title: The relaxant effect of adenosine-5'-alpha, beta-methylenediphosphonate on the longitudinal smooth muscle of the rabbit ileum.
abstract: The response pattern of the isolated longitudinal muscle of the rabbit ileum to adenosine-5'-alpha, beta-methylenediphosphonate (APCP) was found to differ from that caused by adenosine or ATP in that the rapid initial phase of relaxation is absent and that at doses above 10 muM a secondary increase of contractile activity occurs in the continued presence of the nucleotide. This secondary phase was attenuated after indomethacin pretreatment and reestablishement of tone with acetylcholine. Theophylline did not modify APCP-induced relaxations while effectively antagonizing those caused by adenosine. It appears that APCP acts via a receptor site or pathway distinct from that of adenosine or ATP.
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D004164:Diphosphonates / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D010275:Parasympathetic Nervous System / Q000187:drug effects; D011817:Rabbits; D013564:Sympathetic Nervous System / Q000187:drug effects
chemical_list: D004164:Diphosphonates; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000241:Adenosine