Endothelin receptors and their antagonists

Area of Science:

• Nephrology
• Endocrinology
• Pharmacology

Background:

• The human kidney expresses all three endothelin (ET) peptides (ET-1, ET-2, ET-3), with ET-1 being predominant.
• ET-1 and ET-2 bind to ETA and ETB G-protein-coupled receptors; the kidney has a high density of ETB, particularly on renal vascular endothelium.
• ETB activation in the kidney promotes vasodilation and reduces salt/water reabsorption, while ETA activation on smooth muscle causes vasoconstriction.

Purpose of the Study:

• To review the role of ET-receptor antagonism in the human kidney.
• To discuss the potential of selective versus nonselective antagonism in managing renal diseases.

Main Methods:

• Review of existing literature on endothelin peptides and their receptors in the kidney.
• Analysis of studies utilizing selective ET(A) and ET(B) peptide antagonists (e.g., BQ123, BQ788).
• Examination of clinical data for nonpeptide antagonists (e.g., bosentan, macitentan, ambrisentan) in conditions like pulmonary hypertension and diabetic nephropathy.

Main Results:

• ET-1 acts via ETB on renal endothelium to release vasodilators and scavenge plasma ET-1.
• ET-1 activation of ETB in the nephron reduces salt and water reabsorption.
• ETA receptors mediate vasoconstriction and contribute to ET-1's pathophysiological effects in the kidney.

Conclusions:

• ET-receptor antagonism is a significant therapeutic strategy for renal diseases.
• Further research is needed to determine the optimal approach, selective or nonselective antagonism, for specific renal conditions.