To study the influence of cell surface-associated molecules on intercellular communication, C6
glioma cells were cultured both on
plastic and on substrata of
paraformaldehyde-fixed B104
neuroblastoma cells. By then comparing the phenotypic expression of these "cocultured" C6 cells with cells cultured on tissue culture
plastic, the influence of the cellular substratum was determined. The beta-
adrenergic-responsive
cyclic AMP-generating system of C6 cells was compared on these various substrata. We found that fixed beds of
dibutyryl cyclic AMP (
dbcAMP)-treated B104 cells uncoupled beta-receptors from
adenylate cyclase, whereas fixed beds of similarly treated C6 cells did not. However, other cellular properties were not affected by growth atop fixed
dbcAMP-treated B104 cell beds including the rate of C6 cellular proliferation and their rate of
protein synthesis. The cell surface-associated determinant on B104 cells capable of uncoupling the beta-responsive cyclase system of C6 cells is probably a
protein, as judged by its susceptibility to
protease treatment. Other properties of C6 cells were also affected by the various substrata including basal and
hydrocortisone-induced levels of
glycerol phosphate dehydrogenase (GPDH; an oligodendroglial marker) and the rate of
RNA synthesis in these cells.