Studies on sodium transport in rat brain nerve-ending particles.
(1) Nerve-ending particles isolated from crude mitochondrial preparations from rat brain by discontinuous Ficoll density gradient ultracentrifugation were shown to possess a Mg2+ and energy-dependent transport system for Na+. (2) Ouabain or iodoacetate plus cyanide exerted an inhibitory effect on the outflux but not the influx of Na+. (3) When K+ was added to a medium containing particles loaded with Na+ (22Na), an immediate release of Na+ from these particles was observed; this suggests the existence of a Na+-K+ exchange transport system. (4) The K+ effect was inhibited by 10(-4) M-ouabain only at low (about 3.3 mM), but not at high (20 mM), K+ concentrations. (5) The uptake and release of Na+ by the nerve-ending particles were found to be temperature-dependent. (6) Only nerve-ending particles with intact synaptosomal membranes were found to transport Na+ actively.
Illinois State Pediatric Institute, Department of Psychiatry University of Illinois College of Medicine, USA.
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Ling
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Abdel-Latif
D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D007461:Iodoacetates / Q000494:pharmacology; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology; D046529:Microscopy, Electron, Transmission; D009411:Nerve Endings / Q000187:drug effects / Q000502:physiology*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000378:metabolism*; D012975:Sodium Isotopes / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects; D013696:Temperature; D013997:Time Factors
D007461:Iodoacetates; D012975:Sodium Isotopes; D010042:Ouabain; D012964:Sodium; D011188:Potassium