Developmental aspects and neuronal regeneration in the vomeronasal neuroepithelium.

In many vertebrates the vomeronasal organ (VNO) is utilised to detect small non-volatile molecules (pheromones) released in the ambient by conspecifics, which are able to affect the sexual and social behaviour. Pheromone receptors are exposed on sensory bipolar neurones localised in the neuroepithelium of the VNO; central projections of the sensory neurones make synapse in the accessory olfactory bulb. The vomeronasal neuroepithelium develops from the olfactory placode; therefore, in the fetus, the axons of developing sensory neurones are precisely guided to their target in the telencephalon. In the post-natal life, vomeronasal neurones undergo continuous turnover, similar to the main olfactory epithelium, and the axons new neurones must reach the accessory olfactory bulb to establish proper synaptic connections. Therefore, the vomeronasal neuroepithelium is well suited to investigate the mechanisms of axonal guidance and neuronal regeneration. The present review is a synthesis of work carried out in the last several years on the developmental and post-natal regeneration patterns of the vomeronasal neuroepithelium.