Abstract
In the isolated rat stomach perfused with Krebs-Henseleit solution at 36°C, endothelin induced vasoconstriction in a dose-dependent manner. The threshold dose for inducing vasoconstriction was very small, and the pressor response to a bolus injection at 0.1 nmol lasted more than 1 hr. I n contrast, the vasoconstrictor effects of noradrenaline and serotonin were transient. The magnitude of the maximal response to endothelin was almost the same as that to noradrenaline, but greater than that to serotonin. The pressor response to serotonin, but not noradrenaline, was greatly augmented after pretreatment with endothelin. These results suggest that endothelin causes a long-lasting vasoconstriction, which would be associated with its ulcerogenic activity, especially in combination with other vasoactive agents under some pathophysiological conditions.
