EFFECT OF (+ -)-PROPRANOLOL AND CLONIDINE ON STRESS AND CHEMICALLY-INDUCED GASTRIC-ULCERS IN RATS/

The influence of (+/-)-propranolol and clonidine on stress- and variou s chemically induced gastric ulcers in rats, together with their influ ence on various biochemical parameters which affect the development of the induced ulcers, was examined. Pretreatment of rats with (+/-)-pro pranolol (10-100 mg/kg) and with clonidine (0.03-0.3 mg/kg) given oral ly, significantly reduced indomethacin-(30 mg/kg, orally) and resepine - (5 mg/kg, i.p.) induced ulcers. In addition, propranolol pretreatmen t significantly reduced ethanol- and cold-stress-induced ulcers, where as pretreatment with orally given clonidine significantly enhanced the se ulcers. Pretreatment with propranolol significantly increased gastr ic mucus synthesis and the nonprotein sulfhydryl content and reduced g astric lipid peroxidation without affecting gastric acid secretion. Pr etreatment of the animals with clonidine significantly increased gastr ic mucus secretion and decreased total gastric acidity. It did not aff ect the gastric nonprotein sulfhydryl content and lipid peroxidation. The drug-induced effects on the experimentally induced ulcers may be r elated to their induced biochemical alteration in the gastric paramete rs measured.