Memantine can improve chronic ethanol exposure-induced spatial memory impairment in male C57BL/6 mice by reducing hippocampal apoptosis

Addictive drugs modify neurogenesis, synaptogenesis and synaptic plasticity to impair memory formation through neurotransmitter imbalances and signaling dysfunction

Drug abuse changes neurophysiological functions at multiple cellular and molecular levels in the addicted brain. Well-supported scientific evidence suggests that drugs negatively affect memory formation, decision-making and inhibition, and emotional and cognitive behaviors. The mesocorticolimbic brain regions are involved in reward-related learning and habitual drug-seeking/taking behaviors to develop physiological and psychological dependence on the drugs. This review highlights the importance of specific drug-induced chemical imbalances resulting in memory impairment through various neurotransmitter receptor-mediated signaling pathways. The mesocorticolimbic modifications in the expression levels of brain-derived neurotrophic factor (BDNF) and the cAMP-response element binding protein (CREB) impair reward-related memory formation following drug abuse. The contributions of protein kinases and microRNAs (miRNAs), along with the transcriptional and epigenetic regulation have also been considered in memory impairment underlying drug addiction. Overall, we integrate the research on various types of drug-induced memory impairment in distinguished brain regions and provide a comprehensive review with clinical implications addressing the upcoming studies.

The effect of chronic alcohol exposure on spatial memory and BDNF-TrkB- PLCγ1 signaling in the hippocampus of male and female mice

Alcohol is a commonly used drug worldwide, and abuse of alcohol has become a serious public health problem. Alcohol consumption over time can cause cognitive deficits and memory impairment, which is thought to be associated with changes in the hippocampus. Given previously known effects of brain-derived neurotrophic factor (BDNF) in regulating synaptic plasticity and learning and memory, we investigated the effect of chronic alcohol consumption on spatial memory impairment in both sexes and changes in BDNF signaling in the hippocampus. After 4 weeks of intermittent access to 20% alcohol, memory impairment in both male and female mice was evaluated using the Morris water maze and the expression of BDNF, TrkB, phosphorylation of PLCγ1 (p-PLCγ1) and PLCγ1 in the hippocampus was examined using Western blot. As expected, females spent longer escape latencies during the training phase, and both sexes spent shorter time in the target quadrant. Furthermore, after 4 weeks 20% alcohol exposure, we found significantly decreased expression levels of BDNF in the hippocampus of female mice but increased levels in male mice. TrkB and PLCγ1 expression showed no significant change in the hippocampus of both sexes. These findings suggest that chronic alcohol exposure may induce spatial memory impairment in both sexes and opposite changes in expression of BDNF and p-PLCγ1 in the hippocampus of males and females.

Ca2+-Permeable TRPV1 Receptor Mediates Neuroprotective Effects in a Mouse Model of Alzheimer's Disease via BDNF/CREB Signaling Pathway

Transient receptor potential vanilloid 1 (TRPV1) protein is a Ca2+-permeable non-selective cation channel known for its pain modulation pathway. In a previous study, it was discovered that a triple-transgenic Alzheimer's disease (AD) mouse model (3xTg-AD+/+) has anti-AD effects. The expression of proteins in the brain-derived neurotrophic factor (BDNF)/cAMP response element binding protein (CREB) pathway in a 3xTg-AD/TRPV1 transgenic mice model was investigated to better understand the AD regulatory effect of TRPV1 deficiency. The results show that TRPV1 deficiency leads to CREB activation by increasing BDNF levels and promoting phosphorylation of tyrosine receptor kinase B (TrkB), extracellular signal-regulated kinase (ERK), protein kinase B (Akt), and CREB in the hippocampus. Additionally, TRPV1 deficiency-induced CREB activation increases the antiapoptotic factor B-cell lymphoma 2 (Bcl-2) gene, which consequently downregulates Bcl-2-associated X (Bax) expression and decreases cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP), which leads to the prevention of hippocampal apoptosis. In conclusion, TRPV1 deficiency exhibits neuroprotective effects by preventing apoptosis through the BDNF/CREB signal transduction pathway in the hippocampus of 3xTg-AD mice.

Sevoflurane exposure causes neuronal apoptosis and cognitive dysfunction by inducing ER stress via activation of the inositol 1, 4, 5-trisphosphate receptor

The role of the inositol 1, 4, 5-trisphosphate receptor (IP3R) in hippocampal neuronal apoptosis and cognitive dysfunction induced by sevoflurane is currently unclear. Therefore, in this study, we investigated the role of the IP3R in endoplasmic reticulum (ER) stress and hippocampal neuronal apoptosis induced by sevoflurane in aged rats and isolated hippocampal neurons using both in vivo and in vitro experiments, including bioinformatics, functional enrichment analysis, gene set enrichment analysis, hematoxylin, and eosin staining, TUNEL assay, flow cytometry, western blot analysis and transmission electron microscopy. Furthermore, behavioral assessment was performed with the Morris water maze test. We identified 232 differentially expressed genes induced by sevoflurane exposure, including 126 upregulated genes and 106 downregulated genes. Sevoflurane exposure caused cognitive impairment and neuronal injury, and increased p-IP3R levels and ER stress. An IP3R inhibitor, 2-APB, suppressed these changes, while an IP3R agonist, FK-506, aggravated these changes. Together, these findings suggest that sevoflurane exposure causes marked cognitive dysfunction in aged rats and neuronal injury in isolated hippocampal neurons by activating the IP3R and inducing cytoplasmic calcium overload, thereby resulting in ER stress and hippocampal neuronal apoptosis.

GRAPHICAL ABSTRACT

Dichrocephala integrifolia Aqueous Extract Antagonises Chronic and Binges Ethanol Feeding-Induced Memory Dysfunctions: Insights into Antioxidant and Anti-Inflammatory Mechanisms

Ethanol consumption is widely accepted despite its addictive properties and its mind-altering effects. This study aimed to assess the effects of Dichrocephala integrifolia against, memory impairment, on a mouse model of chronic and binges ethanol feeding. Mice were divided, into groups of 8 animals each, and received distilled water, Dichrocephala integrifolia aqueous extract (25; 50; 100; or 200 mg/kg) or memantine (200 mg/kg) once a day, while fe, with Lieber-DeCarli control (sham group only) or Lieber-DeCarli ethanol diet ad libitum for 28 days. The Y maze and the novel object recognition (NOR) tests were used to evaluate spatial short-term and recognition memory, respectively. Malondialdehyde, nitric oxide, glutathione levels, and proinflammatory cytokines (Il-1β, TNF-α, and Il-6) were evaluated in brain homogenates following behavioral assessments. The results showed that chronic ethanol administration in mice was associated with a significant (p < 0.001) reduction in the spontaneous alternation percentage and the discrimination index, in the Y maze and the NOR tests, respectively. It significantly (p < 0.01) increased oxidative stress and inflammation markers levels in the brain. Dichrocephala integrifolia (100 and 200 mg/kg) as well as memantine (200 mg/kg) significantly (p < 0.001) increased the percentage of spontaneous alternation and the discrimination index, in the Y maze and NOR tests, respectively. Dichrocephala integrifolia (100 and 200 mg/kg) likewise memantine (200 mg/kg) significantly (p < 0.01) alleviated ethanol-induced increase, in the brain malondialdehyde level, nitric oxide, Il-1β, TNF-α, and Il-6. From these findings, it can be concluded that Dichrocephala integrifolia counteracted memory impairment, oxidative stress, and neuroinflammation induced by chronic ethanol consumption in mice.

Chinese Medicine, Succinum, Ameliorates Cognitive Impairment of Carotid Artery Ligation Rats and Inhibits Apoptosis of HT22 Hippocampal Cells via Regulation of the GSK3β/β-Catenin Pathway

Succinum is an organic mineral formed from the resin of ancient coniferous and leguminous plants, which is applied for tranquilizing mood, promoting blood circulation, and removing blood stasis in Chinese medicine. For quite a long time, the modern research of succinum mainly focuses on the study of physical and chemical properties and authenticity identification while few reports on its medicinal mechanism. In current study, we evaluated different solvent extracts of succinum on carotid artery ligation rats mimicking vascular dementia. It was found that ethyl acetate extracts of succinum significantly improved the learning and memory abilities of model rats and inhibited neuronal apoptosis in the hippocampus. On a mice hippocampal neuronal cell line (HT22), ethyl acetate extracts of succinum also exerted better action trend in inhibiting cell apoptosis induced by oxygen glucose deprivation (OGD). By using XAV-939 on both in vivo and in vitro studies, it was found that ethyl acetate extracts of succinum might exert these functions by regulating the GSK3β/β-catenin pathway. These studies revealed the neuronal function of succinum, which explained the traditional effects of succinum and provided more modern scientific basis for its clinical application.

Protective effect and mechanism of Lycium barbarum L. polyphenol on cognitive impairment induced by ethanol in mice

BACKGROUND

Chronic excessive ethanol consumption damages the central nervous system and causes neurobehavioral changes, such as cognitive impairment, which is related to oxidative stress and inhibition of neurogenesis in the hippocampus. It is known that promoting neurogenesis improves learning memory, anxiety and depression. Lycium barbarum L. polyphenol (LBP) is the main active ingredient of Lycium barbarum L., which has excellent neuroprotective effects. However, the effects and mechanisms of LBP on ethanol-induced cognitive impairment are unclear.

PURPOSE

To assess the effects and mechanisms of LBP on ethanol-induced cognitive impairment in mice.

METHODS

Eight-weeks-old adult C57BL/6J mice were allowed to drink ethanol (10%) to establish a model of ethanol-induced cognitive impairment. From the 29th day of LBP (25, 50, 100, 200, 400 mg/kg, intragastric administration), the locomotor activity, novel object recognition (NOR), Y maze and Morris water maze (MWM) were sequentially performed to investigate the effect of LBP on ethanol-induced cognitive impairment in mice. Next, enzyme-linked immunosorbent assay, immunofluorescence, and western blotting were used to study the underlying mechanism of LBP on ethanol-induced cognitive impairment.

RESULTS

LBP significantly decreased the escape latency and increased the number of crossings of the original platform in MWM, increased the spontaneous alteration behavior in the Y maze, and increased the preference index in the NOR in ethanol-induced mice. Notably, LBP significantly promoted the proliferation of neural stem cells, neural progenitor cells and neuroblasts, and increased the proportion of activated NSCs in mice with ethanol-induced cognitive impairment. Similarly, LBP significantly increased the number of newborn immature neurons and mature neurons. Moreover, LBP increased the levels of nuclear factor erythroid2-related factor 2 (Nrf2) and the downstream heme oxygenase-1(HO-1) protein expression, which led to a decrease of oxidative stress levels.

CONCLUSION

LBP significantly improves cognitive impairment in ethanol-induced mice, which is attributed to the promotion of hippocampal neurogenesis and reduction of oxidative stress.

AMPAkine CX516 alleviated chronic ethanol exposure-induced neurodegeneration and depressive-like behavior in mice

Chronic ethanol exposure (CEE) is associated with greater neurodegenerative effects and an increased risk of depression disorder. The AMPAR is thought to be involved in depression and a reduction in its GluA1 subunit was observed in the mouse hippocampus after CEE. AMPAkines are positive allosteric modulators of the AMPA receptor and have improved depressive-like behavior. However, the role of AMPARs in CEE-induced depressive-like behavior is not clear. It is unclear whether AMPAkines, positive allosteric agonists of AMPARs, protect against ethanol-induced depression. We investigated the effects of CX516 on ethanol-induced depressive-like behavior in a mouse model. CX516 (5 mg/kg) administration alleviated 20% (m/V) ethanol-induced depressive-like behavior in mice. Furthermore, CX516 significantly diminished the inhibition of the ERK1/2-BDNF-TrkB pathway in the hippocampus of ethanol-exposed mice. In addition, CX516 attenuated the levels of pro-inflammatory (IL-6, IL-1β), apoptosis (BAX, BCL-2), and neurodegeneration (FJC) in the mouse hippocampus induced by CEE.

Chronic Voluntary Alcohol Drinking Causes Anxiety-like Behavior, Thiamine Deficiency, and Brain Damage of Female Crossed High Alcohol Preferring Mice

The central nervous system is vulnerable to chronic alcohol abuse, and alcohol dependence is a chronically relapsing disorder which causes a variety of physical and mental disorders. Appropriate animal models are important for investigating the underlying cellular and molecular mechanisms. The crossed High Alcohol Preferring mice prefer alcohol to water when given free access. In the present study, we used female cHAP mice as a model of chronic voluntary drinking to evaluate the effects of alcohol on neurobehavioral and neuropathological changes. The female cHAP mice had free-choice access to 10% ethanol and water, while control mice had access to water alone at the age of 60-day-old. The mice were exposed to alcohol for 7 months then subjected to neurobehavioral tests including open field (OF), elevated plus maze (EPM), and Morris water maze (MWM). Results from OF and EPM tests suggested that chronic voluntary drinking caused anxiety-like behaviors. After behavior tests, mice were sacrificed, and brain tissues were processed for biochemical analyses. Alcohol altered the levels of several neurotransmitters and neurotrophic factors in the brain including gamma-Aminobutyric acid (GABA), corticotropin-releasing factor, cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor. Alcohol increased the expression of neuroinflammation markers including interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1) and C-C chemokine receptor 2 (CCR2). Alcohol also induced cleaved caspase-3 and glial fibrillary acidic protein, indicative of neurodegeneration and gliosis. In addition, alcohol inhibited the expression of thiamine transporters in the brain and reduced thiamine levels in the blood. Alcohol also caused oxidative stress and endoplasmic reticulum (ER) stress, and stimulated neurogenesis.

Ethanol-Induced Neuronal and Cognitive/Emotional Impairments are Accompanied by Down-Regulated NT3-TrkC-ERK in Hippocampus

AIMS

Ethanol ingestion affects cognition and emotion, which have been attributed to the dysfunction of specific brain structures. Studies of alcoholic patients and animal models consistently identify reduced hippocampal mass as a key ethanol-induced brain adaptation. This study evaluated how neuroadaptation in the hippocampus (Hip) produced by ethanol contributed to related behavioral deficits in male and female rats.

METHODS

Effects of acute, short-term and long-term ethanol exposure on the anxiety-like behavior and recognition memory on adult male and female Sprague-Dawley rats were assessed using elevated plus maze test and novel object recognition test, respectively. In addition, in order to investigate the direct effect of ethanol on hippocampal neurons, primary culture of hippocampal neurons was exposed to ethanol (10, 30 and 90 mM; 1, 24 and 48 h), and viability (CCK-8) and morphology (immunocytochemistry) were analyzed at structural levels. Western blot assays were used to assess protein levels of NT3-TrkC-ERK.

RESULTS

Acute and short-term ethanol exposure exerted anxiolytic effects, whereas long-term ethanol exposure induced anxiogenic responses in both sexes. Short-term ethanol exposure impaired spatial memory only in female rats, whereas long-term ethanol exposure impaired spatial and recognition memory in both sexes. These behavioral impairments and ethanol-induced loss of hippocampal neurons and decreased cell viability were accompanied by downregulated NT3-TrkC-ERK pathway.

CONCLUSION

These results indicate that NT3-TrkC-ERK signaling in the Hip may play an important role in ethanol-induced structural and behavioral impairments.

NCX3 alleviates ethanol-induced apoptosis of SK-N-SH cells via the elimination of intracellular calcium ions

Long-term alcohol intake may cause nerve cell apoptosis and induce various encephalopathies. Previously, we have shown that the expression of Na⁺/Ca²⁺ exchanger 3 (NCX3) was associated with the intracellular calcium concentration ([Ca2+]i) and apoptosis, involved in the spatial memory impairment in male C57BL/6 mice with chronic ethanol (EtOH) exposure. However, the mechanism involved is unclear. Here, we investigated the expression of NCX3 and its protective effect on SK-N-SH cells (a nerve cell line) after EtOH exposure. [Ca²⁺]i was measured using Fluo-3 AM reagent. Cell viability and the apoptotic rate were assayed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) and flow cytometry, respectively. The expression of p-cAMP-responsive element binding protein1(p-CREB 1), NCX3 protein, and mRNA were observed using Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. Cleaved-caspase-3, caspase-3, rabbit anti- poly (ADP-ribose) polymerase-1 (PARP-1) and calpain-1 proteins were used to assess the degree of apoptosis. Our results showed that EtOH increased [Ca²⁺]i and apoptosis of SK-N-SH cells in a concentration- and time-dependent manner. The expression of NCX3 protein and mRNA was up regulated obviously after SK-N-SH cells were treated with EtOH. The phosphorylation levels of Akt and CREB 1 were up regulated in cells treated with EtOH. The expression of NCX3 protein was reduced in the SK-N-SH cells treated with Akt phosphorylation inhibitor (LY294002). The [Ca²⁺]i and apoptosis rate of SK-N-SH cells increased 1.31-fold and 1.52-fold after silencing NCX3 compared with those treated with 200 mM EtOH alone for 2 d. In contrast, the [Ca²⁺]i and apoptosis rate of SK-N-SH cells decreased 0.26-fold and 0.35-fold after overexpression of NCX3 in the 2 d-200 mM EtOH treatment group. These results suggest that NCX3 plays a critical role in neuronal protection via the elimination of intracellular Ca²⁺, which may be a promising target for the prevention and treatment of encephalopathy after ethanol exposure.

Src-mediated Tyr353 phosphorylation of IP3R1 promotes its stability and causes apoptosis in palmitic acid-treated hepatocytes

Palmitic acid (PA)-induced hepatocyte apoptosis is critical for the progression of nonalcoholic fatty liver disease (NAFLD). Inositol 1,4,5-trisphosphate receptor type 1 (IP3R1) is an intracellular Ca²⁺-release channel and is involved in PA-induced hepatocyte apoptosis. While the expression of IP3R1 is elevated in patients with NAFLD and in hepatocytes treated with PA, it remains unclear how PA promotes the expression of IP3R1. In present study, our results showed that PA induced mitochondrial dysfunction and apoptosis, which is accompanied with the increase of the IP3R1 expression in hepatic cells. The inhibition of IP3R1 expression using siRNA ameliorated the PA-induced mitochondrial dysfunction. Furthermore, PA enhanced the stability of the IP3R1 protein instead of an increase in its mRNA levels. PA also promoted the phosphorylation of IP3R1 at the Tyr353 site and increased the phosphorylation of src in hepatic cells. Moreover, an inhibitor of src kinase (SU6656) significantly reduced the Tyr353 phosphorylation of IP3R1 and decreased its stability. In addition, SU6656 improved mitochondrial function and reduced apoptosis in hepatocytes. Conclusion: PA promotes the Tyr353 phosphorylation of IP3R1 by activating the src pathway and increasing the protein stability of IP3R1, which consequently results in mitochondrial Ca²⁺ overload and mitochondrial dysfunction in hepatic cells. Our results also suggested that inhibition of the src/IP3R1 pathway, such as by SU6656, may be a novel potential therapeutic approach for the treatment of NAFLD.

Neuroprotective effects of soy isoflavones on chronic ethanol-induced dementia in male ICR mice

Chronic ethanol intake can lead to dementia by activating neuroinflammation, causing oxidative stress response, reducing cholinergic function and inducing neuronal apoptosis. Soy isoflavones (SIs) exert beneficial effects in a variety of neurodegenerative disorders by acting on the anti-inflammatory, anti-oxidant, anti-apoptotic and neuro-trophic processes. However, at present, it is unknown whether SIs have a neuroprotective effect in chronic ethanol-induced dementia. The aim of the present study was to investigate the effect of SI on chronic ethanol-induced cognitive deficit in mice and explore the underlying mechanisms. The cognition-impaired mouse model was induced by ethanol (2.0 g kg-1, p.o) for 4 weeks. SIs (10, 20 or 40 mg kg-1, p.o) were delivered 1 hour after ethanol administration for 4 weeks. The Morris water maze (MWM) test and the passive avoidance (PA) task were conducted to evaluate the learning and memory abilities. After the behavioral tests, the biochemical parameter assay and western blot analysis were used to explore the underlying mechanisms of its action. SI administration significantly improved the cognitive performance in the MWM and PA tests, regulated the acetylcholinesterase (AChE) activity and acetylcholine (Ach) level, elevated the synaptic plasticity-related protein expressions and inhibited neuron apoptosis-related protein expressions in the cortex and hippocampus of mice. The results revealed that soy isoflavones may provide a possible novel candidate for the prevention and treatment of alcoholic dementia.

Chronic ethanol exposure induces neuroinflammation in H4 cells through TLR3 / NF-κB pathway and anxiety-like behavior in male C57BL/6 mice

Chronic alcoholism has become a major public health problem. Long-term and excessive drinking can lead to a variety of diseases. Chronic ethanol exposure can induce neuroinflammation and anxiety-like behavior, and this may be induced through the Toll-like receptor 3/nuclear factor-κB (TLR3/NF-κB) pathway. Animal experiments were performed using healthy adult male C57BL/6 N mice given 10 % (m/V) or 20 % ethanol solution as the only choice of drinkable fluid for 60, 90 or 180 d. In cell culture experiments, H4 human glioma cells were treated with 100 mM ethanol for 2 d, with the TLR3 gene silenced by RNAi and NF-κB inhibited by ammonium pyrrolidine dithiocarbamate (PDTC, 10 μM). After treatment with ethanol solution for a specific time, the anxiety-like behavior of the mice was tested using the open field test and the elevated plus maze test. Western blotting was used to detect the expression of TLR3, TLR4, NF-κB, IL-1β, IL-6, and TNF-α in the mouse hippocampus and H4 cells. The expression of IL-1β, IL-6 and TNF-α in the supernatant of cell culture medium was detected by ELISA. The open field test showed a decrease in time spent in the central area, and the elevated plus maze test showed a decrease in activity time in the open arm region. These behavioral tests indicated that ethanol caused anxiety-like behavior in mice. The expression levels of TLR3, TLR4, NF-κB, IL-1β, IL-6, and TNF-α increased after ethanol exposure in both the hippocampus of mice and H4 cells. Silencing of the TLR3 gene by RNAi or inhibition of NF-κB by PDTC attenuated the ethanol-induced increase in the expression of inflammatory factors in H4 cells. These findings indicated that chronic ethanol exposure increases the expression of TLR3 and NF-κB and produces neuroinflammation and anxiety-like behavior in male C57BL/6 mice and that ethanol-induced neuroinflammation can be caused through the TLR3/NF-κB pathway.

Effects of Malania oleifera Chun Oil on the Improvement of Learning and Memory Function in Mice

BACKGROUND

The fruits of Malania oleifera Chun & S. K. Lee have been highly sought after medically because its seeds have high oil content (>60%), especially the highest known proportion of nervonic acid (>55%). Objective of the Study. The objective was to explore the effects of different doses of Malania oleifera Chun oil (MOC oil) on the learning and memory of mice and to evaluate whether additional DHA algae oil and vitamin E could help MOC oil improve learning and memory and its possible mechanisms.

METHODS

After 30 days of oral administration of the relevant agents to mice, behavioral tests were conducted as well as detection of oxidative stress parameters (superoxide dismutase, malondialdehyde, and glutathione peroxidase) and biochemical indicators (acetylcholine, acetyl cholinesterase, and choline acetyltransferase) in the hippocampus.

RESULTS

Experimental results demonstrated that MOC oil treatment could markedly improve learning and memory of mouse models in behavioral experiments and increase the activity of GSH-PX in hippocampus and reduce the content of MDA, especially the dose of 46.27 mg/kg. The addition of DHA and VE could better assist MOC oil to improve the learning and memory, and its mechanism may be related to the inhibition of oxidative stress and restrain the activity of AChE and also increase the content of ACh.

CONCLUSION

Our results demonstrated that MOC oil treatment could improve learning and memory impairments. Therefore, we suggest that MOC oil is a potentially important resource for the development of nervonic acid products.

Long-term exposure to ephedrine leads to neurotoxicity and neurobehavioral disorders accompanied by up-regulation of CRF in prefrontal cortex and hippocampus in rhesus macaques

Drug addiction continues to threaten the health and welfare of people worldwide, and ephedrine abuse is a serious drug problem in many areas of the world. Ephedrine toxicity is thought to induce behavioral effects primarily through actions on the central nervous system. The corticotropin-releasing factor (CRF) system plays an important role in regulating behavioral effects induced by addictive drugs, but whether CRF is related to ephedrine toxicity remains unclear. This study seeks to examine whether there is a correlation between the CRF and chronic ephedrine neurotoxicity. To this end, we established a chronic ephedrine (0.4-1.6 mg/kg/d) exposure model in rhesus macaques, assessed its effects on body weight and behavior, examined neuronal changes in the prefrontal cortex and hippocampus, and measured the CRF expression in the prefrontal cortex and hippocampus. After 8-weeks of exposure to ephedrine, the toxic effects of ephedrine included significant weight loss and induction of behavioral changes in rhesus macaques. In particular, in the modeling group, the abnormal behavioral changes mainly manifested as irritability and behavioral sensitization. Meanwhile, the histological abnormalities included neuronal morphological changes, pyknosis and irregular shapes of neurons in the prefrontal cortex and hippocampus. In addition, the expression levels of CRF mRNA and protein were increased in the prefrontal cortex and hippocampus of ephedrine-treated animals. In summary, the finding of this study indicated that ephedrine neurotoxicity can cause neuronal damage in cerebral cortex, which in turn can result in certain neurobehavioral abnormalities, and that CRF expression in prefrontal cortex and hippocampus is elevated in response to ephedrine exposure. These observations suggested that long-term exposure to ephedrine might be causing neurotoxicity and leading to neurobehavioral disorders accompanied by up-regulation of CRF in prefrontal cortex and hippocampus.

Probiotic treatment differentially affects the behavioral and electrophysiological aspects in ethanol exposed animals

OBJECTIVES

Harmful effects of alcohol on brain function including cognitive phenomena are well known. Damage to gut microbiota is linked to neurological disorders. Evidence indicates that intestinal flora can be strengthened by probiotic bacteria. In this study, we evaluated the effect of probiotics administration on LTP induction in rats receiving ethanol.

MATERIALS AND METHODS

To assess if probiotic treatment influences toxic effect of ethanol, vehicle (CON) and probiotic treated (CON+PRO) control rats, and chronic ethanol (CE) exposed and CE probiotic treated (CE+PRO) animals were entered into the experiments. Shuttle box test and in vivo electrophysiological recordings were accomplished to evaluate memory and hippocampal baseline filed excitatory postsynaptic potentials (fEPSPs) and long term potentiation (LTP), respectively.

RESULTS

Ethanol impaired memory in the CE rats. It also diminished the slope size of fEPSPs and prevented LTP induction. While the probiotic supplementation improved memory in the CE+PRO rats, it did not influence synaptic transmission in these animals.

CONCLUSION

Conclusively, behavioral but not electrophysiological aspect of cognition is sensitive to probiotic treatment in the ethanol exposed animals.

Protective effect of apple polyphenols on chronic ethanol exposure-induced neural injury in rats

Apple polyphenols (AP) have attracted much attention due to their various bioactivities. In this study, the protective effect of AP against chronic ethanol exposure-induced neural injury as well as the possible mechanisms were investigated. Body weight, daily average food intake and daily average fluid intake were measured and daily average ethanol consumption was calculated. The influences of AP on motor behavior and memory were detected by locomotor activity test, rotarod test, beam walking test, and Y maze test and novel object recognition test, respectively. The changes of blood ethanol concentration and the oxidative stress were also measured. AP improved chronic ethanol exposure-induced the inhibition of body weight and the decrease of daily average food intake, but did not influence the daily average fluid intake and the daily average ethanol intake, indicating that the improve effect of AP did not result from the decrease of ethanol intake. Motor activity and motor coordination were not influenced after chronic ethanol exposure though the blood ethanol concentration was higher than that in control group. AP improved significantly chronic ethanol-induced the memory impairment and the hippocampal CA1 neurons damage. Further studies found that AP decreased the contents of NO and MDA and increased the levels of T-AOC and GSH in the hippocampus of rats. These results suggest that AP exerts a protective effect against chronic ethanol-induced memory impairment through improving the oxidative stress in the hippocampus.

Effect of Alcohol on Hippocampal-Dependent Plasticity and Behavior: Role of Glutamatergic Synaptic Transmission

Problematic alcohol drinking and alcohol dependence are an increasing health problem worldwide. Alcohol abuse is responsible for approximately 5% of the total deaths in the world, but addictive consumption of it has a substantial impact on neurological and memory disabilities throughout the population. One of the better-studied brain areas involved in cognitive functions is the hippocampus, which is also an essential brain region targeted by ethanol. Accumulated evidence in several rodent models has shown that ethanol treatment produces cognitive impairment in hippocampal-dependent tasks. These adverse effects may be related to the fact that ethanol impairs the cellular and synaptic plasticity mechanisms, including adverse changes in neuronal morphology, spine architecture, neuronal communication, and finally an increase in neuronal death. There is evidence that the damage that occurs in the different brain structures is varied according to the stage of development during which the subjects are exposed to ethanol, and even much earlier exposure to it would cause damage in the adult stage. Studies on the cellular and cognitive deficiencies produced by alcohol in the brain are needed in order to search for new strategies to reduce alcohol neuronal toxicity and to understand its consequences on memory and cognitive performance with emphasis on the crucial stages of development, including prenatal events to adulthood.

Peroxiredoxin II Maintains the Mitochondrial Membrane Potential against Alcohol-Induced Apoptosis in HT22 Cells

Excessive alcohol intake can significantly reduce cognitive function and cause irreversible learning and memory disorders. The brain is particularly vulnerable to alcohol-induced ROS damage; the hippocampus is one of the most sensitive areas of the brain for alcohol neurotoxicity. In the present study, we observed significant increasing of intracellular ROS accumulations in Peroxiredoxin II (Prx II) knockdown HT22 cells, which were induced by alcohol treatments. We also found that the level of ROS in mitochondrial was also increased, resulting in a decrease in the mitochondrial membrane potential. The phosphorylation of GSK3β (Ser9) and anti-apoptotic protein Bcl2 expression levels were significantly downregulated in Prx II knockdown HT22 cells, which suggests that Prx II knockdown HT22 cells were more susceptible to alcohol-induced apoptosis. Scavenging the alcohol-induced ROS with NAC significantly decreased the intracellular ROS levels, as well as the phosphorylation level of GSK3β in Prx II knockdown HT22 cells. Moreover, NAC treatment also dramatically restored the mitochondrial membrane potential and the cellular apoptosis in Prx II knockdown HT22 cells. Our findings suggest that Prx II plays a crucial role in alcohol-induced neuronal cell apoptosis by regulating the cellular ROS levels, especially through regulating the ROS-dependent mitochondrial membrane potential. Consequently, Prx II may be a therapeutic target molecule for alcohol-induced neuronal cell death, which is closely related to ROS-dependent mitochondria dysfunction.

Aging with alcohol-related brain damage: Critical brain circuits associated with cognitive dysfunction

Alcoholism is associated with brain damage and impaired cognitive functioning. The relative contributions of different etiological factors, such as alcohol, thiamine deficiency and age vulnerability, to the development of alcohol-related neuropathology and cognitive impairment are still poorly understood. One reason for this quandary is that both alcohol toxicity and thiamine deficiency produce brain damage and cognitive problems that can be modulated by age at exposure, aging following alcohol toxicity or thiamine deficiency, and aging during chronic alcohol exposure. Pre-clinical models of alcohol-related brain damage (ARBD) have elucidated some of the contributions of ethanol toxicity and thiamine deficiency to neuroinflammation, neuronal loss and functional deficits. However, the critical variable of age at the time of exposure or long-term aging with ARBD has been relatively ignored. Acute thiamine deficiency created a massive increase in neuroimmune genes and proteins within the thalamus and significant increases within the hippocampus and frontal cortex. Chronic ethanol treatment throughout adulthood produced very minor fluctuations in neuroimmune genes, regardless of brain region. Intermittent "binge-type" ethanol during the adolescent period established an intermediate neuroinflammatory response in the hippocampus and frontal cortex, that can persist into adulthood. Chronic excessive drinking throughout adulthood, adolescent intermittent ethanol exposure, and thiamine deficiency all led to a loss of the cholinergic neuronal phenotype within the basal forebrain, reduced hippocampal neurogenesis, and alterations in the frontal cortex. Only thiamine deficiency results in gross pathological lesions of the thalamus. The behavioral impairment following these types of treatments is hierarchical: Thiamine deficiency produces the greatest impairment of hippocampal- and prefrontal-dependent behaviors, chronic ethanol drinking ensues mild impairments on both types of tasks and adolescent intermittent ethanol exposure leads to impairments on frontocortical tasks, with sparing on most hippocampal-dependent tasks. However, our preliminary data suggest that as rodents age following adolescent intermittent ethanol exposure, hippocampal functional deficits began to emerge. A necessary requirement for the advancement of understanding the neural consequences of alcoholism is a more comprehensive assessment and understanding of how excessive alcohol drinking at different development periods (adolescence, early adulthood, middle-aged and aged) influences the trajectory of the aging process, including pathological aging and disease.

Study of the relationship between how ethanol affects learning and memory and the expression of p21 WAF1/CIP1 in the female mouse hippocampus

The purpose of this study was to investigate the effects of different concentrations of ethanol on learning and memory in female mice and the corresponding interaction with histone deacetylase 1(HDAC1), estrogen receptor α(ERα) and p21 ^WAF1/CIP1. Data from the Morris water maze test showed that mice in the 50% ethanol group might experience cognitive impairment, while mice in the 2% ethanol group might experience enhanced cognitive capabilities. The number of damaged neurons in the hippocampal CA1 area in the 50% ethanol group was higher than the numbers observed in other groups. The expression of HDAC1 and ERα proteins was lower in the 50% ethanol group than they were in the control group, while p21 ^WAF1/CIP1 expression was increased. The expression of these proteins in the 2% ethanol group was completely reversed when compared to the 50% ethanol group. p21 ^WAF1/CIP1 was involved in the cognitive change induced by ethanol. The f2 (-400 bp to -800 bp) and f7 (-2400 bp to -2800 bp) fragments in the p21 ^WAF1/CIP1 promoter region were functionally active regions that experienced binding relating to HDAC1 and ERα.

Effects of Chronic Voluntary Alcohol Drinking on Thiamine Concentrations, Endoplasmic Reticulum Stress, and Oxidative Stress in the Brain of Crossed High Alcohol Preferring Mice

Chronic alcohol drinking can damage the central nervous system via many mechanisms. One of these may involve a deficiency of an essential nutrient, thiamine, as a result of chronic alcohol exposure. Although thiamine deficiency (TD) has often been linked to the neuropathology of alcohol-related brain damage, the underlying mechanisms remain to be investigated. The crossed high alcohol preferring (cHAP) mice prefer alcohol to water when they have free access. In this study, we used cHAP mice to determine the effect of chronic voluntary alcohol exposure on thiamine levels and neuropathological changes in the brain. The male cHAP mice were given free-choice access to 10% ethanol (EtOH) and water for 7 months, sacrificed, and thiamine concentrations in the blood plasma and brain were determined by liquid chromatography-mass spectrometry (LC-MS). The expression of thiamine transporters was examined by immunoblotting. In addition, oxidative stress, endoplasmic reticulum (ER) stress, active caspase-3-dependent apoptosis, and neurogenesis in the brain were evaluated. The results indicated that chronic alcohol exposure decreased thiamine levels and thiamine transporters, and increased oxidative stress, ER stress, and neuronal apoptosis in the brains. Interestingly, alcohol exposure also stimulated neurogenesis in the hippocampus which may serve as a compensatory mechanism in response to alcohol-induced brain damage. Our data have demonstrated that cHAP mice are a useful model to study the interaction between chronic alcohol consumption and TD, as well as TD's contributions to the neuropathological processes resulting in alcohol-related brain damage.