CHANGES IN THE NEURAL CELL-ADHESION MOLECULE PATTERNS ON THE RAT GLIAL-CELL SURFACES WITH DEVELOPMENT AND CONTACT FORMATION INVITRO

In monolayer cultures of newborn rat hippocampal cells, immunogold-lab elling at the electron microscope level was used to study quantitative ly the neural cell adhesion molecule (N-CAM) arrangement on the surfac e of glial soma and processes on 5 and 12 days in vitro (DIV). Four co rresponding samples of micrographs were formed. To quantify the labell ing, a stochastic geometry approach was used. Spectra of lateral dista nces between labels as well as simulated images of the surface label a rrangement (invisible in micrographs) were derived and compared. The d ata show that, on both 5 and 12 DIV, N-CAM density on the surface of p rocesses is approximately 2 times higher than that in somata; 12-DIV c ells showing a lower (approximately 25%) N-CAM surface density as comp ared with the 5-DIV cells. This suggests that N-CAM expression in glia surfaces decreases while the cells form contacts, and N-CAM sorting b etween soma and processes remains stable. The simulated topographies o f the lateral N-CAM arrangement might highlight fundamental mechanisms that underlie formation of the neural network.