2-chloro-3-Deazaadenosine (Synonyms: 6-Amino-2-chloropurine riboside,2-CADO,NSC 158900)

2-chloro-3-Deazaadenosine, a stable analog of adenosine, is an agonist for adenosine receptors [1].

Adenosine receptors are members of G-protein-coupled receptors (GPCRs). Extracellular adenosine acts as a local modulator with a generally cytoprotective function in the body. Extracellular adenosine has been implicated in increasing the ratio of oxygen supply to demand, protecting against ischaemic damage by cell conditioning, triggering anti-inflammatory responses and the promotion of angiogenesis [2].

In vitro: The Ki values of 2-chloro-3-Deazaadenosine for A1, A2A, A2B, and A3 receptors were 0.3, 0.08, 25.5, and 1.9 μM, respectively [1]. 2-chloroadenosine (25 μM) increased activity of platelet adenylate cyclase to about 150–160% of the control value. Higher concentrations of 2-chloroadenosine showed less effect above 100 μM [3].

In vivo: In the rat with delayed ischaemic damage, Iterative focal injections of 2-chloroadenosine protected against selective hippocampal CA1 loss [4].

References:
[1] Linden J, Thai T, Figler H, et al.  Characterization of Human A2B Adenosine Receptors: Radioligand Binding, Western Blotting, and Coupling to Gqin Human Embryonic Kidney 293 Cells and HMC-1 Mast Cells[J]. Molecular Pharmacology, 1999, 56(4): 705-713.
[2] Jacobson K A, Gao Z G.  Adenosine receptors as therapeutic targets[J]. Nature Reviews Drug Discovery, 2006, 5(3): 247-264.
[3] Haslam R J, Lynham J A.  Activation and inhibition of blood platelet adenylate cyclase by adenosine or by 2-chloroadenosine[J]. Life Sciences, 1972, 11(23): 1143-1154.
[4] Evans M C, Swan J H, Meldrum B S.  An adenosine analogue, 2-chloroadenosine, protects against long term development of ischaemic cell loss in the rat hippocampus[J]. Neuroscience letters, 1987, 83(3): 287-292.