Department of Physical Therapy, Graduate Institute of Rehabilitation Science, China Medical University, Taichung, Taiwan.
Department of Senior Citizen Service Management, National Taichung University of Science and Technology, Taichung, Taiwan.
Exp Brain Res. 2020 Dec;238(12):2845-2855. doi: 10.1007/s00221-020-05942-4. Epub 2020 Oct 12.
This study explores the involvement of substance P (SP) in the parabrachial nucleus (PBN) and central amygdaloid nucleus (CeA) in the nociception-emotion link and of rats with masticatory myofascial pain (MMP) induced by chronic tetanic eccentric muscle contraction. A total of 18 rats were randomly and equally assigned for MMP (MMP group) and sham-MMP induction (sMMP group). MMP was induced by electrical-stimulated repetitive tetanic eccentric contraction of the masseter muscle for 14 consecutive days. Myofascial trigger points in the masseter muscle were identified by palpable taut bands, increased prevalence of endplate noise (EPN), focal hypoechoic nodules on ultrasound and restricted jaw opening. All animals were killed for morphological and SP immunohistochemical analyses. Chronic tetanic eccentric contraction induced significantly thicker masseter muscle confirmed by hypoechogenicity, increased prevalence and amplitudes of EPN, and limited jaw opening. Immunohistochemically, the SP-like positive neurons increased significantly in PBN and CeA of the MMP group. Our results suggested that MMP increases the SP protein levels in PBN and CeA, which play important roles in MMP-mediated chronic pain processing as well as MMP-related emotional processes.
本研究探讨了在咀嚼肌筋膜疼痛（MMP）大鼠的延髓旁核（PBN）和杏仁中央核（CeA）中，P 物质（SP）参与痛觉-情绪联系的情况，这些大鼠是由慢性痉挛性离心肌肉收缩引起的。共有 18 只大鼠被随机平均分配到 MMP（MMP 组）和假 MMP 诱导（sMMP 组）。通过对咀嚼肌进行电刺激重复痉挛性离心收缩 14 天来诱导 MMP。通过可触及的紧张带、终板噪声（EPN）发生率增加、超声下局灶性低回声结节和开口受限来确定咀嚼肌中的肌筋膜触发点。所有动物均被处死，进行形态学和 SP 免疫组织化学分析。慢性痉挛性离心收缩导致咀嚼肌明显增厚，表现为低回声，EPN 发生率和幅度增加，以及开口受限。免疫组织化学分析显示，MMP 组 PBN 和 CeA 中 SP 样阳性神经元显著增加。我们的结果表明，MMP 增加了 PBN 和 CeA 中的 SP 蛋白水平，这在 MMP 介导的慢性疼痛处理以及 MMP 相关的情绪过程中发挥重要作用。
