| Effect of guinea pig tracheal epithelium on the contraction of rat vascular smooth muscle. |
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O Jung Kwon1, Chul Gyu Yoo1, Sang Heon Cho1, In Won Park1, Young Whan Kim1, Sung Koo Han1, Young Soo Shim1, Keon Youl Kim1, Yong Chol Han1, Seok Hyo Seoh2, Ki Whan Kim2 |
1Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
2Department of Physiology, Seoul National University College of Medicine, Seoul, Korea |
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| Abstract |
It has been weIl known that the integrity of airway epithelium is important in developing of bronchial hyperreactivity or bronchial asthma. But the mechanisms underlying this nonspecific airway hyperresponsiveness are not yet determined.
To evaluate the ability of guinea pig trachea to release an epithelium derived relaxing factor (EpDRF) which relax rat vascular smooth muscle, we performed the coaxial bioassay using guinea pig trachea and rat aoπa. And to evaluate the nature of EpDRF we investigate the influence of methylene blue and indomethacin on the coaxial bioassay.
Results
were as foIlows.
1) Vascular smooth muscle mounted into the epithelium intact trachea which was precontracted with phenylephrine was relaxed by addition of histamine or acetylcholine. But vascular smooth muscle mounted into epithelium denuded trachea failed to be relaxed.
2) Epithelium dependent relaxation of vascular smooth muscle was not affected by pretreatment of methylene blue or indomethacin.
These results strongly suggests that guinea pig tracheal epithelium releases EpDRF which is able to relax rat vasαllar smooth muscle. And EpDRF released by airway epithelium is not related to endothelium derived relaxing factor (EDRF) or cyclooxygenase products. |
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