大鼠下丘脑弓状核年龄性变化的电镜观察

电镜观察大鼠下丘脑弓状核超微结构的年龄变化。结果发现:衰老大鼠弓状核的年龄变化主要发生在弓状核中的暗细胞神经元,出现粗面内质网退化变短,排列失序;高尔基氏器缩小;多聚核蛋白体和神经内分泌物质明显减少。特别引人注目的是在部分暗细胞中出现由双层膜缠绕形成的膜性涡旋体结构。此外,在神经毯出现突触结构异常。突触厚度变薄、间断不连续;神经胶质细胞突起增多,并可进一步形成包绕树突、轴突终末、甚至突触的多层膜环绕的髓鞘样结构。上述研究结果提示,下丘脑弓状核超微结构的年龄性变化是导致神经内分泌系统衰老的主要原因之一。

ULTRASTRUCTURAL STUDY OF AGE-RELATED CHANGES IN THE ARCUATE NECLEUS

Ultrastructure of rat arcuate nucleus during ageing were observed by electron microscope. The age-related changes mainly occurred in dark cells of the arcuate nucleus. The RER became shorter and arranged orderlessly; Golgi complex were smaller: ribosome and neurosecretory granules were apparently decreased. However, The most significant change was that there were endoplasmic reticular whorls in some dark cells of old rats. In addition, The synapses showed some pathologic changes such as thinning, shortening and interuption of synaptic contacts. The processes of neuroglial cell were increased and a special lamellated membranous, myelin sheath-like structures enclosing dendrites, axon terminals and even synapses were found in old rats. These morphologic age-related changes might result in disfunction of neurosecretory cells in the hypothalamus.