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Studies on the effects of chronic ethanol ingestion on the properties of rat brain ribosomes
Author(s) -
Tewari Sujata,
Murray Sandara,
Noble Ernest P.
Publication year - 1978
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490030509
Subject(s) - ribosome , biochemistry , ribosomal rna , ethanol , in vivo , phenylalanine , chemistry , sucrose , puromycin , protein subunit , eukaryotic large ribosomal subunit , rna , biology , protein biosynthesis , amino acid , gene , microbiology and biotechnology
Previous observations have demonstrated decreased in vivo and in vitro protein synthesis by brain ribosomal systems following long‐term ethanol ingestion. For further investigation of the properties of brain ribosomes, the 40S and 60S ribosomal subunits were successfully isolated from control and chronic 10% ethanol‐drinking rats. For a successful dissociation of ribosomes into subunits NH 4 CI, puromycin and a high‐salt treatment at 10°C were essential with a critical concentration of Mg 2+ since ribosomes could not be resolved at less than 7 mM Mg 2+ . Analysis of the A 260 profile of the subunits on the sucrose gradients showed no significant differences between the control and ethanol‐ingesting groups. Studies on 3 H‐labeled ribosomes following in vivo RNA labeling showed correspondence of the radioactive profiles from the incorporation of [5‐ 3 H] orotic acid into RNA with the sucrose gradient absorbance profile of 60S and 40S ribosomal subunits. Furthermore, active reassociation of both subunits occurred at 37°C as demonstrated by the increased [ 14 C]‐phenylalanine incorporation in the presence of poly(U). Results further showed that the poly(U)‐dependent [ 14 C] phenylalanine incorporation was significantly reduced by the subunits from the ethanol‐ingesting animals. These findings suggest that long‐term ingestion of ethanol caused functional changes in the properties of brain ribosomes, specifically on the reassociation process of the two subunits.