title: Existence of alpha(1A)- and alpha(1B)-adrenoceptor subtypes in canine mandibular alveolar arteries.
abstract: 1. The present study attempted to pharmacologically characterize the alpha-adrenoceptor subtypes mediating vasoconstriction in canine isolated and perfused mandibular alveolar artery (MAA). 2. Noradrenaline (NA) and phenylephrine (PE) induced a strong vasoconstriction in a dose-dependent manner. The PE-induced vascular constriction was significantly inhibited by treatment with prazosin. Xylazine evoked a moderate vascular constriction and the xylazine-induced response was suppressed by rauwolscine. The NA-induced response was partially inhibited by rauwolscine and the remaining response to NA was abolished by subsequent administration of prazosin. 3. Treatment of MAA with WB4101 produced a dose-dependent inhibition of NA-induced vasoconstriction. Pretreatment of tissues with 10 micromol/L chloroethylclonidine produced a slight and statistically significant inhibition of NA-induced responses. BMY 7378, a selective alpha(1D)-adrenoceptor antagonist, failed to significantly affect vasoconstrictor responses to NA. 4. The present results suggests that: (i) both alpha(1)- and alpha(2)-adrenoceptors are involved in vasoconstrictor responses in the canine MAA; and (ii) the alpha(1)-adrenoceptors involved in the vasoconstrictor responses in the MAA are characterized as mainly of the alpha(1A)- and partially of the alpha(1B)-adrenoceptor subtype.
authors.affiliation: Department of Pharmacology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Taguchi
authors.forename: X P
authors.initials: XP
authors.lastname: Yang
authors.forename: S
authors.initials: S
authors.lastname: Chiba
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000539:Alveolar Process / Q000098:blood supply*; D000818:Animals; D001158:Arteries / Q000502:physiology*; D003000:Clonidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004146:Dioxanes / Q000494:pharmacology; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008334:Mandible / Q000098:blood supply*; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects; D014991:Xylazine / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D010879:Piperazines; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; D014991:Xylazine; D015016:Yohimbine; C051731:chlorethylclonidine; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; C053428:BMY 7378; D003000:Clonidine; D009638:Norepinephrine; D011224:Prazosin