Facilitation of antagonist motor output through short-latency sensory pathways during postnatal development in the mouse.
Facilitation of antagonist motor output through short-latency sensory pathways during postnatal development in the mouse.
复制标题
在小鼠出生后发育过程中通过短潜伏期感觉通路促进拮抗运动输出。
DOI：
10.1016/j.neulet.2018.03.015
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发表时间：
2018
影响因子：
2.5
通讯作者：
Ladle,DavidR
中科院分区：
文献类型：
--
作者：
Sonner,PatrickM;Ladle,DavidR
通过刺激供应拮抗肌的本体感受传入神经募集的Ia抑制性中间神经元对运动神经元的相互抑制已经被很好地描述。文献中曾报道过下行通路中断后抑制效果的变化，有时甚至是从抑制到促进的转变。我们试图测试这种促进是否可以在正常动物中表达，通过评估未受伤动物的急性制剂中的促进的存在。使用从新生小鼠分离的脊髓制备，在膝屈肌运动神经元（后二头肌半腱肌; PBST）的单突触牵张反射反应的变化进行了监测后，在其他肌肉神经的本体感觉传入的条件刺激。正如预期的相互抑制，调节刺激的四头肌（膝伸肌和PBST拮抗剂）的感觉传入导致抑制牵张反射反应。然而，当甘氨酸能相互抑制通路被应用士的宁阻断时，观察到四头肌条件刺激对牵张反射反应的促进作用。易化引起的低阈值本体感受传入，并发生在lavelet符合双突触电路。出生时的易化程度大于出生后一周。我们的研究结果还表明，相互促进仅限于拮抗肌对，促进PBST反应时，没有观察到闭孔神经供应内收肌的条件。总的来说，这些数据表明，在出生后的第一周内，促进的功效是调制的，而促进的特异性已经建立了出生。
Reciprocal inhibition of motor neurons via Ia inhibitory interneurons recruited by stimulation of proprioceptive afferents supplying antagonist muscles has been well described. Changes in the efficacy of inhibition, and sometimes even a switch from inhibition to facilitation, have been reported in the literature after disruption of descending pathways. We sought to test whether such facilitation could be expressed in normal animals by evaluating the presence of facilitation in acute preparations from uninjured animals. Using an isolated spinal cord preparation from neonatal mice, changes in the monosynaptic stretch reflex response in knee flexor motor neurons (posterior biceps semitendinosus; PBST) were monitored following conditioning stimulation of proprioceptive sensory afferents in other muscle nerves. As expected for reciprocal inhibition, conditioning by stimulation of quadriceps (knee extensors and PBST antagonists) sensory afferents resulted in inhibition of the stretch reflex response. Facilitation, however, of the stretch reflex response by quadriceps conditioning stimulation was observed when the glycinergic reciprocal inhibitory pathway was blocked by application of strychnine. Facilitation was elicited by low-threshold proprioceptive afferents and occurred at latencies consistent with a disynaptic circuit. The magnitude of facilitation was larger at birth than at one week postnatal. Our results also suggest reciprocal facilitation is restricted to antagonist muscle pairs, as facilitation of PBST responses was not observed when conditioned with the obturator nerve supplying the adductor muscles. Overall, these data suggest the efficacy of facilitation is modulated during the first postnatal week, while the specificity of facilitation is already established by birth.