Adenosine A2A receptor and Adenosine A2B receptor (A2A receptor (ADORA2A), A2B receptor (ADORA2B))

Adenosine A2A receptor and Adenosine A2B receptor are closely related members of the G protein-coupled receptor family that bind extracellular adenosine. Both serve as critical modulators of immune and inflammatory responses, tissue protection, angiogenesis, and central nervous system signaling. A2A receptors exhibit high affinity and are most active at lower (nanomolar) adenosine concentrations, while A2B receptors are activated at higher (micromolar) levels and are more prevalent in pathological settings such as hypoxia or cancer. They are considered prominent therapeutic targets across oncology, immunology, neurology, and cardiology. Both have been extensively studied for selective agonist and antagonist development, but their broad biological functions and expression patterns require careful therapeutic application to avoid unwanted immune or cardiovascular side effects. Drugs like caffeine, Etrumadenant, and PBF-1129 illustrate their clinical relevance, particularly for cancer and neurodegenerative disease.

Other names

A2A adenosine receptorADORA2AA2B adenosine receptorADORA2BA2A ARA2B AR

Agonists activate the receptor to suppress inflammation or provide cytoprotection; Antagonists inhibit receptor-mediated immunosuppression, enhance anti-tumor immune response, and modulate neurological symptoms (e.g., in Parkinson’s disease); Antagonists “de-inhibit” immune cells or prolong/strengthen anti-pathogen immune responses