A protein-free diet changes synaptosomal membrane fluidity and tyrosine and glutamate transport.
Synaptosomes were isolated from cerebrums of rats fed standard (20% protein) or protein-free diets for 30 days. Arrhenius plots of their (Na+/K+)ATPase activities revealed a transition temperature of 25.5 degrees C for control rats and 23.4 degrees C for rats on protein-free diet, indicating that the latter increases synaptosomal membrane fluidity. The only change observed in the composition of the synaptosomal membranes was a 26% decrease of sialic acid. In synaptosomes from rats on protein-free diet the uptake of tyrosine was slightly reduced while that of glutamate was not affected. However, the exit of glutamate was reduced.
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Instituto de Investigaciones Citológicas de la Caja de Ahorros de Valencia, Spain.
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Grisolía
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D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D004044:Dietary Proteins / Q000378:metabolism*; D005971:Glutamates / Q000493:pharmacokinetics*; D018698:Glutamic Acid; D008297:Male; D008560:Membrane Fluidity; D008565:Membrane Proteins / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D012794:Sialic Acids / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism*; D014443:Tyrosine / Q000493:pharmacokinetics*
D004044:Dietary Proteins; D005971:Glutamates; D008565:Membrane Proteins; D012794:Sialic Acids; D018698:Glutamic Acid; D014443:Tyrosine; D000254:Sodium-Potassium-Exchanging ATPase; D019158:N-Acetylneuraminic Acid