Anterograde fluorescent labeling of olfactory receptor neurons by Procion and Lucifer dyes

The repetitive irrigation of lamprey and frog olfactory epithelia with the fluorescent dyes Procion yellow MX4R and Lucifer yellow VS, induced the uptake of these dyes by olfactory receptor neurons, resulting in selective staining of the latter. The stained receptors retained the dyes within their cytoplasm during cell dissociation procedures, which proved these fluorescent dyes to be useful cell markers for the identification of olfactory receptor neurons in dissociated cell mixtures.