Fig. 6

Activation of NMDA receptor induces increased permeability of the BBB to various bioactive materials at the capillary level. A Activation of the NMDA receptor induces increased permeability to the immunoglobulin from peripheral system. C57/BL6 mouse was injected retro-orbitally with PBS, NMDA, NMDA with MK801, and MK801 for 1 min. Brain sections were stained with IgG (Green) to visualize the permeability upon its activation. Scale bar indicates 500 μm. B and C Signals of IgG in the parenchymal area for cortex (B) and ventral striatum (C) were measured and quantified by subtracting the total signal of IgG in the vascular area by that of vascular area and depicted as a graph (3 different area each from 3 different animals). D NMDA induces increased accumulation of Transferrin (Green), a marker for the representative transcytosis through the BBB. Scale bar indicates 75 μm. (E–H) Injection of the NMDA induces rapid upregulation of Glut1 and increased permeability to the fluorescently labeled 2-deoxyglucose (2-DG). E NMDA was injected brain sections were stained for Glucose transporter 1 (Glut1, Red). NeuN was counterstained for neuronal cell (Green). F Values of Glut 1 was divided by that of NeuN and the values were depicted as a graph (n = 4). Scale bar indicates 200 μm. G 10 nmol of near infrared (NIR)-2-DG with or without the NMDA was injected. Brain was sectioned and the accumulation of 2-DG (Green) in the brain was scanned with IRDye scanner. Scale bar indicates 2 mm. H Intensity of NIR-2-DG from (G) was quantified and depicted as a graph (n = 3, two-tailed unpaired student t-test, ** indicates where p < 0.01)