Isolation of mature olfactory neurones using retrograde labelling and flow cytometry

Currently we can observe an increasing interest for epithelial olfactory neurones. Several laboratories are involved in elucidation of the odorant-molecule recognition process and transduction cascade which brings information to the olfactory bulb. Others use this model, unique in mammals, to accumulate new knowledge on the neurogenesis phenomenon. Here we describe a simple and efficient method to purify mature olfactory neurone populations extracted from the nasal cavity. The approach relies on retrograde axonal tracing followed by flow cytometry sorting. For this purpose we inject a fluorescent dye (Fast Blue or diI C18(3)) in the olfactory bulb of adult rats. Seven days later, we extract the nasal turbinates and separate the mucosa from the subjacent lamina propria. The tissue is enzymatically dissociated and the labelled cells are sorted with a flow cytometer. Purification of the mature olfactory neurones varies from 80 to 99%.