Shen Jing, Nakanishi Toshio, Gu Hong, Miyagawa-Tomita Sachiko, Wu Gui-Rong, Momma Kazuo, Nakazawa Makoto
Department of Pediatric Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan.
Heart Vessels. 2002 Jul;16(5):181-8. doi: 10.1007/s003800200019.
The role of endothelin in oxygen-induced contraction remains controversial. The present study was designed to investigate the role of endothelin in O2-induced contraction in the isolated ductal preparation of rabbit and rat, using the endothelin receptor antagonists, bosentan (antagonist for both ET-A and ET-B receptors) and BQ 485 (an ET-A selective antagonist). The ductus was isolated from fetal rabbits at 30 days of gestation (term 31 days) and fetal rats at 21 days of gestation (term 22 days). In the rabbit ductus with intact endothelium, 13% of the O2-induced contraction was inhibited by bosentan and 14% by BQ 485. In the rabbit ductus without endothelium, bosentan did not cause significant inhibition of the oxygen-induced contraction. In the rat ductus with intact endothelium, about 44% of the O2-induced contraction was inhibited by bosentan. In the rat ductus without endothelium, O2-induced contraction was 20% less than that in the ductus with intact endothelium. In the rat ductus without endothelium, bosentan further decreased the oxygen-induced contraction by about 24%. These data suggest that (1) endothelin plays a significant role in O2-induced contraction in the isolated ductus arteriosus, (2) there is a species difference in the degree of contribution of endothelin to the O2-induced ductal contraction, and (3) there is a species difference in the degree of contribution of the endothelium and vascular smooth muscle cells to the release of endothelin from the ductus arteriosus.
内皮素在氧诱导的收缩中所起的作用仍存在争议。本研究旨在使用内皮素受体拮抗剂波生坦（ET - A和ET - B受体的拮抗剂）和BQ 485（一种ET - A选择性拮抗剂），研究内皮素在兔和大鼠离体导管制备中氧诱导收缩中的作用。导管取自妊娠30天（足月为31天）的胎兔和妊娠21天（足月为22天）的胎鼠。在具有完整内皮的兔导管中，波生坦抑制了13%的氧诱导收缩，BQ 485抑制了14%。在没有内皮的兔导管中，波生坦对氧诱导的收缩没有产生显著抑制作用。在具有完整内皮的大鼠导管中，波生坦抑制了约44%的氧诱导收缩。在没有内皮的大鼠导管中，氧诱导的收缩比具有完整内皮的导管减少了20%。在没有内皮的大鼠导管中，波生坦进一步使氧诱导的收缩降低了约24%。这些数据表明：（1）内皮素在离体动脉导管的氧诱导收缩中起重要作用；（2）内皮素对氧诱导的导管收缩的贡献程度存在种属差异；（3）内皮和血管平滑肌细胞对动脉导管内皮素释放的贡献程度存在种属差异。
