The Golgi apparatus of satellite cells associated with spinal ganglion neurons: changes with age in the rabbit.

We studied the Golgi apparatus in the satellite cell sheaths enveloping spinal ganglion neurons of rabbits aged 12, 42, and 79 months. We found neither structural changes nor indications of peripheral displacement of this organelle with advancing age. The mean percentage of cytoplasmic volume occupied by the Golgi apparatus decreased significantly passing from young adult to old rabbits. This decrease was only in very minor part a consequence of lipofuscin accumulation, so that the ratio between the total volume of the Golgi apparatus and the functionally active volume of cytoplasm decreased with age. The mean cytoplasmic volume of perineuronal satellite cell sheaths did not change significantly with increasing age, whereas the total volume of the Golgi apparatus within these sheaths decreased significantly with age. This decrease strongly suggests that the activity of satellite cells diminishes in old age, further suggesting that these cells are unable to compensate for the decrease in the neuronal metabolism that a number of authors have described in old age.