AQP4 and Cerebral ischemia: The present study is the first to examine post-ischemic changes in Aqp4 expression or localization in cerebral white matter, and is the first to contrast these changes with those that occur in grey matter astrocytes; all other studies of Aqp4 in the context of cerebral ischemia have focused on grey matter [32–34, 46, 47, 57–59].