Adenosine A3 receptor

The adenosine A3 receptor, also known as ADORA3, is an adenosine receptor, but also denotes the human gene encoding it.

Function
Adenosine A3 receptors are G protein-coupled receptors that couple to Gi/Gq and are involved in a variety of intracellular signaling pathways and physiological functions. It mediates a sustained cardioprotective function during cardiac ischemia, it is involved in the inhibition of neutrophil degranulation in neutrophil-mediated tissue injury, it has been implicated in both neuroprotective and neurodegenerative effects, and it may also mediate both cell proliferation and cell death. Recent publications demonstrate that adenosine A3 receptor antagonists (SSR161421) could have therapeutic potential in bronchial asthma (17,18).

Gene
Multiple transcript variants encoding different isoforms have been found for this gene.

Therapeutic implications
An adenosine A3 receptor agonist (CF-101) is in clinical trials for the treatment of rheumatoid arthritis. In a mouse model of infarction the A3 selective agonist CP-532,903 protected against myocardial ischemia and reperfusion injury.

Selective Ligands
A number of selective A3 ligands are available.

Agonists/Positive Allosteric Modulators

 * 2-(1-Hexynyl)-N-methyladenosine
 * CF-101 (IB-MECA)
 * CF-102
 * 2-Cl-IB-MECA
 * CP-532,903
 * Inosine
 * LUF-6000
 * MRS-3558
 * AST-004

Antagonists/Negative Allosteric Modulators

 * KF-26777
 * MRS-545
 * MRS-1191
 * MRS-1220
 * MRS-1334
 * MRS-1523
 * MRS-3777
 * MRE-3005-F20
 * MRE-3008-F20
 * PSB-11
 * OT-7999
 * VUF-5574
 * SSR161421
 * ISAM-DM10

Inverse Agonists

 * PSB-10