| 1629744 |
Greenamyre JT, Higgins DS, Eller RV: Quantitative autoradiography of dihydrorotenone binding to complex I of the electron transport chain. Arterioscler Thromb Vasc Biol. 2006 Dec;26(12):2614-21. Epub 2006 Oct 5.
Defective complex I activity has been linked to Parkinson's disease and Huntington's disease, but little is known of the regional distribution of this enzyme in the brain. We have developed a quantitative autoradiographic assay using [3H] dihydrorotenone ([3H] DHR) to label and localize complex I in brain tissue sections. Binding was specific and saturable and in the cerebellar molecular layer had a KD of 11.5 +/- 1.3 nM and a Bmax of 11.0 +/- 0.4 nCi/mg of tissue. Unlabeled rotenone and 1-methyl-4-phenylpyridinium ion competed effectively for DHR binding sites. Binding was markedly enhanced by 100 microM NADH. The distribution of complex I in brain, as revealed by DHR autoradiography, is unique but somewhat similar to that of cytochrome oxidase (complex IV). This assay may provide new insight into the roles of complex I in brain function and neurodegeneration. |
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