Saito Yoshiaki, Ezure Kazuhisa, Tanaka Ikuko
Department of Neurobiology, Tokyo Metropolitan Institute for Neuroscience, Tokyo Women's Medical University, Japan.
J Physiol. 2002 May 1;540(Pt 3):1047-60. doi: 10.1113/jphysiol.2001.014985.
Swallowing-related activity was examined in respiratory (n = 60) and non-respiratory (n = 82) neurons that were located in and around the nucleus of the solitary tract (NTS) in decerebrated, neuromuscularly blocked and artificially ventilated rats. Neurons that were orthodromically activated by electrical stimulation of the superior laryngeal nerve (SLN) were identified, and fictive swallowing was evoked by SLN stimulation. The pharyngeal phase of swallowing was monitored by hypoglossal nerve activity. Two types of non-respiratory neurons with swallowing-related bursts were identified: 'early' swallowing neurons (n = 24) fired during periods of hypoglossal bursts, and 'late' swallowing neurons (n = 8) fired after the end of hypoglossal bursts. The remaining non-respiratory neurons were either suppressed (n = 21) or showed no change in activity (n = 29) during swallowing. On the other hand, respiratory neurons with SLN inputs included 56 inspiratory and four expiratory neurons. Inspiratory neurons were classified into two major types: a group of neurons discharged simultaneously with hypoglossal bursts (type 1 neurons, n = 19), while others were silent during bursts but were active during inter-hypoglossal bursts when swallowing was provoked repetitively (type 2 neurons, n = 34). Three of the expiratory neurons fired during hypoglossal bursts. Many of the swallowing-related non-respiratory neurons and the majority of the inspiratory neurons received presumed monosynaptic inputs from the SLN. Details of the distribution and firing patterns of these NTS neurons, which have been revealed for the first time in a fictive swallowing preparation in the rat, suggest their participation in the initiation, pattern formation and mutual inhibition between swallowing and respiration.
在去大脑、神经肌肉阻断并人工通气的大鼠中，对位于孤束核（NTS）及其周围的呼吸性神经元（n = 60）和非呼吸性神经元（n = 82）的吞咽相关活动进行了研究。通过电刺激喉上神经（SLN）逆向激活神经元，并通过SLN刺激诱发假吞咽。通过舌下神经活动监测吞咽的咽部阶段。识别出两种具有吞咽相关爆发的非呼吸性神经元：“早期”吞咽神经元（n = 24）在舌下爆发期间放电，“晚期”吞咽神经元（n = 8）在舌下爆发结束后放电。其余非呼吸性神经元在吞咽期间要么被抑制（n = 21），要么活动无变化（n = 29）。另一方面，具有SLN输入的呼吸性神经元包括56个吸气神经元和4个呼气神经元。吸气神经元分为两大类：一组神经元与舌下爆发同时放电（1型神经元，n = 19），而其他神经元在爆发期间沉默，但在反复诱发吞咽时的舌下爆发间期活跃（2型神经元，n = 34）。3个呼气神经元在舌下爆发期间放电。许多吞咽相关的非呼吸性神经元和大多数吸气神经元接受来自SLN的推测单突触输入。这些NTS神经元的分布和放电模式细节首次在大鼠假吞咽实验中揭示，表明它们参与吞咽和呼吸之间的启动、模式形成和相互抑制。
