Ryan Stephen, McNicholas Walter T, O'Regan Ronan G, Nolan Philip
Departments of Human Anatomy and Physiology, Conway Institute for Biomolecular and Biomedical Research, University College, and Respiratory Sleep Disorders Unit, St. Vincent's University Hospital, Dublin 2, Ireland.
J Appl Physiol (1985). 2003 Apr;94(4):1307-16. doi: 10.1152/japplphysiol.00052.2002. Epub 2002 Dec 20.
The reflex upper airway (UA) motor response to UA negative pressure (UANP) is attenuated by neuromuscular blockade. We hypothesized that this is due to a reduction in the sensitivity of laryngeal mechanoreceptors to changes in UA pressure. We examined the effect of neuromuscular blockade on hypoglossal motor responses to UANP and to asphyxia in 15 anesthetized, thoracotomized, artificially ventilated rats. The activity of laryngeal mechanoreceptors is influenced by contractions of laryngeal and tongue muscles, so we studied the effect of selective denervation of these muscle groups on the UA motor response to UANP and to asphyxia, recording from the pharyngeal branch of the glossopharyngeal nerve (n = 11). We also examined the effect of tongue and laryngeal muscle denervation on superior laryngeal nerve (SLN) afferent activity at different airway transmural pressures (n = 6). Neuromuscular blockade and denervation of laryngeal and tongue muscles significantly reduced baseline UA motor nerve activity (P < 0.05), caused a small but significant attenuation of the motor response to asphyxia, and markedly attenuated the response to UANP. Motor denervation of tongue and laryngeal muscles significantly decreased SLN afferent activity and altered the response to UANP. We conclude that skeletal muscle relaxation reduces the reflex UA motor response to UANP, and this may be due to a reduction in the excitability of UA motor systems as well as a decrease of the response of SLN afferents to UANP.
上呼吸道（UA）对UA负压（UANP）的反射性运动反应会因神经肌肉阻滞而减弱。我们推测这是由于喉机械感受器对UA压力变化的敏感性降低所致。我们研究了神经肌肉阻滞对15只麻醉、开胸、人工通气大鼠舌下运动对UANP和窒息反应的影响。喉机械感受器的活动受喉和舌肌收缩的影响，因此我们通过记录舌咽神经咽支（n = 11），研究了这些肌肉群选择性去神经支配对UA对UANP和窒息反应的运动反应的影响。我们还研究了舌和喉肌去神经支配对不同气道跨壁压力下喉上神经（SLN）传入活动的影响（n = 6）。神经肌肉阻滞以及喉和舌肌去神经支配显著降低了UA运动神经的基线活动（P < 0.05），导致对窒息的运动反应有轻微但显著的减弱，并显著减弱了对UANP的反应。舌和喉肌的运动去神经支配显著降低了SLN传入活动，并改变了对UANP的反应。我们得出结论，骨骼肌松弛会降低UA对UANP的反射性运动反应，这可能是由于UA运动系统兴奋性降低以及SLN传入纤维对UANP的反应减弱所致。
