Brennick M J, Trouard T P, Gmitro A F, Fregosi R F
Department of Physiology, The University of Arizona, Tucson 85721-0093, Arizona, USA.
J Appl Physiol (1985). 2001 Apr;90(4):1373-84. doi: 10.1152/jappl.2001.90.4.1373.
The medial branch (Med) of the hypoglossal nerve innervates the tongue protrudor muscles, whereas the lateral branch (Lat) innervates tongue retractor muscles. Our previous finding that pharyngeal airflow increased during either selective Med stimulation or whole hypoglossal nerve (WHL) stimulation (coactivation of protrudor and retractor muscles) led us to examine how WHL, Med, or Lat stimulation affected tongue movements and nasopharyngeal (NP) and oropharyngeal (OP) airway volume. Electrical stimulation of either WHL, Med, or Lat nerves was performed in anesthetized, tracheotomized rats while magnetic resonance images of the NP and OP were acquired (slice thickness 0.5 mm, in-plane resolution 0.25 mm). NP and OP volume was greater during WHL and Med stimulation vs. no stimulation (P < 0.05). Ventral tongue depression (measured in the midsagittal images) and OP volume were greater during Med stimulation than during WHL stimulation (P < 0.05). Lat stimulation did not alter NP volume (P = 0.39). Our finding that either WHL or Med stimulation dilates the NP and OP airways sheds new light on the control of pharyngeal airway caliber by extrinsic tongue muscles and may lead to new treatments for patients with obstructive sleep apnea.
舌下神经的内侧支（Med）支配舌伸出肌，而外侧支（Lat）支配舌回缩肌。我们之前的研究发现，在选择性内侧支刺激或整个舌下神经（WHL）刺激（伸出肌和回缩肌共同激活）期间，咽部气流会增加，这促使我们研究WHL、Med或Lat刺激如何影响舌运动以及鼻咽（NP）和口咽（OP）气道容积。在麻醉、气管切开的大鼠中对WHL、Med或Lat神经进行电刺激，同时获取NP和OP的磁共振图像（切片厚度0.5毫米，平面分辨率0.25毫米）。与无刺激相比，WHL和Med刺激期间NP和OP容积更大（P < 0.05）。内侧支刺激期间腹侧舌压低（在矢状面图像中测量）和OP容积比WHL刺激期间更大（P < 0.05）。外侧支刺激未改变NP容积（P = 0.39）。我们发现WHL或Med刺激均可扩张NP和OP气道，这为外在舌肌对咽部气道管径的控制提供了新的见解，并可能为阻塞性睡眠呼吸暂停患者带来新的治疗方法。
