Foetal Alcohol Spectrum Disorders and alterations in brain and behaviour

Diffusion MRI of the developing cerebral cortical gray matter can be used to detect abnormalities in tissue microstructure associated with fetal ethanol exposure

Fetal alcohol spectrum disorders (FASDs) comprise a wide range of neurological deficits that result from fetal exposure to ethanol (EtOH), and are the leading cause of environmentally related birth defects and mental retardation in the western world. One aspect of diagnostic and therapeutic intervention strategies that could substantially improve our ability to combat this significant problem would be to facilitate earlier detection of the disorders within individuals. Light microscopy-based investigations performed by several laboratories have previously shown that morphological development of neurons within the early-developing cerebral cortex is abnormal within the brains of animals exposed to EtOH during fetal development. We and others have recently demonstrated that diffusion MRI can be of utility for detecting abnormal cellular morphological development in the developing cerebral cortex. We therefore assessed whether diffusion tensor imaging (DTI) could be used to distinguish the developing cerebral cortices of ex vivo rat pup brains born from dams treated with EtOH (EtOH; 4.5 g/kg, 25%) or calorie-matched quantities of maltose/dextrin (M/D) throughout gestation. Water diffusion and tissue microstructure were investigated using DTI (fractional anisotropy, FA) and histology (anisotropy index, AI), respectively. Both FA and AI decreased with age, and were higher in the EtOH than the M/D group at postnatal ages (P)0, P3, and P6. Additionally, there was a significant correlation between FA and AI measurements. These findings provide evidence that disruptions in cerebral cortical development induced by EtOH exposure can be revealed by water diffusion anisotropy patterns, and that these disruptions are directly related to cerebral cortical differentiation.

Effects of ethanol exposure on nervous system development in zebrafish

Alcohol (ethanol) is a teratogen that adversely affects nervous system development in a wide range of animal species. In humans numerous congenital abnormalities arise as a result of fetal alcohol exposure, leading to a spectrum of disorders referred to as fetal alcohol spectrum disorder (FASD). These abnormalities include craniofacial defects as well as neurological defects that affect a variety of behaviors. These human FASD phenotypes are reproduced in the rodent central nervous system (CNS) following prenatal ethanol exposure. While the study of ethanol effects on zebrafish development has been more limited, several studies have shown that different strains of zebrafish exhibit differential susceptibility to ethanol-induced cyclopia, as well as behavioral deficits. Molecular mechanisms underlying the effects of ethanol on CNS development also appear to be shared between rodent and zebrafish. Thus, zebrafish appear to recapitulate the observed effects of ethanol on human and mouse CNS development, indicating that zebrafish can serve as a complimentary developmental model system to study the molecular basis of FASD. Recent studies examining the effect of ethanol exposure on zebrafish nervous system development are reviewed, with an emphasis on attempts to elucidate possible molecular pathways that may be impacted by developmental ethanol exposure. Recent work from our laboratories supports a role for perturbed extracellular matrix function in the pathology of ethanol exposure during zebrafish CNS development. The use of the zebrafish model to assess the effects of ethanol exposure on adult nervous system function as manifested by changes in zebrafish behavior is also discussed.

Spatial cognition and sexually dimorphic synaptic plasticity balance impairment in rats with chronic prenatal ethanol exposure

Prenatal ethanol exposure can lead to long-lasting impairments in the ability of rats to process spatial information, as well as produce long-lasting deficits in long-term potentiation (LTP), a biological model of learning and memory processing. The present study aimed to examine the sexually dimorphic effects of chronic prenatal ethanol exposure (CPEE) on behavior cognition and synaptic plasticity balance (SPB), and tried to understand a possible mechanism by evaluating the alternation of SPB. The animal model was produced by ethanol exposure throughout gestational period with 4 g/kg bodyweight. Offspring of both male and female were selected and studied on postnatal days 36. Subsequently, the data showed that chronic ethanol exposure resulted in birth weight reduction, losing bodyweight gain, microcephaly and hippocampus weight retardation. In Morris water maze (MWM) test, escape latencies were significantly higher in CPEE-treated rats than that in control ones. They also spent much less time in the target quadrant compared to that of control animals in the probe phase. In addition, it was found that there was a more severe impairment in females than that in males after CPEE treatment. Electrophysiological studies showed that CPEE considerably inhibited hippocampal LTP and facilitated depotentiation in males, while significantly enhanced LTP and suppressed depotentiation in females. A novel index, developed by us, showed that the action of CPEE on SPB was more sensitive in females than that in males, suggesting that it might be an effective index to distinguish the difference of SPB impairment between males and females.

Fate analysis of adult hippocampal progenitors in a murine model of fetal alcohol spectrum disorder (FASD)

Prenatal alcohol exposure can lead to fetal alcohol spectrum disorder (FASD) and associated behavioral impairments that may be linked to disruptions in adult hippocampal neurogenesis. Social and physical enrichment has been proposed as a potential therapeutic approach toward reversing behavioral deficits associated with FASD and is also a potent stimulator of adult hippocampal neurogenesis. In the present study, we utilized a genetic fate mapping approach in nestin-CreER^T2/YFP bitransgenic mice to identify the stage-specific impact of prenatal alcohol exposure on the stepwise maturation of adult hippocampal progenitors. Using a limited alcohol access “drinking-in-the-dark” model of FASD, we confirm previous findings that moderate prenatal alcohol exposure has no effect on adult neurogenesis under standard housing conditions, but abolishes the neurogenic response to enriched environment (EE). Furthermore, we demonstrate that this effect is primarily due to failed EE-mediated survival of postmitotic neurons. Finally, we demonstrate that the neurogenic deficit is associated with impaired spatial pattern recognition, as demonstrated by delayed learning of FASD-EE mice in an A–B contextual discrimination task. These results identify a potential maturational stage-specific mechanism(s) underlying impaired neurogenic function in a preclinical model of FASD, and provide a basis for testing regulatory pathways in this model through conditional and inducible manipulation of gene expression in the adult hippocampal progenitor population.

Loss of motoneurons in the ventral compartment of the rat hypoglossal nucleus following early postnatal exposure to alcohol

Perinatal alcohol exposure (AE) has multiple detrimental effects on cognitive and various behavioral outcomes, but little is known about its impact on the autonomic functions. In a rat model of fetal alcohol spectrum disorders (FASD), we investigated neurochemical and neuroanatomical alterations in two brainstem nuclei, the hypoglossal nucleus (XIIn) and the dorsal nucleus of the vagus nerve (Xdn). One group of male Sprague-Dawley rats (n=6) received 2.625 g/kg ethanol intragastrically twice daily on postnatal days (PD) 4-9, a period equivalent to the third trimester of human pregnancy, and another group (n=6) was sham-intubated. On PD 18-19, the rats were perfused and medullary sections were immunohistochemically processed for choline acetyltransferase (ChAT) or two aminergic receptors that mediate excitatory drive to motoneurons, α₁-adrenergic (α₁-R) and serotonin 2A (5-HT(2A)-R), and c-Fos. Based on ChAT labeling, AE rats had reduced numbers of motoneurons in the ventral XIIn (XIIn-v; 35.4±1.3 motoneurons per side and section vs. 40.0±1.2, p=0.022), but not in the dorsal XIIn or Xdn. Consistent with ChAT data, both the numbers of α₁-R-labeled motoneurons in the XIIn-v and the area of the XIIn-v measured using 5-HT(2A)-R staining were significantly smaller in AE rats (19.7±1.5 vs. 25.0±1.4, p=0.031 and 0.063 mm² ±0.002 vs. 0.074±0.002, p=0.002, respectively). Concurrently, both 5-HT(2A)-R and c-Fos staining tended to be higher in AE rats, suggesting an increased activation. Thus, postnatal AE causes motoneuronal loss in the XIIn-v. This may compromise upper airway control and contribute to increased risk of upper airway obstructions and sudden infant death in FASD victims.

Sensory-motor deficits in children with fetal alcohol spectrum disorder assessed using a robotic virtual reality platform

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is associated with a large number of cognitive and sensory-motor deficits. In particular, the accurate assessment of sensory-motor deficits in children with FASD is not always simple and relies on clinical assessment tools that may be coarse and subjective. Here we present a new approach: using robotic technology to accurately and objectively assess motor deficits of children with FASD in a center-out reaching task.

METHODS

A total of 152 typically developing children and 31 children with FASD, all aged between 5 and 18 were assessed using a robotic exoskeleton device coupled with a virtual reality projection system. Children made reaching movements to 8 peripheral targets in a random order. Reach trajectories were subsequently analyzed to extract 12 parameters that had been previously determined to be good descriptors of a reaching movement, and these parameters were compared for each child with FASD to a normative model derived from the performance of the typically developing population.

RESULTS

Compared with typically developing children, the children with FASD were found to be significantly impaired on most of the parameters measured, with the greatest deficits found in initial movement direction error. Also, children with FASD tended to fail more parameters than typically developing children: 95% of typically developing children failed fewer than 3 parameters compared with 69% of children with FASD. These results were particularly pronounced for younger children.

CONCLUSIONS

The current study has shown that robotic technology is a sensitive and powerful tool that provides increased specificity regarding the type of motor problems exhibited by children with FASD. The high frequency of motor deficits in children with FASD suggests that interventions aimed at stimulating and/or improving motor development should routinely be considered for this population.

DSM-5 criteria for substance use disorders: recommendations and rationale

Since DSM-IV was published in 1994, its approach to substance use disorders has come under scrutiny. Strengths were identified (notably, reliability and validity of dependence), but concerns have also arisen. The DSM-5 Substance-Related Disorders Work Group considered these issues and recommended revisions for DSM-5. General concerns included whether to retain the division into two main disorders (dependence and abuse), whether substance use disorder criteria should be added or removed, and whether an appropriate substance use disorder severity indicator could be identified. Specific issues included possible addition of withdrawal syndromes for several substances, alignment of nicotine criteria with those for other substances, addition of biomarkers, and inclusion of nonsubstance, behavioral addictions.This article presents the major issues and evidence considered by the work group, which included literature reviews and extensive new data analyses. The work group recommendations for DSM-5 revisions included combining abuse and dependence criteria into a single substance use disorder based on consistent findings from over 200,000 study participants, dropping legal problems and adding craving as criteria, adding cannabis and caffeine withdrawal syndromes, aligning tobacco use disorder criteria with other substance use disorders, and moving gambling disorders to the chapter formerly reserved for substance-related disorders. The proposed changes overcome many problems, while further studies will be needed to address issues for which less data were available.

Chronic alcohol alters dendritic spine development in neurons in primary culture

Dendritic spines are specialised membrane protrusions of neuronal dendrites that receive the majority of excitatory synaptic inputs. Abnormal changes in their density, size and morphology have been associated with various neurological and psychiatric disorders, including those deriving from drug addiction. Dendritic spine formation, morphology and synaptic functions are governed by the actin cytoskeleton. Previous in vivo studies have shown that ethanol alters the number and morphology of spines, although the mechanisms underlying these alterations remain unknown. It has also been described how chronic ethanol exposure affects the levels, assembly and cellular organisation of the actin cytoskeleton in hippocampal neurons in primary culture. Therefore, we hypothesised that the ethanol-induced alterations in the number and shape of dendritic spines are due to alterations in the mechanisms regulating actin cytoskeleton integrity. The results presented herein show that chronic exposure to moderate levels of alcohol (30 mM) during the first 2 weeks of culture reduces dendritic spine density and alters the proportion of the different morphologies of these structures in hippocampal neurons, which affects the formation of mature spines. Apparently, these effects are associated with an increase in the G-actin/F-actin ratio due to a reduction of the F-actin fraction, leading to changes in the levels of the different factors regulating the organisation of this cytoskeletal component. The data presented herein indicate that these effects occur between weeks 1 and 2 of culture, an important period in dendritic spines development. These changes may be related to the dysfunction in the memory and learning processes present in children prenatally exposed to ethanol.

Ethanol neurotoxicity in the developing cerebellum: underlying mechanisms and implications

Ethanol is the main constituent of alcoholic beverages that exerts toxicity to neuronal development. Ethanol affects synaptogenesis and prevents proper brain development. In humans, synaptogenesis takes place during the third trimester of pregnancy, and in rodents this period corresponds to the initial few weeks of postnatal development. In this period neuronal maturation and differentiation begin and neuronal cells start migrating to their ultimate destinations. Although the neuronal development of all areas of the brain is affected, the cerebellum and cerebellar neurons are more susceptible to the damaging effects of ethanol. Ethanol’s harmful effects include neuronal cell death, impaired differentiation, reduction of neuronal numbers, and weakening of neuronal plasticity. Neuronal development requires many hormones and growth factors such as retinoic acid, nerve growth factors, and cytokines. These factors regulate development and differentiation of neurons by acting through various receptors and their signaling pathways. Ethanol exposure during development impairs neuronal signaling mechanisms mediated by the N-methyl-d-aspartate (NMDA) receptors, the retinoic acid receptors, and by growth factors such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-I), and basic fibroblast growth factor (bFGF). In combination, these ethanol effects disrupt cellular homeostasis, reduce the survival and migration of neurons, and lead to various developmental defects in the brain. Here we review the signaling mechanisms that are required for proper neuronal development, and how these processes are impaired by ethanol resulting in harmful consequences to brain development.

Long-lasting neural circuit dysfunction following developmental ethanol exposure

Fetal Alcohol Spectrum Disorder (FASD) is a general diagnosis for those exhibiting long-lasting neurobehavioral and cognitive deficiencies as a result of fetal alcohol exposure. It is among the most common causes of mental deficits today. Those impacted are left to rely on advances in our understanding of the nature of early alcohol-induced disorders toward human therapies. Research findings over the last decade have developed a model where ethanol-induced neurodegeneration impacts early neural circuit development, thereby perpetuating subsequent integration and plasticity in vulnerable brain regions. Here we review our current knowledge of FASD neuropathology based on discoveries of long-lasting neurophysiological effects of acute developmental ethanol exposure in animal models. We discuss the important balance between synaptic excitation and inhibition in normal neural network function, and relate the significance of that balance to human FASD as well as related disease states. Finally, we postulate that excitation/inhibition imbalance caused by early ethanol-induced neurodegeneration results in perturbed local and regional network signaling and therefore neurobehavioral pathology.

Involvement of sphingolipids in ethanol neurotoxicity in the developing brain

Ethanol-induced neuronal death during a sensitive period of brain development is considered one of the significant causes of fetal alcohol spectrum disorders (FASD). In rodent models, ethanol triggers robust apoptotic neurodegeneration during a period of active synaptogenesis that occurs around the first two postnatal weeks, equivalent to the third trimester in human fetuses. The ethanol-induced apoptosis is mitochondria-dependent, involving Bax and caspase-3 activation. Such apoptotic pathways are often mediated by sphingolipids, a class of bioactive lipids ubiquitously present in eukaryotic cellular membranes. While the central role of lipids in ethanol liver toxicity is well recognized, the involvement of sphingolipids in ethanol neurotoxicity is less explored despite mounting evidence of their importance in neuronal apoptosis. Nevertheless, recent studies indicate that ethanol-induced neuronal apoptosis in animal models of FASD is mediated or regulated by cellular sphingolipids, including via the pro-apoptotic action of ceramide and through the neuroprotective action of GM1 ganglioside. Such sphingolipid involvement in ethanol neurotoxicity in the developing brain may provide unique targets for therapeutic applications against FASD. Here we summarize findings describing the involvement of sphingolipids in ethanol-induced apoptosis and discuss the possibility that the combined action of various sphingolipids in mitochondria may control neuronal cell fate.

Prenatal ethanol exposure does not cause neurological alterations in adult CD1 mice

Genetic factors are involved in variation in fetal alcohol spectrum disorders (FASD), which is also observed among various inbred mouse strains. The CD1 mouse strain is often used in toxicological and genetic experiments. However, there is little literature using this strain to study long-term neurologic abnormalities of FASD. In the present study, we addressed the effect of prenatal ethanol exposure on neurological alterations in adult CD1 mice. The female CD1 mice received exposure to ethanol solution (10 vol%) starting from 2 weeks before mating up to pups born (postnatal day 1). At 24 weeks after the birth, the prenatal ethanol-exposed mice and control mice showed no difference in spatial learning and memory performance in a Morris water maze. Consistently, pathological changes, such as increased neuronal apoptosis, decreased synaptic protein synaptophysin expression, synaptic loss and reactive astrogliosis, were not observed in the hippocampus of mice prenatally exposed to ethanol. These results suggest that CD1 mice are highly resistant to prenatal alcohol exposure and may serve as genetic modification models of FASD.

Gestational choline supplementation normalized fetal alcohol-induced alterations in histone modifications, DNA methylation, and proopiomelanocortin (POMC) gene expression in β-endorphin-producing POMC neurons of the hypothalamus

BACKGROUND

Prenatal exposure to ethanol (EtOH) reduces the expression of hypothalamic proopiomelanocortin (POMC) gene, known to control various physiological functions including the organismal stress response. In this study, we determined whether the changes in POMC neuronal functions are associated with altered expressions of histone-modifying and DNA-methylating enzymes in POMC-producing neurons, because these enzymes are known to be involved in regulation of gene expression. In addition, we tested whether gestational choline supplementation prevents the adverse effects of EtOH on these neurons.

METHODS

Pregnant rat dams were fed with alcohol-containing liquid diet or control diet during gestational days 7 and 21 with or without choline, and their male offspring rats were used during the adult period. Using double-immunohistochemistry, real-time reverse transcription polymerase chain reaction (RT-PCR) and methylation-specific RT-PCR, we determined protein and mRNA levels of histone-modifying and DNA-methylating enzymes and the changes in POMC gene methylation and expression in the hypothalamus of adult male offspring rats. Additionally, we measured the basal- and lipopolysaccharide (LPS)-induced corticosterone levels in plasma by enzyme-linked immunosorbent assay.

RESULTS

Prenatal EtOH treatment suppressed hypothalamic levels of protein and mRNA of histone activation marks (H3K4me3, Set7/9, acetylated H3K9, phosphorylated H3S10), and increased the repressive marks (H3K9me2, G9a, Setdb1), DNA-methylating enzyme (Dnmt1), and the methyl-CpG-binding protein (MeCP2). The treatment also elevated the level of POMC gene methylation, while it reduced levels of POMC mRNA and β-EP and elevated corticosterone response to LPS. Gestational choline normalized the EtOH-altered protein and the mRNA levels of H3K4me3, Set7/9, H3K9me2, G9a, Setdb1, Dnmt1, and MeCP2. It also normalizes the changes in POMC gene methylation and gene expression, β-EP production, and the corticosterone response to LPS.

CONCLUSIONS

These data suggest that prenatal EtOH modulates histone and DNA methylation in POMC neurons that may be resulting in hypermethylation of POMC gene and reduction in POMC gene expression. Gestational choline supplementation prevents the adverse effects of EtOH on these neurons.

Maternal factors associated with heavy periconceptional alcohol intake and drinking following pregnancy recognition: a post-partum survey of New Zealand women

INTRODUCTION AND AIMS

Alcohol consumption during pregnancy places the foetus at risk of Foetal Alcohol Spectrum Disorders. Little is known about the current prevalence and patterns of alcohol consumption before and following pregnancy recognition in New Zealand.

DESIGN AND METHODS

A retrospective survey of 723 post-partum women resident in maternity wards located across New Zealand was conducted using a self-administered questionnaire. Maternal sociodemographic and obstetric characteristics and alcohol intake before and after pregnancy recognition were assessed.

RESULTS

Of the 968 women invited to participate, 78% agreed. Eighty-two percent of women reported consuming alcohol prior to pregnancy and 20% reported typically consuming >4 New Zealand standard drinks per occasion. Overall, 34% of women reported drinking at some time during pregnancy. Twelve percent of pregnancies were at high risk of heavy alcohol exposure in early gestation. In fully adjusted analysis, pregnancies most at risk were those of indigenous Māori women, Pacific women, smokers and drug users. Almost one-quarter (24%) of drinkers continued to drink following pregnancy recognition, and in fully adjusted analysis, continuing to drink was positively associated with frequency of alcohol consumption before pregnancy (P < 0.001 for linear trend).

DISCUSSION AND CONCLUSIONS

To reduce the burden of alcohol-related harm to the foetus, these findings suggest that New Zealand alcohol policy should be focused not only on promoting total abstinence when planning a pregnancy and when pregnant, but also on reducing 'binge drinking' culture and the frequent consumption of lower levels of alcohol.

Epigenetic inheritance of disease and disease risk

Epigenetic marks in an organism can be altered by environmental factors throughout life. Although changes in the epigenetic code can be positive, some are associated with severe diseases, in particular, cancer and neuropsychiatric disorders. Recent evidence has indicated that certain epigenetic marks can be inherited, and reshape developmental and cellular features over generations. This review examines the challenging possibility that epigenetic changes induced by environmental factors can contribute to some of the inheritance of disease and disease risk. This concept has immense implications for the understanding of biological functions and disease etiology, and provides potential novel strategies for diagnosis and treatment. Examples of epigenetic inheritance relevant to human disease, such as the detrimental effects of traumatic stress or drug/toxic exposure on brain functions, are reviewed. Different possible routes of transmission of epigenetic information involving the germline or germline-independent transfer are discussed, and different mechanisms for the maintenance and transmission of epigenetic information like chromatin remodeling and small noncoding RNAs are considered. Future research directions and remaining major challenges in this field are also outlined. Finally, the adaptive value of epigenetic inheritance, and the cost and benefit of allowing acquired epigenetic marks to persist across generations is critically evaluated.

Maternal drinking behavior and Fetal Alcohol Spectrum Disorders in adolescents with criminal behavior in southern Brazil

Prenatal alcohol exposure can have serious and permanent adverse effects. The developing brain is the most vulnerable organ to the insults of prenatal alcohol exposure. A behavioral phenotype of prenatal alcohol exposure including conduct disorders is also described. This study on a sample of Brazilian adolescents convicted for criminal behavior aimed to evaluate possible clinical features of Fetal Alcohol Syndrome (FAS). These were compared to a control group of school adolescents, as well as tested for other environmental risk factors for antisocial behavior. A sample of 262 institutionalized male adolescents due to criminal behavior and 154 male students aged between 13 and 21 years comprised the study population. Maternal use of alcohol was admitted by 48.8% of the mothers of institutionalized adolescents and by 39.9% of the school students. In this sample of adolescents we could not identify individual cases with a clear diagnosis of FAS, but signs suggestive of FASD were more common in the institutionalized adolescents. Social factors like domestic and family violence were frequent in the risk group, this also being associated to maternal drinking during pregnancy. The inference is that in our sample, criminal behavior is more related to complex interactions between environmental and social issues including prenatal alcohol exposure.

Imbalanced synaptic plasticity induced spatial cognition impairment in male offspring rats treated with chronic prenatal ethanol exposure

BACKGROUND

As chronic prenatal ethanol (EtOH) exposure (CPEE) may cause deficiencies in a variety of behavioral and cognitive functions, the aim of present study is to investigate the effects of CPEE on spatial learning and memory and examine the action of CPEE on synaptic plasticity balance in the hippocampus of adolescent male rats.

METHODS

The animal model was produced by EtOH exposure throughout gestational period with 4 g/kg bodyweight, while the male offspring rats were used in the study. Morris water maze (MWM) test was performed, and then, long-term potentiation (LTP) and depotentiation were recorded from Schaffer collaterals to CA1 region in the hippocampus.

RESULTS

It was shown that escape latencies in learning period and re-acquisition period were prolonged in CPEE-treated group compared with that in control group. Furthermore, LTP was drastically inhibited, and depotentiation was distinctly enhanced in CPEE-treated group compared with that in control group.

CONCLUSIONS

It is suggested that the balance between cognitive stability and flexibility was broken by the bidirectional effects of long-term synaptic plasticity. In addition, the spatial cognition was attenuated by the alteration of synaptic plasticity balance in CPEE-treated male adolescent rats.

Enhanced deficits in long-term potentiation in the adult dentate gyrus with 2nd trimester ethanol consumption

Ethanol exposure during pregnancy can cause structural and functional changes in the brain that can impair cognitive capacity. The hippocampal formation, an area of the brain strongly linked with learning and memory, is particularly vulnerable to the teratogenic effects of ethanol. In the present experiments we sought to determine if the functional effects of developmental ethanol exposure could be linked to ethanol exposure during any single trimester-equivalent. Ethanol exposure during the 1^st or 3^rd trimester-equivalent produced only minor changes in synaptic plasticity in adult offspring. In contrast, ethanol exposure during the 2^nd trimester equivalent resulted in a pronounced decrease in long-term potentiation, indicating that the timing of exposure influences the severity of the deficit. Together, the results from these experiments demonstrate long-lasting alterations in synaptic plasticity as the result of developmental ethanol exposure and dependent on the timing of exposure. Furthermore, these results allude to neural circuit malfunction within the hippocampal formation, perhaps relating to the learning and memory deficits observed in individuals with fetal alcohol spectrum disorders.

Mechanisms of ethanol-induced death of cerebellar granule cells

Maternal ethanol exposure during pregnancy may cause fetal alcohol spectrum disorders (FASD). FASD is the leading cause of mental retardation. The most deleterious effect of fetal alcohol exposure is inducing neuroapoptosis in the developing brain. Ethanol-induced loss of neurons in the central nervous system underlies many of the behavioral deficits observed in FASD. The cerebellum is one of the brain areas that are most susceptible to ethanol during development. Ethanol exposure causes a loss of both cerebellar Purkinje cells and granule cells. This review focuses on the toxic effect of ethanol on cerebellar granule cells (CGC) and the underlying mechanisms. Both in vitro and in vivo studies indicate that ethanol induces apoptotic death of CGC. The vulnerability of CGC to ethanol-induced death diminishes over time as neurons mature. Several mechanisms for ethanol-induced apoptosis of CGC have been suggested. These include inhibition of N-methyl-D-aspartate receptors, interference with signaling by neurotrophic factors, induction of oxidative stress, modulation of retinoid acid signaling, disturbance of potassium channel currents, thiamine deficiency, and disruption of translational regulation. Cultures of CGC provide an excellent system to investigate cellular/molecular mechanisms of ethanol-induced neurodegeneration and to evaluate interventional strategies. This review will also discuss the approaches leading to neuroprotection against ethanol-induced neuroapoptosis.

Ethanol pre-exposure during adolescence or adulthood increases ethanol intake but ethanol-induced conditioned place preference is enhanced only when pre-exposure occurs in adolescence

Behavioral sensitization has been suggested to contribute to uncontrolled alcohol consumption. The aim of this study was to investigate the effects of repeated ethanol administration in adolescent and adult mice on subsequent ethanol consumption and conditioned place preference (CPP). Mice were administered ethanol for 15 consecutive days. This ethanol regimen induced behavioral sensitization to a lesser degree in adolescents than in adults. Following ethanol treatment, mice were subjected to CPP procedure, or given a free choice between water and ethanol solutions. While ethanol-pretreated adult mice did not display a robust ethanol-induced CPP, ethanol induced a significant CPP in mice pretreated with ethanol during adolescence. Ethanol pretreated mice, regardless of age, showed higher ethanol intake to saline-treated mice. The present findings suggest that ethanol-induced neuroadaptations underlying behavioral sensitization may activate mechanisms responsible for enhanced ethanol intake, and also reveals that ethanol pre-exposure during adolescence increases ethanol reward as measured by CPP.

Polyphosphoinositide metabolism and Golgi complex morphology in hippocampal neurons in primary culture is altered by chronic ethanol exposure

AIMS

Ethanol affects not only the cytoskeletal organization and activity, but also intracellular trafficking in neurons in the primary culture. Polyphosphoinositide (PPIn) are essential regulators of many important cell functions, including those mentioned, cytoskeleton integrity and intracellular vesicle trafficking. Since information about the effect of chronic ethanol exposure on PPIn metabolism in neurons is scarce, this study analysed the effect of this treatment on three of these phospholipids.

METHODS

Phosphatidylinositol (PtdIns) levels as well as the activity and/or levels of enzymes involved in their metabolism were analysed in neurons chronically exposed to ethanol. The levels of phospholipases C and D, and phosphatidylethanol formation were also assessed. The consequence of the possible alterations in the levels of PtdIns on the Golgi complex (GC) was also analysed.

RESULTS

We show that phosphatidylinositol (4,5)-bisphosphate and phosphatidylinositol (3,4,5)-trisphosphate levels, both involved in the control of intracellular trafficking and cytoskeleton organization, decrease in ethanol-exposed hippocampal neurons. In contrast, several kinases that participate in the metabolism of these phospholipids, and the level and/or activity of phospholipases C and D, increase in cells after ethanol exposure. Ethanol also promotes phosphatidylethanol formation in neurons, which can result in the suppression of phosphatidic acid synthesis and, therefore, in PPIn biosynthesis. This treatment also lowers the phosphatidylinositol 4-phosphate levels, the main PPIn in the GC, with alterations in their morphology and in the levels of some of the proteins involved in structure maintenance.

CONCLUSIONS

The deregulation of the metabolism of PtdIns may underlie the ethanol-induced alterations on different neuronal processes, including intracellular trafficking and cytoskeletal integrity.

Brief intervention to reduce risky drinking in pregnancy: study protocol for a randomized controlled trial

Background

Risky drinking in pregnancy by UK women is likely to result in many alcohol-exposed pregnancies. Studies from the USA suggest that brief intervention has promise for alcohol risk reduction in antenatal care. However, further research is needed to establish whether this evidence from the USA is applicable to the UK. This pilot study aims to investigate whether pregnant women can be recruited and retained in a randomized controlled trial of brief intervention aimed at reducing risky drinking in women receiving antenatal care.

Methods

The trial will rehearse the parallel-group, non-blinded design and procedures of a subsequent definitive trial. Over 8 months, women aged 18 years and over (target number 2,742) attending their booking appointment with a community midwife (n = 31) in north-east England will be screened for alcohol consumption using the consumption questions of the Alcohol Use Disorders Identification Test (AUDIT-C). Those screening positive, without a history of substance use or alcohol dependence, with no pregnancy complication, and able to give informed consent, will be invited to participate in the trial (target number 120). Midwives will be randomized in a 1:1 ratio to deliver either treatment as usual (control) or structured brief advice and referral for a 20-minute motivational interviewing session with an alcohol health worker (intervention). As well as demographic and health information, baseline measures will include two 7-day time line follow-back questionnaires and the EuroQoL EQ-5D-3 L questionnaire. Measures will be repeated in telephone follow-ups in the third trimester and at 6 months post-partum, when a questionnaire on use of National Health Service and social care resources will also be completed. Information on pregnancy outcomes and stillbirths will be accessed from central health service records before the follow-ups. Primary outcomes will be rates of eligibility, recruitment, intervention delivery, and retention in the study population, to inform power calculations for a definitive trial. The health-economics component will establish how cost-effectiveness will be assessed, and examine which data on health service resource use should be collected in a main trial. Participants’ views on instruments and procedures will be sought to confirm their acceptability.

Discussion

The study will produce a full trial protocol with robust sample-size calculations to extend evidence on effectiveness of screening and brief intervention.

Trial Registration

Current Controlled Trials ISRCTN43218782

Fetal brain function in response to maternal alcohol consumption: early evidence of damage

BACKGROUND

Studies of the adverse neurobehavioral effects of maternal alcohol consumption on the fetus have been largely confined to the postnatal period, after exposure to alcohol has finished. This study explored the brain function of the fetus, at the time of exposure to alcohol, to examine its effect on information processing and stability of performance.

METHODS

Five groups of fetuses, defined by maternal alcohol consumption patterns, were examined: control (no alcohol); moderate (5 to 10 units/wk either drunk evenly across the week or as a binge, in 2 to 3 days); heavy (20+ units/wk drunk evenly or as a binge). Fetal habituation performance was examined on 3 occasions, separated by 7 days, beginning at 35 weeks of gestation. The number of trials required to habituate on each test session and the difference in performance across test sessions were recorded.

RESULTS

Fetuses exposed to heavy binge drinking required significantly more trials to habituate and exhibited a greater variability in performance across all test sessions than the other groups. Maternal drinking, either heavily but evenly or moderately as a binge, resulted in poorer habituation, and moderate binge drinking resulted in greater variability compared with no, or even, drinking.

CONCLUSIONS

Decreased information processing, reflected by poorer habituation, and increased variability in performance may reflect the initial manifestations of structural damage caused by alcohol to the brain. These results will lead to a greater understanding of the effects of alcohol on the fetus's brain, enable the antenatal identification of fetal alcohol spectrum disorders, and lead to the early implementation of better management strategies.

Neuroimmune mechanisms in fetal alcohol spectrum disorder

Fetal alcohol spectrum disorder (FASD) is a major health concern worldwide and results from maternal consumption of alcohol during pregnancy. It produces tremendous individual, social, and economic losses. This review will first summarize the structural, functional, and behavior changes seen in FASD. The development of the neuroimmune system will be then be described with particular emphasis on the role of microglial cells in the normal regulation of homeostatic function in the central nervous system (CNS) including synaptic transmission. The impact of alcohol on the neuroimmune system in the developing CNS will be discussed in the context of several key immune molecules and signaling pathways involved in neuroimmune mechanisms that contribute to FASD. This review concludes with a summary of the development of early therapeutic approaches utilizing immunosuppressive drugs to target alcohol-induced pathologies. The significant role played by neuroimmune mechanisms in alcohol addiction and pathology provides a focus for future research aimed at understanding and treating the consequences of FASD.

Alcohol delays the emergence of the fetal elicited startle response, but only transiently

Prenatal exposure to alcohol may exert a significant detrimental effect on the functioning of the individual's brain, however few studies have examined this before birth. This longitudinal study examined the effect of maternal alcohol consumption on the elicited startle response of the fetus. Two groups of fetuses were examined: one whose mothers drank alcohol (approximately 10 units per week); the other whose mothers did not drink alcohol. Fetuses were examined at 29, 32 and 35 weeks gestation and their startle response observed using ultrasound in response to 2 presentations of a pink noise (70-250Hz) at 90dB(A) separated by 30s. Fetuses exposed to alcohol exhibited a weaker startle response at 29 weeks gestation than did fetuses not exposed to alcohol. There was no difference in the response at 32 and 35 weeks gestation. To ensure that the effects were not due to a more general effect of alcohol on fetal movement, a second experiment compared the spontaneous movements (observed on ultrasound for 45 min) of fetuses whose mothers drank alcohol and fetuses of mothers who didn't drink alcohol. There were no differences in movements exhibited by the fetuses. The results suggest that exposure to alcohol delays the emergence of the elicited startle response at 29 weeks gestation but this delay has disappeared by 32 weeks gestation. The possible role of altered neural development, acute exposure to alcohol and disruptions to the fetus's behavioural repertoire, in mediating these effects are discussed.

Complex Trauma and Prenatal Alcohol Exposure: Clinical Implications

Complex trauma resulting from chronic maltreatment and prenatal alcohol exposure can significantly affect child development and academic outcomes. Children with histories of maltreatment and those with prenatal alcohol exposure exhibit remarkably similar central nervous system impairments. In this article, I will review the effects of each on the brain and discuss clinical implications for these populations of children.

Ethanol exposure alters protein expression in a mouse model of fetal alcohol spectrum disorders

Alcohol exposure during development can result in variable growth retardation and facial dysmorphology known as fetal alcohol spectrum disorders. Although the mechanisms underlying the disorder are not fully understood, recent progress has been made that alcohol induces aberrant changes in gene expression and in the epigenome of embryos. To inform the gene and epigenetic changes in alcohol-induced teratology, we used whole-embryo culture to identify the alcohol-signature protein profile of neurulating C6 mice. Alcohol-treated and control cultures were homogenized, isoelectrically focused, and loaded for 2D gel electrophoresis. Stained gels were cross matched with analytical software. We identified 40 differentially expressed protein spots (P < 0.01), and 9 spots were selected for LC/MS-MS identification. Misregulated proteins include serotransferrin, triosephosphate isomerase and ubiquitin-conjugating enzyme E2 N. Misregulation of serotransferrin and triosephosphate isomerase was confirmed with immunologic analysis. Alteration of proteins with roles in cellular function, cell cycle, and the ubiquitin-proteasome pathway was induced by alcohol. Several misregulated proteins interact with effectors of the NF-κB and Myc transcription factor cascades. Using a whole-embryo culture, we have identified misregulated proteins known to be involved in nervous system development and function.

Alcohol induces Golgi fragmentation in differentiated PC12 cells by deregulating Rab1-dependent ER-to-Golgi transport

In the present study, we analyze the effects of ethanol on the Golgi structure and membrane transport in differentiated PC12 cells, which are used as a model of neurons. Chronic exposure to moderate doses of ethanol induces Golgi fragmentation, a common characteristic of many neurodegenerative diseases. Alcohol impaired the lateral linking of stacks without causing microtubule damage. Extensive immunocytochemical and western blot analyses of representative Golgi proteins showed that few, but important, proteins are significantly affected. Thus, alcohol exposure induced a significant ER-to-Golgi transport delay, the retention of the GTPase Rab1 in the Golgi membranes and the accumulation of tethering factor p115 in the cytosol. These modifications would explain the observed fragmentation. The amount of p115 and the stacking protein GRASP65 increased in alcohol-treated cells, which might be a mechanism to reverse Golgi damage. Importantly, the overexpression of GTP-tagged Rab1 but not of a dominant-negative Rab1 mutant, restored the Golgi morphology, suggesting that this protein is the main target of alcohol. Taken together, our results support the view that alcohol and neurodegenerative diseases such as Parkinson have similar effects on intracellular trafficking and provide new clues on the neuropathology of alcoholism.

Persistent dose-dependent changes in brain structure in young adults with low-to-moderate alcohol exposure in utero

BACKGROUND

Many children with heavy exposure to alcohol in utero display characteristic alterations in brain size and structure. However, the long-term effects of low-to-moderate alcohol exposure on these outcomes are unknown.

METHODS

Using voxel-based morphometry and region-of-interest analyses, we examined the influence of lower doses of alcohol on gray and white matter composition in a prospectively recruited, homogeneous, well-characterized cohort of alcohol-exposed (n = 11, age 19.5 ± 0.3 years) and control (n = 9, age 19.6 ± 0.5 years) young adults. A large proportion of the exposed individuals were born to mothers whose alcohol consumption during pregnancy was in the low-to-moderate range.

RESULTS

There were no differences in total brain volume or total gray or white matter volume between the exposed and control groups. However, gray matter volume was reduced in alcohol-exposed individuals in several areas previously reported to be affected by high levels of exposure, including the left cingulate gyrus, bilateral middle frontal gyri, right middle temporal gyrus, and right caudate nucleus. Notably, this gray matter loss was dose dependent, with higher exposure producing more substantial losses.

CONCLUSIONS

These results indicate that even at low doses, alcohol exposure during pregnancy impacts brain development and that these effects persist into young adulthood.

Caudate volume predicts neurocognitive performance in youth with heavy prenatal alcohol exposure

BACKGROUND

Fetal alcohol spectrum disorders result from heavy prenatal alcohol exposure and are characterized, in some cases, by central nervous system anomalies and cognitive impairment. Regional patterns of neuroanatomical abnormalities suggest that alcohol exerts selective damage on the developing fetal brain. This study assessed brain-behavior relationships in a sample of youth with histories of heavy prenatal alcohol exposure. The aim was to characterize how structural brain alterations observed in our previous studies relate to cognitive deficits commonly reported in individuals with histories of heavy prenatal alcohol exposure.

METHODS

Twenty-one youth (mean age 13 years) with histories of heavy prenatal alcohol exposure and 7 nonexposed healthy comparison subjects underwent structural magnetic resonance imaging and neurobehavioral testing. Regional brain volumes within the alcohol-exposed group were correlated with neuropsychological measures of cognitive control and verbal learning/recall, as these aspects of cognition have previously been shown to be vulnerable to alcohol teratogenesis.

RESULTS

Between-group effect sizes revealed moderate to large cognitive performance and brain volume decrements in alcohol-exposed subjects, compared with typically developing peers. Within the alcohol-exposed group, volume of the caudate nuclei was the most consistent predictor of neuropsychological performance, after controlling for potentially confounding variables including total brain volume, IQ, and age.

CONCLUSIONS

These data are consistent with previous research associating gestational alcohol exposure with structural and functional changes of the caudate nucleus. Our findings extend this previous work by demonstrating that volume reductions of the caudate have behavioral relevance for this population, in relation to cognitive control and verbal learning and recall abilities.

Elevation of GM2 ganglioside during ethanol-induced apoptotic neurodegeneration in the developing mouse brain

GM2 ganglioside in the brain increased during ethanol-induced acute apoptotic neurodegeneration in 7-day-old mice. A small but a significant increase observed 2 h after ethanol exposure was followed by a marked increase around 24 h. Subcellular fractionation of the brain 24 h after ethanol treatment indicated that GM2 increased in synaptic and non-synaptic mitochondrial fractions as well as in a lysosome-enriched fraction characteristic to the ethanol-exposed brain. Immunohistochemical staining of GM2 in the ethanol-treated brain showed strong punctate staining mainly in activated microglia, in which it partially overlapped with staining for LAMP1, a late endosomal/lysosomal marker. Also, there was weaker neuronal staining, which partially co-localized with complex IV, a mitochondrial marker, and was augmented in cleaved caspase 3-positive neurons. In contrast, the control brain showed only faint and diffuse GM2 staining in neurons. Incubation of isolated brain mitochondria with GM2 in vitro induced cytochrome c release in a manner similar to that of GD3 ganglioside. Because ethanol is known to trigger mitochondria-mediated apoptosis with cytochrome c release and caspase 3 activation in the 7-day-old mouse brain, the GM2 elevation in mitochondria may be relevant to neuroapoptosis. Subsequently, activated microglia accumulated GM2, indicating a close relationship between GM2 and ethanol-induced neurodegeneration.

Early exposure to alcohol leads to permanent impairment of dendritic excitability in neocortical pyramidal neurons

Exposure to alcohol in utero is a well known cause of mental retardation in humans. Using experimental models of fetal alcohol spectrum disorder, it has been demonstrated that cortical pyramidal neurons and their projections are profoundly and permanently impaired. Yet, how the functional features of these cells are modified and how such modifications impact cognitive processes is still unknown. To address this, we studied the intrinsic electrophysiological properties of pyramidal neurons in young adult rats (P30-P60) exposed to ethanol inhalation during the first week of postnatal life (P2-P6). Dual whole-cell recordings from the soma and distal apical dendrites were performed and, following the injection of depolarizing current into the dendrites, layer 5 neurons from ethanol-treated (Et) animals displayed a lower number and a shorter duration of dendritic spikes, attributable to a downregulation of calcium electrogenesis. As a consequence, the mean number of action potentials recorded at the soma after dendritic current injection was also lower in Et animals. No significant differences between Et and controls were observed in the firing pattern elicited in layer 5 neurons by steps of depolarizing somatic current, even though the firing rate was significantly lower in Et animals. The firing pattern and the firing rate of layer 2/3 neurons were not affected by alcohol exposure.

The effect of preconception paternal alcohol exposure on epigenetic remodeling of the h19 and rasgrf1 imprinting control regions in mouse offspring

Imprinted loci play a critical role in fetal development. Their expression is often regulated by CCCTC-binding factor (CTCF) protein binding at imprinting control regions (ICRs). Prenatal alcohol exposure has been shown to reduce global DNA methylation in the developing mouse fetus. This study explored the effect of preconception paternal alcohol exposure on DNA methylation at two paternally methylated ICRs (H19 and Rasgrf1) in the sperm of exposed males and somatic DNA of sired offspring. Significant reductions at the H19 CTCF 1 (p = 0.0027) and CTCF 2 (p = 0.0009) binding sites were observed in the offspring of ethanol-treated sires, which was significantly correlated with reduced weight at postnatal days 35–42 (p < 0.05). As birth weight was unaffected and growth was only delayed during the postnatal weaning period, with subsequent re-convergence, we hypothesize that this may be the result of a mental deficit causing delayed establishment of independent feeding following weaning and would explain why this effect is transient. No difference in DNA methylation was observed in the sperm of alcohol-exposed males, indicating that the transmission of the epigenetic signal at conception is not due to altered methylation, but may be the result of an RNA-mediated mechanism or altered chromatin remodeling.

Effect of alcohol consumption in prenatal life, childhood, and adolescence on child development

The effects of alcohol consumption in adults are well described in the literature, while knowledge about the effects of alcohol consumption in children is more limited and less systematic. The present review shows how alcohol consumption may negatively influence the neurobiological and neurobehavioral development of humans. Three different periods of life have been considered: the prenatal term, childhood, and adolescence. For each period, evidence of the short-term and long-term effects of alcohol consumption, including neurodevelopmental effects and associations with subsequent alcohol abuse or dependence, is presented.

Children with heavy prenatal alcohol exposure exhibit deficits when regulating isometric force

BACKGROUND

Production of isometric (i.e., constant) force is an essential component of performing everyday functional tasks, yet no studies have investigated how this type of force is regulated in children with confirmed histories of heavy prenatal alcohol exposure.

METHODS

Children 7 to 17 years old with heavy prenatal alcohol exposure (n = 25) and without exposure (n = 18) applied force to a load cell to generate an isometric force that matched a criterion target force displayed on a computer monitor. Two levels of target force were investigated in combination with 3 levels of visual feedback frequency that appeared on the computer monitor as a series of yellow dots. Force was maintained for 20 seconds and participants completed 6 trials per test condition.

RESULTS

Root-mean-square error, signal-to-noise ratio, and sample entropy indexed response accuracy, response variability, and signal complexity, respectively. The analyses revealed that in comparison with controls, children with gestational ethanol exposure were significantly less accurate and more variable in regulating their force output and generated a response signal with greater regularity and less complexity in the time domain.

CONCLUSIONS

Children with prenatal alcohol exposure experience significant deficits in isometric force production that may impede their ability to perform basic motor skills and activities in everyday tasks.

Default mode network dysfunction in adults with prenatal alcohol exposure

Prenatal alcohol exposure (PAE) is known to cause significant cognitive and attentional dysfunction. Given the relationship between default mode network (DMN) activity and task-related attentional modulation, it is possible that PAE affects activity of this network. In the present study, task-related deactivation as well as structural and resting state functional connectivity of the DMN were examined using diffusional tensor imaging and functional magnetic resonance imaging in non-dysmorphic and dysmorphic PAE populations and compared to healthy controls. The dysmorphic PAE group was found to have reduced DMN deactivation as compared to controls, indicating poorer attentional modulation during the cognitive task. Additionally, structural connectivity and baseline functional connectivity were lower in both PAE groups as compared to controls. Primarily the findings suggest that learning problems seen with PAE may be a combination of general attentional and specific cognitive deficits. A secondary implication is that DMN activity is affected to varying extents depending on the degree of PAE.

Ethanol increases p190RhoGAP activity, leading to actin cytoskeleton rearrangements

We previously reported that cells chronically exposed to ethanol show alterations in actin cytoskeleton organization and dynamics in primary cultures of newborn rat astrocytes, a well-established in vitro model for foetal alcohol spectrum disorders. These alterations were attributed to a decrease in the cellular levels of active RhoA (RhoA-GTP), which in turn was produced by an increase in the total RhoGAP activity. We here provide evidence that p190RhoGAPs are the main factors responsible for such increase. Thus, in astrocytes chronically exposed to ethanol we observe: (i) an increase in p190A- and p190B-associated RhoGAP activity; (ii) a higher binding of p190A and p190B to RhoA-GTP; (iii) a higher p120RasGAP-p190A RhoGAP complex formation; and (iv) the recruitment of both p190RhoGAPs to the plasma membrane. The simultaneous silencing of both p190 isoforms prevents the actin rearrangements and the total RhoGAP activity increase triggered both by ethanol. Therefore, our data directly points p190RhoGAPs as ethanol-exposure molecular targets on glial cells of the CNS.

Molecular and behavioral aspects of the actions of alcohol on the adult and developing brain

The brain is one of the major target organs of alcohol actions. Alcohol abuse can lead to alterations in brain structure and functions and, in some cases, to neurodegeneration. Cognitive deficits and alcohol dependence are highly damaging consequences of alcohol abuse. Clinical and experimental studies have demonstrated that the developing brain is particularly vulnerable to alcohol, and that drinking during gestation can lead to a range of physical, learning and behavioral defects (fetal alcohol spectrum disorders), with the most dramatic presentation corresponding to fetal alcohol syndrome. Recent findings also indicate that adolescence is a stage of brain maturation and that heavy drinking at this stage can have a negative impact on brain structure and functions causing important short- and long-term cognitive and behavioral consequences. The effects of alcohol on the brain are not uniform; some brain areas or cell populations are more vulnerable than others. The prefrontal cortex, the hippocampus, the cerebellum, the white matter and glial cells are particularly susceptible to the effects of ethanol. The molecular actions of alcohol on the brain are complex and involve numerous mechanisms and signaling pathways. Some of the mechanisms involved are common for the adult brain and for the developing brain, while others depend on the developmental stage. During brain ontogeny, alcohol causes irreversible alterations to the brain structure. It also impairs several molecular, neurochemical and cellular events taking place during normal brain development, including alterations in both gene expression regulation and the molecules involved in cell-cell interactions, interference with the mitogenic and growth factor response, enhancement of free radical formation and derangements of glial cell functions. However, in both adult and adolescent brains, alcohol damages specific brain areas through mechanisms involving excitotoxicity, free radical formation and neuroinflammatory damage resulting from activation of the innate immune system mediated by TLR4 receptors. Alcohol also acts on specific membrane proteins, such as neurotransmitter receptors (e.g. NMDA, GABA-A), ion channels (e.g. L-type Ca²⁺ channels, GIRKs), and signaling pathways (e.g. PKA and PKC signaling). These effects might underlie the wide variety of behavioral effects induced by ethanol drinking. The neuroadaptive changes affecting neurotransmission systems which are more sensitive to the acute effects of alcohol occur after long-term alcohol consumption. Alcohol-induced maladaptations in the dopaminergic mesolimbic system, abnormal plastic changes in the reward-related brain areas and genetic and epigenetic factors may all contribute to alcohol reinforcement and alcohol addiction. This manuscript reviews the mechanisms by which ethanol impacts the adult and the developing brain, and causes both neural impairments and cognitive and behavioral dysfunctions. The identification and the understanding of the cellular and molecular mechanisms involved in ethanol toxicity might contribute to the development of treatments and/or therapeutic agents that could reduce or eliminate the deleterious effects of alcohol on the brain.

A study on the influence of ethanol over the primary cultured rat cortical neurons by using the scanning electron microscopy

As an inhibitor and toxic factor of central nervous system, ethanol inhibits the action of the neurons and causes various kinds of neuronal damage. However, the precise mechanisms that ethanol-induced neuronal damage in the central nervous system remain unclear. In spite of thousands of published studies, little information is available on the neurons' morphological alteration in the central nervous system. In this study, we investigated the morphological alterations of the primary cultured rat cortical neurons after they were treated by different concentrations of ethanol using the scanning electron microscopy. Our results showed that the moderate or high concentration of ethanol could lead to morphological changes of these cultured rat cortical neurons, and they were closely associated with the duration of time. Our study will provide a new base for further studies on the effects of ethanol in the central nervous system.

Resveratrol restores Nrf2 level and prevents ethanol-induced toxic effects in the cerebellum of a rodent model of fetal alcohol spectrum disorders

In humans, ethanol exposure during pregnancy produces a wide range of abnormalities in infants collectively known as fetal alcohol spectrum disorders (FASD). Neuronal malformations in FASD manifest as postnatal behavioral and functional disturbances. The cerebellum is particularly sensitive to ethanol during development. In a rodent model of FASD, high doses of ethanol (blood ethanol concentration 80 mM) induces neuronal cell death in the cerebellum. However, information on potential agent(s) that may protect the cerebellum against the toxic effects of ethanol is lacking. Growing evidence suggests that a polyphenolic compound, resveratrol, has antioxidant and neuroprotective properties. Here we studied whether resveratrol (3,5,4'-trihydroxy-trans-stilbene), a phytoalexin found in red grapes and blueberries, protects the cerebellar granule neurons against ethanol-induced cell death. In the present study, we showed that administration of resveratrol (100 mg/kg) to postnatal day 7 rat pups prevents ethanol-induced apoptosis by scavenging reactive oxygen species in the external granule layer of the cerebellum and increases the survival of cerebellar granule cells. It restores ethanol-induced changes in the level of transcription factor nuclear factor-erythroid derived 2-like 2 (nfe2l2, also known as Nrf2) in the nucleus. This in turn retains the expression and activity of its downstream gene targets such as NADPH quinine oxidoreductase 1 and superoxide dismutase in cerebellum of ethanol-exposed pups. These studies indicate that resveratrol exhibits neuroprotective effects in cerebellum by acting at redox regulating proteins in a rodent model of FASD.

The serotonergic anatomy of the developing human medulla oblongata: implications for pediatric disorders of homeostasis

The caudal serotonergic (5-HT) system is a critical component of a medullary "homeostatic network" that regulates protective responses to metabolic stressors such as hypoxia, hypercapnia, and hyperthermia. We define anatomically the caudal 5-HT system in the human medulla as 5-HT neuronal cell bodies located in the raphé (raphé obscurus, raphé magnus, and raphé pallidus), extra-raphé (gigantocellularis, paragigantocellularis lateralis, intermediate reticular zone, lateral reticular nucleus, and nucleus subtrigeminalis), and ventral surface (arcuate nucleus). These 5-HT neurons are adjacent to all of the respiratory- and autonomic-related nuclei in the medulla where they are positioned to modulate directly the responses of these effector nuclei. In the following review, we highlight the topography and development of the caudal 5-HT system in the human fetus and infant, and its inter-relationships with nicotinic, GABAergic, and cytokine receptors. We also summarize pediatric disorders in early life which we term "developmental serotonopathies" of the caudal (as well as rostral) 5-HT domain and which are associated with homeostatic imbalances. The delineation of the development and organization of the human caudal 5-HT system provides the critical foundation for the neuropathologic elucidation of its disorders directly in the human brain.