Makindo Medical Notes"One small step for man, one large step for Makindo" |
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Endothelins are powerful vasoactive peptides with major roles in blood pressure regulation, vascular tone, and pathology. Removal of certain rare tumours (e.g. malignant hemangioendothelioma) can reduce endothelin secretion and lower BP.
Feature | ETA Receptor | ETB Receptor |
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Main Location | Vascular smooth muscle | Endothelial cells & vascular smooth muscle |
Coupling | Gq-protein β IP3 β βCa2+ | Gq-protein β IP3 β βCa2+ |
Primary Effect | Vasoconstriction (β BP, β vascular tone) | Dual action: β Endothelium β NO release β vasodilation β Smooth muscle β vasoconstriction |
Physiological Role | Maintains baseline vascular tone | Balances ETA-mediated constriction by promoting vasodilation & endothelial health |
Pathology | Hypertension, vascular remodelling, heart failure | Endothelial dysfunction (β NO release) worsens vascular disease |
Drug Target | Endothelin receptor antagonists (e.g. bosentan, ambrisentan) block both ETA and ETB, used in pulmonary arterial hypertension (PAH). |