Wang Ying, Tan Bolin, Shi Shuyan, Ye Yang, Che Xianwei
Centre for Cognition and Brain Disorders, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, China.
TMS Centre, Deqing Hospital of Hangzhou Normal University, Hangzhou, Zhejiang, China.
Int J Clin Health Psychol. 2024 Jan-Mar;24(1):100413. doi: 10.1016/j.ijchp.2023.100413. Epub 2023 Oct 27.
Both the primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) rTMS have the potential to reduce certain chronic pain conditions. However, the analgesic mechanisms remain unclear, in which M1- and DLPFC-rTMS may have different impact on the release of dopamine receptor D2 neurotransmissions (DRD2). Using a double-blind, randomised, sham- and placebo-controlled design, this study investigated the influence of DRD2 antagonist on rTMS-induced analgesia and corticospinal excitability across the M1 and DLPFC. Healthy participants in each group (M1, DLPFC, or Sham) received an oral dose of chlorpromazine or placebo before the delivery of rTMS in two separate sessions. Heat pain and cortical excitability were assessed before drug administration and after rTMS intervention. DRD2 antagonist selectively abolished the increased heat pain threshold induced by DLPFC stimulation and increased pain unpleasantness. The absence of analgesic effects in DLPFC stimulation was not accompanied by plastic changes in the corticospinal pathway. In contrast, DRD2 antagonist increased corticospinal excitability and rebalanced excitation-inhibition relationship following motor cortex stimulation, although there were no clear changes in pain experiences. These novel findings together highlight the influence of dopaminergic neurotransmission on rTMS-induced analgesia and corticospinal excitability dependent on stimulation targets.
初级运动皮层（M1）和背外侧前额叶皮层（DLPFC）重复经颅磁刺激（rTMS）都有可能减轻某些慢性疼痛状况。然而，其镇痛机制仍不清楚，其中M1-rTMS和DLPFC-rTMS可能对多巴胺D2受体神经传递（DRD2）的释放有不同影响。本研究采用双盲、随机、假刺激和安慰剂对照设计，调查了DRD2拮抗剂对rTMS诱导的镇痛作用以及M1和DLPFC区域皮质脊髓兴奋性的影响。每组（M1、DLPFC或假刺激组）的健康参与者在两个独立的疗程中接受rTMS治疗前口服一剂氯丙嗪或安慰剂。在给药前和rTMS干预后评估热痛和皮质兴奋性。DRD2拮抗剂选择性地消除了DLPFC刺激引起的热痛阈值升高，并增加了疼痛不适感。DLPFC刺激缺乏镇痛效果并未伴有皮质脊髓通路的可塑性变化。相比之下，DRD2拮抗剂增加了运动皮层刺激后的皮质脊髓兴奋性，并重新平衡了兴奋-抑制关系，尽管疼痛体验没有明显变化。这些新发现共同突出了多巴胺能神经传递对rTMS诱导的镇痛作用和皮质脊髓兴奋性的影响，且这种影响取决于刺激靶点。
