OLFACTORY CELL-CULTURES ON ENSHEATHING CELL MONOLAYERS

Olfactory neurons dissociated from the olfactory mucosa of 4-5-week-ol d Sprague-Dawley rats are plated on either monolayers of ensheathing c ells or cortical astrocytes. It is found that the ensheathing cells su pport a slightly higher percentage of neurite-bearing olfactory neuron s than the astrocytes. Scanning electron microscopy shows that some of the cytoplasmic extensions of the ensheathing cells are closely assoc iated with the olfactory axons while others appear to ensheath them. O lfactory neurons grown on uncoated, poly-L-lysine or laminin-coated gl ass coverslips in the presence of medium conditioned by ensheathing ce lls fail to grow neurites, suggesting that interaction between membran e molecules, and not trophic factors, may be required for neurite grow th. However, it is unlikely that these membrane molecules are L1 and N -cadherin because immunohistochemical staining shows that only a small proportion of the cultured ensheathing cells express L1 (9%) and N-ca dherin (24%).