s6c-sarafotoxin and Bronchial-Spasm

Endothelin (ET-1) caused dose-related contraction of isolated superfused bronchus and pulmonary artery and bronchoconstriction and pulmonary vascular hypertension of the heart lung preparation (HLP) of guinea pig. The specific ETA receptor antagonist BQ 123 completely blocked the responses of the pulmonary artery, but failed to affect those of bronchus and of HLPs. The specific ETB receptor agonist Sarafotoxin S6c caused contractions of bronchus, but not of pulmonary artery, and bronchoconstriction and pulmonary hypertension in HLPs. It is concluded that non-ETA subtype receptors, perhaps ETB, appear to be the main responsible for the potent pulmonary hypertensive effects of ET-1.

Topics: Animals; Bronchi; Bronchial Spasm; Endothelin-1; Guinea Pigs; Hypertension, Pulmonary; In Vitro Techniques; Male; Pulmonary Artery; Receptor, Endothelin B; Receptors, Endothelin; Vasoconstrictor Agents; Viper Venoms