QUANTITATIVE ULTRASTRUCTURAL EVIDENCES SUGGEST NO AGE-RELATED-CHANGESIN BIOSYNTHESIS AND PROCESSING WITHIN PARVOCELLULAR CELLS OF THE PARAVENTRICULAR NUCLEUS IN HAMSTERS

The parvocellular neurons of the parvocellular division of the paraven tricular nucleus (PVPA) were studied in hamsters at six point ages (fr om 3 to 30 months old). Standard manual morphometric techniques were u sed to obtain data of parvocellular activity including nuclear and nuc leolar size, as well as the percentage of the cell occupied by Golgi a pparatus (GA), mitochondria and rough endoplasmic reticulum (RER). Oth er directly age-related parameters like amounts of nuclear invaginatio n and lipofuscin have also been studied. No significant differences in the measured subcellular components were detected among groups studie d, 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 parvocellu lar neurons during aging. Ultrastructural morphometric observations in parvocellular neurons are discussed in relation to synthesizing activ ity and hormone production during aging. (C) 1998 Elsevier Science Ire land Ltd. All rights reserved.