AQP4 and brain edema: Altered AQP4 expression has been observed in a number of conditions including cerebral edema, neuromyelitis optica, epilepsy, brain tumor, Alzheimer’s disease, Parkinson’s disease, depression and drug addiction (Ribeiro Mde et al., 2006; Hirt et al., 2009; Zhao et al., 2012; Rajkowska and Stockmeier, 2013; Rajkowska et al., 2013; Di Benedetto et al., 2016).