We recorded membrane potential changes in 45 pharyngeal motoneurons (PMs) including 33 expiratory modulated and 12 non-respiratory neurons during breathing, swallowing, and coughing in decerebrate paralyzed cats. Four types of membrane potential changes were observed during swallowing: 1) depolarization during swallowing (n = 27), 2) depolarization preceded by a brief (≤ 0.1 s) hyperpolarization (n = 4), 3) longer term (> 0.3 s) hyperpolarization followed by depolarization (n = 11), and 4) hyperpolarization during the latter period of swallowing (n = 3). During coughing PMs showed two types of membrane potential changes (n = 10). Nine neurons exhibited a ramp-like depolarization during the expiratory phase of coughing with the potential peak at the end of expiratory phase. This depolarization was interrupted by a transient repolarization just before the potential peak. The membrane potential of the remaining neuron abruptly depolarized at the onset of the expiratory phase and then gradually decreased even after the end of the expiratory phase. Single shock stimulation of the superior laryngeal nerve (SLN) induced IPSPs in 19 of 21 PMs. Two motoneurons exhibited a SLN-induced EPSP. The present study revealed that PMs receive the central drive, consisting of a combination of excitation and inhibition, from the pattern generator circuitry of breathing, swallowing, and coughing which changes the properties of their membrane potential to generate these motor behaviors of the pharynx. Our data will provide the basis of studies of pharyngeal activity and its control from the medullary neuronal circuitry responsible for the upper airway motor activity.

中文翻译：

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呼吸、吞咽和咳嗽时咽部运动神经元的细胞内活动。

我们记录了 45 个咽部运动神经元 (PM) 的膜电位变化，其中包括 33 个呼气调节神经元和 12 个非呼吸神经元在去脑瘫猫的呼吸、吞咽和咳嗽过程中。在吞咽过程中观察到四种类型的膜电位变化：1) 吞咽过程中的去极化 (n = 27)，2) 去极化之前有短暂的 (≤ 0.1 s) 超极化 (n = 4)，3) 长期 (> 0.3 s)超极化后去极化 (n = 11), 和 4) 在吞咽后期 (n = 3) 的超极化。在咳嗽期间，PM 显示出两种类型的膜电位变化（n = 10）。九个神经元在咳嗽的呼气阶段表现出斜坡状去极化，在呼气阶段结束时出现电位峰值。就在电位峰值之前，这种去极化被瞬态复极化中断。剩余神经元的膜电位在呼气阶段开始时突然去极化，然后甚至在呼气阶段结束后逐渐降低。在 21 名 PM 中的 19 名中，对喉上神经 (SLN) 进行单次电击刺激诱发 IPSP。两个运动神经元表现出 SLN 诱导的 EPSP。目前的研究表明，PMs 从呼吸、吞咽和咳嗽的模式发生器电路接收中枢驱动，包括兴奋和抑制的组合，这改变了它们的膜电位特性，以产生这些咽部的运动行为。