Observations of the spinal ganglion cells of senile mice with the electron microscope

The fine structures of the nerve cells and the satellite cells in the spinal ganglia of senile mice (912 days old) were studied with the electron microscope. 1) A rem a rkable, densely-packed mass of the small granules and the endoplasmic reticula, corresponding to the Nissl bodies, could not be found in any nerve cells. 2) Granulation of the dense mitochondria was one of the remarkable changes of the mitochondria. Another striking change of the mitochondria was the formation of the dense conglomerate. 3) Vacuoles varying in size and shape were attached by the deformed mitochondria. An appearance of the bee-hive-like vacuoles was conspicuous. 4 ) Rarely, was there an appearance of a similar structure to the multivesicular bodies in the cytoplasm of the nerve cells and the satellite cells. 5) The dense inclusion bodies were abundantly found, not only in the cytoplasm of the nerve cells, but also in the cytoplasm of the satellite cells. 6) Multiple Golgi apparatus in small shape were dispersed irregularly throughout the cytoplasm of the nerve cells. In each Golgi zone, small Golgi vesicles were numerous. 7) Multiple, irregular shaped nucleoli were contained in a single nucleus of the nerve cells. Frequently, the nuclear membranes of the nerve cells showed irregular wavy lines.