Jammes Y, Nail B, Mei N, Grimaud C
Respir Physiol. 1987 Mar;67(3):379-89. doi: 10.1016/0034-5687(87)90067-3.
In anesthetized cats, sensory neurons in the superior laryngeal nerves (SLN) were identified with respect to their response to (1) phenyldiguanide (PDG) i.v., (2) mechanical stimulation and (3) lowering temperature in an isolated tracheolaryngeal segment. The activity originating from 107 SLN afferent units activated by PDG was recorded using glass microelectrodes advanced in the nodose ganglion. All tested afferent units increased their discharge rate during direct touching of the airway mucosa. None showed flow or pressure related activity during abrupt changes in constant laryngeal flow or transmural pressure in the isolated segment. Fifteen units were inhibited by cold air. Sixty-two units significantly increased their firing rate when the temperature approached 18 degrees C, reached a peak discharge near 15 degrees C, then their activity decreased or stopped. The response to cold air was compared to cold heliox (79% He-21% O2), which enhanced the respiratory heat loss by conduction. The peak firing rate was significantly higher with heliox (+356% compared to +246% with air), the temperature threshold higher (25 degrees C +/- 1.0 degree C) and the temperature range broader (25-11.5 degrees C). Present results show that a large proportion (58%) of afferent SLN fibres activated by PDG are likely non-proprioceptive units, which are stimulated by cooling the inspired gas. Thermosensitive units in the upper airways may act as sensors of the thermal flux through the airway wall more than as detectors of the absolute value of temperature in the airway lumen.
在麻醉猫中，通过观察其对以下刺激的反应来鉴定喉上神经（SLN）中的感觉神经元：（1）静脉注射苯双胍（PDG）；（2）机械刺激；（3）在离体气管喉部节段中降低温度。使用插入结状神经节的玻璃微电极记录了由PDG激活的107个SLN传入单位的活动。所有测试的传入单位在直接接触气道黏膜时放电率均增加。在离体节段中，当恒定的喉部气流或跨壁压力突然变化时，没有单位显示出与气流或压力相关的活动。15个单位受到冷空气抑制。当温度接近18℃时，62个单位的放电率显著增加，在接近15℃时达到放电峰值，然后其活动降低或停止。将对冷空气的反应与冷氦氧混合气（79%氦-21%氧）进行比较，冷氦氧混合气通过传导增强了呼吸热损失。使用氦氧混合气时的峰值放电率显著更高（与空气相比为+356%，而空气为+246%），温度阈值更高（25℃±1.0℃），温度范围更宽（25 - 11.5℃）。目前的结果表明，由PDG激活的大部分（58%）传入SLN纤维可能是非本体感受单位，它们受到吸入气体冷却的刺激。上呼吸道中的热敏单位可能更多地作为气道壁热通量的传感器，而不是气道腔内温度绝对值的探测器。
