EFFECTS OF ETHANOL ON NEUROBLASTOMA-CELLS IN CULTURE - ROLE OF GANGLIOSIDES IN NEURITOGENESIS AND SUBSTRATE ADHESION

Murine Neuro-2A neuroblastoma cells were exposed to ethanol in culture under two experimental paradigms: (1) short-term (24 hr or less) and low concentrations (0.05 to 0.5%; 8.5 to 86 mM) and (2) Long-term (48 hr at 0.5%; 86 mM), long-term ethanol exposure did not affect Neuro-2A viability, determined by DNA synthesis or the ability to exclude Tryp an Blue, Similarly, long-term ethanol treatment did not inhibit differ entiation, exhibited by the extension of neurites, promoted by either dibutyryl-cyclic-AMP or by incubation with exogenous ganglioside GM1, The incorporation of exogenous ganglioside GM1 into plasma membranes w as not influenced by varying concentrations of ethanol (up to 1.2%; 20 4 mM), In contrast, ethanol did influence Neuro-2A cell attachment to collagen in a dualistic manner, During short-term ethanol exposure, ce ll attachment was enhanced, However, when cells were initially exposed to ethanol for 48 hr a marked inhibition of subsequent attachment was observed, Long-term ethanol exposure also inhibited attachment to oth er substrata, including laminin, fibronectin and vitronectin, Incubati on of Neuro-2A cells with either exogenous ganglioside GM1 or a mixtur e of brain gangliosides partially reversed the inhibition of attachmen t to collagen, This reversal did not appear to be due to any one parti cular ganglioside structure, however, Mixed brain gangliosides were fr actionated into three fractions, according to the number of sialic aci d residues, Each of the three fractions were equally effective in part ially restoring Neuro-2A cell attachment to collagen after long-term e thanol treatment, The results suggest that the mechanism by which thes e effects occur is at the level of plasma membrane fluidity, because b oth ethanol and glycosphingolipid content are known to influence membr ane lateral mobility, although other mechanisms, such as changes in he adgroup hydration, are possible. (C) 1995 Wiley-Liss, Inc.