Orderly recruitment of trigeminal motor neurons in response to selective activation of synaptic inputs by optical stimulation

2014 Fiscal Year Final Research Report

• Project/Area Number: 24659825
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Functional basic dentistry
• Research Institution: Osaka University
• Principal Investigator: KANG Youngnam 大阪大学, 歯学研究科(研究院), 教授 (50177755)
• Co-Investigator(Kenkyū-buntansha): SATO Hajime 大阪大学, 大学院歯学研究科, 助教 (10432452) ; SAITO Mitsuru 大阪大学, 大学院歯学研究科, 講師 (50347770)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: サイズの原理 / 序列動員 / 等尺性収縮 / 運動ニューロン / 入力抵抗 / Ia感覚神経入力 / TASK / 一酸化窒素

Outline of Final Research Achievements

Taking advantage of the synaptic nature that Group Ia inputs onto αMNs in JCMN display frequency facilitation, we demonstrated the orderly recruitment of αMNs in response to conventional electrical stimulation of Ia inputs using dual whole cell recordings and voltage-sensitive dye imaging methods. Since the orderly recruitment of motor units occurs depending on the soma size of αMNs, we next examined the size distribution of jaw-closing MNs in the rat after identifying αMN and γMN by the expressions of orphan nuclear hormone receptor Err3 and neuronal DNA binding protein NeuN. The size distribution of jaw-closing αMNs was bimodal, revealing the presence of many αMNs as small as γMNs. Furthermore, based on the electrophysiological membrane properties, jaw-closing αMNs were divided into two subtypes; larger and smaller αMNs showing A-type K+ current and LTS Ca2+ spike, respectively, and γMNs were identified as displaying a characteristic pulse afterdepolarization.

Free Research Field

神経生理学・口腔生理学