On the one hand, the deletion of α-syntrophin, accompanied by the downregulation of AQP4 in the perivascular membranes of astrocytes, delays/diminishes the development of brain edema in a model of acute hyponatremia as well as after water intoxication, middle cerebral artery occlusion, terminal ischemia/anoxia and hypoosmotic stress [6], [11], [12]. Here, AQP4 is linked to ischemia.