DIFFERENTIATION AND SURVIVAL OF RAT OLFACTORY EPITHELIAL NEURONS IN DISSOCIATED CELL-CULTURE

Olfactory epithelial neurons in mammals are unique in that they continue to differentiate from precursor cells in the adult. These neurons extend long axons into the olfactory bulb. Previous attempts to grow these cells in dissociated cell cultures at low density, have not been entirely satisfactory. We report that when plated at very low density, rat olfactory epithelial neurons will differentiate morphologically and biochemically when cultured on astrocytes, but not on non-cellular substrata, such as polylysine, laminin or fibronectin. We demonstrate with antibodies, that these olfactory epithelial neurons require N-CAM, N-cadherin and L1 for neurite extension. Furthermore, synthetic cadherin-peptides containing the tripeptide HAV which is found in the first extracellular domain of N-cadherin, as well as the amino acids flanking this region, appear to be important in cadherin-mediated neurite growth on astrocytes. Astrocytes also appear to enhance the survival and differentiation of olfactory epithelial neurons from embryonic day 15 and 4-5 week post-natal rats, but this effect is not sustained beyond 5 days in cultures of postnatal epithelium.