Endothelin-1 is involved in hepatic sinusoidal vasoconstriction after ischemia and reperfusion.
Endothelin-1 (ET-1), a vasoactive peptide, causes a significant rise in portal vein pressure, which is most likely a result of severe vasoconstriction in the liver. In this study, the effect of ET-1 on sinusoidal vasoconstriction in the liver after ischemia and reperfusion was directly investigated using intravital microscopy. In anesthetized female Sprague Dawley rats (200-250 g) ischemia of the median and left liver lobes was induced for 90 min by temporary ligation of the left pedicle. After declamping and a 90-min reperfusion period, the livers were exposed for intravital microscopy. Using a Nikon MM-11 fluorescence microscope (545 nm, 330x), a CCD camera (Cohu FK 6990), and a SVHS video recording unit, the hepatic microcirculation was directly investigated. Besides sham groups, two ischemia groups were studied, receiving ET-1 antiserum (anti-ET-1; 0.5 ml; Peptide Inst., Osaka, Japan) or NaCl 0.9% (0.5 ml) 5 min prior to reperfusion of the liver (n = 6/group). Following a transient drop in the mean arterial blood pressure in the anti-ET-1-treated groups, comparable systemic hemodynamic conditions among the four groups were noted during intravital microscopic assessment at the end of the 90-min reperfusion period. Reduction in the sinusoidal diameters during postischemic reperfusion (7.7 +/- 0.5 microm) was prevented by anti-ET-1 treatment (9.6 +/- 0.25 microm; P < 0.01; mean + SEM) back to control values (9.6 +/- 0.32 microm), while most of other microcirculatory parameters did not show significant differences. The results supported further the role of ET-1 in dysregulation of the sinusoidal vascular tone in the liver, e.g., after ischemia and reperfusion.
Department of Surgery, University of Saarland, Homburg/Saar, Germany.
I
I
Marzi
Y
Y
Takei
M
M
Rücker
S
S
Kawano
H
H
Fusamoto
F
F
Walcher
T
T
Kamada
D000818:Animals; D001794:Blood Pressure; D019332:Endothelin-1 / Q000037:antagonists & inhibitors / Q000502:physiology*; D005260:Female; D007511:Ischemia / Q000503:physiopathology*; D008099:Liver / Q000098:blood supply*; D008102:Liver Circulation / Q000502:physiology; D008833:Microcirculation / Q000502:physiology*; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D014661:Vasoconstriction / Q000502:physiology*
D019332:Endothelin-1