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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.

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Brain regional gamma-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 alpha4 and beta3 subunit mRNAs were significantly decreased in several brain regions. The age-related alterations in alpha4 subunit expression were parallel to those caused by lifelong ethanol drinking, whereas aging had no significant effect on beta3 subunit expression. The results suggest that prolonged ethanol consumption leading to blood concentrations of about 10 mM may downregulate the mRNA expression of selected GABAA receptor subunits and that aging might have partly similar effects.

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BACKGROUND: Although the beneficial effects of mild to moderate ethanol consumption have been implied with respect to heart, alcohol abuse has proven to be a major cause of nonischemic cardiomyopathy in Western society. However, the biochemical and molecular mechanisms, which mediate the pathologic cardiac effects of ethanol, remain largely unknown. The aim of the present study was to explore the effects of chronic ethanol exposure on cardiac apoptosis and expression of some of the genes associated with cardiac remodeling in vivo. METHODS: Alcohol-avoiding Alko Non Alcohol rats of both sexes were used. The ethanol-exposed rats (females, n=6; males, n=8) were given 12% (v/v) ethanol as the only available fluid from age of three to 24 months of age. The control rats (females, n=7; males, n=5) had only water available. At the end of the experiment, free walls of left ventricles of hearts were immediately frozen. Cytosolic DNA fragmentation, reflecting apoptosis, was measured using a commercial quantitative sandwich enzyme-linked immunosorbent assay kit, and mRNA levels were analyzed using a quantitative reverse transcriptase-polymerase chain reaction method. RESULTS: Ethanol treatment for two years increased cardiac left ventricular p53 mRNA levels significantly (p=0.014) compared with control rats. The gene expression was also dependent on the gender (p=0.001), so that male rats had higher left ventricular p53 mRNA levels than female rats. However, no significant differences in levels of DNA fragmentation were detected. CONCLUSIONS: Chronic ethanol exposure in vivo induces rat cardiac left ventricular p53 gene expression. Expression of p53 is also gender-dependent, males having higher p53 mRNA levels than females. This preliminary finding suggests a role for the p53 gene in ethanol-induced cardiac remodeling. The results might also have some relevance for the known gender-dependent differences in propensity to cardiovascular disease.

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BACKGROUND: Study of the long-term effects of chronic alcohol consumption in human populations is confounded by genetic and environmental factors. METHODS: The study was intended to investigate the effects on morbidity and survival of lifetime forced ethanol consumption in male and female AA (Alko, Alcohol) and ANA (Alko, Non-Alcohol) rats. The ethanol-exposed rats had 12% ethanol as the only available fluid from 3 to 24 months of age. The control groups had water. Rats that died during the experiment and those that were killed at 24 months of age were all autopsied, and the pathologic findings were recorded. RESULTS: Lifelong ethanol consumption did not change the survival rate of the rats, and had no significant effect on the rates of any of the pathologic measures in either the AA or ANA line of rats, suggesting that this may not be a good animal model for studying the detrimental effects of chronic alcohol. An unexpected, highly significant finding was observed: the AA rats, bred for high voluntary ethanol drinking, lived much longer than the ANA rats, bred for ethanol avoidance. The death rate by 24 months in the AA line was less than one-third of that in the ANA line. This difference was found regardless of whether the animals were maintained on alcohol or water, and in both genders. The AA rats had significantly lower rates of kidney disease, benign tumors, and cardiovascular disease than the ANA animals. CONCLUSIONS: Lifelong ethanol consumption increased neither the mortality nor the morbidity of AA and ANA line of rats. Genes selected in the development of the high drinking AA line have additional effects producing rats that are healthier and living longer than the ANA rats possessing genes resulting in alcohol avoidance.

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BACKGROUND: A rat line developed by selective breeding for high alcohol sensitivity has blunted corticosterone responses to alcohol and stress. In the present study, we determined possible differences in adrenal activation after alcohol and motor performance testing between the alcohol-sensitive alcohol-nontolerant and alcohol-insensitive alcohol-tolerant rats. METHODS: The animals received ethanol (2 g/kg, intraperitoneally), and 30 min later they were subjected to a motor function test (i.e., normal selection test used in the breeding of the lines); the control animals for both rat lines received no treatment and minimal handling. Blood corticosterone and ACTH levels at the single time point were determined by radioimmunoassay, and adrenal activation was determined by in situ hybridization of the immediate early gene c-fos, nor1, nurr1, and NGFI-B mRNA expression. RESULTS: The alcohol nontolerant rats had lower corticosterone but normal ACTH levels after ethanol and motor testing. Adrenal early gene expression of all of the genes studied was strongly induced by the treatment in both rat lines, but the inductions of c-fos, nor1, and nurr1 were significantly lower in the alcohol-sensitive animals. Acute treatment with a high dose of ACTH also induced less adrenal gene expression in the alcohol-sensitive animals. CONCLUSIONS: The results suggest that the reduced adrenal activation is associated with high alcohol sensitivity in a genetic animal model, which is in agreement with the human findings of alcohol insensitivity during glucocorticoid treatment.

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