On lipid inclusions in the neurosecretory cells of the supraoptic nucleus of the white mouse subjected to a chronic salt load

Summary The morphology of the neurosecretory cells of the supraoptic nucleus of white mice on the 3rd, 6th, 10th, 14th, 18th and 30th days after loading animals with 5% NaCl was studied with electron, phase contrast, and light microscopy. Lipid droplets were rarely observed in the cytoplasm of intact animals whereas the number of cells containing lipids, as well as the number and the sizes of the inclusions themselves increased during the experiment. The form and the degree of osmiophilia of the lipid inclusions were found to depend on the fixation method. Empty vacuoles were observed in preparations stained with gallocyanin or paraldehyde-fuchsin and counterstained with Heidenhain's azan. These vacuoles correspond to lipid droplets in electron micrographs because of their localization in adjacent sections, the moment of their appearance in the experiment, and the dynamics of their increase. Solubility of these droplets in ortho-xylol is an additional argument for their lipid nature and accounts for the presence of empty vacuoles. Accumulation of lipids in the neurosecretory cells took place against the background of the extremely increased functional activity of these cells due to intensification of the secretory process.