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09
Feb
Endothelin A Receptor (ETA): A Central Regulator in Cardiovascular Signaling
Exploring the molecular mechanisms and therapeutic implications of ETA in cardiovascular health.
The endothelin A receptor (ETA) is a G protein–coupled receptor (GPCR) that plays a critical role in cardiovascular physiology and pathology. ETA is predominantly expressed in vascular smooth muscle cells and cardiomyocytes, where it mediates the biological effects of endothelin-1 (ET-1), one of the most potent endogenous vasoconstrictor peptides.
Figure 1: Mechanism of ET-1/ETA signaling in vascular cells.
I. Molecular Characteristics
ETA belongs to the class A GPCR family. Its expression is highly localized to ensure targeted cardiovascular response:
- Vascular Smooth Muscle: Regulates tone.
- Cardiac Myocytes: Influences contractility.
- Fibroblasts: Manages structural integrity.
II. Signal Transduction
Binding of ET-1 triggers the Gq/G11 pathway, activating PLC and generating key second messengers:
- IP3: Induces Ca2+ release (Contraction).
- DAG: Activates Protein Kinase C (PKC).
III. Cardiovascular Remodeling
Beyond immediate vasoconstriction, ETA signaling activates mitogen-activated protein kinase (MAPK) cascades, leading to chronic structural changes:
🧬
Proliferation
Smooth Muscle Cells
🫀
Hypertrophy
Cardiomyocytes
🕸️
Fibrosis
Matrix Deposition
IV. Pathophysiological Implications
| Condition | ETA Role |
|---|---|
| Hypertension | Increased peripheral vascular resistance. |
| Heart Failure | Promotion of myocardial remodeling and stiffness. |
| Atherosclerosis | Vascular wall thickening and inflammation. |
V. Therapeutic Significance
Selective ETA antagonists are vital pharmacological tools. They are currently utilized in clinical settings—most notably for Pulmonary Arterial Hypertension (PAH)—to reduce vascular resistance and halt pathological tissue remodeling.
Biofargo team
