Fine Structure of Nerve-Cell Bodies and Satellite Cells in the Trigeminal Ganglion

¹ Department of Anatomy, Medical School, University of Manchester, England

Electron micrographs were prepared from ultrathin sections of normal trigeminal ganglia, which were removed from rats, whose ages ranged fom 3 to 48 days, to determine the fine structure of neuron-cell bodies and their related satellite cells. The findings were correlated with light-microscope preparations that had been stained by routine histologic methods. Cytoplasmic features that were examined included mitochondria, Nissl bodies, the Golgi apparatus, dense inclusion bodies, and neurofilaments. These were compared with corresponding structures in the satellite cells.

Two morphologically distinct nerve-cell types were recognized, viz., dark cells, with an abundance of ribonucleoprotein granules throughout the cytoplasm, and pale cells, in which the granular material formed discrete aggregations. The possible correlation between the two cell types and the presence of myelinated and unmyelinated nerve fibers in the ganglion are discussed.