conducted to investigate the effect of anxiolytic drugs on the development and healing process of gastric mucosal lesions (GML). In order to produce the GML in mice and rats, we employed a communication box paradigm which can differentially induce a physical and psychological stress. The following drugs (2.5, 50.0, 7.5 mg/kg for mice and 5.0, 10.0 mg/kg for rats) were administered orally: diazepam, clotiazepam, ethyl loflazepate and vehicle (0.5% CMC solution). To define the drug effects on the healing process of GML in rats, we applied an endoscopic technique using the ultra-thin fiberscope. The endoscopic observation was performed under ether anesthesia at 1, 24, 36 and 60 hr after the termination of stress. Both diazepam and ethyl loflazepate significantly suppressed the development of GML in mice, while the preventive effect of clotiazepam was less potent than those of the other anxiolytics. In rats, only ethyl loflazepate showed a significant preventive effect. The curative effect of clotiazepam on the healing process of GML in rats was clearly demonstrated, whereas diazepam was ineffective on the healing process. Ethyl loflazepate also showed a tendency to facilitate the healing process of GML. The present study suggests that the application of the endoscopic technique to rats may provide a potential tool for evaluating the curative effect of drugs on the GML.