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Irradiation enhances hippocampus‐dependent cognition in mice deficient in extracellular superoxide dismutase
Author(s) -
Raber Jacob,
Villasana Laura,
Rosenberg Jenna,
Zou Yani,
Huang Ting Ting,
Fike John R.
Publication year - 2011
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.20724
Subject(s) - oxidative stress , superoxide dismutase , hippocampal formation , extracellular , hippocampus , chemistry , nitrotyrosine , oxidative phosphorylation , endocrinology , neuroscience , medicine , biochemistry , biology , enzyme , nitric oxide synthase
The effects of ionizing irradiation on the brain are associated with oxidative stress. While oxidative stress following irradiation is generally viewed as detrimental for hippocampal function, it might have beneficial effects as part of an adaptive or preconditioning response to a subsequent challenge. Here we show that in contrast to what is seen in wild‐type mice, irradiation enhances hippocampus‐ dependent cognitive measures in mice lacking extracellular superoxide dismutase. These outcomes were associated with genotype‐dependent effects on measures of oxidative stress. When cortices and hippocampi were analyzed for nitrotyrosine formation as an index of oxidative stress, the levels were chronically elevated in mice lacking extracellular superoxide dismutase. However, irradiation caused a greater increase in nitrotyrosine levels in wild‐type mice than mice lacking extracellular superoxide dismutase. These paradoxical genotype‐dependent effects of irradiation on measures of oxidative stress and cognitive function underscore potential beneficial effects associated with chronic oxidative stress if it exists prior to a secondary insult such as irradiation. © 2009 Wiley‐Liss, Inc.