Madeira M D, Azevedo F P, Paula-Barbosa M M
Department of Anatomy, Porto Medical School, Portugal.
Histol Histopathol. 1988 Oct;3(4):351-9.
Abundant ectopic granule cells scattered in the cerebellar molecular layer have been observed in 30-day-old hypothyroid rats. Their morphological features indicate that they must be regarded as mature heterotopic cells arrested during their migration towards the granular layer. As their impoverished dendritic trees are identical to those seen in controls, it is unlikely that the lack of thyroid hormones played a major role in the deficient dendritic outgrowth. The study of 180-day-old hypothyroid rats revealed that although ectopic granule cells remained quite numerous, their number per unit surface was lesser than in the 30-day-old hypothyroid group. This finding may be related to the capacity displayed by heterotopic neurons to establish synaptic contacts with the components of the molecular layer. This was inferred by the presence of a peculiar synaptic cell investment formed by axosomatic and somatodendritic contacts in 180-day-old hypothyroid rats which shows that the surviving ectopic granule cells manage to adapt to an adverse milieu.
在30日龄的甲状腺功能减退大鼠中，观察到大量异位颗粒细胞散布于小脑分子层。它们的形态特征表明，必须将它们视为在向颗粒层迁移过程中停滞的成熟异位细胞。由于它们发育不良的树突与对照组中所见的相同，甲状腺激素缺乏在树突生长不足中不太可能起主要作用。对180日龄甲状腺功能减退大鼠的研究表明，尽管异位颗粒细胞仍然相当多，但每单位面积的数量比30日龄甲状腺功能减退组少。这一发现可能与异位神经元与分子层成分建立突触联系的能力有关。这是通过180日龄甲状腺功能减退大鼠中由轴体和体树突接触形成的特殊突触细胞包裹的存在推断出来的，这表明存活的异位颗粒细胞设法适应了不利的环境。
