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目的:探讨不同时段低氧对苯肾上腺素(phenylephrine,PE)诱导的豚鼠肠系膜动脉收缩反应的影响及其作用机制。方法:应用压力肌动图技术,在急性分离的豚鼠肠系膜动脉2级血管(直径300~400μm)上,观察20、40和60 min低氧(95%CO2和5%O2混合)对内皮非依赖的血管收缩剂PE收缩血管直径的影响。结果:PE(0.1~100μmol/L)可以浓度依赖性收缩豚鼠肠系膜动脉。低氧引起生理盐溶液p H值从7.4下降到6.3。低氧能显著抑制PE引起的血管收缩幅度,用正常生理盐溶液洗脱20 min此抑制作用仍难以恢复。低氧抑制PE引起的肠系膜动脉的收缩反应具有时间依赖性,抑制程度依次为低氧60 min>40min>20 min。将生理盐溶液p H降低至6.3也可抑制PE对血管收缩的作用。结论 :低氧能够时间依赖性地抑制PE对豚鼠肠系膜动脉的收缩作用,其作用机制可能与p H的下降有关。
Objective: To investigate the effect and mechanism of hypoxia on the contractile response of mesenteric artery induced by phenylephrine (PE) in guinea pigs at different time points. Methods: The effects of hypoxia (mixed with 95% CO2 and 5% O2) at 20, 40 and 60 min on the endothelium independent of the endothelium were observed in acutely isolated guinea pig mesenteric arterial grade 2 vessels (300-400 μm in diameter) The effect of vasoconstrictor on contractile blood vessel diameter. Results: PE (0.1 ~ 100μmol / L) could constrict guinea pig mesenteric artery in a concentration - dependent manner. Hypoxia caused physiological saline solution p H value decreased from 7.4 to 6.3. Hypoxia can significantly inhibit the vasoconstriction induced by PE, which is still difficult to recover with normal physiological saline solution for 20 min. Hypoxia inhibited the contraction of mesenteric artery induced by PE in a time-dependent manner, followed by hypoxia 60 min> 40 min> 20 min. Reducing p H in physiological saline to 6.3 also inhibited the effect of PE on vasoconstriction. CONCLUSION: Hypoxia can inhibit the contraction of mesenteric artery in guinea pigs in a time-dependent manner, which may be related to the decrease of p H.