【摘要】 可乐宁收缩豚鼠主—肺门支气管,显著增强组胺对此标本的收缩作用。电场刺激豚鼠离体肺门支气管引起长时程,对阿托品不敏感,可被 P 物质拮抗剂（Substance PAntagonist,SPA）所抑制的收缩反应。在心得安存在下,可乐宁对此收缩反应有显著抑制作用。抗原攻击鸡卵蛋白致敏豚鼠离体主—肺支气管引起双相收缩反应,即快速收缩相和缓慢收缩相。据本实验室将另文发表的实验结果,此双相收缩反应的快收缩相主要和组胺释放相关,而其缓慢收缩相则主要归因子分布在存呼吸道内 P 物质（Substance P）感觉神经纤维释放 SP。可乐宁对此双相收缩反应的两相均有显著抑制作用,尤其是其缓慢收缩相。育享宾可完全阻断上述可乐宁的抑制作用。这些实验结果提示,可乐宁对电场刺激和抗原攻击所引起的支气管平滑肌收缩具有显著抑制作用。此抑制作用的机理可能和可乐宁激动分布于呼吸道内 SP 感觉神经末稍上的α₂肾上腺素受体,从而抑制 SP 释放有关。更多还原

【Abstract】 CTClonidin（C）contraeted guinea pig main-hilus bronchi（GPM- lib）and enhanced the contractile effect of histamine on the preparation significantly.Electrical field stimulation（EFS）induced a long lasting contraction of guinea pig hilus bronchi which was resistant to atropine, but sensitive to substance p antagonist.in the presence of propranolol, C inhibited the response significantly.This indiditory effect of C could be abolishod dy yohimbine（Y）.Antigen challenge of GPMHB sensitized by dval dumin evoked a doudle phase contraction consisting of a rapid contraction anb a slow contration.According to our results which will be published in other paper,the rapid contraction was mainly induced by histamine and the slow cnotraction by release of substance P（SP）from SP sensory nerve fibre enbings in the respiratory tract.C inhibited the double phase contraction significantly,especially its slow contraction. Y blockeb the inhibitory effect of C completely.These results show that C significantly inhibits the contractioas of guinea pig bronchi in vitro ir.duced by EFS and antigen challenge and suggest that the mechanism of the inhibition of C might be related to its exciting effect on the α₂-abr- cnoceptor which exists on SPsensory nerve fidre endings and exerts an inhibitory contrnl of SP release.更多还原