Identification of the medullary swallowing regions in the rat
Identification of the medullary swallowing regions in the rat
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DOI：
10.1007/bf00236530
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发表时间：
2004
影响因子：
2
通讯作者：
J. Kessler;A. Jean
中科院分区：
文献类型：
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作者：
J. Kessler;A. Jean
本研究的目的是确定参与大鼠吞咽反射组织的中心结构。使用同心双极电极，系统地探索延髓和脑桥，以确定哪些中心区域通过诱导吞咽对刺激做出反应。这些区域位于延髓背侧，是孤束、孤束核（NST）和邻近的网状结构。刺激腹侧脑桥髓质区域对于吞咽反射的启动是无效的。使用细胞外微电极记录髓质吞咽神经元的活动。这些吞咽神经元以一阵尖峰反应（吞咽活动），这与刺激上喉神经（SLN）引起的吞咽反射密切相关。在 SLN 刺激下，一些吞咽神经元的活动在短暂的潜伏期后还显示出由 1 或 2 个尖峰组成的初始反应。根据吞咽神经元的位置和初始反应的潜伏期，吞咽神经元被分为两组。 I 组神经元位于延髓的背侧区域，对应于 NST 和相邻的网状结构。所有这些神经元都表现出具有非常短的潜伏期（1至4毫秒）的初始反应，大多数这些神经元的吞咽活动在吞咽运动序列开始之前就开始了。 II组神经元位于对应于疑核和周围网状结构的腹侧区域，或者位于对应于舌下核及其附近的背侧和内侧区域。其中一些神经元还表现出对 SLN 刺激的初始反应，但潜伏期较长（7-12 毫秒）。动物的运动麻痹（通过注射箭毒进行）并不影响属于任一组的神经元的吞咽活动。因此，所研究的髓质神经元的吞咽活动是真正的中枢活动。结论：所研究的吞咽神经元属于延髓吞咽中枢； II组神经元是形成吞咽中枢传出阶段的运动神经元和中间神经元，I组神经元是主要属于吞咽运动序列编程的中枢的中间神经元。
The aim of the present study was to identify the central structures involved in the organization of the swallowing reflex in the rat. Using concentric bipolar electrodes, the medulla and pons were systematically explored in order to determine which central areas responded to stimulation by inducing swallowing. These areas, which were located in the dorsal medulla oblongata, were the solitary tract, the nucleus of the solitary tract (NST) and the adjacent reticular formation. Stimulation of the ventral ponto-medullary regions was ineffective with regard to the initiation of the swallowing reflex. The activity of medullary swallowing neurons was recorded using extracellular microelectrodes. These swallowing neurons responded with a burst of spikes (swallowing activity) which was closely linked to the swallowing reflex elicited by stimulation of the superior laryngeal nerve (SLN). Under SLN stimulation, the activity of some of the swallowing neurons furthermore showed an initial response consisting of 1 or 2 spikes after a brief latency. According to their location and the latency of their initial response, swallowing neurons were divided into two groups. Group I neurons were located in a dorsal area of the medulla oblongata corresponding to the NST and the adjacent reticular formation. All these neurons exhibited an initial response with a very short latency (1 to 4 ms), the swallowing activity of most of these neurons started before the onset of the swallowing motor sequence. Group II neurons were located either in a ventral area corresponding to the nucleus ambiguus and the surrounding reticular formation or in a dorsal and medial area corresponding to the hypoglossal nucleus and its vicinity. Some of these neurons also exhibited an initial response to SLN stimulation, but with a longer latency (7–12 ms). Motor paralysis of the animal (performed by curare injection) did not affect the swallowing activity of the neurons belonging to either group. Thus, the swallowing activity of the medullary neurons studied was a truly central activity. It is concluded that the swallowing neurons studied belonged to the medullary swallowing center; the group II neurons were motoneurons and interneurons forming the efferent stage of the swallowing center, and the group I neurons were the interneurons which largely belong to the center which programs the swallowing motor sequence.