Constriction of mouse hepatic venules and sinusoids by endothelins through ETB receptor subtype.
OBJECTIVE
This study was conducted to examine the effects of endothelin (ET)-1 and ET-3 on hepatic venules and sinusoids and to identify the subtypes of ET receptors.


METHODS
Hepatic venules and sinusoids of anesthetized mice were observed at the edge of the liver. ET-1, ET-3 and sarafotoxin (S6c, a selective ETB receptor agonist) were applied topically over the microvasculature.


RESULTS
ET-1, ET-3 and S6c (1-100 microM, 30 microliters) induced dose-dependent vasoconstriction of the portal venules, the sinusoids and the central venules. The ETs and S6c were equipotent for these microvessels. BQ-123 (a selective ETA receptor antagonist) inhibited the constrictive effects of ET-3 (not of ET-1) on the portal venules and central venules, whereas it had no inhibitory effect on the sinusoids.


CONCLUSIONS
In mouse hepatic venules and sinusoids, the vasoconstriction induced by ET-1 and ET-3 was mediated mainly through the ETB receptor subtype and partly through an unknown BQ-123-sensitive ET receptor subtype in the portal and central venules, and only through the ETB receptor subtype in the sinusoids.
Ito
Y
Y
Department of Surgery, Kitasato University School of Medicine, Kanagawa, Japan.
Katori
M
M
Majima
M
M
Kakita
A
A
D000818:Animals; D019332:Endothelin-1 / Q000494:pharmacology*; D019334:Endothelin-3 / Q000494:pharmacology*; D008099:Liver / Q000098:blood supply*; D008297:Male; D051379:Mice; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000819:agonists / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014699:Venules / Q000187:drug effects / Q000502:physiology; D014757:Viper Venoms / Q000494:pharmacology
D019332:Endothelin-1; D019334:Endothelin-3; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6