Chronic exposure to moderate hypoxia elicits structural and functional changes in the microvascular network of the mammalian CNS. Hypoxia-induced angiogenesis can be elicited and studied by a relatively simple experimental method. Rats or mice can be exposed to mild hypoxia in a hypobaric chamber, or alternatively in a normobaric hypoxia chamber. After 3 weeks, the animals are perfused and fixed, the brain removed, and paraffin embedded and sectioned at 5 μm. The sections are stained for the blood-brain barrier glucose transporter (GLUT-1) by immunohistochemistry, capillary profiles identified and counted as a measure of angiogenesis.