Teratogenic effects of alcohol on brain development

Developmental disabilities across the world: A scientometric review from 1936 to 2020

BACKGROUND

Developmental disabilities have been largely studied in the past years. Their etiological mechanisms have been underpinned to the interactions between genetic and environmental factors. These factors show variability across the world. Thus, it is important to understand where the set of knowledge obtained on developmental disabilities originates from and whether it is generalizable to low- and middle-income countries.

AIMS

This study aims to understand the origins of the available literature on developmental disabilities, keeping a focus on parenting, and identify the main trend of research.

METHODS AND PROCEDURE

A sample of 11,315 publications from 1936 to 2020 were collected from Scopus and a graphical country analysis was conducted. Furthermore, a qualitative approach enabled the clustering of references by keywords into four main areas: "Expression of the disorder", "Physiological Factors", "How it is studied" and "Environmental factors". For each area, a document co-citation analysis (DCA) on CiteSpace software was performed.

OUTCOMES AND RESULTS

Results highlight the leading role of North America in the study of developmental disabilities. Trends in the literature and the documents' scientific relevance are discussed in details.

CONCLUSIONS AND IMPLICATIONS

Results demand for investigation in different socio-economical settings to generalize our knowledge. What this paper adds? The current paper tries to provide insight into the origins of the literature on developmental disabilities with a focus on parenting, together with an analysis of the trends of research in the field. The paper consisted of a multi-disciplinary and multi-method review. In fact, the review tried to integrate the analysis of the relation between developmental disabilities with a closer look at the scientific contributions to the field across the world. Specifically, the paper integrates a total of 11,315 papers published on almost a century of research (from 1936 to 2020). An initial qualitative analysis on keywords was combined to a subsequent quantitative approach in order to maximize the comprehension of the impact of almost a century of scientific contributions. Specifically, documents were studied with temporal and structural metrics on a scientometric approach. This allowed the exploration of patterns within the literature available on Scopus in a quantitative way. This method not only assessed the importance of single documents within the network. As a matter of fact, the document co-citation analysis used on CiteSpace software provided insight into the relations existing between multiple documents in the field of research. As a result, the leading role of North America in the literature of developmental disabilities and parenting emerged. This was accompanied by the review of the main trends of research within the existing literature.

Impact of Wnt/β-catenin signaling on ethanol-induced changes in brain endothelial cell permeability

Chronic exposure to ethanol is associated with enhanced leakiness in the brain microvessel endothelial cells that form the blood-brain barrier (BBB). As previous studies suggested Wnt/β-catenin signaling could improve the BBB phenotype of brain endothelial cells, we examined the extent to which Wnt signaling is altered following ethanol exposure, using both a cell culture model of the BBB and mice exposed to ethanol, and the ability of Wnt activation to reverse the permeability effects of ethanol. The human brain endothelial cells, hCMEC/D3, were exposed to ethanol (17-200 mM) for various periods of time (0-96 hr) and Wnt signaling, as well as expression of downstream genes influencing BBB integrity in the cell monolayers were monitored. Determination of Wnt signaling in both brain homogenates and brain microvessels from mice exposed to ethanol was also performed. The effects of ethanol on the permeability of the hCMEC/D3 monolayers were examined using both small molecular weight (sodium fluorescein) and large molecular weight (IRdye 800CW PEG) fluorescent markers. Exposure of hCMEC/D3 to ethanol (50 mM) caused a down-regulation of Wnt/β-catenin signaling, a reduction of tight junction protein expression and up-regulation of plasmalemma vesicle associated protein (PLVAP). A similar reduction in Wnt/β-catenin activity in both cortical brain homogenates and isolated cortical cerebral microvessels were observed in mice. Other areas such as cerebellum and striatum displayed as much as 3-6 fold increases in Dkk-1, an endogenous Wnt inhibitor. Ethanol exposure caused significant changes in both sodium fluorescein and IRdye 800CW PEG permeability (2-fold compared to control). The ethanol-induced increases in permeability were attenuated by treatment with known Wnt activators (i.e. LiCl or Wnt3a). Additional screens of CNS active agents with possible Wnt activity indicated fluoxetine could also prevent the permeability effects of ethanol. These studies suggest that ethanol-induced changes in brain microvessel permeability can be reversed through activation of Wnt signaling.

Early Ethanol Exposure Inhibits the Differentiation of Hippocampal Dentate Gyrus Granule Cells in a Mouse Model of Fetal Alcohol Spectrum Disorders

BACKGROUND

Alcohol consumption during pregnancy may damage the developing central nervous system of the fetus and lead to brain structural and functional deficits in the children, known as fetal alcohol spectrum disorders. The underlying mechanisms have not been fully elucidated. Previously, using a third trimester-equivalent mouse model, ethanol (EtOH)-induced behavioral deficits (including spatial learning and memory dysfunction) in the mice were detected on postnatal day (PD) 35. The hippocampal formation is critically involved in spatial learning/memory and contains 2 major neuron populations: the pyramidal cells in the hippocampus proper and the dentate gyrus granule cells (DGGCs) in the dentate gyrus (DG). In rodents, while the pyramidal cells are almost exclusively generated prenatally, the DG granule neurons are majorly generated during the first 2 weeks postnatally, which coincides with the period of EtOH exposure in our mouse model. Therefore, in the current study the effects of EtOH exposure on the development of the DGGCs were examined.

METHODS

C57BL/6 mice were treated with 4 g/kg of EtOH by intubation on PD 4 to 10 to mimic alcohol exposure to the fetus during the third trimester in humans, and the development of DGGCs was examined by immunohistochemistry and quantified on PD 35.

RESULTS

EtOH exposure does not affect the number of total or newly generated DGGCs, but reduces the number of mature DGGCs on PD 35 in both male and female mice. The ratio of immature DGGCs over total DGGCs was increased, and the ratio of mature DGGCs over total DGGCs was decreased by EtOH exposure. In addition, no sex-dependent effects of EtOH treatment were detected.

CONCLUSION

Our data indicate that EtOH exposure in mice during PD 4 to 10 does not affect the generation/proliferation but inhibits the differentiation of the DGGCs on PD 35.

Effects of ethanol and varenicline on female Sprague-Dawley rats in a third trimester model of fetal alcohol syndrome

Perinatal ethanol exposure disrupts a variety of developmental processes in neurons important for establishing a healthy brain. These ethanol-induced impairments known as fetal alcohol spectrum disorder (FASD) are not fully understood, and currently, there is no effective treatment. Further, growing evidence suggests that adult females are more susceptible to ethanol, with the effects of perinatal ethanol exposure also being sexually divergent. Female models have been historically underutilized in neurophysiological investigations, but here, we used a third-trimester binge-ethanol model of FASD to examine changes to basal forebrain (BF) physiology and behavior in female Sprague-Dawley rats. We also tested varenicline as a potential cholinomimetic therapeutic. Rat pups were gavage-treated with binge-like ethanol, varenicline and ethanol, and varenicline alone. Using patch-clamp electrophysiology in BF slices, we observed that binge-ethanol exposure increased spontaneous post-synaptic current (sPSC) frequency. Varenicline exposure alone also enhanced sPSC frequency. Varenicline plus ethanol co-treatment prevented the sPSC frequency increase. Changes in BF synaptic transmission persisted into adolescence after binge-ethanol treatment. Behaviorally, binge-ethanol treated females displayed increased anxiety (thigmotaxis) and demonstrated learning deficits in the water maze. Varenicline/ethanol co-treatment was effective at reducing these behavioral deficits. In the open field, ethanol-treated rats displayed longer distances traveled and spent less time in the center of the open field box. Co-treated rats displayed less anxiety, demonstrating a possible effect of varenicline on this measure. In conclusion, ethanol-induced changes in both BF synaptic transmission and behavior were reduced by varenicline in female rats, supporting a role for cholinergic therapeutics in FASD treatment.

Maternal iron nutriture as a critical modulator of fetal alcohol spectrum disorder risk in alcohol-exposed pregnancies

Alcohol consumption during pregnancy places the fetus at risk for permanent physical, cognitive, and behavioral impairments, collectively termed fetal alcohol spectrum disorder (FASD). However, prenatal alcohol exposure (PAE) outcomes vary widely, and growing evidence suggests that maternal nutrition is a modifying factor. Certain nutrients, such as iron, may modulate FASD outcomes. Untreated gestational iron deficiency (ID) causes persistent neurodevelopmental deficits in the offspring that affect many of the same domains damaged by PAE. Although chronic alcohol consumption enhances iron uptake and elevates liver iron stores in adult alcoholics, alcohol-abusing premenopausal women often have low iron reserves due to menstruation, childbirth, and poor diet. Recent investigations show that low iron reserves during pregnancy are strongly associated with a worsening of several hallmark features in FASD including reduced growth and impaired associative learning. This review discusses recent clinical and animal model findings that maternal ID worsens fetal outcomes in response to PAE. It also discusses underlying mechanisms by which PAE disrupts maternal and fetal iron homeostasis. We suggest that alcohol-exposed ID pregnancies contribute to the severe end of the FASD spectrum.

Binge alcohol consumption in emerging adults: anterior cingulate cortical "thinness" is associated with alcohol use patterns

BACKGROUND

The brain undergoes dynamic and requisite changes into the early 20s that are associated with improved cognitive efficiency, particularly in prefrontal regions that are still undergoing neuromaturation. As alcohol consumption is typically initiated and progresses to binge drinking (BD) during this time, the objective of the present study was to investigate the impact of binge alcohol consumption on frontal lobe cortical thickness in emerging adults.

METHODS

Twenty-three binge drinking (11 females, mean age 22.0 ± 1.2) and 31 light drinking (15 females, mean age 21.5 ± 1.6) emerging adults underwent high-resolution magnetic resonance imaging at 3 Tesla. Cortical surface reconstruction and thickness estimation were performed using FreeSurfer for 3 a priori brain regions of interest: bilateral anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and parieto-occipital sulcus (POS). Cortical thickness measurements were then compared between binge drinker (BD) and light drinker (LD) groups.

RESULTS

Cortical thickness was significantly lower in BD than LD in the right middle ACC (mid-ACC; p ≤ 0.05) and in the left dorsal PCC (dPCC; p ≤ 0.01). No significant differences in cortical thickness were observed in the POS. Cortical thickness in the mid-ACC correlated negatively with higher quantity and frequency of drinks consumed (p < 0.01) and positively with the number of days elapsed since most recent use (p < 0.05). Furthermore, less cortical thickness in the mid-ACC in the BD group alone correlated with reported patterns of high quantity and frequency of alcohol consumption (p ≤ 0.05).

CONCLUSIONS

Findings suggest that past and recent patterns of intermittent heavy alcohol consumption are associated with less frontal cortical thickness (i.e., "thinness") of the right mid-ACC and left dPCC in emerging adults, but not the POS. While cortical thinness could have predated binge drinking, this pattern of maladaptive consumption may have acute neurotoxic effects that interfere with the finalization of neuromaturational processes in the vulnerable frontal cortex, resulting in increased microarchitectural pruning.

Effects of one- and three-day binge alcohol exposure in neonatal C57BL/6 mice on spatial learning and memory in adolescence and adulthood

Binge-like alcohol exposure during the early postnatal period in rats and mice causes deficits in spatial learning and memory that persist into adulthood. Wozniak et al. (2004) reported that heavy binge alcohol exposure on postnatal day 7 (PD 7) in C57BL/6 (B6) mice produced profound spatial learning deficits in the Morris water maze when tested in adolescence (P30-39); when tested in adulthood, however, the deficits were greatly attenuated. Using a similar PD 7 binge alcohol exposure paradigm in B6 mice, we tested whether a single-day (PD 7 only) alcohol treatment produced place learning deficits in both adolescence and in adulthood, and further tested whether a more extended (3-day, PD 7-9) alcohol exposure would induce more severe and enduring deficits. B6 mice were given either 2 subcutaneous injections of alcohol (2.5 g/kg each) 2 h apart on PD 7 or on PD 7-9, and compared with controls that received saline vehicle injections and controls that received no injections. The alcohol injections on PD 7 produced average peak blood alcohol concentrations of 472 mg/dL and evoked typical patterns of activated caspase-3-positive neurons in the cortex, hippocampal formation, and striatum 6 h after the last injection. Mice were given standard place training or random location training in the Morris water maze either as adolescents (PD 30-39) or adults (PD 70-79). The adolescents acquired the place learning more slowly than adults, and the alcohol treatments produced only modest place acquisition deficits. In contrast, both the PD7 and the PD 7-9 alcohol treatments resulted in large and significant spatial learning impairments in adults. In contrast to the previous findings of Wozniak et al. (2004), these results indicate that binge alcohol exposure in the 3rd trimester equivalent produces significant and enduring deficits in spatial learning in B6 mice.

Dietary intake, nutrition, and fetal alcohol spectrum disorders in the Western Cape Province of South Africa

In this study, we describe the nutritional status of women from a South African community with very high rates of fetal alcohol spectrum disorders (FASD). Nutrient intake (24-h recall) of mothers of children with FASD was compared to mothers of normal controls. Nutrient adequacy was assessed using Dietary Reference Intakes (DRIs). More than 50% of all mothers were below the Estimated Average Requirement (EAR) for vitamins A, D, E, and C, thiamin, riboflavin, vitamin B6, folate, calcium, magnesium, iron, and zinc. Mean intakes were below the Adequate Intake (AI) for vitamin K, potassium, and choline. Mothers of children with FASD reported significantly lower intake of calcium, docosapentaenoic acid (DPA), riboflavin, and choline than controls. Lower intake of multiple key nutrients correlates significantly with heavy drinking. Poor diet quality and multiple nutritional inadequacies coupled with prenatal alcohol exposure may increase the risk for FASD in this population.

Zebrafish model systems for developmental neurobehavioral toxicology

Zebrafish offer many advantages that complement classic mammalian models for the study of normal development as well as for the teratogenic effects of exposure to hazardous compounds. The clear chorion and embryo of the zebrafish allow for continuous visualization of the anatomical changes associated with development, which, along with short maturation times and the capability of complex behavior, makes this model particularly useful for measuring changes to the developing nervous system. Moreover, the rich array of developmental, behavioral, and molecular benefits offered by the zebrafish have contributed to an increasing demand for the use of zebrafish in behavioral teratology. Essential for this endeavor has been the development of a battery of tests to evaluate a spectrum of behavior in zebrafish. Measures of sensorimotor plasticity, emotional function, cognition and social interaction have been used to characterize the persisting adverse effects of developmental exposure to a variety of chemicals including therapeutic drugs, drugs of abuse and environmental toxicants. In this review, we present and discuss such tests and data from a range of developmental neurobehavioral toxicology studies using zebrafish as a model. Zebrafish provide a key intermediate model between high throughput in vitro screens and the classic mammalian models as they have the accessibility of in vitro models and the complex functional capabilities of mammalian models.

Maternal factors predicting cognitive and behavioral characteristics of children with fetal alcohol spectrum disorders

OBJECTIVE

To provide an analysis of multiple predictors of cognitive and behavioral traits for children with fetal alcohol spectrum disorders (FASDs).

METHOD

Multivariate correlation techniques were used with maternal and child data from epidemiologic studies in a community in South Africa. Data on 561 first-grade children with fetal alcohol syndrome (FAS), partial FAS (PFAS), and not FASD and their mothers were analyzed by grouping 19 maternal variables into categories (physical, demographic, childbearing, and drinking) and used in structural equation models (SEMs) to assess correlates of child intelligence (verbal and nonverbal) and behavior.

RESULTS

A first SEM using only 7 maternal alcohol use variables to predict cognitive/behavioral traits was statistically significant (B = 3.10, p < .05) but explained only 17.3% of the variance. The second model incorporated multiple maternal variables and was statistically significant explaining 55.3% of the variance. Significantly correlated with low intelligence and problem behavior were demographic (B = 3.83, p < .05) (low maternal education, low socioeconomic status [SES], and rural residence) and maternal physical characteristics (B = 2.70, p < .05) (short stature, small head circumference, and low weight). Childbearing history and alcohol use composites were not statistically significant in the final complex model and were overpowered by SES and maternal physical traits.

CONCLUSIONS

Although other analytic techniques have amply demonstrated the negative effects of maternal drinking on intelligence and behavior, this highly controlled analysis of multiple maternal influences reveals that maternal demographics and physical traits make a significant enabling or disabling contribution to child functioning in FASD.

Low dose prenatal ethanol exposure induces anxiety-like behaviour and alters dendritic morphology in the basolateral amygdala of rat offspring

Prenatal exposure to high levels of alcohol is strongly associated with poor cognitive outcomes particularly in relation to learning and memory. It is also becoming more evident that anxiety disorders and anxiety-like behaviour can be associated with prenatal alcohol exposure. This study used a rat model to determine if prenatal exposure to a relatively small amount of alcohol would result in anxiety-like behaviour and to determine if this was associated with morphological changes in the basolateral amygdala. Pregnant Sprague Dawley rats were fed a liquid diet containing either no alcohol (Control) or 6% (vol/vol) ethanol (EtOH) throughout gestation. Male and Female offspring underwent behavioural testing at 8 months (Adult) or 15 months (Aged) of age. Rats were perfusion fixed and brains were collected at the end of behavioural testing for morphological analysis of pyramidal neuron number and dendritic morphology within the basolateral amygdala. EtOH exposed offspring displayed anxiety-like behaviour in the elevated plus maze, holeboard and emergence tests. Although sexually dimorphic behaviour was apparent, sex did not impact anxiety-like behaviour induced by prenatal alcohol exposure. This increase in anxiety – like behaviour could not be attributed to a change in pyramidal cell number within the BLA but rather was associated with an increase in dendritic spines along the apical dendrite which is indicative of an increase in synaptic connectivity and activity within these neurons. This study is the first to link increases in anxiety like behaviour to structural changes within the basolateral amygdala in a model of prenatal ethanol exposure. In addition, this study has shown that exposure to even a relatively small amount of alcohol during development leads to long term alterations in anxiety-like behaviour.

Does antenatal tobacco or alcohol exposure influence a child's cerebral palsy? A population-based study

Antenatal tobacco and alcohol exposure are established risk factors for premature birth and an independent risk factor for cerebral palsy. Both exert adverse effects on fetal development. In children with cerebral palsy, whether antenatal exposure to tobacco or alcohol is associated with a difference in clinical profile remains unknown. The Quebec Cerebral Palsy Registry was used to compare neurologic subtypes, gross motor functional impairment, and comorbidities in children with cerebral palsy who were or were not prenatally exposed to alcohol or tobacco. Information on in utero exposure was available in 249 children with cerebral palsy born from 1999-2002, of whom 77 were exposed to alcohol and 62 to tobacco in utero. No association was evident between exposure to tobacco or alcohol during pregnancy and neurologic subtype, Gross Motor Function Classification System score, mean number of comorbidities experienced, or each of eight comorbidities explored. Adjusting for prematurity or low birth weight exerted no effect on these results. In utero exposure to tobacco or alcohol does not assist in predicting clinical profiles of cerebral palsy.

Maternal risk factors predicting child physical characteristics and dysmorphology in fetal alcohol syndrome and partial fetal alcohol syndrome

BACKGROUND

Previous research in South Africa revealed very high rates of fetal alcohol syndrome (FAS), of 46-89 per 1000 among young children. Maternal and child data from studies in this community summarize the multiple predictors of FAS and partial fetal alcohol syndrome (PFAS).

METHOD

Sequential regression was employed to examine influences on child physical characteristics and dysmorphology from four categories of maternal traits: physical, demographic, childbearing, and drinking. Then, a structural equation model (SEM) was constructed to predict influences on child physical characteristics.

RESULTS

Individual sequential regressions revealed that maternal drinking measures were the most powerful predictors of a child's physical anomalies (R² = .30, p < .001), followed by maternal demographics (R² = .24, p < .001), maternal physical characteristics (R²=.15, p < .001), and childbearing variables (R² = .06, p < .001). The SEM utilized both individual variables and the four composite categories of maternal traits to predict a set of child physical characteristics, including a total dysmorphology score. As predicted, drinking behavior is a relatively strong predictor of child physical characteristics (β = 0.61, p < .001), even when all other maternal risk variables are included; higher levels of drinking predict child physical anomalies.

CONCLUSIONS

Overall, the SEM model explains 62% of the variance in child physical anomalies. As expected, drinking variables explain the most variance. But this highly controlled estimation of multiple effects also reveals a significant contribution played by maternal demographics and, to a lesser degree, maternal physical and childbearing variables.

Administration of memantine during ethanol withdrawal in neonatal rats: effects on long-term ethanol-induced motor incoordination and cerebellar Purkinje cell loss

BACKGROUND

Alcohol consumption during pregnancy can damage the developing fetus, illustrated by central nervous system dysfunction and deficits in motor and cognitive abilities. Binge drinking has been associated with an increased risk of fetal alcohol spectrum disorders, likely due to increased episodes of ethanol withdrawal. We hypothesized that overactivity of the N-methyl-D-aspartate (NMDA) receptor during ethanol withdrawal leads to excitotoxic cell death in the developing brain. Consistent with this, administration of NMDA receptor antagonists (e.g., MK-801) during withdrawal can attenuate ethanol's teratogenic effects. The aim of this study was to determine whether administration of memantine, an NMDA receptor antagonist, during ethanol withdrawal could effectively attenuate ethanol-related deficits, without the adverse side effects associated with other NMDA receptor antagonists.

METHODS

Sprague-Dawley pups were exposed to 6.0 g/kg ethanol or isocaloric maltose solution via intubation on postnatal day 6, a period of brain development equivalent to a portion of the 3rd trimester. Twenty-four and 36 hours after ethanol, subjects were injected with 0, 10, or 15 mg/kg memantine, totaling doses of 0, 20, or 30 mg/kg. Motor coordination was tested on a parallel bar task and the total number of cerebellar Purkinje cells was estimated using unbiased stereology.

RESULTS

Alcohol exposure induced significant parallel bar motor incoordination and reduced Purkinje cell number. Memantine administration significantly attenuated both ethanol-associated motor deficits and cerebellar cell loss in a dose-dependent manner.

CONCLUSIONS

Memantine was neuroprotective when administered during ethanol withdrawal. These data provide further support that ethanol withdrawal contributes to fetal alcohol spectrum disorders.

Enhanced case management to prevent fetal alcohol spectrum disorders in Northern Plains communities

Women proven to be extremely high risk for drinking during pregnancy were provided case management (CM) enhanced with strategies derived from motivational interviewing (MI) as a part of a comprehensive Fetal Alcohol Syndrome (FAS) epidemiology and prevention program in four American Indian communities in Northern Plains states. Data on the first women enrolled (n=131) revealed that they have extreme issues with alcohol abuse to overcome. Sixty-five percent of these women have experienced extensive alcohol use within their immediate family. At intake, 24% of CM clients reported binge drinking one or more days in the preceding week. Heavy drinking resulted in estimated blood alcohol concentrations (BAC) as high as .576 using the BACCUS methodology. Project staff has attempted to actively engage each of these women in CM. Clients have been in CM an average of 17.2 months (SD=16.6). The mean number of significant contacts (face-to-face or telephone MI sessions) was 19. Thirty-one percent of the women entered some type of formal alcohol or drug treatment while in CM. Data were collected at 6 month intervals from 6 to 72 months after enrollment. Consumption of alcohol, as measured by both quantity and frequency measures, was reduced at 6 months. Thirty-eight percent of enrolled women reported complete abstinence from alcohol use at 6 months, and the number of binges while drinking in CM declined significantly from 15 at baseline to 4.3 at 6 months. However, mean peak BACs for the heavy drinking sessions were still problematic for those who continued to drink. They ranged from .234 to .275 from baseline to 12 month follow-up, but the total number of binges was reduced substantially at 12 months as well. Furthermore, the most important outcomes are the status of the children born while in CM. One hundred and forty nine pregnancies have occurred among these women, and 76% of those pregnancies have resulted in normal deliveries, and only two children born in CM are suspected of having some form of severe FASD. At 6, 12, 18, and 24 month follow-up milestones, 70% of the women who were not currently pregnant were protected from having a child with FAS by not drinking, using birth control, or both. Other measures of CM success include enrolling in school, regaining custody of children, completing substance abuse treatment, probation from the criminal justice system, substantial periods of abstinence, enrolling in programs to improve life skills, and employment.

Agmatine reduces balance deficits in a rat model of third trimester binge-like ethanol exposure

This study examined the effects of binge-like ethanol (ETOH) exposure in neonatal rats on a cerebellar-mediated balance task, and the ability of agmatine, an n-methyl-d-aspartate receptor (NMDAR) modulator, to reverse such effects. Five neonatal treatments groups were used, including ETOH (6.0 g/kg/day), AG (20 mg/kg), ETOH plus AG (6.0 g/kg/day and 20 mg/kg), a maltose control, and a non-treated control. Ethanol was administered via oral intubation twice daily for eight days, (AG was administered with the last ETOH intubation only). Two exposure periods were used; PND 1-8 or PND 8-15. On PND 31-33, balance performance on a single dowel was tested. Treatment with AG during withdrawal in ETOH exposed animals improved performance relative to ETOH alone among the PND 1-8 exposure period. ETOH exposure during the 2nd postnatal week did not impair balance. These findings provide further support that exposure to ETOH during critical developmental periods can impair performance on a cerebellar-dependent balance task. Of perhaps greater significance, co-administration of agmatine reduced these deficits suggesting that NMDA modulation via polyamine blockade may provide a novel approach to attenuating damage associated with binge-like ETOH consumption.

The Effect of Oral Consumption of Perchlorate, Alone and in Combination with Ethanol, on Plasma Thyroid Hormone and Brain Catecholamine Concentrations in the Rat

Literature has reported a controversy concerning the effects of the environmental pollutant perchlorate on pertinent physiological systems. However, no research to date has evaluated the effect of concomitant consumption of perchlorate and an additional environmental contaminant on physiological systems. The present preliminary investigation served to assess the effects of oral consumption of perchlorate, alone and in combination with ethanol, on thyroid hormone and brain catecholamine concentrations in female rats of gestational age. Forty, female Myers' high ethanol-preferring rats were randomly assigned to 1 of 7 groups that received: (1) deionized water, both bottles (2) deionized water and 10% ethanol (v/v), two separate bottles (3) 300 microg/l perchlorate solution in deionized water, both bottles (4) 300 microg/l perchlorate in deionized water and in 10% ethanol (v/v), two separate bottles (5) 3000 microg/l perchlorate solution in deionized water, both bottles (6) 3000 microg/l perchlorate in deionized water and in 10% ethanol (v/v), two separate bottles (7) 0.01% propylthiouracil solution in deionized water, both bottles. At cessation of the treatment period, plasma triiodothyronine (T3) and thyroxine (T4) levels were measured by radioimmunoassay and brain area concentrations of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and norepinephrine were measured by high performance liquid chromatography. Perchlorate consumption, alone and/or in combination with ethanol consumption, failed to produce significant alterations from control values for triiodothyronine, thyroxine, dopamine, DOPAC, or norepinephrine. The data suggest that the no-observed effect level of perchlorate consumption on thyroid hormone and brain catecholamine concentrations is above the 3000 microg/l concentration in the adult female rat.

Developmental changes in Ca2+-regulated functions of early postnatal Purkinje neurons

Ca(2+) influx through L-type Ca(2+) channels regulates several different cellular processes in developing Purkinje neurons, including activation of transcription factors and expression of cellular proteins. In the current studies, we examined the age dependence of these actions of Ca(2+) during the early developmental period. Purkinje neurons acutely isolated from postnatal day 4-8 rat pups were studied. We also examined the sensitivity of the Ca(2+)-regulated processes to a toxic environmental factor (ethanol) known to show age-dependent actions on developing Purkinje neurons. Results show that Ca(2+) activation of the transcription factor cAMP-responsive element binding protein (CREB) and Ca(2+)-induced alterations in the level of the apoptotic enzyme caspase 3 show both dose and age dependence in the early-developing Purkinje neurons. Interestingly, the age dependence was opposite for the two proteins. Ca(2+) regulation of calbindin, a Ca(2+) binding protein, was dose dependent but showed little age dependence. Exposure to ethanol altered Ca(2+) activation of pCREB in an age-dependent manner but did not alter Ca(2+) regulation of caspase 3 or calbindin levels. Taken together, these results show that the downstream effects of Ca(2+) signaling have age-dependent components during early Purkinje neuron development. This age dependence may play an important role in the normal developmental program and could contribute to the critical window of sensitivity observed for certain toxic agents during early development.

Acute ethanol inhibits extracellular signal-regulated kinase, protein kinase B, and adenosine 3':5'-cyclic monophosphate response element binding protein activity in an age- and brain region-specific manner

BACKGROUND

As little as a single episode of exposure of the developing brain to ethanol can result in developmental neuropathology and mental retardation. Extracellular signal-regulated kinases (ERKs), protein kinase B (PKB), and adenosine 3':5'-cyclic monophosphate response element binding protein (CREB) are messenger molecules that play important roles in neuronal plasticity and survival. This study was undertaken to examine the effects of acute ethanol on ERK, PKB, and CREB activation in the brain.

METHODS

Immunoblot analysis was used to determine the effects of a 1-hr exposure of ethanol on levels of phospho-ERC in primary cortical cultures and in the cerebral cortex, hippocampus, and cerebellum of postnatal day 5 (PN5), postnatal day 21 (PN21), and adult rats.

RESULTS

In cortical cultures, ethanol (100 mM) significantly reduced activity-dependent activation of phospho-ERK, phospho-PKB, and phospho-CREB by approximately 50%. In PN5 rats, ethanol (3.5 g/kg) inhibited both phospho-ERK and phospho-PKB in the cerebral cortex and hippocampus but was without effect in the cerebellum. A similar brain region-specific inhibition of phospho-ERK was observed in PN21 rats, whereas in adult rats, ethanol inhibited phospho-ERK in all three brain regions. In contrast, ethanol had no effect on phospho-PKB in either PN21 or adult rats. Without exception, ethanol inhibited phospho-CREB in an identical brain region- and age-dependent manner as was observed for phospho-ERK. Finally, administration of the NMDA antagonist MK-801 (0.5 mg/kg) to PN5 rats had no effect on phospho-ERK or phospho-PKB levels in any brain region.

CONCLUSION

The results demonstrate that acute ethanol inhibits ERK/PKB/CREB signaling in brain. This inhibition occurs in an age- and brain region-specific manner, with inhibition of PKB restricted to a time during the brain growth-spurt period. Furthermore, the lack of effect of MK-801 suggests that inhibition of NMDA receptors is unlikely to play a major role in binge ethanol inhibition of ERK/PKB/CREB signaling in vivo.

Alcohol consumption and other maternal risk factors for fetal alcohol syndrome among three distinct samples of women before, during, and after pregnancy: the risk is relative

Data were obtained from three samples of women of childbearing age. One sample of women is from prenatal clinics serving Plains Indian women. The second sample is of women from the Plains whose children were referred to special diagnostic developmental clinics, as their children were believed to have developmental issues consistent with prenatal alcohol consumption. The third sample is of women from South Africa, each of whom has given birth to a child diagnosed with full fetal alcohol syndrome (FAS). Data across samples conform to expected trends on many variables. For example, the maternal age at time of pregnancy, a major risk factor for FAS, ranged from a mean of 23.5 years for the prenatal clinic sample, to 23.8 years for the developmental clinic sample, to 27.6 for the sample of women who have delivered children with FAS. Other variables of maternal risk for FAS expected from the extant literature, such as high gravidity and parity, binge drinking, heavy intergenerational drinking in the mother's extended family and immediate social network, and length of drinking career, were compared across the three samples with variable results. However, normative measures of drinking problems are unreliable when reported across cultures. An unexpected finding from this three-sample comparison was the differential risk found when comparing U.S. women to South African women. Women in the U.S. Plains Indian samples report a high consumption of alcohol in a binge pattern of drinking, yet there is less detectable damage to the fetus than among the South African women. Body mass index (BMI) and lifelong and current nutrition may have a substantial impact, along with the above factors, in relative risk for an FAS birth. The level of risk for producing a child with FAS is influenced by environmental and behavioral conditions that vary between populations and among individual women. Also, because many syndromes are genetically based, there is a need for full behavioral and genetic histories of the mother, family, and child being studied. Collecting extensive behavioral information as well as genetic histories will provide the requisite information for making an accurate diagnosis of FAS.

A study of the behavioral effects of prenatal ethanol exposure in mice fed a diet marginally deficient in essential fatty acids for two generations

This study investigated the effects of prenatal ethanol exposure on measures of fecundity, growth, behavioral development and learning in mice that had been fed a diet, marginal in essential fatty acid (EFA) content for two generations. The first generation of mice were fed one of two diets (adequate or marginal EFA) from conception. They were mated at 10 weeks, and from days 5 to 17 of gestation dams on each diet were fed equivalent daily amounts of a liquid diet containing either 22.5% of the calories as ethanol or with maltose-dextrin substituted isocalorically for ethanol. An additional control group was fed lab chow ad libitum. Offspring were maintained on their respective diets after weaning. The marginal-EFA diet led to a large increase in perinatal mortality; it also decreased body and brain weight in the surviving pups, and retarded behavioural development. Ethanol retarded behavioral development in females, and delayed the acquisition of learning the position of an escape platform in a T water-maze in the mice fed the adequate-EFA diet. The effects of ethanol did not appear to be worse in the mice fed the marginal-EFA diet, but these data must be considered in light of the high mortality on this diet, where only the healthiest pups may have survived.

Prenatal ethanol exposure, generalized learning impairment, and medial prefrontal cortical deficits in rats

Prenatal ethanol exposure may cause neurological damage and subsequent mental retardation in humans, with learning deficits similar to those following damage to the prefrontal cortex. This study examined cognitive dysfunction and cortical damage after prenatal exposure to ethanol using a chronic administration model. Pregnant Sprague-Dawley rats received one of three diets during gestation: a liquid diet containing 35% ethanol-derived calories (ETOH), an isocaloric liquid diet (ISO), or standard chow (CHOW). Subjects were obtained from ETOH dams with blood alcohol concentrations (BACs) above 90 mg/dl and corresponding ISO and CHOW controls (one male pup/litter; n=6 pups/group). At approximately 90 days of age, subjects began training on a series of unique auditory discrimination problems using a successive go/no-go procedure. A criterion of 85% accuracy determined when a rat continued to the next problem. Subjects completed a varying number of problems within a 30-session limit, after which all rats were tested on a tone/click discrimination and reversal. Subjects were then sacrificed and neuronal number in the medial prefrontal cortex (mPFC) was estimated by the optical fractionator method. Prenatal ethanol exposure induced significant cell loss in the mPFC, which was associated with significantly impaired reversal learning. Poor performance by ETOH subjects on the tone/click reversal indicates a transfer of training deficit that may reflect failures of inhibitory control.

Effects of voluntary ethanol drinking on [125I]insulin-like growth factor-I, [125I]insulin-like growth factor-II and [125I]insulin receptor binding in the mouse hippocampus and cerebellum

Chronic exposure to ethanol can induce widespread cell loss in the brain, in some cases even causing dementia. Although the underlying mechanism associated with ethanol toxicity has not yet been established, it is suggested that one of the ways in which ethanol disrupts neuronal functioning/survival is by targeting the actions of mitogenic growth factors. Insulin-like growth factors-I and -II and insulin are structurally related polypeptides with potent mitogenic and metabolic effects on the central and peripheral nervous systems. These growth factors and their respective receptors are widely distributed throughout the brain, including the hippocampus and cerebellum. Evidence indicates that ethanol can decrease plasma levels of insulin-like growth factors and can also inhibit the growth-promoting and cell survival effects of these growth factors under in vitro conditions. The present study was designed to determine if voluntary ethanol consumption over a 21-day period could alter [125I]insulin-like growth factor-I, [125I]insulin-like growth factor-II and [125I]insulin receptor-binding sites in the hippocampus and cerebellum-areas known to be severely affected following chronic exposure to ethanol. C57BL/6 mice were presented with either water only or a choice of water and a 10% v/v ethanol solution. Mice with access to the ethanol solution drank an average of 5.35+/-0.77 g of ethanol/kg body weight per day. [125I]Insulin-like growth factor-I receptor-binding sites were found to be significantly increased in all subfields of the hippocampal formation, but not in the cerebellum, of ethanol-treated mice compared to controls. [125I]Insulin-like growth factor-II and [125I]insulin receptor-binding sites, on the other hand, did not exhibit any alterations either in the hippocampus or cerebellum following chronic exposure to ethanol. These results, in keeping with earlier reports, suggest that hippocampal insulin-like growth factor-I is more sensitive to ethanol treatment than either insulin-like growth factor-II or insulin, and the observed increase in the [125I]insulin-like growth factor-I receptor levels possibly reflects an activity-dependent response to prevent/slow down neuronal degeneration and/or to regulate subtle functional alterations that follow chronic exposure to ethanol.

Effects of prenatal alcohol exposure on the hippocampus: spatial behavior, electrophysiology, and neuroanatomy

Prenatal exposure to alcohol can result in fetal alcohol syndrome (FAS), characterized by growth retardation, facial dysmorphologies, and a host of neurobehavioral impairments. Neurobehavioral effects in FAS, and in alcohol-related neurodevelopmental disorder, include poor learning and memory, attentional deficits, and motor dysfunction. Many of these behavioral deficits can be modeled in rodents. This paper reviews the literature suggesting that many fetal alcohol effects result, at least in part, from teratogenic effects of alcohol on the hippocampus. Neurobehavioral studies show that animals exposed prenatally to alcohol are impaired in many of the same spatial learning and memory tasks sensitive to hippocampal damage, including T-mazes, the Morris water maze, and the radial arm maze. Direct evidence for hippocampal involvement is provided by neuroanatomical studies of the hippocampus documenting reduced numbers of neurons, lower dendritic spine density on pyramidal neurons, and decreased morphological plasticity after environmental enrichment in rats exposed prenatally to alcohol. Electrophysiological studies also demonstrate changes in synaptic activity in in vitro hippocampal brain slices isolated from prenatal alcohol-exposed animals. Considered together, these observations demonstrate that prenatal exposure to alcohol can result in abnormal hippocampal development and function. Such studies provide a better understanding of neurological deficits associated with FAS in humans, and may also contribute to the development of strategies to ameliorate the effects of prenatal alcohol exposure on behavior.

Amelioration of fetal alcohol-related neurodevelopmental disorders in rats: exploring pharmacological and environmental treatments

Fetal alcohol syndrome (FAS) and alcohol-related neurodevelopmental disorders (ARNDs) in children are characterized by life-long compromises in learning, memory, and adaptive responses. Until the advent of effective prevention measures, it will remain necessary to seek ways to treat the life-long neurobehavioral consequences of prenatal alcohol exposure. To date, there are no clinical remedies to recommend for either specific or global fetal alcohol effects. This article reviews our basic research in animal models that assesses the potential of global environmental manipulations or specific psychopharmacological treatments to ameliorate the neurobehavioral effects of prenatal exposure to alcohol. Postweaning environmental enrichment can improve behavioral performance and ameliorate or even eliminate deficits in prenatal alcohol-exposed rats, although there is persistent impairment in neuronal plasticity, as indicated by the failure of hippocampal pyramidal cells to increase dendrite spine density. Behavioral and neural responses to CNS stimulants differ in rats exposed prenatally to alcohol, although it is not clear that these shifts in dose-response curves would predict benefit to children. Although the present results may sound a note of optimism for the development of effective treatment strategies for children with FAS or ARNDs, it is important to consider that application of these findings in rodents may not be straightforward. We also need to know the critical features of specific environments that influence brain development, and the limits of pharmacotherapy, as well as critical periods of exposure. Continued study of the beneficial, ameliorative effects of environmental enrichment, rehabilitative training, and of pharmacological therapies in animal models, will remain a valuable source of information for eventually devising treatments specific for children with FAS and ARNDs.

Effects of continuous versus intermittent ethanol exposure on rat sympathetic neurons

BACKGROUND

Binge ethanol exposure is known to induce degeneration of central nervous system (CNS) neurons. Sympathetic hyperactivity has been related to ethanol withdrawal symptoms, but the effects of repeated withdrawals on peripheral sympathetic neurons have not been studied previously.

METHODS

The effects of continuous versus intermittent ethanol consumption on sympathetic neurons of the superior cervical ganglion (SCG) were studied in male Wistar rats. Two-month-old rats were divided into three groups: one group with ethanol (10% v/v) as the drinking fluid throughout the 51/2-month experiment (continuous, n = 9), one group drinking ethanol on 4 days/week and water on 3 days/week (intermittent, n = 9), and a control group (n = 9) with water as the only available fluid. All groups had food ad libitum. SCG volume, neuron density, and total number of neurons were measured by using unbiased morphometric methods.

RESULTS

As the mean daily ethanol consumption did not differ between the two ethanol-exposed groups (continuous 5.7 g/kg/day versus intermittent 5.8 g/kg/day), the total dose of ethanol consumed was 42% smaller in the intermittent group. The total number of SCG neurons decreased by 28%, and neuron density by 23%, in the intermittent group compared with the control group, whereas no significant neuron loss was observed in the continuous group. The volume of the SCG was similar in all study groups. The results suggest that repeated ethanol withdrawals, rather than ethanol exposure per se, are deleterious to sympathetic neurons.

CONCLUSIONS

Ethanol-induced degeneration of neurons is not only related to the amount of ethanol consumed, but also to the patterns of drinking.

Abnormalities in neuronal process extension, hippocampal development, and the ventricular system of L1 knockout mice

In humans, mutations in the L1 cell adhesion molecule are associated with a neurological syndrome termed CRASH, which includes corpus callosum agenesis, mental retardation, adducted thumbs, spasticity, and hydrocephalus. A mouse model with a null mutation in the L1 gene (Cohen et al., 1997) was analyzed for brain abnormalities by Nissl and Golgi staining and immunocytochemistry. In the motor, somatosensory, and visual cortex, many pyramidal neurons in layer V exhibited undulating apical dendrites that did not reach layer I. The hippocampus of L1 mutant mice was smaller than normal, with fewer pyramidal and granule cells. The corpus callosum of L1-minus mice was reduced in size because of the failure of many callosal axons to cross the midline. Enlarged ventricles and septal abnormalities were also features of the mutant mouse brain. Immunoperoxidase staining showed that L1 was abundant in developing neurons at embryonic day 18 (E18) in wild-type cerebral cortex, hippocampus, and corpus callosum and then declined to low levels with maturation. In the E18 cortex, L1 colocalized with microtubule-associated protein 2, a marker of dendrites and somata. These new findings suggest new roles for L1 in the mechanism of cortical dendrite differentiation, as well as in guidance of callosal axons and regulation of hippocampal development. The phenotype of the L1 mutant mouse indicates that it is a potentially valuable model for the human CRASH syndrome.

An optimised procedure for prenatal ethanol exposure with determination of its effects on central nervous system connections

We describe the protocol set-up to investigate an experimental model of foetal alcohol syndrome in the rat. The protocol has been devised to expose specific cell populations of the central nervous system to ethanol during their neurogenesis and has been applied to the study of diencephalo-telencephalic connections. We were able to demonstrate specific permanent changes of the adult thalamo-cortical circuitry. Our protocol can be applied to study other aspects of central nervous system-ethanol interactions, such as neurotransmitter and receptor patterns. It can also represent a useful tool to test the effects of different diets to prevent nutritional deficiencies and the efficacy of drug treatments to prevent foetal alcohol syndrome. We have shown in fact that ethanol-induced thalamo-cortical alterations are partially prevented by concurrent administration of acetyl-L-carnitine. Finally, the present protocol can be used to investigate the effects of ethanol exposure on the development of different brain structures. To this purpose, the gestational period for ethanol exposure must be chosen according to the peak of neurogenesis for the investigated structure.

Ethanol selectively interferes with the trophic action of NMDA and carbachol on cultured cerebellar granule neurons undergoing apoptosis

Exposure of mature rat cerebellar granule neurons to non-depolarizing conditions (5 mM K+) for 24 h resulted in the onset of apoptosis. NMDA, forskolin, carbachol and GABA attenuated low K+-induced toxicity, although to a different extent, with NMDA and GABA being the most effective agents. When cells were co-exposed for 24 h to ethanol, the survival promoting action of NMDA and carbachol, but not that of forskolin and GABA, was attenuated. By contrast, a 24 h cell pre-treatment with ethanol, followed by its removal prior to K+ deprivation, was ineffective towards the neurotrophic action of NMDA and carbachol. The concomitant presence of alcohol and neurotrophic factors was not required for the pro-apoptotic effect of ethanol to be manifest after a long-term alcohol exposure: inhibition of NMDA- and carbachol-mediated neurotrophism was still observed when cells were pre-exposed for 72 h to alcohol in depolarizing conditions, prior to the challenge with 5 mM K+-containing medium and the test compounds in the absence of ethanol. The present study shows that ethanol promotes apoptotic cell death of cultured cerebellar neurons by selectively inhibiting the neurotrophic effect of NMDA and carbachol, and suggests that alcohol may cause permanent changes in the control mechanisms of apoptosis: this finding may have significant implications for the in vivo toxicity of prenatal ethanol exposure on the developing cerebellum.

Therapeutic effects of complex motor training on motor performance deficits induced by neonatal binge-like alcohol exposure in rats . I. Behavioral results

The effects of complex motor task learning on subsequent motor performance of adult rats exposed to alcohol on postnatal days 4 through 9 were studied. Male and female Long-Evans rats were assigned to one of three treatments: (1) alcohol exposure (AE) via artificial rearing to 4.5.g kg-1 day-1 of ethanol in a binge-like manner (two consecutive feedings), (2) gastrostomy control (GC) fed isocaloric milk formula via artificial rearing, and (3) suckling control (SC), where pups remained with lactating dams. After completion of the treatments, the pups were fostered back to lactating dams, and after weaning they were raised in standard cages (two-three animals per cage) until they were 6 months old. Rats from each of the postnatal treatments then spent 20 days in one of three conditions: (1) inactive condition (IC), (2) motor control condition (MC) (running on a flat oval track), or (3) rehabilitation condition (RC) (learning to traverse a set of 10 elevated obstacles). After that all the animals were tested on three tasks, sensitive to balance and coordination deficits (parallel bars, rope climbing and traversing a rotating rod). On parallel bars, both male and female rats demonstrated the same pattern of outcomes: AE-IC rats made significantly more mistakes (slips and falls) than IC rats from both control groups. After 20 days of training in the RC condition, there were no differences between AE and both SC and GC animals in their ability to perform on the parallel bars test. On rope climbing, female animals showed a similar pattern of abilities: AE-IC rats were the worst group; exercising did not significantly improve the AE rats' ability to climb, whereas the RC groups (SC, GC and AE) all performed near asymptote and there were no significant differences among three neonatal treatment groups. There was a substantial effect of the male rats' heavier body weight on climbing ability, and this may have prevented the deficits in AE rats behavior from being detected. Nevertheless, male animals from all three postnatal treatments (SC, GC and AE) were significantly better on this task after RC. Female and male rats from all three postnatal groups demonstrated significantly better performance on the rotarod task after 20 days of 'rehabilitation'. These results suggest that complex motor skill learning improves some of the motor performance deficits produced by postnatal exposure to alcohol and can potentially serve as a model for rehabilitative intervention.

Neonatal alcohol exposure reduces NMDA induced Ca2+ signaling in developing cerebellar granule neurons

Glutamatergic neurotransmission through NMDA receptors is critical for both neurogenesis and mature function of the central nervous system (CNS), and is thought to be one target for developmentally-induced damage by alcohol to brain function. In the current study we examined Ca2+ signaling linked to NMDA receptor activation as a potential site for alcohol's detrimental effects on the developing nervous system. We compared Ca2+ signals to NMDA in granule neurons cultured from cerebella of rat neonates exposed to alcohol (ethanol) during development with responses to NMDA recorded in separated control groups. Alcohol exposure was by the vapor chamber method on postnatal days 4-7. An intermittent exposure paradigm was used where the pups were exposed to alcohol vapor for 2. 5 h/day to produce peak BALs of approximately 320 mg%. Control pups were placed in an alcohol-free chamber for a similar time period or remained with their mother. After culture under alcohol-free conditions for up to 9 days, Ca2+ signaling in response to NMDA was measured using fura-2 Ca2+ imaging. Results show that the peak amplitude of the Ca2+ signal to NMDA was significantly smaller in cultured granule neurons obtained from alcohol-treated pups compared to granule neurons from control pups. In contrast, the Ca2+ signal to K+ depolarization was not depressed by the alcohol treatment. Resting Ca2+ levels were also altered by the alcohol treatment. These results show that intermittent alcohol exposure during development in vivo can induce long-term changes in CNS neurons that affect the Ca2+ signaling pathway linked to NMDA receptors and resting Ca2+ levels. Such changes could play an important role in the CNS dysfunction associated with alcohol exposure during CNS development.

Fetal alcohol syndrome: a Japanese perspective

To estimate and prevent the effects of prenatal alcohol on the central nervous system (CNS), brain dysfunction in fetal alcohol syndrome (FAS) and fetal alcohol effects (FAE) was compared by both epidemiological and experimental studies. The FAS infants exhibited a more severe degree of CNS involvement than the FAE infants. The CNS involvement features were developmental delay and intellectual impairment in both FAS and FAE. The increased risk of low birth weight and CNS involvement were much more significant in women who were heavy drinkers or alcoholics and smoked. The beneficial effect of supplementary zinc on the fetal cerebrum of FAS or FAE rats was limited, never reaching the unexposed control level. One of the most vulnerable structures in the rat fetus exposed to ethanol in utero was the synaptic formation in the hippocampus. The consistent dysmorphogenesis of synapses during early brain development may be associated with the functional impairment of the CNS in FAS and FAE.

The development of the blood-brain barrier in alcohol-exposed rats

Circulating horseradish peroxidase (HRP) was used as a tracer to determine if the blood-brain barrier to protein was altered by dietary prenatal alcohol exposure. Animals were prepared for light microscopic visualization of HRP after HRP infusion on gestational days 16, 18, 20, 22 and postnatal day 4. There was no consistent evidence of HRP leakage through the BBB in the alcohol-exposed animals compared to control animals. Capillary endothelial cells and perivascular astrocytic endfeet were morphologically characterized by electron microscopy in rat optic nerve and cerebellum following dietary prenatal and postnatal ethanol exposure. Photomontages of optic nerve capillaries from G20 and P5 animals and cerebellar capillaries from P15 animals were examined for evidences of effects of alcohol on the development of the capillaries and adjacent astroglial endfeet. There was no consistent evidence of any alcohol-induced effect that could indicate a disruption of the vessel, the endothelial tight junctions, the perivascular glial limiting membranes, or the extent of vascular ensheathment by astrocytic endfeet.

Teratogenic actions of ethanol in the mouse: a minireview

The deleterious effects of prenatal ethanol exposure have been extensively documented in clinical and experimental studies. This paper provides an overview of work conducted with mice to examine the myriad of adverse consequences that result from embryonic/fetal exposure to ethanol. All of the hallmark features of the clinical fetal alcohol syndrome have been demonstrated in mice, including prenatal and postnatal growth retardation, structural malformations and behavioral abnormalities associated with central nervous system dysfunction. As expected, the severity and profile of effects is related to both dosage level and timing of exposure. In addition, these effects have been demonstrated following acute and chronic exposure, with a variety of routes of administration employed. Furthermore, a number of strains have been used in these studies and the variant response (susceptibility) to the teratogenic actions of ethanol exhibited among different mouse strains support the notion that genetic factors govern, at least in part, vulnerability to these effects of ethanol. More recent studies using mouse models have focused on examining potential mechanisms underlying the full spectrum of ethanol's teratogenic actions.

What research with animals is telling us about alcohol-related neurodevelopmental disorder

The substantial advances in understanding fetal alcohol syndrome over the past 20 years were made in large part because of research with animals. This review illustrates recent progress in animal research by focusing primarily on the central nervous system effects of prenatal alcohol exposure. Current findings suggest further progress in understanding consequences, risk factors, mechanisms, prevention and treatment will depend on continued research with animals.

New evidence for neurobehavioral effects of in utero cocaine exposure

Most studies of prenatal cocaine exposure have found gestational age or intrauterine growth deficits but few, if any, cognitive effects. In a large, well-controlled study we detected cognitive deficits in relation to heavy cocaine exposure. These findings demonstrate that prenatal exposure to cocaine at sufficiently high doses early in pregnancy has the potential to produce cognitive changes in infants and that more focused, narrow-band tests may be necessary to detect these subtle neurobehavioral effects. A total of 464 inner-city, black infants whose mothers were recruited prenatally on the basis of pregnancy alcohol and cocaine use were tested at 6.5, 12, and 13 months of age. Standard analyses, based on presence or absence of cocaine use during pregnancy, confirmed effects on gestational age but failed to detect cognitive effects. A new approach to identifying heavy users found that heavy exposure early in pregnancy was related to faster responsiveness on an infant visual expectancy test but to poorer recognition memory and information processing, deficits consistent with prior human and animal findings. These persistent neurobehavioral effects of heavy prenatal cocaine exposure appear to be direct effects of exposure and independent of effects on gestational age.

Proliferation of astroglia from the adult human cerebrum is inhibited by ethanol in vitro

Chronic alcoholism is associated with atrophy of the adult brain, while fetal exposure to ethanol can cause microencephaly. Since astroglial pathology is a common feature of ethanol exposure in both humans and animal models, the direct influence of ethanol on proliferation of human astroglia from the gray and white matter of adult temporal lobe was determined and compared. Astroglial cultures were exposed to constant concentrations of ethanol at realistic social and clinical levels (0.1, 0.2 or 0.5%; w/v) for 1 to 5 days. Proliferation was quantified by bromodeoxyuridine labeling and enumeration of replicating cells. Ethanol exposure significantly inhibited proliferation of both gray and white matter astroglia in a dose and duration dependent manner. Gray matter was slightly more sensitive than white matter to inhibition by low to moderate concentrations of ethanol; in contrast, white matter was more sensitive to high ethanol concentrations. Maximum inhibition was 20% in gray matter and 25% in white matter. Human astroglial proliferation was directly inhibited in the absence of neurons, microglia, neuronal degeneration or systemic factors that have confounded in vivo studies. Restricted astroglial proliferation may underlie aspects of the astroglial pathology associated with ethanol exposure.

Trends in the anatomical organization and functional significance of the mammalian thalamus

The last decade has witnessed major changes in the experimental approach to the study of the thalamus and to the analysis of the anatomical and functional interrelations between thalamic nuclei and cortical areas. The present review focuses on the novel anatomical approaches to thalamo-cortical connections and thalamic functions in the historical framework of the classical studies on the thalamus. In the light of the most recent data it is here discussed that: a) the thalamus can subserve different functions according to functional changes in the cortical and subcortical afferent systems; b) the multifarious thalamic cellular entities play a crucial role in the different functional states.

Development of glial cells cultured from prenatally alcohol treated rat brain: effect of supplementation of the maternal alcohol diet with a grape extract

The aim of this work was to investigate the effect of supplementation of a maternal alcohol diet with a grape extract on glial cell development. Glial cells were cultured during 4 weeks from cortical brain cells of the new born offspring in DMEM medium supplemented with fetal calf serum. Enzymatic markers of nerve cell development were measured (enolase isoenzymes and glutamine synthetase). Since alcohol consumption produces free radicals the antioxidant system superoxide dismutase was also investigated. Compared to the decrease found in only alcohol treated animals, all parameters except neuron-specific enolase were antagonized and even stimulated after grape extract supplementation. The effect was more important after only 1 month than 3 months of treatment. Also in the total brain an alcohol antagonizing effect and a glutamine synthetase activation were found. Our data demonstrate that addition of a grape extract to the maternal alcohol diet may partially or completely overcome the alcohol induced retardation of glial cell development.

Prenatal alcohol exposure and the effects of environmental enrichment on hippocampal dendritic spine density

The effects of environmental enrichment on synaptic spine density in hippocampal area CAI were examined in rats exposed prenatally to alcohol. Pregnant dams were given ethanol via intragastric intubation (6 g/kg/day) from gestational days 8 through 19, or given isocaloric sucrose. An untreated control group was also used. After weaning, offspring from the three groups were then reared for 10 weeks in either isolated (caged alone, not handled) or enriched (group housed with "toys," handled) conditions. Animals were then sacrificed, the brains Golgi impregnated, and CAI pyramidal cell apical and basilar spine densities quantified. Among isolated animals there were no significant differences between control and alcohol-exposed groups. In general, environmental enrichment increased apical or basilar spine densities in untreated and sucrose controls. However, in prenatal alcohol-exposed animals, environmental enrichment did not increase spine densities. Because the environmental enrichment acted postnatally, these findings suggest that the effects of prenatal alcohol exposure included decreased neural plasticity enduring into early adulthood. Such a reduction in neuroanatomical plasticity in hippocampus may be associated with cognitive impairments found following prenatal alcohol exposure.

Alterations of the thalamo-cortical system in rats prenatally exposed to ethanol are prevented by concurrent administration of acetyl-L-carnitine

We previously demonstrated that adult rats prenatally exposed to ethanol display permanent damages of thalamo-cortical connections [18,19,33]. Here the effect of simultaneous administration of ethanol and acetyl-L-carnitine has been investigated. Adult animals underwent cortical or thalamic injections of horseradish peroxidase and both anterograde and retrograde thalamic and cortical labeling have been analyzed. Ethanol-induced changes of thalamo-cortical circuits are prevented by concurrent administration of acetyl-L-carnitine. Possible mechanisms underlying this effect are discussed.

Influence of chronic alcohol treatment on the GFAP-immunoreactivity in astrocytes of the hippocampus in rats

The influence of long term application of 5% (v/v) ethanol over a period of 36 weeks and 10% (v/v) ethanol over a period of 4,12 and 36 weeks to Wistar rats was investigated. The qualitative alterations of astrocytes and quantitative changes of glial fibrillary acidic protein-immunoreactivity (GFAP-IR) in selected regions of the dorsal hippocampus were examined, using anti-GFAP and the avidin-biotin immunoperoxidase technique. After prolonged (36 weeks) consumption of 5% (v/v) ethanol insignificant alterations were observed. The administration of 10% (v/v) ethanol over 4 and 12 weeks led to an increase of the total GFAP-IR in the examined brain regions. Hypertrophy of the cell bodies and cytoplasmic processes were seen. After 36 weeks decreased total GFAP-IR was measured in all examined brain regions. Cell bodies and fibrillary processes stained less heavily, the number and length of the fibrillary processes decreased and the number of astrocytes in certain hippocampal regions (e.g. in stratum moleculare of the dentate gyrus) appeared reduced. The results show that exposition to ethanol led to the appearance of different astrocytic phenotypes, depending on the concentration and duration of ethanol application, on the age of animals and on hippocampal regions. It is suggested that GFAP can be used as a specific marker for ethanol-induced alterations of astrocytes.

Fetal alcohol and thymocyte phenotypes in offspring: response to food deprivation

Restriction of food availability is a reliable stimulus that leads to significant hypothalamo-pituitary-adrenal (HPA) activation to which rats do not habituate. Based on our previous data that indicated that the HPA response to some, but not all, stressful stimuli is significantly greater in adult offspring of Sprague-Dawley dams exposed to 35% alcohol during the last 2 weeks of gestation than that of control rats and on the mounting neuroendocrine-immune literature that describes the role of pituitary-adrenal products in modulating cellular immunity, we hypothesized that the outcomes of food restriction would be significantly more marked in fetal alcohol-exposed (FAE) offspring, compared with control rats. Data we report herein show that--whereas food restriction at 30-35 days of age produced significant changes in body weight, thymus weight-to-body weight ratio, adrenal weight-to-body weight ratio, plasma corticosterone levels, and in thymocyte number, as well as in the percentage and absolute number of CD4+ and CD8+ thymocytes that express CD45RC-FAE and control rats were equally affected. We conclude that food restriction is another example of a stressful stimulus that fails to distinguish satisfactorily between FAE and control rats of prepubertal age.