Adenosine receptor A1; Adenosine receptor A2A (A1AR; A2AAR)

Adenosine receptor A1 and A2A subtypes are integral membrane proteins in the G protein-coupled receptor family, activated by extracellular adenosine. A1 receptors are predominantly inhibitory, slowing metabolic activity in the brain and suppressing neurotransmitter release, with a key protective role in neurons and the heart. A2A receptors, in contrast, stimulate adenylate cyclase, increase cAMP, and have prominent anti-inflammatory and neuro-modulatory roles, especially in the brain and immune cells. Both subtypes are highly relevant in diverse diseases—cardiovascular, neurological, and oncological settings—and are targeted by numerous clinically used and investigational drugs.

Other names

Adenosine A1 receptorAdenosine A2A receptorA1ARA2AARP1 receptor subtypes A1 and A2A

Agonists bind and activate the receptor, triggering downstream G protein-mediated signaling, altering adenylate cyclase activity (A1 inhibits, A2A stimulates) Antagonists block receptor activation, modulating neurotransmission and cardiovascular function Selective modulation of neurotransmitter release, inflammatory pathways, or cardiac conduction