Yu Qingquan, Cao Wanying, Wang Xiaoyu, He Wei, Sun Xiaoyue, Chen Lizhen, Su Yangshuai, Zhang Zhiyun, Jing Xianghong
Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People's Republic of China.
J Pain Res. 2023 Mar 7;16:695-706. doi: 10.2147/JPR.S396481. eCollection 2023.
Spinal wide dynamic range (WDR) neurons are well studied in pain models and they play critical roles in regulating nociception. Evidence has started to accumulate that acupuncture produces a good analgesic effect via activating different primary fibers with distinct intensities. The purpose of the present study was to compare the distinct intensities of pre-electroacupuncture (pre-EA) at local muscular receptive fields (RFs), adjacent or contralateral non-RFs regulating the nociceptive discharges of spinal WDR neurons evoked by hypertonic saline (HS).
Spinal segments of electrophysiological recording were identified by neural tracers applied at the left gastrocnemius muscle. The thresholds of Aβ (T), Aδ (T) and C (T) components of WDR neurons were measured to determine the intensity of pre-EA by extracellular recording. The discharges of WDR neurons induced by distinct intensities of pre-EA and 200 µL HS (6%) injection in left gastrocnemius muscle of rats were observed by extracellular recording.
The spinal segments of WDR neurons were confirmed in lumbar (L)5-6 area according to the projective segments of dorsal root ganglion. T, T and T of WDR neurons was determined to be 0.5, 1, and 2 mA, respectively. The pre-EA with intensities of T ( < 0.05), T ( < 0.05), T ( < 0.05) or 2T ( < 0.01) at ipsilateral adjacent non-RFs significantly reduced the discharges of WDR neurons, while at local RFs only pre-EA of T ( < 0.05), T ( < 0.05) and 2T ( < 0.01) could inhibit the nociceptive discharges. In addition, intensity of pre-EA at contralateral non-RFs should reach at least T to effectively inhibit the firing rates of WDR neurons ( < 0.01).
Pre-EA could suppress nociceptive discharges of WDR neurons and the inhibitory effects were dependent on the distinct intensities and locations of stimulation.
脊髓广动力范围（WDR）神经元在疼痛模型中已得到充分研究，它们在调节伤害感受中发挥关键作用。已有证据开始积累，表明针刺通过激活不同强度的不同初级纤维产生良好的镇痛效果。本研究的目的是比较在局部肌肉感受野（RFs）、调节高渗盐水（HS）诱发的脊髓WDR神经元伤害性放电的相邻或对侧非感受野进行电针预处理（pre-EA）时的不同强度。
通过将神经示踪剂应用于左侧腓肠肌来确定电生理记录的脊髓节段。通过细胞外记录测量WDR神经元的Aβ（T）、Aδ（T）和C（T）成分的阈值，以确定pre-EA的强度。通过细胞外记录观察不同强度的pre-EA和在大鼠左侧腓肠肌注射200 μL HS（6%）所诱导的WDR神经元放电。
根据背根神经节的投射节段，在腰（L）5 - 6区域确认了WDR神经元的脊髓节段。WDR神经元的T、T和T分别确定为0.5、1和2 mA。在同侧相邻非感受野处，强度为T（<0.05）、T（<0.05）、T（<0.05）或2T（<0.01）的pre-EA显著减少了WDR神经元的放电，而在局部感受野处，只有强度为T（<0.05）、T（<0.05）和2T（<0.01）的pre-EA能抑制伤害性放电。此外，对侧非感受野处的pre-EA强度至少应达到T才能有效抑制WDR神经元的放电频率（<0.01）。
pre-EA可抑制WDR神经元的伤害性放电，且抑制作用取决于刺激的不同强度和位置。
