Torisu Tetsurou, Wang Kelun, Svensson Peter, De Laat Antoon, Fujii Hiroyuki, Arendt-Nielsen Lars
Center for Sensory-Motor Interaction, Laboratory for Human Experimental Pain Research, Aalborg University, Fredrik Bajers Vej 7 D-3, 9220 Aalborg, Denmark.
Exp Brain Res. 2006 Oct;174(3):566-74. doi: 10.1007/s00221-006-0497-4. Epub 2006 May 6.
The purpose of this study was to investigate the effects of jaw-muscle fatigue evoked by low-level tooth-clenching followed by the induction of experimental muscle pain by injection of glutamate on the perception of fatigue and pain and on the resting electromyographic (EMG) activity. In addition, the role of gender on these interactions was studied. The EMG activities of bilateral masseter (MAL, MAR) and temporalis (TAL, TAR) muscles in 11 healthy young women and 12 men were measured before (Baseline) and after tooth-clenching for 30 min at 10% of maximal force (Post1), after subsequent glutamate (Glu) or isotonic saline (Iso) injection into the MAL following the tooth-clenching (Post2) and 60 min after tooth-clenching (Post3). The intensities of fatigue, fatigue-related muscle pain and headache-like symptoms were scored on 0-10 cm visual analog scales (VAS). The glutamate-evoked pain was continuously scored on an electronic VAS. Sustained low-level tooth-clenching consistently produced fatigue sensation, fatigue-related muscle pain and headache-like symptoms in both genders with significantly higher fatigue VAS scores in men than in women, while the accompanying increase in the resting EMG activity appears higher in women than in men in the masseter muscles. In this study no gender differences were found for the perceived amount of experimental pain induced by glutamate injection. Additional increases of the resting EMG activity after injections occurred only in men in the injected masseter muscle and non-injected temporalis muscles. The present findings provide new information on the complex influence of gender on sensory-motor integration in the trigeminal system which may contribute to differences in susceptibility to develop musculoskeletal pain problems.
本研究的目的是调查低强度紧咬牙诱发的颌面部肌肉疲劳，随后通过注射谷氨酸诱导实验性肌肉疼痛，对疲劳和疼痛感知以及静息肌电图（EMG）活动的影响。此外，还研究了性别在这些相互作用中的作用。在11名健康年轻女性和12名男性中，测量双侧咬肌（MAL、MAR）和颞肌（TAL、TAR）在紧咬牙前（基线）、以最大力量的10%紧咬牙30分钟后（Post1）、紧咬牙后向MAL注射谷氨酸（Glu）或等渗盐水（Iso）后（Post2）以及紧咬牙60分钟后（Post3）的EMG活动。在0-10厘米视觉模拟量表（VAS）上对疲劳、与疲劳相关的肌肉疼痛和头痛样症状的强度进行评分。用电子VAS持续记录谷氨酸诱发的疼痛。持续的低强度紧咬牙在两性中均持续产生疲劳感、与疲劳相关的肌肉疼痛和头痛样症状，男性的疲劳VAS评分显著高于女性，而咬肌静息EMG活动的伴随增加在女性中似乎高于男性。在本研究中，未发现谷氨酸注射诱发的实验性疼痛的感知量存在性别差异。注射后静息EMG活动的额外增加仅发生在注射侧咬肌和未注射侧颞肌的男性中。本研究结果为性别对三叉神经系统感觉运动整合的复杂影响提供了新信息，这可能有助于解释在发展肌肉骨骼疼痛问题易感性方面的差异。
