Cell migration from the olfactory neuroepithelium of neonatal and adult rodents.

This study reports the presence of olfactory cell clusters in postnatal and adult animals within the lamina propria of the olfactory mucosa and the nerve fiber layer of the olfactory bulb. The results obtained from mice and rats, partially or totally unilaterally bulbectomized, have been compared with observations in intact control animals. Light microscopic observation has shown that, in bulbectomized animals, the clusters are present in both experimental and normal sides and are usually associated with olfactory axon bundles. Moreover, when compared with intact animals, differences are present in terms of number of clusters and regions from where they originate. The morphological identity of the cells of the clusters with the globose basal cell of the olfactory neuroepithelium could be demonstrated with the electron microscope. By autoradiographic means, it was possible to show that they originate from the olfactory neurogenetic matrix and migrate along olfactory axon bundles. Interestingly, the migrating cells do not express olfactory marker protein. Altogether, these observations suggest that the olfactory matrix may be capable of originating neural elements other than olfactory receptor neurons.