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Autoradiographic study of iron‐binding sites in the rat brain: Distribution and relationship to aging
Author(s) -
Barkai A. I.,
Durkin M.,
Dwork A. J.,
Nelson H. D.
Publication year - 1991
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.490290314
Subject(s) - binding site , chemistry , biophysics , white matter , substantia nigra , lipid peroxidation , cerebral cortex , parenchyma , biochemistry , biology , endocrinology , antioxidant , medicine , botany , dopaminergic , radiology , magnetic resonance imaging , dopamine
Specific binding of 59 Fe to various brain structures was investigated in rats using nanomolar concentrations of 59 FeCl 3 and quantitative aiitoradiography. Saturation studies revealed high affinity binding ( k d in the nanomolar range) with binding sites density ( B max ) which varied in different brain regions from 462 fmol per mg tissue in the central thalamic nuclei to over 4 pmol per mg tissue in the cerebral peduncle. Binding was seen in both white and gray matter structures. B max values for frontal cortex, dentate gy‐rus, and substantia nigra were significantly lower in older rats. The distribution of 59 Fe binding sites was not consistent with the distribution of brain iron as reported by other investigators. 59 Fe binding was reduced significantly in the presence of free radicals. These observations suggest that high affinity binding sites for iron are localized differentially in various brain structures and may play an important role in the translocation and storage of potentially harmful ferric cations in brain. The finding that the capacity of the brain tissue to bind iron diminished with age in discrete brain regions suggests that in the aged animal, the removal of “free” iron from the cellular domain may be impaired in such regions, leading to increased susceptibility to iron‐enhanced lipid peroxidation and cell death.