INHIBITION OF FLEXOR BURST GENERATION BY LOADING ANKLE EXTENSOR MUSCLES IN WALKING CATS
INHIBITION OF FLEXOR BURST GENERATION BY LOADING ANKLE EXTENSOR MUSCLES IN WALKING CATS
复制标题
DOI：
10.1016/0006-8993(80)90206-1
复制
发表时间：
1980-01-01
期刊：
影响因子：
2.9
通讯作者：
PEARSON, KG
中科院分区：
文献类型：
--
作者：
DUYSENS, J;PEARSON, KG
通过在跑步机上行走的哺乳动物前期猫，研究了小腿三头肌踝伸肌本体感觉输入在控制行走中的作用。除踝伸肌(小腿三头肌)和踝屈肌(胫骨前肌)外，几乎所有的小腿肌肉失神经后，左后肢被固定在1个位置。在其余3条完整肢体行走时，固定后腿的独立踝屈伸肌节律性交替收缩。当单独的小腿三头肌被拉伸，使主动收缩的力量增加到4公斤以上时，这些节律性收缩就消失了。在保持伸展状态下，踝屈肌和伸肌的周期性收缩在伸展的小腿三头肌的力量逐渐减小并下降到4公斤以下后才恢复。由刺激前根S1或由大幅度振动产生的小腿三头肌等长收缩也可导致踝屈肌突然消失。通过将踝关节夹在屈曲位置以伸展踝关节，也可以在单个完整的后腿的所有肌肉中产生运动节律的抑制。在所有这些情况下，对侧后腿步速的增加与节律性运动活动的抑制有关。代表后肢伸肌负荷的小腿三头肌本体感受器可能抑制后肢屈曲的中枢产生。在正常行走过程中，这一机制在站立时可能非常重要，以防止在完全需要后肢伸展来支撑动物体重的时候启动摆动阶段。启动摆动的一个必要条件，但并不总是充分的，可能是腿部伸肌的卸载。
The role of proprioceptive input from the ankle extensor triceps surae in the control of walking was examined in premammillary cats walking on a treadmill. The left hindlimb was rigidly fixed in 1 position after denervating almost all the leg muscles except the ankle extensor (triceps surae) and ankle flexor (tibialis anterior). Rhythmic alternating contractions of the isolated ankle flexor and extensor occurred in the fixed hindleg during periods of walking in the other 3 intact limbs. These rhythmic contractions disappeared when the isolated triceps surae was stretched so as to increase the force of the active contractions beyond 4 kg. With maintained stretch the periodic contractions in the ankle flexor and extensor returned only after the force in the stretched triceps surae gradually decreased and fell below about 4 kg. Isometric contractions of the triceps surae produced either by stimulation of ventral root S1 or by large amplitude vibrations also led to the sudden disappearance of ankle flexor bursts. Inhibition of the locomotory rhythm could also be produced in all muscles of a single intact hindleg by clamping the ankle joint in a flexed position so as to stretch the ankle extensor. In all these cases, an increased rate of stepping of the contralateral hindleg was associated with the inhibition of the rhythmic locomotory activity. Triceps surae proprioceptors signalling the presence of loading of the hindlimb extensor muscles probably inhibit the central generation of hindlimb flexion. During normal walking this mechanism could be of major importance during stance to prevent the initiation of the swing phase of a time when hindlimb extension is fully needed to support the weight of the animal. A necessary but not always sufficient condition for the initiation of swing motion may be an unloading of leg extensor muscles.