THE ROLE OF GASTRIC MUSCLE-RELAXATION IN CYTOPROTECTION INDUCED BY SAN-HUANG-XIE-XIN-TANG IN RATS

We examined the mechanism of the protective effect of San-huang-xie-xi n-tang (SHXT), a traditional oriental drug, on the gastric mucosa. SHX T, given intraduodenally, inhibited the gastric secretion in pylorus-l igated rats. SHXT, given orally 30 min before the administration of as pirin, HCl-aspirin and ethanol, protected the gastric mucosa from thes e agent-induced gastric lesions, although it had no effect on the gast ric lesions induced by indomethacin and water immersion stress. Oral a dministration of SHXT increased gastric contents (muscle relaxation) w hen they were measured 30 min after SHXT administration. SHXT also inh ibited carbachol-contracted gastric muscle in vitro. Neither increased gastric contents nor inhibited ethanol lesions of SHXT were observed when these were tested 4 h after SHXT administration. Pretreatment wit h indomethacin which is a prostaglandin synthesis inhibitor, and N-eth ylmaleimide which is a sulfhydryl blocker did not influence either the increased gastric contents or inhibited ethanol lesions of SHXT. Thes e results indicate that gastric muscle relaxation plays an important r ole in the gastric protective mechanisms of SHXT, and the endogenous p rostaglandins and the sulfhydryl compounds are not necessary for the a ction of SHXT.