title: Vascular catecholamine sensitivity during pregnancy in the ewe.
abstract: Four pregnant and four castrated ewes were chronically instrumented for the measurement of external iliac blood flow to test the hypothesis that pregnancy alters alpha-adrenergic sensitivity in a major regional circulation. Complete dose-response curves were generated to methoxamine, phenylephrine, and norepinephrine. Pregnancy was associated with no change in methoxamine sensitivity, an increase in phenylephrine sensitivity, and a decrease in norepinephrine sensitivity. These differential changes in drug sensitivity suggest (1) the alpha 1-receptor population is functionally similar between the two groups of animals, (2) uptake 1 is inhibited, and (3) either catechol-O-methyltransferase activity is increased or the alpha 2- or beta-receptor population changes in this circulation during pregnancy. These data illustrate the complexity of the change in the adrenergic system during pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, University of Vermont College of Medicine, Burlington 05405.
authors.forename: M K
authors.initials: MK
authors.lastname: McLaughlin
authors.forename: T M
authors.initials: TM
authors.lastname: Keve
authors.forename: R
authors.initials: R
authors.lastname: Cooke
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001835:Body Weight; D004305:Dose-Response Relationship, Drug; D005260:Female; D007083:Iliac Artery / Q000187:drug effects / Q000502:physiology; D008729:Methoxamine / Q000494:pharmacology*; D009132:Muscles / Q000098:blood supply*; D009638:Norepinephrine / Q000494:pharmacology*; D010477:Perfusion; D010656:Phenylephrine / Q000494:pharmacology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011312:Pressure; D012756:Sheep; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D010656:Phenylephrine; D008729:Methoxamine; D009638:Norepinephrine