Bertoni-Freddari C, Fattoretti P, Casoli T, Caselli U, Meier-Ruge W
Neurobiology of Aging Laboratory, Italian National Research Centers on Aging Research Department, Ancona, Italy.
Anal Quant Cytol Histol. 1996 Jun;18(3):209-13.
To search for a deterioration threshold of synaptic ultrastructure in physiologic aging and senile dementia of Alzheimer's type (SDAT).
The numerical density (Nu), average area (S) and surface density (Su) of the synaptic contact zones were investigated in the hippocampus and cerebellum from adults, elderly and SDAT patients by means of computer-assisted morphometry.
The Nu and surface Su densities of the synapses decreased while the size of S enlarged in elderly and SDAT patients vs. the adults. By plotting Nu vs. S, the adult group showed a very high percentage of small junctions. In contrast, elderly and dementia patients demonstrated two overlapping populations of enlarged contacts. In SDAT the synapse-to-neuron ratio was decreased by 48% in the hippocampus and by 56% in the cerebellum.
Our findings support the concept that the degeneration of synaptic contacts per se should be considered a crucial step in the progression of senile dementia, but the identification of a discrete deterioration threshold of synaptic morphology between aging and SDAT is not feasible at present.
探寻生理性衰老及阿尔茨海默型老年痴呆症（SDAT）中突触超微结构的恶化阈值。
通过计算机辅助形态测量法，对成年人、老年人及SDAT患者海马体和小脑中突触接触区的数值密度（Nu）、平均面积（S）和表面密度（Su）进行研究。
与成年人相比，老年人及SDAT患者突触的Nu和表面Su密度降低，而S的大小增大。通过绘制Nu与S的关系图，成年组显示出非常高比例的小连接。相比之下，老年人及痴呆患者表现出两个重叠的扩大接触群体。在SDAT中，海马体中突触与神经元的比例降低了48%，小脑中降低了56%。
我们的研究结果支持这样一种观点，即突触接触本身的退化应被视为老年痴呆症进展中的关键步骤，但目前尚无法确定衰老与SDAT之间突触形态离散恶化阈值。
