We describe a simple and low cost technique for introducing high concentration of fluorescent and calcium-sensitive dyes into neurons or any neuronal tract using a polyethylene suction pipette.
Blivis, D., O'Donovan, M. J. Retrograde Loading of Nerves, Tracts, and Spinal Roots with Fluorescent Dyes. J. Vis. Exp. (62), e4008, doi:10.3791/4008 (2012).