The fine structure of neurons and satellite cells in the trigeminal ganglion of cat and monkey.

Abstract

AbstractNeurons and satellite cells in the trigeminal ganglion of cats and monkeys fixed by aldehyde perfusion were examined in the electron microscope. The fixative employed and its tonicity appear to be critical factors in accounting for some of the differences noted in earlier descriptions. With satisfactory preservation, only one variety of neuron is seen on the basis of cytoplasmic and nuclear features, although there is a substantial size range. Interdigitating processes of neurons into the satellite cell capsule probably accounts for the axon terminals and intracapsular nerve nets reported in early metallic impregnation studies. Axonal glomeruli are encased in satellite cells and become myelinated by Schwann cells as the axon leaves the region of the neuron soma.Satellite cells reveal layers of attenuated processes forming unusual membrane complexes around the axons. The external surfaces of the satellite cells are completely invested with a prominent basal lamina, which is continuous with that surrounding the Schwann cell at the first “internode.”