2 0 0 0 覚醒ウサギにおける咀嚼時開口反射の変調様式
- 著者
- ラーマン ムスタフィジュー 山村 健介 井上 誠 黒瀬 雅之 山田 好秋
- 出版者
- 日本生理学会
- 雑誌
- 日本生理学会大会発表要旨集
- 巻号頁・発行日
- vol.2005, pp.S172, 2005
Previous studies have shown that the jaw-opening reflex (JOR) is modulated during mastication. However in these studies, analyses have been carried out for limited period within the masticatory sequence (i.e. from food intake to just before swallow). Our aim is to study if the modulatory pattern of the JOR is consistent throughout the masticatory sequence in awake rabbits. The masticatory sequence was divided into three masticatory periods (preparatory, rhythmic-chewing and preswallow periods) based on the jaw movement patterns and the activity pattern of the jaw muscles. Electromyographic activity of the jaw-opening muscle (Digastric) and the jaw movement trajectories were recorded. Repetitive electrical stimulation (single pulse, 0.2 ms duration at a rate of 1 Hz, 1.2 times the threshold) of the inferior alveolar nerve was conducted before (for control response) and during mastication to evoke the JOR. The amplitude of the JOR was normalized to the control response and the modulatory pattern of the JOR was compared among the masticatory periods. The JOR was generally suppressed during the rhythmic-chewing and the preswallow periods; the suppressive effect was phasically weakened in the middle part of the jaw opening during the rhythmic-chewing period. On the other hand, the reflex was not only suppressed but also facilitated during the preparatory period. The results suggest that the modulatory pattern of the jaw-opening reflex is different among the masticatory periods. <b>[Jpn J Physiol 55 Suppl:S172 (2005)]</b>
1 0 0 0 OA ストレスが顎関節痛を増強させる脳神経メカニズム
心理ストレスは歯科領域での痛みを増大させる。本課題ではストレスが咬筋の痛みを増大させる生体機構を、脳神経系の機能変化と想定し、基礎的に解明した。三叉神経脊髄路核尾側亜核(Vc)に着目した。これまでの研究によってVc部は顎顔面部の痛みの応答を制御する部位であることが解明されているからである。繰り返しストレス処置を加えると、咬筋への侵害刺激による Vcの興奮性は有意に増大することが明らかになった。さらに選択的セロトニン再取り込み阻害剤を繰り返し投与するとストレスによるVcの興奮性の増大は低下することがわかった。つまりストレスによるセロトニン機構の変調が咬筋の痛みを増大させることがわかった。