SQ22536 (9-(tetrahydrofuran-2-yl)-9h-purin-6-amine) , the adenosine analogue 9-(Tetrahydro-2-furyl)adenine, inhibited adenylate cyclase activity of crude membrane preparations from catfish (Ictalurus melas) and rat isolated hepatocytes in a non-competitive manner.

SQ22536(250 μMol/L) attenuates the inhibitory effect of adenosine against ADP-induced platelet aggregation from 8±5 to 57±5%, respectively (p<0.001). SQ22536 also attenuates an increase of intraplatelet levels of cAMP by adenosine from 29±2 to 9±1 pmol/108 platelets (p<0.05). It has no effect on the platelet antiaggregant activity of inosine (1 to 4 mmol/L) and ADP-induced platelet aggregation[4].

SQ22536 abolishes the renal protective effects of liraglutide in KK/Ta-Akita mice. the amelioration of glomerular histopathological damage by liraglutide is eliminated in KK/Ta-Akita mice treated with liraglutide in combination with SQ22536. Renal cAMP does not increase after treatment with SQ22536. In a word, the beneficial actions of liraglutide for treatment of nephropathy are inhibited by the adenylate cyclase inhibitor SQ22536[5].

HMC-1 cells and hCBMCs are plated in 48-well plates and serum-starved overnight. The next day, cells are preincubated with SQ22536 at the indicated concentrations for 30 min before stimulation with CRH (100 nM for HMC-1 or 1 μM for hCBMC) for 3 min in the presence or absence of SQ22536 in serum-free culture media. Cell lysates are then prepared and assayed for protein kinase A activity using ELISA.(Only for Reference)