Effects of Chronic Ethanol Administration on the Expression Levels of Neurotrophic Factors in the Rat Hippocampus

Abstract

Summary: Chronic ethanol consumption has adverse effects on the central nervous system. Hippocampus is one of the target sites of ethanol neurotoxicity. Hippocampal damage is known to result in impairment of learning and memory. This study was aimed to determine whether chronic ethanol consumption could alter the expression levels of brainderived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) mRNAs in the hippocampus. Male Wistar rats were given unrestricted access to a liquid diet containing 5% (v/v) ethanol as the sole fluid source for 19 weeks beginning at 10 weeks of age. The expression levels of BDNF and GDNF mRNAs in the hippocampus were analyzed by real-time reverse transcription-polymerase chain reaction (RT-PCR) analysis. The present study revealed that chronic ethanol consumption did not result in significant changes in the expression levels of BDNF and GDNF mRNAs. Our present results showed no significant alteration in the expression of these neurotrophic factors; these results will lead to further studies to examine the possible alterations in the gene expression of various neurotrophins that are related to hippocampal functions including learning and memory.

Effect of Oral Resveratrol on the BDNF Gene Expression in the Hippocampus of the Rat Brain

“…Our data showed that levels of BDNF mRNA in the hippocampus of this group of rats were not significantly different from those of saline treated animals ( Table 2). This finding is in line with the data published by other investigators [17,18].…”

“…There are some controversies in the literature regarding the effects of ethanol on the expression of BDNF in rat brain [15]. Although some studies had reported that ethanol decreased BDNF mRNA [16], more recent studies have shown no changes in the hippocampal BDNF levels [17,18]. To test the possible interference of ethanol with our data, we orally treated a group of rats by ethanol 10% for the same period of time as described above.…”

Alcohol and adult hippocampal neurogenesis: Promiscuous drug, wanton effects

“…These findings are particularly noteworthy because of the significant comorbidity between AUDs and mood disorders coupled with this striking overlap in the pathophysiology of AUDs and mood (Kalkman, 2009; Martinotti et al, 2012; Post, 2007; Schmidt and Duman, 2007; Schuckit and Monteiro, 1988). However, results of BDNF studies vary widely, some have found no change in hippocampal BDNF (Okamoto et al, 2006; Miller at al., 2002) or an increase in BDNF in the cortex (Baek et al, 1996). These disparities may be related to the animal model, age, or the time course of neurobiological events with regard to whether the animal is intoxicated, dependent, and/or dependent but in abstinence.…”

Ethanol–BDNF interactions: Still more questions than answers

“…This variability is not surprising since the receptor is not significantly regulated at the level of mRNA expression but shows significant down-regulation at the protein level with chronic BDNF treatment (Frank et al, 1996;Frank et al, 1997); one would therefore expect reciprocal regulation of BDNF and TrkB. The data on BDNF protein and mRNA levels are also inconsistent, with some studies showing no change in hippocampal BDNF levels (Miller et al, 2002;Okamoto et al, 2006), while others show a decrease in BDNF (MacLennan et al 1995, Tapia-Arancibia et al, 2001. Surprisingly, two of the studies showing disparate effects in the same brain region are from the same laboratory.…”