Research on the functional role of endothelial cells in vascular contraction in the developing vassels

1 .动脉导管：本研究探讨了内皮在o2诱导的动脉导管收缩中的作用。测定孕30天（孕31天）胎兔离体动脉导管的等距收缩力和[Ca]i。动脉导管初始灌注低氧控制液，充氧溶液诱导动脉导管收缩。在内膜完整的导管中，O2诱导收缩，并与[Ca]i升高有关。在没有内皮的情况下，我们观察到o2诱导的收缩和[Ca]i的增加。在没有内膜的情况下，o2诱导的收缩和[Ca]i的升高都被消除了。这些数据表明，内皮细胞并不是关闭动脉导管的氧传感器。ii .肺动脉：在磷酸酯预处理的肺动脉中，酸中毒导致成人收缩量增加，而新生儿没有。Ca在新生儿和成人中均显著升高，成人的升高幅度大于新生儿。在去内皮的血管中，酸中毒对收缩、细胞内pH和钙的影响与内皮完整的血管相似。我们得出结论，在酸中毒诱导的血管收缩中，内皮在血管收缩中不起主要作用。

I.Ductus artriosus : The present study investigated the role of the endothelium in O2-induced ductal contraction. The force of isometric contraction and [Ca]i of the ductus arteriosus isolated from fetal rabbits at 30 days of gestation (term 31 days) were measured. The ductus arteriosus was initially superfused with hypoxic control solutions and contraction was induced by application of oxygenated solutions. In the intima-intact ductus, O2 induced contraction and it was associated with increases in [Ca]i. In the absence of the endothelium, both the O2-induced contraction and increases in [Ca]i were observed. In the absence of the intima, both the O2-induced contraction and increases in [Ca]i were eliminated. These data suggest that the endothelium is not an oxygen sensor for the closure of the ductus arteriosus.II.Pulmonary artery : In the pulmonary artery pretreated by phorbol ester, acidosis caused big increase in contraction in the adult, but not in the newborn. Ca increased significantly in the newborn and adult, and the increase in the adult was greater than in the newborn. In the vessels in which the endothelium was removed, the effect of acidosis on contraction, intracellular pH, and calcium was similar to that in the vessels in which the endothelium was intact. We conclude that in the acidosis-induced contraction, the endothelium does not play a major role in vessel contraction.