title: Vascular reactivity of human internal mammary and gastroepiploic arteries.
abstract: Patency rates of bypass graft conduits are thought to be influenced by the determinants of vascular tone. This study has comparatively examined the response of the human internal mammary and gastroepiploic arteries to potassium, noradrenaline, dopamine, 5-hydroxytryptamine, thromboxane, and histamine. The response to potassium was significantly greater in the gastroepiploic artery (Emax = 79.5 +/- 9.6 mN) than in the internal mammary artery (Emax = 27.0 +/- 6.4 mN). Dose-related constrictions were observed in both vessels to all agonists except histamine, which was ineffective in the gastroepiploic artery. Noradrenaline and dopamine produced comparable dose-related constrictions in each vessel, with similar EC50 and Emax (expressed as a percentage of potassium response) values, but 5-hydroxytryptamine (Emax, gastroepiploic = 10.8% +/- 1.9%; internal mammary = 71.8% +/- 21.2%) and thromboxane (Emax, gastroepiploic = 116.7% +/- 4.0%; internal mammary = 169.6% +/- 19.4%) were more efficacious in their constriction of the mammary artery; the potencies were similar. We conclude that there is a heterogeneity of response to some vasoconstrictors between the human internal mammary and gastroepiploic arteries. The internal mammary artery may be more predisposed to events that initiate vasospastic disorders.
authors.affiliation: National Heart and Lung Institute, Harefield Hospital, Middlesex, United Kingdom.
authors.forename: G S
authors.initials: GS
authors.lastname: O'Neil
authors.forename: A H
authors.initials: AH
authors.lastname: Chester
authors.forename: C J
authors.initials: CJ
authors.lastname: Schyns
authors.forename: S
authors.initials: S
authors.lastname: Tadjkarimi
authors.forename: J R
authors.initials: JR
authors.lastname: Pepper
authors.forename: M H
authors.initials: MH
authors.lastname: Yacoub
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001158:Arteries / Q000502:physiology; D002648:Child; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D008323:Mammary Arteries / Q000187:drug effects*; D008875:Middle Aged; D009638:Norepinephrine / Q000494:pharmacology; D009852:Omentum / Q000098:blood supply*; D011188:Potassium / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D013270:Stomach / Q000098:blood supply*; D013931:Thromboxanes / Q000494:pharmacology; D014661:Vasoconstriction
chemical_list: D013931:Thromboxanes; D012701:Serotonin; D006632:Histamine; D011188:Potassium; D009638:Norepinephrine