Nuclear bodies, similar to those described in various types of cells, are frequently observed in the sympathetic neurons of the rabbit superior cervical ganglia both before and after postganglionic section. The bodies are 0.3 to 1.5 μ in diameter and either consist of spheres of finely granular material or else possess a dense outer cortex surrounding a less dense central zone which may contain small dense masses similar to chromatin and/or large (500 Å) or small (200 Å) dense granules. Many bodies of the latter type are unusual in that their central regions are filled with dense parallel filaments (50 and 100 Å in diameter). The thicker filaments are often arranged in an hexagonal array.

The function of nuclear bodies is unknown although they have been implicated in protein synthesis. Counts of nuclear bodies were made in a large number of normal nerve cell nuclei and compared with those present in a similar number of neurons at various times after axon section. However no statistically significant difference in the numbers of nuclear bodies could be detected between normal and chromatolytic neurons. Thus the increased protein synthesis following axon section does not affect the number or structure of neuronal nuclear bodies.