ETHANOL EXPOSURE ALTERS THE DEVELOPMENT OF SEROTONERGIC NEURONS IN CHICK SPINAL-CORD

Exposure to ethanol is known to alter the development of the serotoner gic system. However, previous studies have examined large populations of cells and have not determined the effects of ethanol on individual serotonergic neurons. In the present study, the effects of various con centrations of ethanol on the development of single serotonergic neuro ns in the chick embryo spinal cord were determined using immunohistoch emical techniques. Between embryonic day 7 (E7) and E14, ethanol admin istrations produced in ovo alcohol concentrations of: a) low dose, 30- 60 mg/dl, b) medium dose, 150-200 mg/dl, or c) high dose, 240-300 mg/d l. In animals exposed to the medium and high ethanol doses, the normal developmental increase in cross-sectional area of the somata was not observed. At all stages examined, the numbers of primary and nonprimar y processes were significantly lower in ethanol-treated groups compare d to controls, These data indicate that ethanol exposure induces dose- dependent alterations in the development of identified spinal cord neu rons. The ethanol-induced changes may be involved in the motor dysfunc tion observed after embryonic ethanol exposure.