OLFACTORY ENSHEATHING CELLS DO NOT REQUIRE L-ASCORBIC-ACID IN-VITRO TO ASSEMBLE A BASAL LAMINA OR TO MYELINATE DORSAL-ROOT GANGLION NEURITES

Ensheathing cells reside within both the PNS and CNS portions of the primary olfactory pathway and provide a glial covering and support for the unmyelinated olfactory axons. In vivo, these ensheathing cells express a mixture of astrocyte-specific and Schwann cell-specific phenotypic features. When grown in vitro in the presence of DRG neurons however, these ensheathing cells were observed to myelinate DRG neurites. The purpose of the present study was to determine whether ensheathing cells, like Schwann cells, require the addition of ascorbic acid to the medium in order to assemble a basal lamina and a myelin sheath. Our findings indicate that ensheathing cells can myelinate DRG neurites regardless of whether ascorbic acid is included in the growth medium and that these glial cells can assemble a basal lamina in the absence of added ascorbic acid. It appears from these results that Schwann cells and ensheathing cells have different growth media requirements for the assembly of a basal lamina.