Loughner B, Miller J, Broumand V, Cooper B
Midwest Center for Head Pain Management, Upper Valley Medical Center, Troy, OH 45373, USA.
Exp Brain Res. 1997 Feb;113(2):311-26. doi: 10.1007/BF02450329.
Chronic pain in the temporomandibular (TM) joint is predominantly manifested in women. We examined biomechanical and neural factors that could contribute to this differential representation. Relationships between jaw rotation, soft tissue strains and soft tissue forces were examined in the goat TM joint. Strains were minimal until the jaw was rotated beyond the normal range of motion (7.25 deg). There were no significant differences in rotation-strain patterns in males and females. Stress developed as strains were introduced by jaw rotation. Gender differences were observed. Males manifested higher failure loads (15.94 +/- 1.98 and 11.37 +/- 2.02 N, for males and females respectively) and higher elastic stiffness than females (5.62 +/- 1.19 N/mm and 1.64 +/- 0.31 N/mm, for males and females respectively). Recordings were made from cell bodies in the trigeminal ganglion whose distal processes innervated the retrodiscal tissue of the temporomandibular joint of the goat (n = 48). Nociceptor reactivity was characterized with respect to the capacity to transduce mandibular rotation (rotation-interval functions; n = 29). On the basis of established relationships between rotation, strain and tissue forces, rotation-interval functions were transformed into strain-interval and force-interval functions. Comparisons were made between nociceptor properties grouped by gender. No differences in properties were observed when nociceptors were characterized with respect to jaw rotation; however, gender differences were obtained when nociceptor reactivity was characterized with respect to retrodiscal strains or forces. Consistent with smaller failure loads, nociceptors of retrodiscal tissues of females manifested a smaller range (1.12 vs 4.33 N), force to average (1.51 vs 4.64 N), force to minimum (0.95 vs 2.48 N) and force to asymptotic discharge (2.07 vs 6.81 N). Consistent with lower elastic stiffness, nociceptors of female tissues manifested higher average strain (54.4% vs 41.9%) and peak strain (74.0% vs 58.1%) to asymptotic discharge relative to those sampled from male tissues. The implications of these findings for TM joint injury and chronic pain are considered.
颞下颌关节（TM）的慢性疼痛在女性中更为常见。我们研究了可能导致这种性别差异的生物力学和神经因素。在山羊颞下颌关节中研究了下颌旋转、软组织应变和软组织力之间的关系。在下颌旋转超出正常运动范围（7.25度）之前，应变极小。男性和女性的旋转-应变模式没有显著差异。随着下颌旋转引入应变，应力逐渐产生。观察到了性别差异。男性表现出比女性更高的破坏载荷（男性分别为15.94±1.98 N和女性为11.37±2.02 N）以及更高的弹性刚度（男性分别为5.62±1.19 N/mm和女性为1.64±0.31 N/mm）。从三叉神经节的细胞体进行记录，其远端突起支配山羊颞下颌关节的盘后组织（n = 48）。根据感受伤害性刺激的感受器转导下颌旋转的能力（旋转-间隔函数；n = 29）对其反应性进行了表征。基于已建立的旋转、应变和组织力之间的关系，将旋转-间隔函数转换为应变-间隔函数和力-间隔函数。对按性别分组的伤害性感受器特性进行了比较。当根据下颌旋转对伤害性感受器进行表征时，未观察到特性上的差异；然而，当根据盘后应变或力对伤害性感受器反应性进行表征时，发现了性别差异。与较小的破坏载荷一致，女性盘后组织的伤害性感受器表现出更小的范围（1.12对4.33 N）、平均力（1.51对4.64 N）、最小力（0.95对2.48 N）和渐近放电力（2.07对6.81 N）。与较低的弹性刚度一致，相对于从男性组织中采样的伤害性感受器，女性组织的伤害性感受器在渐近放电时表现出更高的平均应变（54.4%对41.9%）和峰值应变（74.0%对58.1%）。考虑了这些发现对颞下颌关节损伤和慢性疼痛的影响。
