Effects of Prostaglandin Biosynthesis Inhibitors and Ouabain on Duodenal Mucosa and HCO₃^- Secretion in Rats

抄録

A single injection (s.c.) of prostaglandin biosynthesis inhibitors such as indomethacin (5 mg/kg), aspirin (200 mg/kg) and quinacrine (100 mg/kg) or a Na⁺·K⁺ ATPase inhibitor such as ouabain (10 mg/kg) significantly reduced the adaptive increase of HCO₃^-- output caused by acid in the duodenum of anesthetized rats. These agents had no effect on basal duodenal HCO₃^- secretion and histamine-stimulated gastric acid secretion. Either of these agents, when given alone, had no effect on the duodenal mucosa of conscious rats, but produced damage in the proximal duodenum within 8 hr when given together with histamine (40 mg/kg × 3, s.c., every 2.5 hr). A significant relationship was found between the degrees of inhibition of acid-induced HCO₃^- output and the severity of duodenal lesions induced by these drugs (r=0.8620, P<0.01). These results suggest that an impairment of the mechanisms related to acid-induced HCO₃^- secretion may be particularly relevant to the pathogenesis of duodenal lesions.