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Endothelin-1 increases arterial sensitivity to 5-hydroxytryptamine.
1Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107.
European Journal of Pharmacology
|September 21, 1990
Summary
Endothelin-1 (ET-1) sensitizes rabbit aorta to 5-hydroxytryptamine (5-HT), potentially promoting vasospasm. This effect occurs without altering the maximum force generated by 5-HT.
Area of Science:
- Pharmacology
- Cardiovascular Physiology
Background:
- Endothelin-1 (ET-1) is a potent vasoconstrictor.
- 5-hydroxytryptamine (5-HT) plays a role in vascular tone and platelet aggregation.
Purpose of the Study:
- To investigate the effect of ET-1 pretreatment on rabbit aortic ring sensitivity to 5-HT.
- To determine if ET-1 influences endothelium-dependent relaxations.
Main Methods:
- Rabbit aortic rings were pretreated with varying concentrations of ET-1 or vehicle.
- Isometric contractions to cumulative 5-HT additions were recorded.
- Acetylcholine-induced relaxations were assessed.
Main Results:
- ET-1 pretreatment significantly increased arterial sensitivity (EC50) to 5-HT in a dose-dependent manner (1.9- to 3.5-fold).
- Peak 5-HT-induced contraction force remained unaffected.
- ET-1 did not alter acetylcholine-induced, endothelium-dependent relaxations.
Conclusions:
- ET-1 enhances arterial sensitivity to 5-HT, suggesting a mechanism for ET-1-induced vasospasm.
- This sensitization may involve 5-HT released from platelets.
- ET-1 does not impair endothelium-dependent vasodilation.
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