Endothelin B receptor

Endothelin B receptor (ET_B receptor) is a G protein-coupled receptor that is activated by endothelin peptide ligands, specifically ET-1, ET-2, and ET-3. This receptor is involved in various physiological and pathological processes, including vasoconstriction and vasodilation, which affect blood pressure and blood flow. It also plays a role in the development of certain diseases, such as pulmonary arterial hypertension (PAH) and cancer.

Function

The ET_B receptor mediates several important physiological functions. It is expressed in various tissues, including vascular endothelium, smooth muscle cells, and the central nervous system. In the vascular system, activation of the ET_B receptor by endothelin leads to vasodilation, a process that involves the release of nitric oxide (NO) and prostacyclin (PGI₂) from endothelial cells. This receptor also plays a critical role in clearing endothelin from the circulation, thereby regulating its levels and minimizing its vasoconstrictive effects.

In addition to its vasodilatory effects, the ET_B receptor is involved in promoting sodium excretion in the kidneys, which contributes to its role in blood pressure regulation. It also influences cell proliferation and survival, which has implications for both tissue repair and oncogenesis.

Pathology

Abnormalities in ET_B receptor function or expression are associated with several diseases. In PAH, a condition characterized by high blood pressure in the arteries of the lungs, the balance between the ET_A and ET_B receptors may be disrupted, leading to excessive vasoconstriction and vascular remodeling. ET_B receptor antagonists, along with ET_A receptor antagonists, are being explored as potential treatments for PAH.

The role of the ET_B receptor in cancer is complex and varies among different types of cancer. It can influence tumor growth, angiogenesis, and metastasis. Research is ongoing to understand the potential of targeting the ET_B receptor in cancer therapy.

Genetics

The gene encoding the ET_B receptor is located on human chromosome 13. Mutations in this gene can lead to disorders such as Hirschsprung's disease, a congenital condition characterized by the absence of nerve cells in parts of the intestine, leading to severe constipation or intestinal obstruction.

Pharmacology

The pharmacological modulation of the ET_B receptor is of interest for treating various cardiovascular and renal diseases. ET_B receptor antagonists and agonists are being developed and tested for their therapeutic potential. Understanding the precise roles of the ET_B receptor in health and disease is crucial for the development of targeted therapies.

See also

• Endothelin
• Endothelin receptor
• G protein-coupled receptor
• Pulmonary arterial hypertension
• Vasoconstriction
• Vasodilation