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

I. Dendritriosus：本研究探讨了内皮细胞在O2诱导的导管收缩中的作用。测定孕30天（足月31天）胎兔动脉导管等长收缩力和[Ca]i。动脉导管最初用低氧对照溶液灌注，并通过应用含氧溶液诱导收缩。在内膜完整的导管中，O2引起收缩，并且与[Ca]i的增加相关。在没有内皮的情况下，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的增加都被消除。这些数据表明，内皮细胞不是动脉导管关闭的氧传感器。II.肺动脉：在佛波酯预处理的肺动脉，酸中毒引起的收缩在成人，但不是在新生儿大增加。新生儿和成人的Ca均显著升高，且成人的升高幅度大于新生儿。在去除内皮的血管中，酸中毒对收缩、细胞内pH值和钙的影响与内皮完整的血管相似。我们的结论是，在酸中毒引起的收缩，内皮细胞不发挥主要作用的血管收缩。

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.