Olfactory cell cultures on ensheathing cell monolayers.

Olfactory neurons dissociated from the olfactory mucosa of 4-5-week-old Sprague-Dawley rats are plated on either monolayers of ensheathing cells or cortical astrocytes. It is found that the ensheathing cells support a slightly higher percentage of neurite-bearing olfactory neurons than the astrocytes. Scanning electron microscopy shows that some of the cytoplasmic extensions of the ensheathing cells are closely associated with the olfactory axons while others appear to ensheath them. Olfactory neurons grown on uncoated, poly-L-lysine or laminin-coated glass coverslips in the presence of medium conditioned by ensheathing cells fail to grow neurites, suggesting that interaction between membrane molecules, and not trophic factors, may be required for neurite growth. 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-cadherin (24%).