Isolation of plasma membranes from rat brain.

Abstract A method is described for the isolation of plasma membranes from synaptosomal fractions prepared on isotonic Ficoll density gradients. Fractions obtained were analysed chemically and enzymatically and appear to be over 85% plasma membrane. The major contaminant consists of outer mitochondrial membranes, presumably released from mitochondria during the osmotic shock treatment. Putative neuronal membrane markers, gangliosides and sodium, potassium-dependent ATPase, were enriched over 10-fold in these membranes in comparison to the homogenate. Low activities of 2′,3′-cyclic AMP 3′-phosphohydrolase were detected in these membrane preparations, which suggests some contamination with glial cell plasma membrane. The suitability of these preparations for chemical, enzymatic and metabolic studies is discussed.