Pharmacological studies on the active factors derived from airway epithelial cells.

气道上皮细胞不仅是气道刺激物质如有毒气体或抗原的扩散屏障，而且通过恢复多种活性因子在调节气道肌张力中起重要作用。也就是说，气道上皮细胞释放两种以上的因子，其中一种抑制兴奋性神经效应子传递，另一种调节气道平滑肌细胞的静息膜电位。为了鉴定这些因子，我们培养气道上皮细胞并使用培养的上清液。培养上清液完全或部分抑制上皮剥脱细支气管对电场刺激的收缩反应，并抑制兴奋性连接电位。体外培养的气管上皮细胞产生前列腺素，外源性PGE_2抑制狗气管和细支气管突触前兴奋性神经效应传递。因此，我们用放射免疫法测定了前列腺素E_2（PGE_2）的含量， ...更多信息 游泳者血清中的蛋白质含量在3.1-23.8ng/ml之间。培养上清中高浓度的PGE_2参与了收缩的抑制。吲哚美辛可抑制PGE_2的合成，从而阻断上清对神经元收缩和兴奋性连接电位的抑制作用。提示PGE_2是气道上皮细胞释放的抑制兴奋性神经效应传递的因子之一。为鉴定上皮源性超极化因子（EpDHF），我们将上清液冷冻干燥，然后用Sephacryl S-100 HR凝胶过滤层析，再用c_反相高效液相<18>层析。超极化实验表明，洗脱峰中的活性成分与低分子量（10-20 KD）一致。用蛋白水解酶对HPLC纯化的活性组分进行酶处理，结果消除了超极化活性。结果表明，存在于培养的上皮上清液中的活性因子（EpDHF）1本质上是一种肽。少

Airway epithelial cells do not simply act as diffusion barriers against airway stimulating substances such as toxic gases or antigens, but play an important role in regulation of the airway muscle tone by rekeasing multiple active factors. Namely, airway epitelial cells release more than two factors, one of which inhibits excitatory neuro-effector tranamission and an other which modulates the resting membrane potential of the airway smooth muscle cells. To identify these factors we cultured airway epithelial cells and used the cultuured supernatants. Cultured supernatants completely or partially suppressed the contractile response of epithelium-denuded bronchioles to electrical field stimulation and suppressed the excitatory junction potentials. Cultured epithelial cells produce prostaglandins, and exogenously applied PGE_2 inhibits excitatory neuro-effector transmission presynaptically in the dog trachea and bronchioles. Therefore we radioimmunoassayd the amounts of PGE_2 in the super … More natants, which ranged between 3.1-23.8ng/ml. A high concentration of PGE_2 in the supernatant was associated with aboliton of the twitch contraction. Indomethacin, which suppresses the synthesis of PGE_2 in the suprenatants, prevented the inhibitory effect of supernatants on the twitch contractions and excitatoty junction potentials. Thus we concluded that one of the factors which is released from the airway epithelial cells and inhibits excitatory neuro-effector transmission is PGE_2. In an attempt to identify the epithelium derived hyperpolarizing factor (EpDHF) , we freeze-dried the supernatants and then applied them to Gel-filtration chromatograohy on Sephacryl S-100HR and then high-perfoamace liquid chromatofraphy on a c_<18> reversed-phase column. Hyperpolarization assay of the chromatographic fractions showed that active factors eluted in peaks coincided with low molecular weights (10-20 KD). Enzymatic treatment with proteolytic enzymes of the HPLC-purified active fraction resuletd in the abolition of hyperpolarizing activity.The results suggest that the active factor (EpDHF) 1 that was present in the cultured epithelial supenatants was a peptide in nature. Less