*5.7. Brain Capillary Isolation*

Brain capillaries were isolated as previously described [18,72,86]. Mice were euthanised by CO<sup>2</sup> inhalation and decapitated, brains were removed, dissected, and homogenised in cold PBS buffer (2.7 mM KCl, 1.46 mM KH2PO4, 136.9 mM NaCl, 8.1 mM Na2HPO4, 5 mM D-glucose, 1 mM sodium pyruvate, pH 7.4). Ficoll® was added to the brain homogenate to a final concentration of 15% and the Ficoll®/brain mixture was centrifuged at 5800× *g* for 15 min at 4 ◦C. After resuspending the pellet in 1% BSA/PBS, the capillary suspension was passed over a glass bead column to purify capillaries from debris and red blood cells. Capillaries adhering to the glass beads were collected by gentle agitation in 1% BSA/PBS, washed with BSA-free PBS and used for experiments.
