Preparation of plasma membrane from isolated neurons

A bulk fraction enriched with respect to neuronal ceil bodies was used as starting material for the isolation of neuronal plasma membrane The cells were gently homogenized in isotonic sucrose and a crude membrane containing fracuon sedimented at 3000 g. Subsequently, the membrane fraction was purified on a discontinuous sucrose density gradient between 35 % and 25 5 % sucrose (w/w). Enzymatic analyses showed a 4-5-fold enrichment in plasma membrane markers, and a 10-15% contamination of mitochondrial and microsomal mate-riM. Electron mmrographs of the membrane fraction confirmed the enzymatic data Fragmented membranes were found, mainly in vesicular form No ribosomes, but a few mitochondria and some multilamellar membranes were seen.