轴突再支配过程中大鼠脊髓Ⅲ板层树突变化的电镜观察

本文利用保留背根(L4)的动物模型,电镜下观察测量了术后4天和35天大鼠脊髓Ⅲ板层树突的形态学变化。结果表明,树突在脊髓可塑过程中既没增加数目,也没改变直径。部份大中型树突内反而出现了由小到大,以致融合的泡状结构。我们认为,这些泡状结构是树突变性的又一形式。其早期作用可能是吸引轴突定向生长,晚期则阻碍或抑制冲动的传递。

ELECTRON MICROSCOPICAL OBERSERVATION ON CHANGES OF DENDRITES IN LAMINA III OF RAT SPINAL CORD DURING AXONAL REINNERVATION

The female rats were subjected to unilateral lumbar dorsal rhizotomy, sparing L4, allowed to survive for acute and chronic periods, the perfused and prepared for EM. The results indicated that neither number nor diameter of dendrites altered after operation. On the contrary, large and medium-sized dendrites appeared vacuoles which varied in size. It seems that large vacuoles formed by fusing of small one and of the hollowed out a dendrite. We suggest that those vacuoles are another kind of degeneration of dendrites whose degenerating produduets may stimulate the growth of axons toward to the target at the early phase. At the late phase, it may inhibil or obstruct transmission of impulse as destruction of dendrites.