Czéh G
Department of Anatomy, University Medical School, Pécs, Hungary.
Neuroscience. 1976 Dec;1(6):469-75. doi: 10.1016/0306-4522(76)90098-1.
Responses to ventral root stimulation were studied in spinal cords in situ in unanesthetized frogs. Extracellular as well as intracellular recordings from motoneurons indicated that considerable depolarization of the dendrites occurred in the response to ventral root volley. Active components of this dendritic depolarization could also be observed. Extracellularly, negative field potentials were recorded both in the vicinity of motoneuron cell bodies and in areas occupied mostly by motoneuron dendrites. The refractory period of the negativity recorded at the vicinity of dendrites was longer than in the vicinity of somata. Changes in antidromic excitability were studied by the double volley technique. Augmentation of the field potential to a test volley was observed during the period of dendritic depolarization, followed by a longer-lasting period of depression of the test response. It is concluded that an action potential in frog motoneurons induces depolarization of the dendrites. The depolarized dendrites can generate local action potentials and can produce negative field potentials remotely from the somatic pool. The response of dendrites to stimulation of the ventral root has particular importance in the recurrent facilitation of the frog motoneurons.
在未麻醉青蛙的脊髓原位研究了对腹根刺激的反应。运动神经元的细胞外和细胞内记录表明，在对腹根冲动的反应中，树突发生了相当程度的去极化。这种树突去极化的活性成分也可以观察到。在细胞外，在运动神经元细胞体附近以及主要由运动神经元树突占据的区域记录到负向场电位。在树突附近记录到的负电位的不应期比在胞体附近更长。通过双脉冲技术研究了逆向兴奋性的变化。在树突去极化期间观察到对测试脉冲的场电位增强，随后是测试反应的持续时间更长的抑制期。结论是，青蛙运动神经元中的动作电位会诱导树突去极化。去极化的树突可以产生局部动作电位，并可以在远离体细胞池的地方产生负向场电位。树突对腹根刺激的反应在青蛙运动神经元的反复易化中具有特殊重要性。
