Vascular effects of 7-epiclusianone, a prenylated benzophenone from Rheedia gardneriana, on the rat aorta.
The vascular effects of 7-epiclusianone on the rat aorta were investigated. In the rat aortic rings with functional endothelia, 7-epiclusianone up to 10microM induced a concentration-dependent vasodilatation of the sustained contractions induced by phenylephrine (0.3microM). At concentrations higher than 10microM, 7-epiclusianone induced a concentration-dependent contraction in the aortic rings. The vasodilator effect of 7-epiclusianone was drastically decreased with L-NAME (100microM) as well as in endothelium-denuded aortic rings. Moreover, indomethacin (10microM) induced a significant shift to the left in the vasodilator but did not modify the vasoconstrictor effect of 7-epiclusianone. In arteries without pre-contraction, 7-epiclusianone (3-100microM) induced concentration-dependent contraction only in endothelium-intact and in the presence of L-NAME (100microM). This effect was inhibited by indomethacin (10microM) and ZM230487 (1microM), selective inhibitors of cyclooxygenase and of 5-lipoxygenase, respectively. We can conclude that at low concentrations 7-epiclusianone induces an endothelium-dependent vasodilator effect in rat aortic rings. At higher concentrations and in conditions where NO synthase was inhibited, 7-epiclusianone induces a vasocontractile effect. Nitric oxide seems to participate in the vasodilatation, while endothelial cyclooxygenase- and 5-lipoxygenase-derived products play a role in the vasoconstrictor effect.
Cruz
A J
AJ
Departamento de Farmacologia, Universidade Federal de Minas Gerais, Belo Horizonte-MG, Brazil.
Lemos
V S
VS
dos Santos
M H
MH
Nagem
T J
TJ
Cortes
S F
SF
D000818:Animals; D001011:Aorta / Q000187:drug effects*; D001577:Benzophenones / Q000494:pharmacology*; D016227:Benzoquinones / Q000494:pharmacology*; D028084:Clusiaceae; D004305:Dose-Response Relationship, Drug; D020128:Inhibitory Concentration 50; D008297:Male; D008517:Phytotherapy; D017368:Protein Prenylation; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
C118110:7-epiclusianone; D001577:Benzophenones; D016227:Benzoquinones; D014665:Vasodilator Agents