Localization of extracellular superoxide dismutase in adult mouse brain

Extracellular superoxide dismutase (EC-SOD) is one of three mammalian SOD i sozymes. Although there is knowledge of the functional role of EC-SOD in ar teries, little is known about the function of EC-SOD in other tissues, incl uding the brain. As a first step toward improving our understanding of EC-S OD in the brain, pre studied the localization of EC-SOD in the central nerv ous system of the adult mouse using immunohistochemistry. We detected EC-SO D staining in a subpopulation of neurons throughout the brain as well as in tanycytes in the mediobasal hypothalamus. Particularly prominent EC-SOD st aining was observed in neurons of the hilar region of the hippocampus, the lateral habenular nucleus of the thalamus, and the suprachiasmatic nuclei o f the hypothalamus. Substantial numbers of neurons were distributed through out the striatum and cortex; the morphology and distribution of these cells was similar to neurons previously shown to contain the neuronal isoform of nitric oxide synthase. In contrast to other regions with prominent EC-SOD immunoreactivity, EC-SOD localization in tanycytes occurred in a region lac king a blood-brain barrier. The high levels of EC-SOD present in discrete p opulations of cells in these regions suggest that EC-SOD plays an important , specialized role in the physiology and/or pathology in the brain. (C) 199 9 Elsevier Science B.V. All rights reserved.