TY - JOUR T1 - Adenosine-Sensitive Adenylate Cyclase in Rat Striatal Homogenates and Its Relationship to Dopamine- and Ca<sup>2+</sup>-Sensitive Adenylate Cyclases JF - Molecular Pharmacology JO - Mol Pharmacol SP - 662 LP - 670 VL - 13 IS - 4 AU - JOËL PRÉMONT AU - MICHÈLE PEREZ AU - JOËL BOCKAERT Y1 - 1977/07/01 UR - http://molpharm.aspetjournals.org/content/13/4/662.abstract N2 - Rat striatal homogenates were found to contain adenosine-sensitive adenylate cyclase, which could be fully stimulated by endogenous adenosine under standard adenylate cyclase assay conditions. Adenosine present in the adenylate cyclase assay had two origins, the homogenate and ATP hydrolysis during incubation. Theophylline, caffeine, and isobutylmethylxanthine inhibited the adenosine-sensitive adenylate cyclase. At low concentrations, theophylline inhibition was competitive (KI = 20 µM). The adenosine present in the assay could be removed by using adenosine deaminase. It was then possible to stimulate the adenosine-sensitive adenylate cyclase by adenosine analogues resistant to adenosine deaminase treatment, such as 2-chloroadenosine, N6-phenylisopropyladenosine, and 5'-deoxyadenosine, which was a partial agonist. Adenine, inosine, 5'-AMP, and ATP were neither agonists non antagonists. In addition to adenosine-sensitive adenylate cyclase, rat striatal homogenates contain Ca2+- and dopamine-sensitive adenylate cyclases. Each of these three adenylate cyclase systems was found to be independent of the others. ACKNOWLEDGMENTS We are indebted to Drs. J. P. Tassin, A. M. Thierry, and J. Glowinski for their helpful criticisms of this work, and to Miss M. Dreyfus and Mrs. M. Guérin for their help in the preparation of the manuscript. ER -