Alpha-2A adrenergic receptor (ADRA2A) (ADRA2A)

The Alpha-2A adrenergic receptor (ADRA2A) is a G protein-coupled receptor that mediates the physiological effects of catecholamines like norepinephrine and epinephrine [UniProt P08913, NCBI Gene 150]. It is predominantly located on presynaptic nerve terminals where it acts as an autoreceptor to inhibit further neurotransmitter release via Gi/o protein signaling [StatPearls NBK430851]. This receptor is essential for regulating central sympathetic outflow, making it a key target for antihypertensive and sedative medications. In the prefrontal cortex, ADRA2A activation improves cognitive functions, which underlies its use in treating Attention Deficit Hyperactivity Disorder (ADHD) [StatPearls NBK430851]. Clinically, agonists like dexmedetomidine are used for intensive care sedation, while others like brimonidine treat glaucoma by reducing intraocular pressure [DrugBank DB00699]. Despite its therapeutic utility, targeting this receptor can lead to side effects such as bradycardia and hypotension due to its systemic sympatholytic activity.

Other names

Alpha-2A adrenoceptorAlpha-2A adrenoreceptorADRA2ADRA2L1ADRAR

Agonists bind to the Alpha-2A adrenergic receptor, triggering the activation of Gi/o heterotrimeric G proteins. This leads to the inhibition of adenylate cyclase, decreasing intracellular cAMP levels, and the modulation of ion channels, such as the inhibition of N-type calcium channels and activation of G protein-coupled inwardly rectifying potassium (GIRK) channels [UniProt P08913, StatPearls NBK430851]. These cellular events result in hyperpolarization and the suppression of neurotransmitter release, particularly norepinephrine, leading to a reduction in sympathetic tone [DrugBank DB00699].