title: Electron-microscopic immunolabelling of vasoactive substances in human umbilical endothelial cells and their actions in early and late pregnancy.
abstract: Human umbilical vessels are devoid of nerves and therefore endothelial cells may play an important role in the control of feto-placental blood flow. The pharmacological effects of 5-hydroxytryptamine, histamine and endothelin were examined in umbilical arteries and veins from legal terminations (gestational age 8-17 weeks, n=12) and normal term vaginal deliveries (gestational age 38-41, n=12). Immunocytochemistry of human unbilical vessels indicated that 5-hydroxytryptamine, histamine and endothelin were localised in subpopulations of endothelial cells of both artery and vein in late, but not early, pregnancy. 5-Hydroxytryptamine (10 nM-30 microM) caused sustained concentration-dependent contractions in all vessels from early and late pregnancy. Histamine (0.1 microM-30 mM) also caused sustained contractions in all vessels from late pregnancy but only 27% of arteries and 41% of veins from early pregnancy responded. Endothelin (10 pM-30 nM) caused slow long-lasting contractions in all vessels from early and late pregnancy. Atrial natriuretic peptide and neuropeptide Y did not alter vascular tone. The endothelium may thus play an autocrine/paracrine role, by synthesizing and releasing the above reactive substances in late pregnancy to influence feto-placental blood flow.
authors.affiliation: Department of Anatomy and Developmental Biology and Centre for Neuroscience, University College London, Gower Street, London, WC1E 6BT, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: Sexton
authors.forename: A
authors.initials: A
authors.lastname: Loesch
authors.forename: M
authors.initials: M
authors.lastname: Turmaine
authors.forename: S
authors.initials: S
authors.lastname: Miah
authors.forename: G
authors.initials: G
authors.lastname: Burnstock
mesh_terms: D001158:Arteries / Q000737:chemistry / Q000276:immunology; D009320:Atrial Natriuretic Factor / Q000032:analysis; D016232:Endothelins / Q000276:immunology*; D004730:Endothelium, Vascular / Q000737:chemistry / Q000276:immunology*; D005260:Female; D006632:Histamine / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009478:Neuropeptide Y / Q000032:analysis; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011263:Pregnancy Trimester, Third; D012701:Serotonin / Q000276:immunology*; D014471:Umbilical Veins / Q000737:chemistry / Q000276:immunology; D014472:Umbilicus / Q000098:blood supply*
chemical_list: D016232:Endothelins; D009478:Neuropeptide Y; D012701:Serotonin; D006632:Histamine; D009320:Atrial Natriuretic Factor