title: Different contributions of ATP and noradrenaline to neurotransmission in the isolated canine intermediate auricular artery.
abstract: Vasoconstrictor responses elicited by periarterial electrical nerve stimulation were analyzed pharmacologically in the canine isolated, perfused intermediate auricular artery. Phentolamine (10 microM) significantly inhibited the vasoconstrictor responses to stimulation at 5 Hz and over but not those to stimulation at frequencies below 5 Hz. Additionally administered alpha, beta-methylene ATP (1 microM) abolished the phentolamine-resistant vasoconstrictions at all frequencies used in this study. In contrast, suramin (100 microM) inhibited the vasoconstrictor responses to stimulation at 5 Hz and below but not those to stimulation at frequencies higher than 5 Hz. Phentolamine abolished the suramin-resistant vasoconstriction at all frequencies. Phentolamine and alpha, beta-methylene ATP selectively abolished the vasoconstrictor responses to exogenous noradrenaline and ATP, respectively. These results show that the co-transmission of noradrenaline and ATP exists at sympathetic nerve terminals in the canine intermediate auricular artery, and that purinergic transmission is mainly involved in the vasoconstrictor responses to low-frequency nerve stimulation.
authors.affiliation: Department of Pharmacology, School of Medicine, Shinshu University, Matsumoto, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Haniuda
authors.forename: T
authors.initials: T
authors.lastname: Nakane
authors.forename: S
authors.initials: S
authors.lastname: Chiba
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000294:innervation*; D004285:Dogs; D004423:Ear / Q000098:blood supply* / Q000294:innervation; D004558:Electric Stimulation; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D010646:Phentolamine / Q000494:pharmacology; D058919:Purinergic P2 Receptor Antagonists; D013498:Suramin / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000187:drug effects; D013565:Sympatholytics / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D058919:Purinergic P2 Receptor Antagonists; D013565:Sympatholytics; D014662:Vasoconstrictor Agents; D013779:Tetrodotoxin; D013498:Suramin; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; D009638:Norepinephrine; D010646:Phentolamine; D006145:Guanethidine