Alpha-1B adrenergic receptor

Transduction mechanisms
Agonists
Antagonists
Inverse agonists
Positive allosteric modulators
Negative allosteric modulators

The alpha-1B adrenergic receptor (ADRA1B) is a G protein-coupled receptor involved in the regulation of vascular smooth muscle tone and blood pressure. It is one of the three subtypes of alpha-1 adrenergic receptors, the others being alpha-1A and alpha-1D. These receptors are activated by the catecholamines, epinephrine (adrenaline), and norepinephrine (noradrenaline), which are produced by the adrenal glands and sympathetic nervous system. Activation of the alpha-1B adrenergic receptor leads to vasoconstriction, which increases blood pressure and reduces blood flow to certain areas.

Function

The alpha-1B adrenergic receptor plays a crucial role in maintaining vascular tone and blood pressure regulation. It is predominantly expressed in vascular smooth muscle cells, where its activation leads to vasoconstriction. This receptor subtype is also found in the heart and brain, where it contributes to the regulation of cardiac output and cerebral blood flow, respectively.

Clinical Significance

Alterations in alpha-1B adrenergic receptor function or expression can contribute to various cardiovascular disorders, including hypertension, heart failure, and atherosclerosis. Drugs that target this receptor, such as alpha blockers, are used in the treatment of conditions like hypertension and benign prostatic hyperplasia (BPH).

Pharmacology

Alpha blockers or alpha-1 antagonists are a class of drugs that inhibit the action of alpha-1B and other alpha-1 adrenergic receptors. These medications are used to treat several conditions, including high blood pressure, BPH, and some forms of heart failure. By blocking the action of catecholamines at these receptors, alpha blockers reduce vascular resistance and lower blood pressure.

Genetics

The gene encoding the alpha-1B adrenergic receptor is located on human chromosome 5. Variations in this gene may influence individual responses to drugs targeting this receptor and susceptibility to cardiovascular diseases.

See Also

• Alpha-1 adrenergic receptor
• Alpha-2 adrenergic receptor
• Beta adrenergic receptor
• G protein-coupled receptor
• Vascular smooth muscle
• Blood pressure