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心血管発生・基礎研究③

[II-P-132] シクロオキシゲナーゼ阻害薬は鳥類動脈管を収縮させる

^○赤池 徹, 伊藤 伶奈, 齋藤 綾子, 梶村 いちげ, 南沢 享 (東京慈恵会医科大学　細胞生理学)

Keywords:ductus arteriosus, prostaglandin, indomethacin

Background: Ductus arteriosus (DA) is an essential fetal artery that connects the main pulmonary artery and the descending aorta. Decreases of circulating prostaglandin E₂ (PGE₂) transferred from its placenta close mammalian DA right after birth. Avian DA also closes after birth although avian has no placenta that is a source of PGE₂ in rodent and mammalian. Previous research demonstrated that PGE₂ signal pathway is not involved in constriction of isolated chicken DA. However, in vivo effects of PGE₂ in avian DA is not fully clarified.Aim: The aim of this study is to elucidate effects of PGE₂ in chicken DA closure.Method and results: First, we measured expressions of PGE₂ in chicken at day 19 embryo by enzyme immunoassay. Blood concentration of PGE₂ in chicken was significantly higher than that of rat at termed embryo. And, PGE₂ in the chicken DA tissues was higher expressed than that of the chicken aorta tissues. These data suggested that PGE₂ works on fetal chicken DA. Next, we performed a rapid whole-body freezing method to evaluate DA closure in vivo. We measured internal diameter of DA and the aorta at 4hrs after in ovo injection of indomethacin. Indomethacin decreased the internal diameter ratio of DA and the aorta at day 19 embryo in vivo. These data suggested that PGE₂ is an important factor in avian DA closure although avian has no placenta that is a source of PGE₂. Conclusion: Inhibition of cyclooxygenase contracts chicken DA. Prostaglandin E2₂signal may play an important role in an acute response of chicken DA closure.