Breathing and control of upper airway

为了检查呼吸控制和上气道控制之间的相关性，在麻醉犬中进行了以下研究：1）在分级吸气负荷、高氧高碳酸血症和正常碳酸血症低氧状态下，获得压力-流量关系; 2）研究环杓后肌和鼻翼肌对腓肠肌电刺激的肌电图反应，（3）研究电刺激颏舌肌对上气道阻力的影响。结果发现：（1）压力-流量关系随吸气负荷、高碳酸血症和缺氧的增加而上移;（2）电刺激腓肠肌环杓肌神经和鼻翼肌肌电反应迅速增强，刺激腓肠肌环杓肌神经和鼻翼肌肌电反应消失;（3）上气道阻力随电刺激频率的增加而降低。在20-50 Hz之间下降尤其迅速。这些结果表明，上气道通畅性受到呼吸和非呼吸肌和/或体液刺激引起的呼吸控制器激活的影响，颏舌肌本身的张力对维持上气道通畅性很重要。

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.