NEURAL MECHANISMS UNDERLYING THE CLASP-KNIFE REFLEX IN THE CAT .1. CHARACTERISTICS OF THE REFLEX
NEURAL MECHANISMS UNDERLYING THE CLASP-KNIFE REFLEX IN THE CAT .1. CHARACTERISTICS OF THE REFLEX
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DOI：
10.1152/jn.1990.64.4.1303
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发表时间：
1990-10-01
影响因子：
2.5
通讯作者：
RYMER, WZ
中科院分区：
文献类型：
--
作者：
CLELAND, CL;RYMER, WZ
1.本研究的目的是通过使用伸展和等长收缩的踝关节伸肌和屈肌在去脑猫的双侧背侧半横断的脊髓在节段T12的折刀反射的特点。2.伸肌的拉伸引起了同侧伸肌和协同伸肌的抑制。同源抑制和协同抑制之间的相似性表明，相似的神经机制负责。3.同源性和协同性扣刀抑制表现出几个特征性特征：1）抑制仅由产生显著肌肉力量的大拉伸引起。短的伸展，不产生大的力量只引起兴奋：2）的幅度增加，随着初始运动输出的增加，扣刀抑制，反映在水平的整流肌电图;（3）斜坡-保持牵张诱发的反射性抑制的时程表现为斜坡牵张过程中肌电的分段、斜坡牵张结束时抑制的动态超调、在持续牵拉过程中，抑制缓慢但通常完全衰减; 4）抑制持续到牵拉终止之后; 5）抑制表现出对重复牵拉的适应。4.等长收缩比目鱼肌或内侧腓肠肌，产生的电刺激的肌肉神经，也引起了强大的协同反射抑制通过类似的机制，拉伸诱发，扣刀抑制。拉伸引起了更大程度的抑制比收缩，表明受体响应拉伸和收缩有助于扣刀抑制。5.通过拉伸比目鱼肌或内侧腓肠肌产生的反射效应并不局限于同侧肌和近侧协同肌。整个后肢的伸肌被抑制，屈肌被兴奋，这与皮肤刺激引起的屈曲-撤回反射的模式一致。6.屈肌，胫骨前肌的拉伸，引起了相同的空间模式和时间过程的反射动作作为伸肌的拉伸-抑制伸肌和屈肌的兴奋，整个后肢，包括homomerous兴奋的胫骨前肌。7.我们的结论是，无论是高尔基体腱器官，也不次级纺锤体传入可能有助于显着的扣刀抑制，因为他们的反应，拉伸和等长收缩不同的反射动作引起的拉伸和收缩。（400字处截断摘要）
1. The goal of this study was to characterize the clasp-knife reflex by the use of stretch and isometric contraction of ankle extensor and flexor muscles in decerebrated cats with bilateral dorsal hemisections of their spinal cords at segment T12. 2. Stretch of an extensor muscle evoked inhibition in both homonymous and synergistic extensor muscles. The similarities between homonymous and synergistic inhibition suggest that similar neural mechanisms were responsible. 3. Homonymous and synergistic clasp-knife inhibition showed several characteristic features: 1) inhibition was evoked only by large stretches that produced significant muscle force. Short stretches that did not produce large forces evoked only excitation; 2) the magnitude of clasp-knife inhibition increased with increasing initial motor output, as reflected in the level of rectified EMG; 3) the time course of reflex inhibition evoked by ramp-and-hold stretch was characterized by segmentation of EMG during ramp stretch, dynamic overshoot of inhibition at the end-of-ramp stretch, and slow but usually complete decay of inhibition during maintained stretch; 4) inhibition persisted beyond the termination of stretch, and 5) inhibition showed adaptation to repeated stretch. 4. Isometric contraction of the soleus or medial gastrocnemius, produced by electrical stimulation of the muscle nerve, also evoked powerful synergistic-reflex inhibition via similar mechanisms as stretch-evoked, clasp-knife inhibition. Stretch evoked a greater degree of inhibition than did contraction, indicating that receptors responsive to both stretch and contraction contribute to clasp-knife inhibition. 5. The reflex effects produced by stretching the soleus or medial gastrocnemius were not confined to the homonymous and close synergistic muscles. Extensor muscles were inhibited and flexor muscles were excited throughout the hindlimb, which paralleled the pattern of a flexion-withdrawal reflex evoked by cutaneous stimulation. 6. Stretch of a flexor muscle, the tibialis anterior, evoked the same spatial pattern and time course of reflex action as stretch of an extensor muscle--inhibition of extensor muscles and excitation of flexor muscles throughout the hindlimb, including homonymous excitation of the tibialis anterior. 7. We conclude that neither Golgi tendon organs nor secondary spindle afferents are likely to contribute significantly to clasp-knife inhibition because their responses to stretch and isometric contraction differ from the reflex actions evoked by stretch and contraction.(ABSTRACT TRUNCATED AT 400 WORDS)