Alpha-2B adrenergic receptor and Alpha-2C adrenergic receptor (Alpha-2B-AR and Alpha-2C-AR (alternatively, α2B-AR and α2C-AR))

Alpha-2B and Alpha-2C adrenergic receptors are subtypes of the alpha-2 adrenergic receptor family, which are G protein-coupled receptors primarily involved in inhibiting neurotransmitter release via presynaptic negative feedback in the sympathetic nervous system. The Alpha-2B adrenergic receptor (encoded by ADRA2B) is predominantly found in the peripheral vasculature and mediates vasoconstriction and the hypertensive response to sympathetic stimulation. The Alpha-2C adrenergic receptor (encoded by ADRA2C) is highly expressed in several central nervous system regions and is implicated in modulating the startle reflex, stress response, and locomotor activity. Both subtypes contribute to the regulation of neurotransmitter (e.g., dopamine, serotonin, norepinephrine) exocytosis, cardiovascular homeostasis, and central modulation of sympathetic tone. Alterations in their function or expression are linked to cardiovascular disease, neuropsychiatric conditions, and variable responses to drugs targeting the adrenergic system. Note: For structured data or therapeutic targeting, the Alpha-2B adrenergic receptor and Alpha-2C adrenergic receptor should be treated as distinct entities, not as a single merged target.

Other names

Alpha-2B adrenoceptorAlpha-2C adrenoceptorα2B-adrenergic receptorα2C-adrenergic receptorADRA2B (gene symbol for Alpha-2B)ADRA2C (gene symbol for Alpha-2C)

Agonists: Inhibit adenylyl cyclase via Gi protein, leading to reduced cAMP and inhibition of neurotransmitter (especially norepinephrine) release. Antagonists: Block autoreceptor feedback, increasing norepinephrine release. Blood pressure regulation: Alpha-2B mediates vasoconstriction and hypertensive response; Alpha-2C modulates neurotransmission predominantly at low stimulation frequencies. Some antagonists (e.g., mirtazapine) block presynaptic autoreceptor function, thus increasing synaptic norepinephrine and serotonin