运动诱发的镇痛效应:脊髓、皮层下和皮层机制

Exercise Induced Hypoalgesia:Spinal,Subcortical,and Cortical Mechanisms

在健康受试者或部分慢性疼痛人群中,一定强度和时长的运动锻炼或针对性的运动疗法,已被广泛验证可以有效提高疼痛阈值并改善疼痛症状。上述运动诱发的镇痛效应(exercise induced hypoalgesia,EIH)被认为与痛觉内源性调控系统在神经系统不同水平上的调控作用紧密联系;合适类型的运动刺激可以在脊髓水平诱发镇痛效应,亦可激活脊髓以上高位中枢神经系统的痛觉内源性调控系统,进而对脊髓水平的伤害性反应进行调控。病理性痛状态下,EIH的产生与运动皮层的激活水平以及痛觉下行抑制作用均有关。研究脊髓、皮层下和皮层水平EIH效应的确切机制,将为非药物运动手段预防疼痛慢性化提供帮助。

Exercise with adequate intensity and duration or specialized exercise therapy have been widely proven to be effective in enhancing pain thresholds or increasing pain tolerance in healthy subjects or chronic pain patients.Exercise induced hypoalgesia(EIH)may involve various central structures in the endogenous pain modulation;motor stimulation with different types can activate either spinal cord induced local inhibition or supraspinal structures induced descending pain inhibition influencing the nociception at the spinal cord level.At the spinal level,continued exercise can down-regulate the expression of IL-1β,IL-6 and TNF-α,while the transient hypoalgesia effect of voluntary movement could be elicited by gate control of the dorsal horn;at supraspinal and subcortical levels,endogenous opioids,cannabinoids,and 5-HT-related descending inhibition of PAG and RVM can be modulated by exercise with different intensity,while the nociceptive discrimination of the thalamus and cognitive processing of the basal amygdala might also be affected by the somatosensory input of exercise,respectively;at cortical level,M1 can be activated by voluntary movement,r TMS or t DCS showed a significant antinociceptive effect in patients with chronic pain,while the DLPFC,MOPFC and insula associated with exercise have also been proven to participate in the EIH effect.In pathological pain state,the EIH is affected with the limited activity of motor cortex and the impaired function of descending pain inhibition,while the active treatment with exercise at non-affected body parts can still partially reverse the pain sensitization and induce the EIH effect.The investigation of EIH effect at spinal,subcortical and cortical levels will assist one to better understand EIH mechanisms,and help to provide the prevention of chronic pain via non-pharmacological exercise therapy.