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Pyeongpaesan (øÁøËߤ) has been used in Korea for many centuries as a treatment for respiratory disease. The effect of Pyeongpaesan (øÁøËߤ) on tracheal smooth muscle is not known. The purpose of the present study is to determine the effect of Pyeongpaesan (øÁøËߤ) on histamine and acetylcholine induced tracheal smooth muscle contraction in rats and guinea pigs. Guinea pig (500 g, male) and Sprague Dawley rats (200 g, male) were killed by exposure and a segment (8-10 mm) of the thoracic trachea from each rat and guinea pig was cut into equal segments and mounted ¡¯in pairs¡¯ in a tissue bath. Contractile force was measured with force displacement transducers under 0.5 g loading tension. The dose of histamine (His) and acetylcholine (Ach) which evoked 50% of maximal response () was obtained from cumulative dose response curves for histamine and acetylcholine . Contractions evoked by His and Ach were inhibited significantly by Pyeongpaesan (øÁøËߤ). In guinea pig tracheal smooth muscle, the mean percent inhibition of acetylcholine induced contraction was 13.5% (p<0.05) after Pyeongpaesan (øÁøËߤ), $64.6\(p<0.01)\;after\;30{\mu}l/ml$ Pyeongpaesan (øÁøËߤ), and $92.8\(p<0.01)\;after\;100{\mu}l/ml$ Pyeongpaesan (øÁøËߤ). In rat tracheal smooth muscle, the mean percent inhibition of acetylcholine induced contraction was $60.9\(p<0.01)\;after\;30{\mu}l/ml$ Pyeongpaesan (øÁøËߤ), and $91.2\(p<0.01)\;after\;100{\mu}l/ml$ Pyeongpaesan (øÁøËߤ). Also, in guinea pig tracheal smooth muscle, the mean percent inhibition of histamine induced contraction was $104.8\(p<0.01)\;after\;30{\mu}l/ml$ Pyeongpaesan (øÁøËߤ) and $142.3\(p<0.01)\;after\;100{\mu}l/ml$ Pyeongpaesan (øÁøËߤ). In rat tracheal smooth muscle, the mean percent inhibition of histamine induced contraction was $63.7\(p<0.01)\;after\;30{\mu}l/ml$ Pyeongpaesan (øÁøËߤ), and $107.5\(p<0.01)\;after\;100{\mu}l/ml$ Pyeongpaesan (øÁøËߤ). Propranolol slightly but significantly attenuated the inhibitory effects of Pyeongpaesan (øÁøËߤ). Following treatment with propranolol, the mean percent inhibition caused by Pyeongpaesan (øÁøËߤ) fell to 15.7% (p<0.05) in guinea pig induced by acetylcholine contraction and the mean percent inhibition caused by Pyeongpaesan (øÁøËߤ) fell to 22.3% (p<0.05) in guinea pig induced by histamine contraction and by Pyeongpaesan (øÁøËߤ) fell to 28.7% (p<0.01) in rat induced by histamine contraction. Indomethacin and methylene blue did not significantly alter the inhibitory effect of Pyeongpaesan (øÁøËߤ). Also, I could find the effects of Pyeongpaesan (øÁøËߤ) and Pyeongpaesanga (øÁøËߤʥ) morphine on the tracheal smooth muscle in guinea pig and rat did not change significantly. These results indicate that Pyeongpaesan. (øÁøËߤ) can relax histamine and acetylcholine-induced contraction of guinea pig and rat tracheal smooth muscle, and that this inhibition involves sympathetic effects and the release of cyclooxygenase products.
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