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Endothelin 1 causes pulmonary vasodilation in rats
K Hasunuma1, D M Rodman, R F O'Brien
1Department of Medicine, University of Colorado Health Sciences Center, Denver 80262.
The American Journal of Physiology
|July 1, 1990
Summary
Endothelin 1 (ET-1) dilates rat pulmonary vasculature, potentially via K+ channels. This peptide shows promise for treating pulmonary vasoconstriction.
Area of Science:
- Cardiovascular Physiology
- Pulmonary Circulation
- Endocrinology
Background:
- Endothelin 1 (ET-1) is an endothelial cell-derived peptide known to cause systemic vasodilation.
- The effects of low ET-1 concentrations on the pulmonary vascular bed remain largely unexplored.
Purpose of the Study:
- To investigate the potential of Endothelin 1 (ET-1) to dilate the pulmonary vascular bed.
- To elucidate the underlying mechanisms of ET-1-induced pulmonary vasodilation.
Main Methods:
- Experiments were conducted using isolated blood- and salt solution-perfused rat lungs.
- Studies also involved conscious catheterized rats exposed to hypoxic conditions.
- Pharmacological agents were used to block specific ion channels and signaling pathways.
Main Results:
- Low concentrations of ET-1 induced transient partial vasodilation in hypoxic blood-perfused lungs.
- Intravenous ET-1 reversed hypoxic pulmonary vasoconstriction in conscious rats.
- Vasodilation was partially inhibited by K+ channel blockers and Na+-K+ pump inhibitors, suggesting a role for ion transport.
Conclusions:
- Endothelin 1 (ET-1) acts as a potent pulmonary vasodilator in rats.
- The mechanism of ET-1-induced pulmonary vasodilation involves ATP-sensitive K+ channels and membrane hyperpolarization.