alpha-adrenergic receptor
Học thuậtThân thiện
Definition
Noun: * Alpha-adrenergic receptor: A type of protein molecule, specifically a receptor, located on the surface of certain cells (e.g., smooth muscle cells, nerve cells). It binds to and is activated by the neurotransmitters norepinephrine (noradrenaline) and epinephrine (adrenaline). When activated, it mediates specific physiological responses primarily associated with the sympathetic nervous system, such as vasoconstriction (narrowing of blood vessels).
Usage Examples
- Noun:
- The medication works by selectively blocking the alpha-adrenergic receptor.
- Stimulation of the alpha-adrenergic receptor in blood vessels leads to an increase in blood pressure.
- Researchers are studying the role of the alpha-adrenergic receptor in smooth muscle contraction.
Advanced Usage
- The term is often used in pharmacology and physiology to describe drug action. For example, "alpha-adrenergic agonists" are drugs that stimulate these receptors, while "alpha-adrenergic antagonists" or "alpha-blockers" are drugs that inhibit them.
- It is frequently abbreviated in technical literature as α-adrenergic receptor or α-adrenoceptor.
Variants and Related Words
- Alpha-1 adrenergic receptor (α1): A subtype that primarily mediates smooth muscle contraction (e.g., in blood vessels, the prostate, the urethral sphincter).
- Alpha-2 adrenergic receptor (α2): A subtype often found on nerve terminals; its activation typically inhibits the further release of norepinephrine, providing a feedback mechanism.
- Adrenoceptor: A broader term for receptors that respond to epinephrine and norepinephrine, encompassing both alpha and beta types.
Synonyms
- Alpha-adrenoceptor
- Alpha receptor
Related Phrases / Concepts
- Sympathetic nervous system: The part of the autonomic nervous system with which alpha-adrenergic receptors are closely associated.
- Catecholamine: The class of neurotransmitters (including norepinephrine and epinephrine) that activate adrenergic receptors.
- G-protein coupled receptor (GPCR): The large family of receptor proteins to which the alpha-adrenergic receptor belongs.
Noun
- receptors postulated to exist on nerve cell membranes of the sympathetic nervous system in order to explain the specificity of certain agents that affect only some sympathetic activities (such as vasoconstriction and relaxation of intestinal muscles and contraction of smooth muscles)