多沙唑嗪对映体对豚鼠离体气管环的作用

Effects of doxazosin enantiomers in trachea rings isolated from guinea pig

目的:研究R-多沙唑嗪(R-doxazosin,R-DOX)、S-多沙唑嗪(S-doxazosin,S-DOX)和rac-多沙唑嗪(rac-doxazosin,rac-DOX)对豚鼠离体气管环的作用。方法:采用豚鼠离体气管环,观察DOX对映体对离体气管环静息张力、卡巴胆碱诱发收缩反应以及异丙肾上腺素诱发舒张反应的影响。结果:10和30μmol.L-1DOX对映体对豚鼠离体气管环静息张力无显著性影响(P>0.05)。S-DOX 10μmol.L-1使卡巴胆碱诱发豚鼠离体气管环收缩反应的Emax明显增大(P<0.05),但卡巴胆碱的EC50未发生明显改变。相反,同浓度R-DOX明显降低卡巴胆碱诱发的豚鼠离体气管环收缩反应的Emax(P<0.05),但使卡巴胆碱的EC50明显减小。S-DOX 10μmol.L-1明显抑制异丙肾上腺素诱发的豚鼠离体气管环舒张反应量效曲线,并使异丙肾上腺素的EC50明显增大(P<0.05)。R-DOX,rac-DOX和S-DOX 30μmol.L-1均不影响异丙肾上腺素的舒张反应量效曲线。结论:在豚鼠离体气管环标本S-DOX使卡巴胆碱诱发收缩反应的Emax明显增大,且明显抑制异丙肾上腺素的舒张反应。

Objective： To observe the effects of doxazosin enantiomers （R-doxazosin, S-doxazosin and rac doxazosin） on contractile and relaxant responses of the trachea rings isolated from guinea pig. Methods： Effects of doxazosin enantiomers on the resting tension, contractile response to carbachol and relaxant response to isoprenaline were observed in the tracheal rings isolated from guinea pig. Results： Doxazosin enantiomers at 10 - 30μmol·L^-1 did not affect the resting tension of trachea rings （p 〉0.05）. S-Doxazosin at 10 μmol·L^-1 significantly increased the Emax of the contractile response to carbachol （p 〈0.05） , but did not affect the EC50 of carbachol. However, R- doxazosin at 10 μmol·L^-1 significantly decreased the Emax of contractile response to carbachol （p 〈0.05） and the EC50 of carbachol. S-Doxazosin at 10 μmol·L^-1 significantly inhibited the relaxant responses to isoprenaline （p 〈 0.05） and increased the EC50 of isoprenaline. S-Doxazosin, R-doxazosin and rac-doxazosin at 30 μmol·L^-1 had no effect on the relaxant responses to isoprenaline. Conclusion： S-Doxazosin increases the Emax of the contractile response to carbachol and inhibits the relaxant responses to isoprenaline in the trachea rings isolated from guinea pig.