Fine structural features of light and dark cells in the trigeminal ganglion of the rat

Summary Prolonged fixation times and handling procedures designed to minimize the introduction of post mortem artifact were used in preparation of rat trigeminal ganglia for fine structural study. Larger, more numerous, light neurons and smaller, less numerous, dark neurons were observed. Major fine structural differences included a more discrete clumping of Nissl substance and more neurofilaments in the light compared with the dark cell. The results suggest that these differences are not artifacts of preparation.