Ethanol exerts differential effects on high affinity choline uptake in neuron-enriched cultures from 8-day-old chick...

Neuronal-enriched cultures were prepared from 8-day-old chick embryo cerebral hemispheres and exposed to ethanol (50 mM) from day 4 to 8 in culture. At day 8, both control and ethanol-treated cultures were processed for [3H]choline uptake in situ. Uptake was performed on cultures containing either Na(+)-plus or Na(+)-free (Li+) HEPES buffer. Total choline uptake as well as Na(+)-dependent and Na(+)-independent choline uptake were calculated. The Km and Vmax were calculated using the Lineweaver-Burke analysis. Our analysis of the data revealed that ethanol-treated cultures exhibited two values for Vmax, one similar to that found in control cultures and one significantly lower than controls. No differences were observed in Km values between control and ethanol-treated cultures. We interpret the low Vmax to represent a population of cholinergic neurons which have been arrested at an immature stage as a result of ethanol insult.