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Renal microvascular effects of endothelin
R M Edwards1, W Trizna, E H Ohlstein
1Department of Pharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406-0939.
The American Journal of Physiology
|August 1, 1990
Summary
Endothelin-1, -2, and -3 (ETs) potently constrict kidney arterioles, affecting renal hemodynamics. Calcium channel blockers influenced ET-1 responses in afferent but not efferent arterioles.
Area of Science:
- Nephrology
- Renal Physiology
- Vascular Biology
Background:
- Endothelin peptides (ETs) are potent vasoactive substances.
- Their specific roles in regulating renal microvasculature require further elucidation.
Purpose of the Study:
- To investigate the effects of endothelin-1, -2, and -3 (ET-1, -2, -3) on afferent and efferent arteriole lumen diameter in rabbit kidneys.
- To examine the influence of calcium channel blockers on ET-induced vasoconstriction.
Main Methods:
- Isolated rabbit afferent and efferent arterioles were used to assess vasoconstrictive responses.
- Concentration-response curves for ET-1, -2, and -3 were generated.
- The effects of nicardipine and verapamil on ET-1-mediated constriction were evaluated.
Main Results:
- ET-1, -2, and -3 caused concentration-dependent vasoconstriction in both afferent and efferent arterioles.
- ET-1 and ET-2 were more potent vasoconstrictors than ET-3 in both vascular segments.
- Nicardipine and verapamil attenuated ET-1-induced constriction in afferent arterioles but not in efferent arterioles.
Conclusions:
- Endothelin peptides are potent vasoconstrictors of the renal pre- and post-glomerular microvasculature.
- Differential sensitivity to calcium channel blockers suggests distinct signaling pathways in afferent versus efferent arterioles.
- ETs may play a significant role in regulating renal hemodynamics.