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The purpose of the present study was to examine the combined effects of aging and lifelong ethanol exposure on the levels of monoamine neurotransmitters in different regions of the brain. This work is part of a project addressing interactions of aging and lifelong ethanol consumption in alcohol-preferring AA (Alko Alcohol) line of rats, selected for high voluntary consumption of ethanol. Intake of ethanol on the level of 4.5-5 g/kg/day for about 20 months induced only limited changes in the neurotransmitter levels; the concentration of noradrenaline was significantly reduced in the frontal cortex. There was also a trend towards lower levels of dopamine and 5-hydroxytryptamine (5-HT) in the frontal cortex, and towards a lower noradrenaline level in the dorsal cortex. Aging was associated with a decreased concentration of dopamine in the dorsal cortex and with a declining trend in the striatum. The levels of 5-HT in the limbic forebrain were higher in the aged than in the young animals, and in the striatum, there was a trend towards higher levels in older animals. The data suggest that a continuous intake of moderate amounts of ethanol does not enhance the age-related alterations in brain monoamine neurotransmission, while the decline in the brain level of dopamine associated with aging may be a factor contributing to age-related neurological disorders. [ABSTRACT FROM AUTHOR]

Abstract: Brain regional γ-aminobutyric acid type A (GABAA) receptor subunit mRNA expression was studied in ethanol-preferring AA (Alko, Alcohol) rats after moderate ethanol drinking for up to 2 years of age. In situ hybridization with oligonucleotide probes specific for 13 different subunits was used with coronal cryostat sections of the brains. Selective alterations were observed by ethanol exposure and/or aging in signals for several subunits. Most interestingly, the putative highly ethanol-sensitive α4 and β3 subunit mRNAs were significantly decreased in several brain regions. The age-related alterations in α4 subunit expression were parallel to those caused by lifelong ethanol drinking, whereas aging had no significant effect on β3 subunit expression. The results suggest that prolonged ethanol consumption leading to blood concentrations of about 10mM may downregulate the mRNA expression of selected GABAA receptor subunits and that aging might have partly similar effects. [Copyright &y& Elsevier]

Aging and chronic alcohol consumption can cause degenerative changes in the cerebellar cortex. In this study, the effects of aging and lifelong alcohol consumption on cerebellar cortical layer volumes (molecular and granular) and also white matter layer volumes were studied in alcohol-preferring (AA) and nonpreferring (ANA) rats of both sexes. The ethanol-consuming animals (EtOH) had 12% (w/v) ethanol as the only available fluid from 4 to 22 months of age, whereas the young (3 month) and old controls (24 months) had only water to drink. The volumes of molecular, granular, and white matter layers of the cerebellar vermis in folia II, IV, VII, and X were measured by using systematic sampling and a point-counting method. The volumes of the granular and white matter layers showed consistent increase between 3 and 24 months of age, whereas the volume of the molecular layer remained unchanged with increasing age. Individual ethanol intake was measured over a 1-week period at the beginning and at the end of chronic ethanol exposure. Significant (ANOVA, P= 0.000) sex difference was found in the drinking behavior in both lines, with females consuming more alcohol than males (daily ethanol consumption at 22 months of age 3.2 ± 0.3 vs. 7.1 ± 0.3 g/kg for AA males and females; 3.2 ± 0.3 vs. 5.4 ± 0.4 g/kg for ANA males and females, respectively). The only ethanol-induced effect on the cerebellum was observed in ANA-EtOH females with a 15% reduction in the volumes of the molecular and granular layer in folium II compared with age-matched controls and a significant ( P < 0.05, analysis of covariance with ethanol intake as a covariate) line difference in folium II (molecular and granular layers) was observed between ANA-EtOH females and AA-EtOH females. Furthermore, the volume of the molecular layer in folium II was significantly ( P < 0.05, analysis of covariance with ethanol intake and body weights as covariates) reduced for ANA-EtOH females, compared with ANA-EtOH males indicating a sex difference in the cerebellar degeneration due to chronic alcohol consumption. Of the three layers studied, the white matter layer was the most resistant layer to the effects caused by chronic alcohol consumption. In view of the fact that AA and ANA rats of both sexes differ regarding the drinking behavior and ethanol metabolism, they provide an important model for further research on ethanol-induced pathological changes in the central nervous system. [ABSTRACT FROM AUTHOR]