Procion Brown: An Intracellular Dye for Light and Electron Microscopy

Abstract
Procion browvn has been used to inject lamprey giant interneutros. The dye is opaque to both light and electrons, and imparts a pink color to the neuron in situ during iontophoresis. It has the advantage over cobaltolus chloride that postinjection treatment with ammonium sulfide is eliminated and the integrity of the surrounding neuropil is ensured.