Hishinuma M, Yamaguchi T
Institute of Basic Medical Sciences, Tsukuba University, Japan.
Brain Res. 1989 Mar 13;482(1):184-8. doi: 10.1016/0006-8993(89)90559-3.
During cat forelimb fictive locomotion, short-latency reflex pathways were examined by recording nerve discharges and intracellularly from motoneurones. Stimulation of cutaneous afferents, superficial radial nerves, evoked trisynaptic excitation of the elbow flexors, biceps brachii and brachialis, and stimulation of muscle afferents, deep radial nerves, evoked oligosynaptic, i.e. monosynaptic and disynaptic excitation of the flexors. The short-latency excitatory postsynaptic potentials (EPSPs) evoked from both nerves were rhythmically modulated; they were facilitated during the flexion phase and suppressed during the extension phase. Stimulation of high threshold muscle afferents evoked EPSPs with a central delay of ca. 4.2 ms, which were depressed throughout episodes of fictive locomotion. Since the short-latency EPSPs and longer-latency EPSPs in the same motoneurone were differently influenced during fictive locomotion, the effects observed could not be explained by changes occurring at only the motoneuronal level but they probably occurred at the premotoneuronal level. In addition, short-latency cutaneous excitation of the distal muscles, innervated by the median and ulnar nerves, was little modulated during fictive locomotion.
在猫前肢的虚构运动过程中，通过记录神经放电和运动神经元的细胞内活动来检测短潜伏期反射通路。刺激皮肤传入神经，即桡浅神经，可诱发屈肘肌（肱二头肌和肱肌）的三突触兴奋；刺激肌肉传入神经，即桡深神经，可诱发屈肌的寡突触兴奋，即单突触和双突触兴奋。来自这两条神经诱发的短潜伏期兴奋性突触后电位（EPSP）呈节律性调制；它们在屈曲期增强，在伸展期受到抑制。刺激高阈值肌肉传入神经诱发的EPSP，其中心延迟约为4.2毫秒，在整个虚构运动过程中均受到抑制。由于在虚构运动过程中，同一运动神经元的短潜伏期EPSP和长潜伏期EPSP受到不同的影响，因此观察到的效应不能仅用运动神经元水平上发生的变化来解释，而可能发生在运动神经元前水平。此外，由正中神经和尺神经支配的远端肌肉的短潜伏期皮肤兴奋在虚构运动过程中几乎没有受到调制。
