title: ATP release evoked by isoprenaline from adrenergic nerves of guinea pig atrium.
abstract: Mode and site of release of ATP evoked by isoprenaline were evaluated in the electrically driven left atrial segment of guinea pig. The peak release of ATP 5 min after 1 microM isoprenaline was inhibited by 1 microM propranolol and 1 microM butoxamine, but not by 1 microM atenolol, showing that the ATP release is due to stimulation of the presynaptic beta 2-adrenoceptor by isoprenaline. The maximum ATP release was markedly reduced by Ca2+/calmodulin antagonists, W-7 and trifluoperazine, and by a mitotic inhibitor, vinblastine. Further, the release was similarly inhibited by myosin light chain kinase inhibitors, ML-7 and wortmannin. Nifedipine, a Ca(2+)-channel blocker, decreased the release of ATP evoked by isoprenaline. By contrast, Bay K 8644, a Ca(2+)-channel opener, tended to enhance the ATP release. These findings suggest that isoprenaline produces ATP release from adrenergic nerve terminals of atrium, implying that ATP serves as a co-transmitter.
authors.affiliation: Department of Pharmacology, School of Medicine, Fukuoka University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tokunaga
authors.forename: T
authors.initials: T
authors.lastname: Katsuragi
authors.forename: C
authors.initials: C
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Furukawa
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002120:Calcium Channel Agonists / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002147:Calmodulin / Q000037:antagonists & inhibitors; D004558:Electric Stimulation; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors; D009638:Norepinephrine / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000319:Adrenergic beta-Antagonists; D002120:Calcium Channel Agonists; D002121:Calcium Channel Blockers; D002147:Calmodulin; D000255:Adenosine Triphosphate; D009219:Myosin-Light-Chain Kinase; D007545:Isoproterenol; D009638:Norepinephrine