多巴胺对急性间歇性低氧诱导的大鼠颈动脉体低氧敏感性的影响*

目的: 观察急性间歇性低氧刺激后大鼠颈动脉体对低氧的敏感性以及多巴胺对颈动脉体低氧敏感性的影响。方法: 将分离SD大鼠的颈动脉体-窦神经移入到孵育槽,然后把分离的窦神经吸入到记录的玻璃电极中行电信号记录。记录基线部分缓冲液充入气体为95% O₂+ 5% CO₂混合气,低氧应激给予5% O₂+ 5% CO₂+ 90% N₂混合气,低氧刺激给予30 s,95% O₂ + 5% CO₂给予90 s,共10个循环,每组实验大鼠数量n大于等于5。结果: 大鼠离体的颈动脉体,给予急性间歇性低氧应激,再给予低氧刺激,窦神经较之前低氧刺激放电活动增强。但加入多巴胺后,可以抑制窦神经对低氧的反应,急性间歇性低氧后,多巴胺对窦神经的低氧放电活动抑制作用加强。结论: 大鼠颈动脉体给予急性间歇性低氧可增强窦神经对低氧的反应,多巴胺可抑制急性低氧诱导的颈动脉体对低氧敏感性的增强。

Effect of dopamine on the sensitivity of carotid body to hypoxia induced by acute intermittent hypoxia in rats

Objective: To investigate the sensitivity of carotid body to hypoxia and the effect of dopamine on the sensitivity of carotid body to hypoxia after acute intermittent hypoxia stimulation in rats. Methods: The isolated carotid body-sinus nerve in rat was transferred to incubator, and then the isolated sinus nerve was inhaled into the recorded glass electrode for recording electrical signals. The baseline buffer was bubbled with 95% O ₂ + 5% CO ₂ mixture gas, and the hypoxic stress was treated with 5% O ₂ + 5% CO ₂ + 90% N₂ mixture gas, hypoxic stimulation was given for 30 seconds, 95% O ₂ + 5% CO ₂ for 90 seconds, a total of 10 cycles. No less than 5 rats in each group. Results: In this experiment, the electrical activity of sinus nerve isolated from rats was enhanced by hypoxia stimulation after acute intermittent hypoxia, but the response of sinus nerve to hypoxia was inhibited by dopamine. Before acute intermittent hypoxic stress, dopamine also inhibited the firing activity of sinus nerve, but after acute intermittent hypoxic cycle, the inhibition of dopamine on the firing activity of sinus nerve was strengthened. Conclusion: Acute intermittent hypoxia enhances the response of sinus nerve isolated from rats to hypoxia, dopamine inhibits the enhancement of carotid body sensitivity to hypoxia induced by acute intermittent hypoxic.