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Endothelin produces pulmonary vasoconstriction and systemic vasodilation
H L Lippton1, T A Hauth, W R Summer
1Department of Medicine, Louisiana State Medical Center, New Orleans 70112.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|February 1, 1989
Summary
Endothelin, a peptide from endothelial cells, caused mild pulmonary vasoconstriction but significant systemic vasodilation in cats. This suggests endothelin plays a key role in regulating peripheral vascular tone.
Area of Science:
- Cardiovascular Physiology
- Endothelial Cell Biology
- Vascular Pharmacology
Background:
- Endothelin is a novel polypeptide originating from endothelial cells.
- Its physiological effects on the cardiovascular system require elucidation.
Purpose of the Study:
- To investigate the in vivo effects of porcine endothelin on pulmonary and systemic hemodynamics.
- To determine endothelin's role in regulating vascular tone.
Main Methods:
- Anesthetized, intact-chest cats were used under controlled hemodynamic conditions.
- Porcine endothelin was administered via bolus injections and atrial infusions.
- Pulmonary and systemic vascular responses were measured, including effects of beta 2-adrenoceptor blockade.
Main Results:
- Endothelin induced a mild vasoconstrictor response in the pulmonary vascular bed.
- Systemic arterial pressure decreased, indicating vasodilation, with increased cardiac output and decreased systemic vascular resistance.
- The systemic vasodilator effect was independent of beta 2-adrenoceptor activation and significant first-pass pulmonary metabolism was not observed.
Conclusions:
- Endothelin exhibits potent vasodilator activity in the systemic circulation.
- Its weaker effect on pulmonary vessels suggests a primary role in regulating peripheral vasomotor tone.
- This study provides the first in vivo characterization of endothelin's hemodynamic activity.