LIGHT AND ELECTRON-MICROSCOPIC DEMONSTRATION OF CHOLESTEROL DISTRIBUTION IN MEMBRANE STRUCTURES OF THE RAT AUDITORY-CORTEX

As part of our investigations on the changes in the cortex of differen t stages of ontogeny, the aim of this study was to analyse the cholest erol distribution in the auditory cortex of adult rats. The light micr oscopic Schultz reaction as well as electron microscopic thin sections and freeze-etching combined with a cholesterol specific marker were a pplied to cholesterol demonstration. High and low cholesterol areas we re found in the plasma membrane and membranes of some organelles. A lo w cholesterol content was observed in the membranes of the Golgi appar atus, mitochondria and junctional contacts. A very low cholesterol con tent was found in the pre- and postsynaptic membranes. High cholestero l contents were present in the neuronal and glial non-junctional plasm a membranes. The cholesterol distribution in the membranes of the endo plasmic reticulum and nuclear envelope appeared to be different.