Saito Yoshiaki, Ezure Kazuhisa, Tanaka Ikuko
Department of Neurobiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashi-dai, Fuchu, Tokyo 183-8526, Japan.
Brain Res. 2002 Nov 29;956(2):262-7. doi: 10.1016/s0006-8993(02)03549-7.
We examined the swallowing-related intracellular activity of motoneurons of the superior laryngeal nerve (SLN) in decerebrate, paralyzed and artificially-ventilated rats, to elucidate the neuronal mechanism of the pharyngo-esophageal and laryngo-esophageal coordination during swallowing. The majority of the SLN motoneurons exhibited respiratory rhythm (n=16; 13 inspiratory, one expiratory and two non-respiratory neurons). During fictive swallowing evoked by electrical stimulation of the SLN, all these motoneurons showed a hyperpolarization-depolarization sequence in their membrane potentials. The hyperpolarization, which was shown to consist of inhibitory postsynaptic potentials, started at the onset of the hypoglossal swallowing burst, lasted during the burst, and was followed by a depolarization at the end of the burst. This hyperpolarization-depolarization pattern implies that the SLN motoneurons may be involved in the 'inhibitory chain' within the swallowing pattern generator, which may be cardinal in the sequential activation of different populations of motoneurons innervating the swallowing-related muscles.
我们研究了去大脑、瘫痪并人工通气的大鼠喉上神经（SLN）运动神经元与吞咽相关的细胞内活动，以阐明吞咽过程中咽食管和喉食管协调的神经机制。大多数SLN运动神经元表现出呼吸节律（n = 16；13个吸气神经元、1个呼气神经元和2个非呼吸神经元）。在通过电刺激SLN诱发的虚拟吞咽过程中，所有这些运动神经元的膜电位均呈现超极化 - 去极化序列。超极化由抑制性突触后电位组成，始于舌下吞咽爆发开始时，在爆发期间持续，随后在爆发结束时出现去极化。这种超极化 - 去极化模式表明，SLN运动神经元可能参与吞咽模式发生器内的“抑制链”，这可能是支配吞咽相关肌肉的不同运动神经元群体顺序激活的关键。
