Smith C A, Ainsworth D M, Henderson K S, Dempsey J A
John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin, Madison.
Respir Physiol. 1990 Oct;82(1):123-36. doi: 10.1016/0034-5687(90)90029-x.
Respiratory muscle EMG responses to transient, specific carotid body excitation (NaCN, hypoxia) and inhibition (dopamine, hyperoxia) were studied in 7 unanesthetized standing dogs while intact (N = 7) and during bilateral cold block of the vagi (N = 3). In all dogs carotid body excitation augmented the EMG activities of both expiratory muscles (triangularis sterni, TS; transversus abdominis, TA) and the (inspiratory) crural diaphragm (CR); carotid body inhibition significantly reduced phasic EMG activities in all muscles. With vagal blockade the response of the TS to carotid body stimulation was increased; that of the TA was essentially unchanged from the intact state. In all dogs expiratory muscle recruitment in response to carotid body excitation/inhibition could either precede or follow that of the CR. We conclude that in response to specific, transient carotid body excitation or inhibition: (1) Changes in CR, TS and TA EMGs are qualitatively similar. (2) Vagal feedback is strongly inhibitory to TS and excitatory to TA. (3) Changes in expiratory muscle EMGs do not require preceding changes in the CR. Carotid body stimulation contributes significantly to the generation of phasic expiratory activity during eupnea.
在7只未麻醉的站立犬中，研究了呼吸肌肌电图（EMG）对短暂、特定的颈动脉体兴奋（氰化钠、低氧）和抑制（多巴胺、高氧）的反应，实验分完整状态（N = 7）和双侧迷走神经冷阻滞状态（N = 3）进行。在所有犬中，颈动脉体兴奋增强了呼气肌（胸骨三角肌，TS；腹横肌，TA）和（吸气）膈脚（CR）的EMG活动；颈动脉体抑制显著降低了所有肌肉的阶段性EMG活动。迷走神经阻滞后，TS对颈动脉体刺激的反应增强；TA的反应与完整状态基本无变化。在所有犬中，呼气肌对颈动脉体兴奋/抑制的募集反应可先于或后于CR。我们得出结论，对于特定的短暂颈动脉体兴奋或抑制：（1）CR、TS和TA的EMG变化在性质上相似。（2）迷走神经反馈对TS有强烈抑制作用，对TA有兴奋作用。（3）呼气肌EMG的变化不需要CR先发生变化。颈动脉体刺激对平静呼吸时阶段性呼气活动的产生有显著贡献。
