Small, Intensely Fluorescent Granule-containing Cells in the Sympathetic Ganglion of the Rat

Abstract

In a study, among typical ganglion cells, occasional small cells were observed to exhibit an extremely bright yellow fluorescence. It was later shown that the fluorescence of these cells, called ‘small intensely fluorescent cells’ (SIF cells) remained essentially unchanged after division of pre- or postganglionic nerves close to the ganglion although the latter caused an almost complete disappearance of histochemically demonstrable catecholamines from the cytoplasm of the ordinary ganglion cells. The small cells were, therefore, considered a new variety of non-chromaffin amine-storing cells, and because the color of the fluorescence was yellow, a monoamine, perhaps 5-hydroxytryptamine, was thought to be stored in the secretory granules of the SIF cells in the same manner as catecholamines in the adrenal medulla. The study presented in this chapter was undertaken to study the constancy, number, and distribution of the SIF cells, as yet almost unexamined, as well as the problem of the amine responsible for their intense formaldehyde-induced fluorescence. Sometimes the SIF cell processes surrounded ganglion cells in intimate contact with them, and their beadings were impinging on the ganglion cell cytoplasm. Clusters of SIF cells were also observed among nerve tracts inside the ganglion in preganglionic or postganglionic nerve trunks near the ganglion and sometimes directly on ganglion cell bodies. © 1971, Elsevier B.V. All rights reserved.