title: Endothelin B receptors on vascular smooth muscle cells of the human umbilical vein mediate vasoconstriction.
abstract: OBJECTIVE
  To test the hypothesis that smooth muscle cells of the human umbilical vein have vasoconstricting endothelin B (ETB) receptors.
  
  
  METHODS
  In strip preparations of human umbilical veins isometric tension after exposure to the selective ETB receptor agonist sarafotoxin S6c (S6c) was compared to the tension before S6c exposure (set as 100%).
  
  
  RESULTS
  In intact preparations S6c induced vasoconstriction only at the highest concentration applied (10(-8)M; 149.5 +/- 12.5 vs. 100%, p < 0.05). In contrast, in endothelium-denuded preparations S6c induced vasoconstriction already at the lowest S6c concentration investigated (10(-11)M; 111.7 +/- 4.3 vs. 100%, p < 0.05).
  
  
  CONCLUSIONS
  The vasoconstricting effect of S6c in endothelium-denuded human umbilical vein preparations points to smooth muscle cell ETB receptor activation.
authors.affiliation: Department of Pediatrics, Charité, Berlin, Germany. eva.mildenberger@web.de
authors.forename: Eva
authors.initials: E
authors.lastname: Mildenberger
authors.forename: Beatrix
authors.initials: B
authors.lastname: Biesel
authors.forename: Gunter
authors.initials: G
authors.lastname: Siegel
authors.forename: Hans T
authors.initials: HT
authors.lastname: Versmold
mesh_terms: D006801:Humans; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000502:physiology; D044023:Receptor, Endothelin B / Q000502:physiology*; D014471:Umbilical Veins / Q000187:drug effects / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014757:Viper Venoms / Q000494:pharmacology*
chemical_list: D044023:Receptor, Endothelin B; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6