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PRECURSOR INCORPORATION INTO CORTICAL PROTEIN DURING FIRST EXPOSURE OF RATS TO LIGHT; CELLULAR LOCALIZATION OF EFFECTS
Author(s) -
Rose S. P. R.,
Sinha A. K.,
Broomhead S.
Publication year - 1973
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1973.tb05999.x
Subject(s) - neuropil , visual cortex , biology , cortical spreading depression , in vivo , cortex (anatomy) , medicine , endocrinology , chemistry , neuroscience , biochemistry , central nervous system , microbiology and biotechnology , migraine
—The rate of incorporation of [ 3 H]lysine into acid‐insoluble material in vivo was determined in neurons and neuropil from the visual cortex of dark‐reared rats, littermates exposed to the light for varying lengths of time and normally reared controls. Following onset of light exposure, the elevation of incorporation was confined to the neuronal fraction. On continuous exposure for up to 96 h, the level of incorporation in the neuronal fraction dropped to that of the dark control value. In dark‐reared animals, the rate of incorporation in the neuronal fraction was 68 per cent of that in neuropil, in normals it was 150 per cent. On onset of exposure, the ratio in light exposed animals approached the normal level, but on prolonged continuous exposure both light exposed and normal ratios dropped to the dark control value once more. This drop did not occur if the animals were exposed to a 12 h light/dark cycle. These results are taken as suggesting that part of the protein synthesis of the visual cortex is functionally controlled, and that neuronal and neuropil fractions show a metabolic relationship which can be affected by environmental changes. The failure to show a depression of incorporation in prolonged exposure, by comparison with earlier results under somewhat different behavioural conditions, was taken as further evidence for the ‘state‐dependence’ of a number of brain biochemical parameters.