Effect of Guanethidine on the Ultrastructure of the Small, Granule‐containing Cells in Cultures of Rat Sympathetic Ganglia1

Abstract

Abstract:Sympathetic chain ganglia of newborn rats were cultured in Rose chambers with and without guanethidine. After one week, the cultures were examined by light microscopy for formaldehyde‐induced catecholamine fluorescence and by electron microscopy after fixation in 5% glutaraldehyde and 1% osmium tetroxide. Guanethidine sulphate (2 mg/l) caused an increase in the number of the small, intensely fluorescent (SIF) cells in the ganglion explants. Electron microscopic examination of guanethidine‐containing cultures revealed an increased number of small, granule‐containing (SGC) cells, which corresponded in size and shape to the SIF cells. Round vesicles (about 100 nm in diameter) and elongated vesicles (about 80 nm in cross section and about 200 nm in length) containing an electron‐dense core were observed in the cytoplasm of the SGC cells both in control and guanethidine‐containing cultures. The granular vesicles were most frequent in the periphery of the cytoplasm. In ganglia cultured with guanethidine, most SGC cells observed contained a greatly reduced number of granular vesicles as compared to SGC cells of the control cultures.