Ethanol suppression of locus coeruleus neurons: relevancy to the fetal alcohol syndrome.

The effect of intraperitoneal injection and microiontophoretic application of ethanol on spontaneous single neuron activity of adult rat locus coeruleus was studied. Systemic administration of ethanol (1-2 g/kg) markedly slowed a majority of locus coeruleus neurons. Direct application of ethanol also substantially suppressed locus coeruleus cell firing in the absence of any detectable membrane effects. Percent inhibition of firing rate ranged from 6% to 100% with ejection currents up to 40NA for 40 sec. These data demonstrate ethanol can directly suppress locus coeruleus unit activity. Since locus coeruleus neurons are present at a relatively early fetal age, maternal consumption of ethanol during gestation could profoundly influence the development and function of fetal central noradrenergic processes.