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Pulmonary vascular response to endothelin in rats
B Raffestin1, S Adnot, S Eddahibi
1Laboratoire de Physiologie, Hôpital Antonine Béclère, Clamart, France.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|February 1, 1991
Summary
Endothelin (ET) is a potent systemic vasoconstrictor in rats, causing increased systemic arterial pressure and decreased cardiac output. However, its effects on pulmonary vascular resistance are minimal, suggesting differential vascular responses to ET.
Area of Science:
- Cardiovascular Physiology
- Pulmonary Circulation
- Endothelin Biology
Background:
- Endothelin (ET) is a potent vasoconstrictor peptide.
- Its specific effects on the pulmonary vasculature require further investigation.
Purpose of the Study:
- To investigate the pulmonary vascular response to endothelin (ET) in rats.
- To compare the systemic and pulmonary vascular effects of ET.
Main Methods:
- Administered incremental intravenous boluses of ET-1 in conscious rats.
- Utilized autonomic blockade (hexamethonium, atropine) and meclofenamate.
- Studied ET effects on isolated rat lungs and anesthetized ventilated rats.
Main Results:
- ET-1 caused dose-dependent increases in systemic arterial pressure and decreases in cardiac output and heart rate.
- Pulmonary arterial pressure and resistance showed minimal changes, except at very high doses.
- ET-1 induced pulmonary edema in isolated lungs and decreased lung compliance in ventilated rats.
Conclusions:
- Circulating endothelin is a more potent constrictor of the systemic circulation than the pulmonary vascular bed in rats.
- The pulmonary vascular bed exhibits a blunted response to ET compared to the systemic circulation.