Endothelin B receptors on vascular smooth muscle cells of the human umbilical vein mediate vasoconstriction.
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.
Mildenberger
Eva
E
Department of Pediatrics, Charité, Berlin, Germany. eva.mildenberger@web.de
Biesel
Beatrix
B
Siegel
Gunter
G
Versmold
Hans T
HT
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*
D044023:Receptor, Endothelin B; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6