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Vasoconstrictions mediated by an endothelium-derived vasoconstricting factor (EDCF)
Basic Research in Cardiology
|September 1, 1989
Summary
The endothelium releases a vasoconstricting factor (EDCF) when oxygen levels drop, causing vasospasms. This factor
Area of Science:
- Vascular biology
- Endothelial function
- Physiology
Background:
- Endothelial dysfunction is implicated in vasospasm.
- The role of endothelium in oxygen-dependent vasoconstriction requires further elucidation.
Purpose of the Study:
- To investigate the endothelium's role in generating vasospasms under reduced oxygen supply.
- To identify the mechanisms and mediators involved in endothelium-derived vasoconstriction.
Main Methods:
- Isolated rabbit aorta, pig coronary artery, and pulmonary artery segments were used.
- Vascular tone was measured by pressure gradients during perfusion with normoxic or oxygen-deprived Tyrode's solution.
- Endothelial function was assessed via acetylcholine-induced vasodilation.
Main Results:
- Oxygen deprivation induced a long-lasting vasoconstriction in endothelium-denuded segments downstream of intact endothelium.
- This vasoconstriction was inhibited by dexamethasone, indomethacin, and methylene blue.
- It was attenuated by a TXA2 antagonist but not by radical scavengers or lipoxygenase inhibitors.
Conclusions:
- The endothelium releases an endothelium-derived constricting factor (EDCF) at low pO2 (<550 mm Hg).
- EDCF generation appears to involve phospholipase A2 and cyclooxygenase pathways.
- EDCF is likely not a prostanoid itself, suggesting a novel vasoconstrictive mediator.