Quantitative fluorescence microscopy provides high resolution imaging of passive diffusion and P-gp mediated efflux at the in vivo blood-brain barrier

Quantitative fluorescence microscopy provides significant insight into various fields. A novel method to calculate the blood to brain transfer rates of the dyes is presented. Rhodamine 123 is subject to p-glycoprotein mediated efflux and can be increased nearly 20-fold with p-glycoprotein inhibition. Once dyes have crossed the BBB, diffusion of the dye molecule is not instantaneous.