Breathing and control of upper airway

为探讨呼吸控制与上呼吸道控制的相关性，在麻醉犬上进行了以下研究：1)分级吸气负荷、高氧性高碳酸血症和正常低氧血症时的压力-流量关系；2)研究电刺激腓肠肌对环鳗后肌和鼻翼肌电的反应；3)电刺激颧舌肌对上呼吸道阻力的影响。我们发现：1)压力-流量关系随着吸气负荷、高碳酸血症和低氧程度的增加而上移；2)电刺激完整神经对腓肠肌的刺激开始时，环鹭肌电和鼻翼肌电的反应迅速增加，这种反应被周围神经断端刺激腓肠肌所消除；3)上呼吸道阻力随刺激频率的增加而降低，尤其是在20~50赫兹之间迅速降低。这些结果表明，呼吸和非呼吸肌和/或体液刺激的神经刺激激活了呼吸控制器，从而影响了上呼吸道的通畅，舌骨肌本身的张力对维持上呼吸道的通畅是重要的。

To examine the correlation between control of breathing and control of upper airway, the following studies were undertaken in anesthetized dogs: 1) pressure-flow relationship were obtained during graded inspiratory loading, hyperoxic hypercapnia and normocapnic hypoxemia, 2) responses of electromyogram of posterior cricoarytenoid muscle and alae nasi to electrical stimulation of gastrocnemius were studied, and 3) effects of electrical stimulation of genioglossue muscle on upper airway resistance were studied. We found that 1) pressure-flow relationship shifted upwards with increase in inspiratory loading, hypercapnia and hypoxia, 2) response of cricoarytenoid EMG and alae nasi EMG increased repidly at onset of electrical stimulation of the intact nerve to gastrocnemius, and this response was disappeared by stimulation of peripheral cut end of the nerve to gastrocnemius, and 3) Upper airway resistance decreased with stimulation-frequency dependency, particulary repidly decreased between 20-50 Hz. These findings suggest that upper airway patency was affected by activation of respiratory controller due to neural stimule from respiratory and non-respiratory muscles and/or humoral stimuli, and tone of genioglossus muscle itself would be important to maintain upper airway patency.