title: Increase of [3H]clonidine binding sites induced by adenosine receptor agonists in rat vas deferens in vitro.
abstract: In vitro binding experiments were done to study the effects of adenosine receptor agonists on induction of [3H]clonidine binding sites in rat vasa deferentia by reserpine. In the presence of 1 microM adenosine and 2-chloroadenosine, respectively, the specific binding of [3H]clonidine to vas deferens homogenates of reserpine-treated rats increased 38 and 42% over the control value. The increase in binding sites induced by adenosine was inhibited by the adenosine receptor antagonist theophylline. No effect of 1 microM 2-chloroadenosine on the beta-adrenoceptor or alpha 1-adrenoceptor was detected. The results imply a direct interaction between alpha 2-adrenoceptor and adenosine receptor and suggest that stimulated adenosine receptors unmasked [3H]clonidine binding sites in membranes of rat vas deferens.
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D003000:Clonidine / Q000378:metabolism*; D004082:Dihydroalprenolol; D004146:Dioxanes; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000187:drug effects*; D011983:Receptors, Purinergic; D012110:Reserpine / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects
chemical_list: D004146:Dioxanes; D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; D004082:Dihydroalprenolol; D012110:Reserpine; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D003000:Clonidine