title: Characterization of small arteries isolated from the human placental chorionic plate.
abstract: Despite the essential role of the placenta in pregnancy, the control of the blood flow within the fetoplacental circulation is poorly understood. A handful of myography studies have directly assessed the role of vasoactive agonists in fetoplacental vasculature contractility but have used a range of steady-state conditions. Our aim, therefore, was to determine the optimal vessel diameter and oxygen tension to assess vascular function in small arteries isolated from the chorionic plate of normal term placentae. Biopsies were obtained from term placentae from uncomplicated pregnancies. Small arteries were dissected from the chorionic plate, mounted onto a wire myograph in HCO3(-) -buffered physiological salt solution at 37 degrees C and equilibrated for 20 min. Two methods for normalization of the optimal length/diameter for contractility of chorionic plate small arteries were assessed. Both classical normalization (CN) and length-tension curve (LTC) methods produced similar data. These data were agonist-independent. Data for CN and LTC were unaffected but maximal force generation (for U46619) was decreased in reduced oxygen tensions. Using conditions for optimal tension production in chorionic plate small arteries the thromboxane-mimetic U46619 produced the greatest and most reproducible constrictive effect. Relaxations were only achieved with endothelial-independent agonists (sodium nitroprusside and papaverine).
authors.affiliation: Maternal and Fetal Health Research Centre, University of Manchester, Academic Unit of Obstetrics and Gynaecology and Reproductive Health Care, St Mary's Hospital, Whitworth Park, Manchester, M13 0JH, UK. Mark.Wareing@man.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Wareing
authors.forename: I P
authors.initials: IP
authors.lastname: Crocker
authors.forename: A Y
authors.initials: AY
authors.lastname: Warren
authors.forename: M J
authors.initials: MJ
authors.lastname: Taggart
authors.forename: P N
authors.initials: PN
authors.lastname: Baker
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000328:Adult; D001158:Arteries / Q000187:drug effects / Q000502:physiology*; D002824:Chorionic Villi / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D010101:Oxygen Consumption / Q000502:physiology; D010208:Papaverine / Q000494:pharmacology; D011247:Pregnancy; D012039:Regional Blood Flow / Q000502:physiology; D015203:Reproducibility of Results; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D010208:Papaverine