REACTIONS OF RAT SYMPATHETIC NEURONS TO ETHANOL EXPOSURE ARE AGE-DEPENDENT

Age-differences in the sensitivity of peripheral sympathetic neurons t o chronic ethanol exposure and ethanol withdrawal were studied in male Wistar rats aged 4 months, 12 months, or 24 to 25 months. The superio r cervical ganglia (SCG) of the young (4 months) and the 2-year-old ra ts responded to a 12-day or 4-week ethanol exposure with significantly increased catecholamine turnover, while the ganglia of the middle-age d rats (12 months) showed only a minor increase in the intensity of ca techolamine fluorescence and tyrosine hydroxylase immunoreactivity. Ex tensive neuronal vacuolation was found in the 4 months ethanol-exposed SCG, probably as a reaction of a subpopulation of neurons to increase d stimulation. Ethanol-induced neuronal loss was most prominent in the SCG of the oldest age group. Contrary to the marked changes in SCG fu nctional and morphometric parameters, the pelvic sympathetic neurons i n the hypogastric ganglion showed no significant changes after ethanol exposure. The pattern of ethanol-induced morphological alterations fo und in the present study did not provide unambiguous support for eithe r the ''accelerated aging'' or the ''increased vulnerability'' concept regarding ethanol-aging interactions in the nervous system.