Alpha-2A adrenergic receptor and Alpha-2C adrenergic receptor (ADRA2A/ADRA2C)

The Alpha-2A adrenergic receptor and Alpha-2C adrenergic receptor are G protein-coupled receptors that mediate physiological responses to the catecholamines epinephrine and norepinephrine (UniProt P08913; UniProt P18813). These receptors are primarily located on presynaptic neurons where they act as inhibitory autoreceptors, reducing the release of neurotransmitters through the inhibition of adenylate cyclase and the subsequent decrease in intracellular cAMP levels (NCBI Gene ID 150). Synephrine, a sympathomimetic alkaloid found in Citrus aurantium, is a ligand that interacts with these receptors, although its pharmacological profile is complex and often involves higher affinity for other adrenergic subtypes like beta-3 (PubChem CID 10384; Mercader et al., 2011). In clinical and supplemental contexts, these receptors are involved in the regulation of blood pressure, sedation, and lipolysis, making them targets for treating hypertension, ADHD, and obesity (StatPearls, 2023). Therapeutic use of drugs targeting these receptors, including synephrine-containing supplements, requires careful monitoring due to potential cardiovascular side effects such as hypertension and tachycardia resulting from systemic sympathomimetic activation (NIH Office of Dietary Supplements, 2023). The Alpha-2A subtype is particularly associated with sedation and analgesia, while the Alpha-2C subtype is linked to the modulation of stress responses and locomotor activity (UniProt P18813). Together, these receptors represent a critical junction in autonomic nervous system control and metabolic regulation.

Other names

ADRA2AADRA2CAlpha-2A adrenoreceptorAlpha-2C adrenoreceptorAlpha-2A/2C-AR

Agonism of these receptors activates Gi proteins, which inhibits adenylate cyclase and reduces cAMP levels, leading to the inhibition of neurotransmitter release and various downstream physiological effects.