The critical period for ethanol effects on cholinergic neuronal expression in neuroblast-enriched cultures derived from 3-day-old chick embryo: NGF ameliorates the cholinotoxic effects of ethanol.

Studies from our laboratory have established that ethanol exerts morphological and biochemical neurotoxic effects during early neuroembryogenesis in the chick brain both in ovo and in culture. In the present study, we further localized the critical period for ethanol effects on cholinergic neuronal expression using neuroblast-enriched cultures derived from 3-day-old chick embryos. Moreover, we report that NGF attenuated the cholinotoxic effects of ethanol. We used the following experimental paradigms: cultures treated with ethanol alone either C0-C3 or C4-C10; NGF alone C0-C4 or C4-C10; ethanol and NGF given concomitantly; ethanol given first then replaced with NGF in the medium; or NGF given first then replaced with ethanol in the medium. The results revealed: (1) the cholinotoxic effect of ethanol occurs between culture days C0 and C4 with day 3 appearing to be most critical; (2) similarly, the critical period for the cholinotoxic effects of NGF is during early neuroblast differentiation, culture days C0-C4; (3) NGF can prevent the cholinotoxic effects of ethanol only if both ethanol and NGF are given concomitantly or if ethanol is given first, then culture is replaced with NGF-containing medium.