人类下肢交互性Ia抑制的强直后增强

Sato T, Tsuboi T, Miyazaki M, Sakamoto K

School of Human Sciences, Waseda University, Tokorozawa, Saitama, Japan.

J Electromyogr Kinesiol. 1999 Feb;9(1):59-66. doi: 10.1016/s1050-6411(98)00024-8.

The purpose of this study was to investigate how reciprocal Ia inhibition is changed during muscle fatigue of lower limb muscle, induced with a voluntary contraction or height frequency electrical stimulation. Reciprocal Ia inhibition from ankle flexors to extensors has been investigated in 12 healthy subjects. Hoffmann reflex (H-reflex) in the soleus muscle was used to monitor changes in the amount of reciprocal Ia inhibition from common peroneal nerve as demonstrated during voluntary dorsi or planterflexion and 50 Hz electrical stimulation induced dorsi or planterflexion. The test soleus H-reflex was kept at 20-25% of maximum directly evoked motor response (M response) and the strength of the conditioning common peroneal nerve stimulation was kept at 1.0 x motor threshold. At rest, weak la inhibition was demonstrated in 12 subjects, maximal inhibition from the common peroneal nerve was 28.8%. During voluntary dorsiflexion and 50 Hz electrical stimulation induced dorsiflexion, there absolute amounts of inhibition increased as compared to at rest, and decreased or disappeared during voluntary planterflexion and 50 Hz electrical stimulation induced planterflexion as compared to at rest. During voluntary or electrical stimulation induced agonist muscle fatigue, the inhibition of the soleus H-reflex from the common peroneal nerve was greater during voluntary dorsiflexion (maximal, 11.1%) and 50 Hz (maximal, 6.7%) electrical stimulation induced dorsiflexion than at rest. The inhibition was decreased or disappeared during voluntary planterflexion 50 Hz electrical stimulation induced planterflexion. It was concluded that the results were considered to support the hypothesis that alpha-motoneurones and la inhibitory intemeurones link to antagonist motoneurones in reciprocal inhibition. The diminished reciprocal Ia inhibition of voluntary contraction during muscle fatigue as compared to electrical stimulation, is discussed in relation to its possible contribution to ankle stability.

本研究的目的是调查在由自愿收缩或高频电刺激诱发的下肢肌肉疲劳期间，交互性Ia抑制是如何变化的。对12名健康受试者的从踝部屈肌到伸肌的交互性Ia抑制进行了研究。比目鱼肌的霍夫曼反射（H反射）被用于监测在自愿背屈或跖屈以及50Hz电刺激诱发的背屈或跖屈过程中，来自腓总神经的交互性Ia抑制量的变化。测试的比目鱼肌H反射保持在最大直接诱发运动反应（M反应）的20%-25%，条件性腓总神经刺激的强度保持在1.0倍运动阈值。在静息状态下，12名受试者表现出较弱的Ia抑制，来自腓总神经的最大抑制为28.8%。在自愿背屈和50Hz电刺激诱发的背屈过程中，与静息时相比，抑制的绝对量增加；而在自愿跖屈和50Hz电刺激诱发的跖屈过程中，与静息时相比，抑制量减少或消失。在自愿或电刺激诱发激动剂肌肉疲劳期间，在自愿背屈（最大，11.1%）和50Hz（最大，6.7%）电刺激诱发的背屈过程中，来自腓总神经对比目鱼肌H反射的抑制比静息时更大。在自愿跖屈和50Hz电刺激诱发的跖屈过程中，抑制减少或消失。研究得出结论，这些结果被认为支持以下假设：在交互抑制中，α运动神经元和Ia抑制性中间神经元与拮抗运动神经元相连接。与电刺激相比，肌肉疲劳期间自愿收缩的交互性Ia抑制减弱，本文讨论了其对踝关节稳定性可能的贡献。