Effects of Endothelin-1 on Duodenal Bicarbonate Secretion and Mucosal Integrity in Rats

Koji Takeuchi ； Shinichi Sugamoto ； Keizo Suzuki ； Shoji Kawauchi ； Osamu Furukawa

《The Chinese Journal of Physiology》 42卷3期 (1999/09) Pp. 129-135

並列摘要

Effects of endothelin-1 on gastric acid secretion, duodenal HCO3ˉ secretion, and duodenal mucosal integrity were investigated in anesthetized rats, in comparison with those of TY-10957, a stable analogue of prostacyclin. A rat stomach mounted on an ex-vivo chamber or a proximal duodenal loop was perfused with saline, and gastric acid or duodenal HCO3ˉ secretion was measured using a pH-stat method and by adding 100 mM NaOH or 10 mM HCI, respectively. Duodenal lesions were induced by mepirizole (200 mg/kg) given subcutaneously. Intravenous administration of endothelin-1 (0.6 and 1 nmol/kg) caused an increase of duodenal HCO3ˉ secretion with concomitant elevation of blood pressure; this effect was antagonized by co-administrahon of BQ-123 (ET(subscript A) antagonist; 3 mg/kg, i.v.) and significantly mitigated by vagotomy. Likewise, endothelin-1 caused a significant decrease in histamine-stimulated acid secretion, and this effect was also significantly antagonized by BQ-123. Although TY-10957 (10 and 30 mg/kg, i.v.) produced a temporal decrease of blood pressure, this agent caused not only an increase of duodenal HCO3ˉ secretion, independent of vagal nerves, but also a decrease of acid secretion as well. In addition, both endothelin-l and TY-10957 significantly prevented mepirizole-induced duodenal lesions at the doses that caused an increase of duodenal HCO3ˉ secretion and a decrease of gastric acid secretion. These results suggest that endothelin-1 affects the duodenal mucosal integrity by modifying both gastric acid and duodenal HC03ˉ secretions, the effects being mediated by ETA receptors.

並列關鍵字

Endothelin-1 ； prostacyclin ； acid secretion ； HCO3ˉ secretion ； duodenal lesion