Adenosine induces contractions in suncus ileum.
Purinoceptor-mediated responses were characterized in the ileum of Suncus murinus. Adenosine as well as adenosine 5'-triphosphate (ATP) contracted the ileum in a concentration-dependent manner. Contractile responses to transmural electrical stimulation were attenuated by adenosine only at high concentrations. Theophylline competitively blocked the adenosine-induced contraction. Atropine also inhibited the adenosine-induced contraction but in a non-competitive manner. The ATP-induced contraction was not affected by theophylline, atropine or alpha, beta-methylene ATP. Indomethacin shifted the concentration-response curves for adenosine and ATP to the right. These results suggest that adenosine elicited contractions via direct stimulation of postsynaptic P1-purinoceptors and postsynaptic potentiation of the acetylcholine response. Suncus ileum will be a unique model for the analyses of purinoceptor-mediated responses.
Nagata
K
K
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Saito
H
H
Matsuki
N
N
D000241:Adenosine / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D007082:Ileum / Q000187:drug effects* / Q000502:physiology; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D011323:Primates; D011983:Receptors, Purinergic / Q000187:drug effects / Q000378:metabolism; D013806:Theophylline / Q000494:pharmacology
D011983:Receptors, Purinergic; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D001285:Atropine; D000255:Adenosine Triphosphate; D013806:Theophylline; D000241:Adenosine; D007213:Indomethacin