Fattoretti P, Bertoni-Freddari C, Caselli U, Paoloni R
Centre for Surgical Research, INRCA Research Department, Ancona.
Boll Soc Ital Biol Sper. 1995 May-Jun;71(5-6):119-24.
A computer-assisted morphometric study has been carried out on the ultrastructural features of the cholinergic synaptic junctional areas in the dentate gyrus supragranular layer of 11-month-old female Wistar rats and in littermates fed a vitamin E deficient diet for 10 months. The number of synapses/micro m(3) (numerical density: Nv), the average area of the junctional zones (S) and the total synaptic contact area/micro m(3) (surface density: Sv) were the three parameters taken into account. Nv and Sv significantly decreased, while S increased in the vitamin E deficient group. A size distribution of S showed that while in the normally fed animals the percentage of an enlarged synapses (0.16 micro m(2)>) accounts for 19% of the whole population, in the vitamin E deficient rats it raises at 44%. Relating the number of synapses to the number of dentate gyrus granule cells, the synapse-to-neurone ratio appeared to be decreased by 30% in the vitamin E deficient animals. It is currently reported that number (Nv) and size (S) of the synapses are in a close inverse relationship which aims at maintaining constant the total synaptic surface area (Sv) in a discrete volume of the neuropil, therefore, taken together per experimental group of rats, these parameters represent a reliable index of the synaptic morphological plasticity. Our present findings clearly document that the structural dynamics of the hippocampal cholinergic synapses are markedly affected by the absence of vitamin E from the diet and, in turn, support that an increased peroxidative stress may play a central role in the widely reported vulnerability of the cholinergic terminals with advancing age.
对11月龄雌性Wistar大鼠齿状回颗粒上层胆碱能突触连接区域的超微结构特征，以及喂食10个月维生素E缺乏饮食的同窝幼崽进行了计算机辅助形态计量学研究。考虑了三个参数：每立方微米的突触数量（数值密度：Nv）、连接区的平均面积（S）和每立方微米的总突触接触面积（表面密度：Sv）。在维生素E缺乏组中，Nv和Sv显著降低，而S增加。S的大小分布表明，正常喂食的动物中，增大的突触（>0.16平方微米）的百分比占整个群体的19%，而在维生素E缺乏的大鼠中，这一比例升至44%。将突触数量与齿状回颗粒细胞数量相关联，维生素E缺乏的动物中突触与神经元的比例似乎降低了30%。目前报道，突触的数量（Nv）和大小（S）呈密切的反比关系，目的是在神经毡的离散体积中保持总突触表面积（Sv）恒定，因此，每组实验大鼠的这些参数共同代表了突触形态可塑性的可靠指标。我们目前的研究结果清楚地证明，饮食中缺乏维生素E会显著影响海马胆碱能突触的结构动态，进而支持增加的过氧化应激可能在广泛报道的胆碱能终末随着年龄增长而出现的易损性中起核心作用。
