Ethanol-induced Memory Deficits Research Articles

Adolescent binge ethanol impacts H3K36me3 regulation of synaptic genes.

Adolescence is marked in part by the ongoing development of the prefrontal cortex (PFC). Binge ethanol use during this critical stage in neurodevelopment induces significant structural changes to the PFC, as well as cognitive and behavioral deficits that can last into adulthood. Previous studies showed that adolescent binge ethanol causes lasting deficits in working memory, decreases in the expression of chromatin remodeling genes responsible for the methylation of histone 3 lysine 36 (H3K36), and global decreases in H3K36 in the PFC. H3K36me3 is present within the coding region of actively-transcribed genes, and safeguards against aberrant, cryptic transcription by RNA Polymerase II. We hypothesize that altered methylation of H3K36 could play a role in adolescent binge ethanol-induced memory deficits. To investigate this at the molecular level, ethanol (4 g/kg, i.g.) or water was administered intermittently to adolescent mice. RNA-and ChIP-sequencing were then performed within the same tissue to determine gene expression changes and identify genes and loci where H3K36me3 was disrupted by ethanol. We further assessed ethanol-induced changes at the transcription level with differential exon-use and cryptic transcription analysis - a hallmark of decreased H3K36me3. Here, we found ethanol-induced changes to the gene expression and H3K36me3-regulation of synaptic-related genes in all our analyses. Notably, H3K36me3 was differentially trimethylated between ethanol and control conditions at synaptic-related genes, and Snap25 and Cplx1 showed evidence of cryptic transcription in males and females treated with ethanol during adolescence. Our results provide preliminary evidence that ethanol-induced changes to H3K36me3 during adolescent neurodevelopment may be linked to synaptic dysregulation at the transcriptional level, which may explain the reported ethanol-induced changes to PFC synaptic function.

Synthesis and Biological Evaluation of Benzimidazole Derivatives as Potential Neuroprotective Agents in an Ethanol-Induced Rodent Model.

Alzheimer's disease (AD) is the most devastating and progressive neurodegenerative disease in middle to elder aged people, which can be exacerbated by lifestyle factors. Recent longitudinal studies demonstrated that alcohol consumption exacerbates memory impairments in adults. However, the underlying mechanism of alcohol-induced memory impairment is still elusive. The increased cellular manifestation of reactive oxygen species (ROS) and the production of numerous proinflammatory markers play a critical role in the neurodegeneration and pathogenesis of AD. Therefore, reducing neurodegeneration by decreasing oxidative stress and neuroinflammation may provide a potential therapeutic roadmap for the treatment of AD. In this study, eight new benzimidazole acetamide derivatives (FP1, FP2, FP5-FP10) were synthesized and characterized to investigate its neuroprotective effects in ethanol-induced neurodegeneration in a rat model. Further, three derivatives (FP1, FP7, and FP8) were selected for in vivo molecular analysis based on preliminary in vitro antioxidant screening assay. Molecular docking analysis was performed to assess the affinity of synthesized benzimidazole acetamide derivatives against selected proinflammatory targets (TNF-α, IL-6). Biochemical analysis revealed elevated expression of neuroinflammatory markers (TNF-α, NF-κB, IL-6, NLRP3), increased cellular oxidative stress, and reduced antioxidant enzymes in ethanol-exposed rats brain. Notably, pretreatment with new benzimidazole acetamide derivatives (FP1, FP7, and FP8) significantly modulated the ethanol-induced memory deficits, oxidative stress, and proinflammatory markers (TNF-α, NF-κB, IL-6, NLRP3) in the cortex. The multipurpose nature of acetamide containing benzimidazole nucleus and its versatile affinity toward numerous receptors highlight its multistep targeting potential. These results indicated the neuroprotective potential of benzimidazole acetamide derivatives (FP1, FP7, and FP8) as novel therapeutic candidates in ethanol-induced neurodegeneration which may partially be due to inhibition of the neuroinflammatory-oxidative stress vicious cycle.

Oral administration of lutein attenuates ethanol-induced memory deficit in rats by restoration of acetylcholinesterase activity

The excessive consumption of alcohol affects the central nervous system, resulting in memory and learning deficits. Lutein is a carotenoid known for its antioxidant properties, which can be able to prevent neurodegenerative diseases and cognitive deficits. In the present study, we evaluated the effect of lutein on ethanol-induced memory deficits in the object recognition task in adult rats, as well as the possible involvement of oxidative stress and cholinergic system. Wistar rats were randomly divided into two groups receiving lutein (50 mg/kg) or olive oil (1 mL/kg) by oral gavage once daily for 14 days. On day 8 each group was divided again into two groups receiving either ethanol (3 g/kg) or saline by oral gavage once daily for 7 days. After the last administration, the animals were submitted on the object recognition task 24 h later (on days 15, 16 and 17). After the behavioral test, the hippocampus and cerebral cortex were removed for the determination of oxidative stress indicators (superoxide dismutase, thiobarbituric acid reactive substances, and non-protein thiol) and acetylcholinesterase activity. Ethanol administration induced a memory deficit and increased acetylcholinesterase activity, however, it did not alter the parameters of oxidative stress, evaluated in the cortex and hippocampus. Oral administration of lutein (50 mg/kg during 14 days) attenuated memory deficit and the increase of acetylcholinesterase activity induced by ethanol. These results provide evidence that lutein is an alternative treatment for ethanol-induced memory deficit, and suggest the involvement of cholinergic system.

Curcumin ameliorates ethanol-induced memory deficits and enhanced brain nitric oxide synthase activity in mice

Ethanol consumption has well-known deleterious effects on memory. However, the mechanism by which ethanol exerts its effects on memory has received little attention, which has retarded the identification and development of effective therapeutic strategies against ethanol toxicity. The aim of this study was to explore the neuronal mechanisms underlying the protective action of curcumin, a natural polyphenolic compound of Curcuma longa, against ethanol-induced memory deficits. Adult mice were pretreated with curcumin (40 mg/kg, i.p.) before administration of ethanol (1 g/kg, i.p.) for the memory acquisition measurement, or were sacrificed 30 min later for evaluation of regional brain differences in the nitric oxide synthase (NOS) activity and nitric oxide (NO) concentration. The results showed that pretreatment with curcumin significantly ameliorated the memory deficits resulting from acute ethanol administration to mice in the novel object recognition and inhibitory avoidance tasks. Furthermore, acute ethanol treatment increased the NOS activity and NO production in brain regions associated with memory including prefrontal cortex (PFC), amygdala and hippocampus, while this enhancement was suppressed by pretreatment with curcumin. Taken together, these results suggest that the protective effects of curcumin on acute ethanol-induced memory deficits are mediated, at least in part, by suppressing NOS activity in the brain of mice. Thus, manipulation of the NOS/NO signaling pathway might be beneficial for the prevention of ethanol toxicity.

Gender differences in retrieval from long-term memory following acute intoxication with ethanol

The present study investigated the effects of ethanol on retrieval from long-term memory by using a set of cognitive decision tasks. Male and female subjects were administered either 0.0 or 1.0 milliliter of ethanol per kilogram of body weight, and then asked to make physical, lexical, and semantic decisions about pairs of words. In general, intoxicated subjects responded significantly slower than sober subjects on all decision types. In addition, female subjects demonstrated greater performance deficits than males when intoxicated. The results suggested that the reduction in speed was not due to a simple slowing of motor responses. Rather the ethanol induced memory deficits may result from the slowing of cognitive operations that impair the efficiency of working memory. Several reasons were proposed for the observed difference in reaction to intoxication between male and female subjects, including neuroendocrine processes and cognitive differences.

No improvement in ethanol-induced memory deficits after administration of a vasopressin analog

Acute ingestion of ethanol impairs memory, an effect which might be related to ethanol-induced inhibition of vasopressin release. This was studied using tests of memory and cognitive function in 26 normal subjects before and after ethanol ingestion. Equal numbers of subjects received randomly, by double-blind intranasal administration, placebo or 1-desamino-8-D-arginine vasopressin prior to ethanol ingestion. Administration of the vasopressin analog did not reverse the ethanol-induced deficits in memory and cognitive function.