This article reviews recent studies on the alterations occurring in the brain vessel wall of the mdx mouse, an animal model with genetic defects in a region homologous with the human Duchenne muscular dystrophy (DMD) gene. These alterations affect both endothelial and astroglial cells and are associated with opened tight junctions, swollen perivascular astrocyte processes and a reduction in the expression of tight junctions associated proteins, ie. zonula occludens and of a specific water channel i.e. aquaporin-4, suggesting that some neurological dyspfunctions of mdx mice and DMD patients could be associated with changes in brain osmotic equilibrium.