arl-67156 and isoalloxazine

To investigate the participation of adenosine receptors in the adenosine 5'-triphosphate (ATP)-induced relaxation in the corpus cavernosum penis (CCP) of rabbits.. The ATP-induced relaxation was assessed on the noradrenaline precontracted CCP of rabbits in the presence and absence of 8-(3-chlorostyryl)caffeine (CSC); an adenosine A(2A) receptor antagonist; alloxazine and MRS1754; adenosine A(2B) receptor antagonists; and ARL67156, an inhibitor of ecto-nucleoside triphosphate diphosphohydrolases.. Adenosine and ATP relaxed the noradrenaline precontracted CCP of rabbits in a concentration-dependent manner. The adenosine- and ATP-induced relaxations were suppressed by alloxazine and MRS1754, but not by 8-(3-chlorostyryl)caffeine. ARL67156 potentiated the ATP-induced relaxation but not the adenosine-induced one. MRS1754 suppressed the ATP-induced relaxation potentiated by ARL67156.. The above results suggest that, in the CCP of rabbits, the adenosine receptor mediating adenosine-induced relaxation is of the A(2B) receptor and the ATP directly causes relaxation through the A(2B) receptor on the CCP.

Topics: Acetamides; Adenosine; Adenosine A2 Receptor Agonists; Adenosine A2 Receptor Antagonists; Adenosine Triphosphate; Animals; Caffeine; Flavins; Male; Muscle Relaxation; Muscle, Smooth; Penile Erection; Penis; Purinergic P1 Receptor Agonists; Purinergic P1 Receptor Antagonists; Purinergic P2 Receptor Agonists; Purinergic P2 Receptor Antagonists; Purines; Rabbits; Receptor, Adenosine A2A; Receptor, Adenosine A2B; Receptors, Purinergic P1; Receptors, Purinergic P2