title: The buoyant density of synaptic plasma membranes from the cerebral cortex of neonatal rats.
abstract: A fraction enriched in synaptic plasma membranes was prepared from neonatal (5-6 day old) rat cerebral cortex. The procedure was based on a method used to prepare synaptic plasma membranes from adult cerebral cortex. Critical steps were monitored by electron microscopy. Synaptic plasma membranes from neonatal cerebral cortex sedimented as a broad peak between 0.9 M and 1.1 M sucrose. In contrast, the majority of adult synaptic plasma membranes have been reported to sediment to 1.2 M sucorose. The activities of various enzyme markers were determined in subfractions of neonatal preparations in order to estimate contamination. The specific activities of these markers indicated substantial contamination of the neonatal synaptic plasma membrane fractions by microsomes and glia.
mesh_terms: D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000032:analysis; D000251:Adenosine Triphosphatases / Q000032:analysis; D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D002458:Cell Fractionation / Q000379:methods; D002540:Cerebral Cortex / Q000648:ultrastructure*; D003576:Electron Transport Complex IV / Q000032:analysis; D005260:Female; D009251:NADPH-Ferrihemoprotein Reductase / Q000032:analysis; D009708:Nucleotidases / Q000032:analysis; D011188:Potassium / Q000494:pharmacology; D012313:RNA / Q000032:analysis; D051381:Rats; D012964:Sodium / Q000494:pharmacology; D013570:Synaptic Membranes / Q000032:analysis / Q000201:enzymology / Q000648:ultrastructure
chemical_list: D012313:RNA; D012964:Sodium; D009251:NADPH-Ferrihemoprotein Reductase; D003576:Electron Transport Complex IV; D009708:Nucleotidases; D000469:Alkaline Phosphatase; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D000251:Adenosine Triphosphatases; D011188:Potassium