adenosine A2A

Class

receptor antagonist

Adenosine A2A is a cell-surface receptor that responds to adenosine, a small molecule released when tissue is stressed, injured, or metabolically active. It belongs to the G-protein-coupled receptor family and, when activated, raises levels of a signaling molecule called cyclic AMP inside cells. This receptor is expressed in two settings that matter for disease. In the brain, it sits on neurons within circuits that control movement, where it works in opposition to dopamine signaling; blocking it can partially compensate for dopamine loss. In the immune system and in tumors, adenosine accumulates in oxygen-poor, inflamed, or malignant tissue and engages A2A on T cells and natural killer cells, dampening their ability to attack abnormal or infected cells. Antagonists that block A2A are therefore explored in two distinct contexts: as add-on therapy for movement disorders where dopamine signaling is deficient, and as a way to relieve adenosine-driven suppression of anti-tumor immunity, often alongside other immune-activating approaches. The shared thread across both uses is interruption of an inhibitory signal, whether on neuronal circuits or on immune cells, restoring activity that adenosine would otherwise hold in check.