Quantitative ultrastructural evidences suggest no age-related changes in biosynthesis and processing within parvocellular cells of the paraventricular nucleus in hamsters

The parvocellular neurons of the parvocellular division of the paraventricular nucleus (PVPA) were studied in hamsters at six point ages (from 3 to 30 months old). Standard manual morphometric techniques were used to obtain data of parvocellular activity including nuclear and nucleolar size, as well as the percentage of the cell occupied by Golgi apparatus (GA), mitochondria and rough endoplasmic reticulum (RER). Other directly age-related parameters like amounts of nuclear invagination and lipofuscin have also been studied. No significant differences in the measured subcellular components were detected among groups studied, except slight increases in lipofuscin. No age-related changes were found in the synthesizing apparatus, but a significant decrease in the cell area was observed in older groups. This finding could suggest a reduction in absolute terms in the protein synthesis of the parvocellular neurons during aging. Ultrastructural morphometric observations in parvocellular neurons are discussed in relation to synthesizing activity and hormone production during aging. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.