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Analysis of neural mechanisms of transformation from sucking to mastication in in vitro brain preparations.

体外脑制剂中从吸吮到咀嚼转变的神经机制分析。

基本信息

批准号：
11671837
负责人：
KATAKURA Nobuo
金额：
$ 2.24万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11671837/
关键词：
sucking mastication mice isolated brain preparation NMDA rhythm generation hypoglossal nerve trigeminal nerve 摘出脳幹標本リズム活動

项目摘要

Feeding behavior of mammals changes from sucking to mastication, coinciding with the teeth eruption. In adult mammals, it is thought that the neurons involved in the rhythm generation of mastication locate in the lower brainstem and distributed along rostro-caudal axis. The purpose of this study was to investigate the neural organization of the rhythm generation of sucking in in vitro preprarations. Rhythmical sucking-like activity (RSA) is known to be induced in the hypoglossal nerve (XIIn) in an isolated brainstem-spinal cord preparation from newborn rats with bath application of N-methyl-D-aspartate (NMDA). Since natural sucking consists of well-coordinated rhythmical activities of the tongue, face, and jaw muscles, it is assumed that the trigeminal (V) and facial (VII) motoneurons would show rhythmical activities during the RSA.In this study, I tried (1 ) to induce rhythmical activities in these nerves during NMDA application, and (2) if they are induced, to locate the structures essential for generation of the NMDA-induced rhythmical activities. Experiments were performed on brainstem-spinal cord preparations isolated from newborn mice with or without the orofacial structure. Neural activities were recorded from each nerve with suction electrodes. Movements of the tongue and jaw were recorded with a CCD camera system. It was found that (1) bath application of NMDA induced RSA in the V, VII, and XII ns, (2) it also induced rhythmical sucking-like movements of the jaw and tongue, and (3) after complete transections of the brainstem between the V and VII ns as well as the pontomedullary junction, NMDA still induced the RSA in the V, VII, and XII ns, These results demonstrate that separate rhythm generators for the NMDA-induced activities are located at the respective levels in the brainstem, and that the reorganization of the CPG(s) itself would be necessary for the conversion from sucking to mastication.

哺乳动物的摄食行为从吸吮转变为咀嚼，与牙齿的长出相一致。在成年哺乳动物中，参与咀嚼节律产生的神经元被认为位于脑干下部，沿头尾轴分布。本研究的目的是探讨体外制剂中吸吮节律产生的神经组织。已知n -甲基- d -天冬氨酸（NMDA）在新生大鼠离体脑干-脊髓制备中诱导舌下神经（XIIn）的节律性吮吸样活动（RSA）。由于自然吸吮由舌头、面部和下颌肌肉协调良好的有节奏的活动组成，我们假设三叉神经(V)和面部（VII）运动神经元在RSA过程中会表现出有节奏的活动。在本研究中，我尝试(1)在NMDA应用期间诱导这些神经的节律性活动，(2)如果它们被诱导，则定位NMDA诱导的节律性活动产生所必需的结构。实验对新生小鼠的脑干-脊髓制备进行了分离，并对有无颅面结构进行了实验。用吸电极记录各神经的神经活动。用CCD相机系统记录舌头和下巴的运动。发现(1)浴应用V, NMDA诱导RSA的七世,和十二ns,(2)它还诱导有节奏的sucking-like下颚和舌头的运动,和(3)之间的完全横断脑干V和七ns以及pontomedullary结,仍然NMDA诱导的RSA V,七世,和十二ns,这些结果说明单独的节奏发电机NMDA-induced活动位于脑干的各自的水平,CPG(s)本身的重组对于从吸吮到咀嚼的转变是必要的。