Mitsuhashi T
Department of Otorhinolaryngology and Physiology, School of Medicine, Chiba University.
Nihon Jibiinkoka Gakkai Kaiho. 1990 Jul;93(7):1020-33. doi: 10.3950/jibiinkoka.93.1020.
It is generally considered that the vocal cord is finely and reflexively controlled during phonation. In order to investigate the effect of vibratory stimulation of the subglottis on laryngeal reflex, experiments have been performed using cats' larynx under urethane-chloralose general anesthesia. The effect of vibration was estimated by the latency and the area of integrated EMG of the reflex. The glottic closure reflex was induced by electrical stimulation of the internal branch of the superior laryngeal nerve (ISLN) and electromyogram was recorded from contralateral Thyroarytenoid muscle (TA). When ISLN was stimulated, short latency response (early response) and long latency response (late response) in TA was observed. Maximum responses were obtained during the transitional phase, namely, from inspiration to expiration, especially before the denervation of ISLN from the larynx. This phase was tentatively designated as "phase I", being followed by "phase II", the phase prior to "phase I", as "phase III". Vibratory stimulation (100 or 200Hz, 40 microns), applied to the contralateral subglottic portion as a conditioning stimulation, had no effect on early response but enhanced late response, particularly in phase I. After denervation of ISLN, the vibratory effect on late response became phase independent. Furthermore, when the vibratory frequency was elevated from 100Hz to 350Hz at 50Hz interval in phase I, vibration effect was observed in all frequencies investigated. Maximum effect was obtained at 300Hz. However, after denervation of ISLN, this effect was minimized, and no peak observed. The vibratory effects disappeared soon after local anesthesia of the subglottic mucosa. These results suggest that the activity of the mechanoreceptors to vibration in the subglottic mucosa enhances reflexive contraction of the contralateral TA primarily via the recurrent laryngeal nerve and partially via ISLN, both of which are indispensable for reflexive laryngeal control. It is conceivable that early response is one of the primitive reflexes for the protection of the lower airway, and late response is a sort of more evolved reflexes involved in vibration and respiration during phonation.
一般认为，发声时声带受到精细且反射性的控制。为了研究声门下振动刺激对喉反射的影响，在氨基甲酸乙酯 - 氯醛糖全身麻醉下，使用猫的喉部进行了实验。通过反射的潜伏期和肌电图积分面积来评估振动的效果。通过刺激喉上神经内支（ISLN）诱发声门闭合反射，并记录对侧甲杓肌（TA）的肌电图。当刺激ISLN时，在TA中观察到短潜伏期反应（早期反应）和长潜伏期反应（晚期反应）。在过渡阶段，即从吸气到呼气期间，尤其是在ISLN从喉部去神经支配之前，可获得最大反应。此阶段暂定为“阶段I”，其之前的阶段“阶段II”，之后的阶段“阶段III”。作为条件刺激施加于对侧声门下部分的振动刺激（100或200Hz，40微米），对早期反应无影响，但增强了晚期反应，特别是在阶段I。ISLN去神经支配后，对晚期反应的振动效应变得与阶段无关。此外，当在阶段I中将振动频率以50Hz的间隔从100Hz提高到350Hz时，在所研究的所有频率中均观察到振动效应。在300Hz时获得最大效应。然而，ISLN去神经支配后，这种效应最小化，且未观察到峰值。声门下黏膜局部麻醉后，振动效应很快消失。这些结果表明，声门下黏膜中对振动的机械感受器的活动主要通过喉返神经并部分通过ISLN增强对侧TA的反射性收缩，这两者对于喉反射控制都是不可或缺的。可以想象，早期反应是保护下呼吸道的原始反射之一，而晚期反应是一种在发声过程中参与振动和呼吸的更进化的反射。
