Baret M, Katz R, Lamy J C, Pénicaud A, Wargon I
E03 49 INSERM, Service de Médecine Physique et Réadaptation, Hôpital La Salpêtrière, 75651 Paris cedex 13, France.
Exp Brain Res. 2003 Sep;152(1):133-6. doi: 10.1007/s00221-003-1547-9. Epub 2003 Jul 24.
Reciprocal inhibition between ankle flexors and extensors has been the subject of numerous studies in Man. They have demonstrated that this reciprocal inhibition is in all likelihood caused by a disynaptic pathway at least partly fed by Ia afferents. It is thus generally agreed that this reciprocally organized inhibition between ankle flexors and extensors in Man is similar to the reciprocal Ia inhibition described in the cat. This conclusion has, however, been challenged, when Jankowska and McCrea described in the cat a non-reciprocal group I inhibition involving interneurones co-excited by Ia and Ib afferents and mediating inhibition to both antagonistic and non-antagonistic motoneurones. The only way to distinguish between reciprocal Ia inhibition and non-reciprocal group I inhibition is to test if the inhibition is blocked by recurrent inhibition, since only Ia interneurones are inhibited by recurrent inhibition. In the present study, reciprocal inhibition from soleus to tibialis anterior was thus investigated following activation of soleus-coupled Renshaw cells in normal human subjects. It was found that reciprocal inhibition induced in tibialis anterior motoneurones by the activation of soleus group I afferents is deeply depressed by activation of soleus-coupled Renshaw cells. This finding provides the missing data to identify disynaptic inhibition between antagonistic ankle muscles as a reciprocal Ia inhibition.
踝关节屈肌与伸肌之间的交互抑制一直是人类众多研究的主题。这些研究表明，这种交互抑制很可能是由至少部分由Ia传入纤维提供输入的双突触通路引起的。因此，人们普遍认为，人类踝关节屈肌与伸肌之间这种相互组织的抑制类似于猫中描述的交互Ia抑制。然而，当扬科夫斯卡和麦克雷在猫中描述了一种非交互性的I类抑制时，这一结论受到了挑战，这种抑制涉及由Ia和Ib传入纤维共同兴奋的中间神经元，并介导对拮抗和非拮抗运动神经元的抑制。区分交互Ia抑制和非交互性I类抑制的唯一方法是测试这种抑制是否被回返性抑制阻断，因为只有Ia中间神经元会被回返性抑制所抑制。在本研究中，因此在正常人类受试者中激活比目鱼肌耦合的闰绍细胞后，研究了从比目鱼肌到胫骨前肌的交互抑制。结果发现，比目鱼肌I类传入纤维的激活在胫骨前肌运动神经元中诱导的交互抑制，会因比目鱼肌耦合的闰绍细胞的激活而被显著抑制。这一发现提供了缺失的数据，以确定拮抗踝关节肌肉之间的双突触抑制为交互Ia抑制。
