Endothelin-1 increases airway mucosa blood flow in the pig

The vascular effects of bolus intravenous injections (4.5, 45 and 450 pmol.kg-1) of porcine endothelin-1 on the bronchial and nasal circulations were investigated in ten anesthetized pigs. Endothelin-1 produced a dose-dependent and long-lasting increase in bronchial blood flow with a concomitant rise in systemic arterial pressure suggesting vasodilatation. The highest doses of endothelin-1 also caused a slight decrease in the nasal vascular resistance. Furthermore, the vascular responses to endothelin-1 were not modified in systemically capsaicin pretreated animals or after pretreatment with a cyclocoxygenase inhibitor, diclofenac. Our results suggest that endothelin-1 has a potent and regional vasodiator effect of the bronchial circulation.