Evidence against ATP being the nonadrenergic, noncholinergic inhibitory transmitter in guinea pig stomach.
THe adenosine-sensitive P1 purinoceptor antagonists 8-phenyl theophylline and 8-(p-bromophenyl)theophylline (4 microM) antagonized ATP-induced relaxation of spontaneous tone in guinea pig stomach, but caused no significant modification of relaxation to electrical field stimulation (0.2 - 10 Hz, 1 msec for 30 sec, atropine 1.5 microM, and guanethidine 4 microM treated). These results suggest that in fundic muscle ATP acts via hydrolysis to adenosine, with subsequent activation of P1 purinoceptors, and that ATP is not the nonadrenergic, noncholinergic inhibitory transmitter in stomach fundus.
D000255:Adenosine Triphosphate / Q000502:physiology*; D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009433:Neural Inhibition / Q000187:drug effects*; D018377:Neurotransmitter Agents / Q000502:physiology*; D011955:Receptors, Drug / Q000187:drug effects; D011983:Receptors, Purinergic; D013270:Stomach / Q000187:drug effects / Q000294:innervation*; D013806:Theophylline / Q000031:analogs & derivatives / Q000494:pharmacology
D018377:Neurotransmitter Agents; D011955:Receptors, Drug; D011983:Receptors, Purinergic; D000255:Adenosine Triphosphate; D013806:Theophylline; C028322:8-phenyltheophylline