[Age-related morphological changes in the suprachiasmatic nucleus of the rat hypothalamus]

A comparative ultrastructural investigation of the hypothalamic suprachiasmatic nuclei (SCN) of young, adult and senescent SD male rats was carried out. The neurons and neuroglial cells in SCN of the senile rats displayed more lipofuscin (Lipo) accumulation in comparison with those of the younger animals. Golgi apparatus (Gol) of the three age groups converted from well-ordered cisternae to irregular ones with extensive dilatation and vacuolization. More neuroglial cells with broader somatic membrane appositional to that of neuron participated in satellitosis in the senile age group. Some unusual structures such as special arrangements of the rough endoplasmic reticula and multilamellar neuroglial envelope (Mge) wrapping neurite were encountered in the perikarya of some neurons or SCN neuropile respectively.