Effects of Lifelong Ethanol Consumption on Rat Sympathetic Neurons

In this experiment we studied the effects of aging and lifelong ethanol consumption on rat peripheral sympathetic neurons. The aim was to find out the possible differences in the vulnerability to ethanol-induced neuronal degeneration between rats of both genders, or between the alcohol-avoiding (ANA) and the alcohol-preferring (AA) lines of rat. The superior cervical ganglia (SCG) of 40 male and 41 female AA and ANA rats were analyzed. The ethanol-exposed groups had 12% ethanol as the only available fluid from 3 to 24 months of age. The young (3 months) and old (24 months) control groups had water instead. SCG neuronal density, volume, and total neuron number were measured by unbiased morphometric methods. No gender difference was seen in either the volume of the SCG or in the SCG neuron number. The volume of the ganglion was significantly increased with age, but the total neuron number did not change. Neuronal density was significantly decreased with age, but lifelong ethanol consumption induced no further decrease. SCG neuron number in the ethanol-exposed groups did not differ from the age-matched or young control groups, but a significant negative correlation (r = −0.70, p<0.01) was seen between individual ethanol consumption and the number of SCG neurons in the female rats. The amount of lipopigment in the SCG was increased in the ethanol-exposed male rats. These results suggest that the peripheral sympathetic neurons are rather resistant to ethanol-induced degeneration, and that no major gender or line differences exist in this respect.