Vasocontractions of the in-vitro toad aortas induced by endothelin-1 and sarafotoxin-S6b.
Dose-dependent tension curves were recorded from the in vitro toad aortas by administration of endothelin-1 and sarafotoxin-S6b. The maximal contractile tensions by both drugs were evoked at a 10(-8) M concentration. By a single dose application (10(-8) M) of endothelin-1 and sarafotoxin-S6b to both endothelium-preserved and denuded vessels, the induction of the endothelium-dependent vasocontraction occurs after 2 min of administration. Ultrastructural changes of Weibel-Palade bodies such as decrease in electron density, swelling with a wide peripheral halo, and expulsion of their contents in a manner of exocytosis become evident within 2 min after administration of these drugs. These findings indicate that some vasocontractile substances in Weibel-Palade bodies are extracellularly discharged by endothelin-1 and sarafotoxin-S6b.
Doi
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Y
Department of Anatomy, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
Fujimoto
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S
D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D002025:Bufonidae / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D014661:Vasoconstriction / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014757:Viper Venoms / Q000494:pharmacology*
D016232:Endothelins; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6