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Localization and Characterization of Binding Sites with High Affinity for [ 3 H]Ouabain in Cerebral Cortex of Rabbit Brain Using Quantitative Autoradiography
Author(s) -
Antonelli Marta C.,
Baskin Denis G.,
Garland Miriam,
Stahl William L.
Publication year - 1989
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.1471-4159.1989.tb10916.x
Subject(s) - ouabain , cerebral cortex , cortex (anatomy) , chemistry , rabbit (cipher) , neuroscience , biophysics , biology , sodium , computer science , organic chemistry , computer security
[ 3 H]Ouabain binding was studied in sections of rabbit somatosensory cortex by quantitative autoradiography and in rabbit brain microsomal membranes using a conventional filtration assay. K D values of 8–12 n M for specific high‐affinity binding of [ 3 H]ouabain were found by both methods. High‐affinity binding was not uniformly distributed in somatosensory cortex and was localized predominantly to laminae 1,3, and 4. [ 3 H]Ouabain binding in tissue sections was stimulated by the ligands Mg 2+ /Pi or Mg 2+ /ATP/Na + and was inhibited by K + (IC 50 = 0.7–0.9 m M ), N ‐ethylmaleimide, 5,5′‐dithiobis(2‐nitrobenzoic acid), and erythrosin B. We conclude that [ 3 H]ouabain is reversibly and specifically bound with high affinity in rabbit brain tissue sections under conditions that favor phosphorylation of Na + ,K + ‐ATPase. Quantitative autoradiography is a powerful tool for assessing the affinity and number of specific ouabain binding sites in brain tissue.