Role of endothelin in the circulatory changes associated with small bowel strangulation obstruction in pigs: Effects of the endothelin receptor antagonist bosentan
J. Fevang et al., Role of endothelin in the circulatory changes associated with small bowel strangulation obstruction in pigs: Effects of the endothelin receptor antagonist bosentan, J SURG RES, 96(2), 2001, pp. 224-232
Background. We have previously shown that experimental strangulation obstru
ction leads to increased release and concentration of endothelin-1 (ET-1) i
n venous blood from the strangulated bowel loop. The present study focuses
on the microcirculatory effects of the released ET-1 in strangulation obstr
uction.
Methods. In anesthetized pigs strangulation obstruction was induced by incr
easing pressure in a baby pressure gasket placed around a loop of ileum unt
il venous pressure reached 45 mm Hg. The pigs were randomly allocated into
two groups. The nonselective ETA/ETB antagonist bosentan was administered i
ntravenously (5 mg kg(-1)) to eight pigs (bosentan group) 30 min before str
angulation, which was maintained for 90 min. Another eight pigs were treate
d in same manner except for the bosentan injection (control group).
Results. The concentration of ET in arterial and intestinal venous blood in
creased markedly after intravenous administration of bosentan. Intravenous
infusion of bosentan was followed by a reduction in systemic arterial blood
pressure. Bosentan reduced vascular resistance and increased blood flow in
the normal intestinal mucosa. It also reduced muscularis blood how in the
beginning of the experiment. In strangulated small bowel bosentan inhibited
the increase in vascular resistance usually caused by strangulation obstru
ction. Muscularis blood how in strangulated small bowel was not affected by
bosentan.
Conclusion. Endothelin is involved in the normal regulation of arterial blo
od pressure. The increase in vascular resistance associated with strangulat
ion obstruction is caused mainly by locally released endothelin. (C) 2001 A
cademic Press.