Summary of the distribution of adenosine receptors
| A1 Receptor | A2AReceptor | A2B Receptor | A3 Receptor |
|---|---|---|---|
| High expression | High expression | High expression | High expression |
| Brain (cortex, cerebellum, hippocampus). Dorsal horn of spinal cord. Eye, adrenal gland, atria | Spleen, thymus, leukocytes (both lymphocytes and granulocytes), blood platelets. Striatopallidal GABAergic neurons (in caudate-putamen, nucleus accumbens, tuberculum olfactorium), olfactory bulb | Cecum, colon, bladder | Testis (rat), mast cells (rat) |
| Intermediate levels | Intermediate levels | Intermediate levels | Intermediate levels |
| Other brain regions. Skeletal muscle, liver, kidney, adipose tissue, salivary glands, esophagus, colon, antrum, testis | Heart, lung, blood vessels | Lung, blood vessels, eye, median eminence, mast cells | Cerebellum (human?), hippocampus (human?), lung, spleen (sheep), pineal |
| Low levels | Low levels | Low levels | Low levels |
| Lung (but probably higher in bronchi), pancreas | Other brain regions | Adipose tissue, adrenal gland, brain, kidney, liver, ovary, pituitary gland | Thyroid, most of brain, adrenal gland, spleen (human), liver, kidney, heart, intestine, testis (human) |
Data where there is correspondence between mRNA distribution and receptor distribution are given in bold. Data based mainly or exclusively on distribution of mRNA are given in ordinary letters. Ambiguous data (including major species differences) are given in italics.