Effects of endothelins on fluid and NaCl absorption across the jejunum anesthetized dogs

The aim of this study was to investigate the effects of endothelins on fluid the NaCl absorption across the jejunum, the jejunal fluid and NaCl absorption and mesenteric hemodynamics in jejunal loops in anesthetized dogs during infusion of saline, endothelin-1 or endothelin-3 into the superior mesenteric artery. Infusion of endothelin-3 decreased the net fluid, Na+, and Cl- absorption; however, saline and endothelin-1 had no effect. To investigate the role of nitric oxide and soluble guanylate cyclase activation in the mechanisms underlying endothelin-3-induced decrease in fluid and electrolyte absorption, measurements were obtained in the presence of the nitric oxide synthesis inhibitor, nitro-L-arginine methyl ester (L-NAME) or the soluble guanylate cyclase inhibitor, methylene blue. The endothelin-3-induced decrease in absorption was not influenced by the pretreatment with inhibitors. These results suggest that the endothelin-3 response was not mediated by nitric oxide or soluble guanylate cyclase.