Physiological study of effects of occlusal function on head posture and autonomic function

首先，研究了与咀嚼运动相关的节律性头部运动及其神经肌肉控制机制。在清醒的自由咀嚼过程中，记录了头部运动和颈部肌肉(胸锁乳突肌和头半棘肌)的肌电活动。兔子周期性地移动头部，并具有与咀嚼下颌运动相同的节奏特征，但方向相反。头屈肌(SM)在闭合期和开口期分别呈现双相活动。头部伸肌(SS)呈强直性活动。在头部固定的麻醉动物上，记录皮质诱发的节律性下颌运动时的SM和SS肌电活动。SM只有在闭口期才活跃，牙齿接触可增强SM的活性。无论牙齿接触与否，SS在音调上都很活跃。这些结果提示，头部屈肌可能通过反射作用参与牙齿负荷后的头部运动，头部伸肌可能在紧张性活动中起固定头部的作用。其次，在麻醉大鼠上观察了牙周力感受器和合口肌的肌梭传入信号对肾上腺神经活动的影响。对上切牙施加压力刺激后，肾上腺神经活动增加。被动张口时，肾上腺神经活动无明显变化。在皮质诱发的有节奏的下巴运动中，在相对的门牙之间放置一根木棍，显著地促进了神经的发育。活动。切断牙周韧带后，未观察到使用木棍对肾上腺神经活动的促进作用。这些结果表明，来自牙周机械感受器的传入信号促进肾上腺神经的活动，而来自肌梭的信号不影响该活动。

Firstly, rhythmical head movements associated with the masticatory movement and its neuromuscular control mechanism were investigated in rabbits. Head movements and EMG activities of neck muscles (sternomastoid, SM ; and semispinalis capitis, SS) were recorded in awake unrestrained rabbits during chewing. The rabbits moved their heads cyclically and with the same rhythmical characteristics of the masticatory jaw movement but in the opposite direction. The SM (head flexor muscle) showed biphasic activities in the jaw closing and opening phases respectively. The SS (head extensor muscles) were tonically active. The SM and SS EMG activities were recorded during cortically evoked rhythmical jaw movements in anesthetized animals with the head fixed. The SM was active only in the jaw closing phase, the activity was enhanced by tooth contact. The SS was tonically active regardless of tooth contact. These results suggest that the head flexor muscle may contribute to the head movement after loading the tooth by reflex action, and the head extensor muscles may play a role on fixing the head with tonic activity.Secondary, the effects of afferent signals from the periodontal mechanoreceptors and muscle spindles of jaw-closing muscles on adrenal nerve activity were examined using anesthetized rats. The activity of adrenal nerve increased when pressure stimulation was applied to the upper incisors. When the jaw was opened passively, there was no significant change in the adrenal nerve activity. Placing a wooden-stick between the opposing incisors during cortically evoked rhythmical jaw movements markedly facilitated the nerve. activity. After denervation of the periodontal ligament, the facilitation of adrenal nerve activity due to application of the wooden-stick was not observed. These results indicate that afferent signals from periodontal mechanoreceptors facilitate adrenal nerve activity and that signals from muscle spindles do not affect the activity.