Kawai Y
Nihon Seirigaku Zasshi. 1982;44(10):587-99.
Intracellular potentials of forelimb motoneurons of pyramidal cats were recorded by glass microelectrodes following repetitive stimulation of the contralateral pericruciate cortex, and patterns of the postsynaptic potentials (PSPs) evoked thereby were analysed. The motoneurons tested were identified by antidromic invasion from either of the following nerves: long (lo. T), lateral (la. T) and medial (med. T) heads of triceps, anconeus (Anc), biceps (Bi), deep radial (dR), median (M) and ulnar (U). The motoneurons were classified into fast and slow motoneurons on the basis of the duration of afterhyperpolarization (AHP) and the axonal conduction velocity. All of Anc and 65% of med. T motoneurons were classified into slow motoneurons. On the other hand, 35% of med. T, 84% of lo. T and la. T motoneurons were classified into fast motoneurons. About 70% of motoneurons innervating Bi and wrist controlling muscles (dR, M and U) were classified into fast motoneurons and the rest into slow motoneurons. Repetitive stimulation of the pericruciate cortex produced predominantly inhibitory PSPs (I-type) or mixed PSPs (M-type) in 67% of Anc and 56% of slow triceps motoneurons, while it evoked predominantly excitatory PSPs (E-type) in 97% of fast triceps motoneurons. Thus, patterns of PSPs in elbow extensor (Anc and triceps) motoneurons produced by cortical stimulation were in general excitatory to fast and inhibitory to slow motoneurons, similarly to the case in hindlimb motoneurons. In dR, M and U motoneurons, cortical stimulation produced E-type (84%) or M-type (16%) PSPs in fast motoneurons, while it evoked M-type (55%) or E-type (45%) PSPs in slow motoneurons. Patterns of PSPs in these motoneurons produced by cortical stimulation had a tendency similar to the case in triceps motoneurons; excitatory components of PSPs were predominant in fast motoneurons and inhibitory components were mainly observed in slow motoneurons. In most fast and slow Bi motoneurons, E-type or M-type PSPs were observed when the precruciate area was stimulated. With post-cruciate stimulation, however, excitatory components became smaller and inhibitory components were marked and changes in the pattern of PSPs were observed in 37% of motoneurons, as compared with precruciate stimulation. Thus, in Bi motoneurons, the qualitative difference of patterns of PSPs evoked by cortical stimulation in fast and slow motoneurons, as observed definitely in triceps motoneurons described avobe, was not clearly recognized.
用玻璃微电极记录了锥体猫前肢运动神经元的细胞内电位，记录是在对侧十字周皮层进行重复刺激之后进行的，并分析了由此诱发的突触后电位（PSP）模式。通过来自以下任一神经的逆向冲动来识别所测试的运动神经元：肱三头肌长头（lo.T）、外侧头（la.T）和内侧头（med.T）、肘肌（Anc）、肱二头肌（Bi）、桡神经深支（dR）、正中神经（M）和尺神经（U）。根据超极化后电位（AHP）的持续时间和轴突传导速度，将运动神经元分为快运动神经元和慢运动神经元。所有肘肌运动神经元和65%的肱三头肌内侧头运动神经元被归类为慢运动神经元。另一方面，35%的肱三头肌内侧头运动神经元、84%的肱三头肌长头和外侧头运动神经元被归类为快运动神经元。支配肱二头肌和控制腕部肌肉（桡神经深支、正中神经和尺神经）的运动神经元中，约70%被归类为快运动神经元，其余为慢运动神经元。对十字周皮层的重复刺激在67%的肘肌和56%的慢肱三头肌运动神经元中主要产生抑制性PSP（I型）或混合性PSP（M型），而在97%的快肱三头肌运动神经元中主要诱发兴奋性PSP（E型）。因此，皮层刺激在伸肘（肘肌和肱三头肌）运动神经元中产生的PSP模式，一般对快运动神经元是兴奋性的，对慢运动神经元是抑制性的，这与后肢运动神经元的情况类似。在桡神经深支、正中神经和尺神经运动神经元中，皮层刺激在快运动神经元中产生E型（84%）或M型（16%）PSP，而在慢运动神经元中诱发M型（55%）或E型（45%）PSP。皮层刺激在这些运动神经元中产生的PSP模式具有与肱三头肌运动神经元情况相似的趋势；PSP的兴奋性成分在快运动神经元中占主导，抑制性成分主要在慢运动神经元中观察到。在大多数快和慢的肱二头肌运动神经元中，当刺激十字前区时观察到E型或M型PSP。然而，与十字前区刺激相比，在十字后区刺激时，兴奋性成分变小，抑制性成分明显，并且在37%的运动神经元中观察到PSP模式的变化。因此，在肱二头肌运动神经元中，快和慢运动神经元中皮层刺激诱发的PSP模式的质的差异，不像上述肱三头肌运动神经元那样明确地被识别出来。
