Early handling can attenuate adverse effects of fetal ethanol exposure

Maternal Ethanol Exposure-Induced Cardiac Fibrosis is Associated with Changes in TGF-β and SIRT1/FOXO3a Signaling in Male Rat Offspring: A Three-Month Follow-up Study

Ethanol exposure during pregnancy induces cardiac fibrosis in the fetal heart. However, the mechanisms by which consumption of ethanol induces fibrotic changes are not known. Pregnant rats were received ethanol 4.5 g/kg BW once per day from the 7th day of pregnancy (GD7) throughout lactation. Our findings demonstrated that, area of fibrosis increased in cardiac tissue in the pups on both postnatal day twenty one (PN21) and postnatal day ninety (PN90) after prenatal and early postnatal period ethanol treatment compared with the controls. It was accompanied by a decline in the expression of SIRT1 protein along with the elevation of FOXO3a and TGF-β protein expressions which were determined by western blot. Overall, our data reveal that prenatal alcohol usage increase in fibrotic regions in the pup hearts possibly by regulating TGF-β, FOXO3a and SIRT1 protein levels. These are potential therapeutic molecular targets that can be modulated to protect heart against maternal ethanol exposure.

Effects of postnatal ethanol exposure and maternal separation on mood, cognition and hippocampal arborization in adolescent rats

Ethanol exposure and early life stress during brain development are associated with an increased risk of developing psychiatric disorders. We used a third-trimester equivalent model of fetal alcohol spectrum disorders combined with a maternal separation (MS) protocol to evaluate whether these stressors cause sexually dimorphic behavioral and hippocampal dendritic arborization responses in adolescent rats. Wistar rat pups were divided into four experimental groups: 1) Control; 2) MS (MS, for 3 h/day from postnatal (PND) 2 to PND14); 3) EtOH (EtOH, 5 g/kg/day, i.p., PND2, 4, 6, 8, and 10); 4) EtOH + MS. All animals were divided into two cohorts and subjected to a battery of behavioral tests when they reached adolescence (PND37-44). Animals from cohort 1 were submitted to: 1) the open field test; 2) self-cleaning behavior (PND38); and 3) the motivation test (PND39-41). Animals from cohort 2 were submitted to: 1) the novel object recognition (PND37-39); 2) social investigation test (PND40); and 3) Morris water maze test (PND41-44). At PND45, the animals were euthanized, and the brains were collected for subsequent dendritic analysis. Postnatal ethanol exposure (PEE) caused anxiety-like behavior in females and reduced motivation, and increased hippocampal dendritic arborization in both sexes. MS reduced body weight, increased locomotor activity in females, and increased motivation, and hippocampal dendritic arborization in both sexes. We found that males from the EtOH + MS groups are more socially engaged than females, who were more interested in sweets than males. Altogether, these data suggest that early life adverse conditions may alter behavior in a sex-dependent manner in adolescent rats.

A new look at neurobehavioral development in rhesus monkey neonates (Macaca mulatta)

The Brazelton Neonatal Behavioral Assessment Scale (NBAS) evaluates a newborn infant's autonomic, motor, state, temperament, and social-attentional systems, which can help to identify infants at risk of developmental problems. Given the prevalence of rhesus monkeys being used as an animal model for human development, here we aimed to validate a standardized test battery modeled after the NBAS for use with nonhuman primates called the Infant Behavioral Assessment Scale (IBAS), employing exploratory structural equation modeling using a large sample of rhesus macaque neonates (n = 1,056). Furthermore, we examined the repeated assessments of the common factors within the same infants to describe any changes in performance over time, taking into account two independent variables (infant sex and rearing condition) that can potentially affect developmental outcomes. Results revealed three factors (Orientation, State Control, and Motor Activity) that all increased over the 1st month of life. While infant sex did not have an effect on any factor, nursery-rearing led to higher scores on Orientation but lower scores on State Control and Motor Activity. These results validate the IBAS as a reliable and valuable research tool for use with rhesus macaque infants and suggest that differences in rearing conditions can affect developmental trajectories and potentially pre-expose infants to heightened levels of cognitive and emotional deficiencies.

Neonatal alcohol exposure augments voluntary ethanol intake in the absence of potentiated anxiety-like behavior induced by chronic intermittent ethanol vapor exposure

Individuals fetally exposed to alcohol have a disproportionate risk for developing lifetime alcohol dependence, an association that may be confounded by the presence of comorbid conditions, such as anxiety. Anxiety is also observed following fetal alcohol exposure and is known to exacerbate ethanol consumption, highlighting the utility of animal models to assess this relationship. The present study evaluated the impact of third-trimester equivalent ethanol exposure on ethanol consumption and anxiety-like, marble burying behavior in adult, male C57BL/6 mice following exposure to chronic intermittent ethanol vapor, proposed to model dependence. Neonatal mice (P5-6, 2.5-3.0 g) were administered one injection of saline or ethanol (2.5 g/kg, subcutaneously [s.c.]). Pre-vapor marble burying and limited-access two-bottle choice ethanol intake (15% v/v, 2 h) were comparable in adults (8 weeks of age) across neonatal treatment groups. Five consecutive drinking sessions were repeated 72 h after each weekly ethanol vapor exposure procedure for a total of five vapor/drinking cycles. Consistent with prior research, an increase in voluntary ethanol drinking was observed in vapor-exposed, neonatal saline-treated mice throughout the study starting after the second vapor cycle compared to both air-exposed control groups. In neonatal ethanol-treated mice, this increase in ethanol intake and preference following vapor exposure was accelerated, being observed after the first vapor cycle, and observed at an augmented level compared to vapor-exposed, neonatal saline-treated mice and air controls for both neonatal conditions. Conversely, marble burying was enhanced equivalently in vapor-exposed mice from either neonatal treatment group relative to their respective air-exposed controls. These data recapitulate clinical observations of enhanced sensitivity for alcohol dependence following developmental alcohol exposure, which may reflect enhanced motivational drive rather than potentiated negative affect. The present model will facilitate the future exploration of mechanisms that underlie increased risk for alcohol use after early developmental exposure.

Sex-specific effects of developmental alcohol exposure on cocaine-induced place preference in adulthood

Fetal Alcohol Syndrome (FAS) is associated with high rates of drug addiction in adulthood. One possible basis for increased drug use in this population is altered sensitivity to drug-associated contexts. This experiment utilized a rat model of FASD to examine behavioral and neural changes in the processing of drug cues in adulthood. Alcohol was given by intragastric intubation to pregnant rats throughout gestation and to rat pups during the early postnatal period (ET group). Controls consisted of a non-treated group (NC) and a pair-fed group given the intubation procedure without alcohol (IC). On postnatal day (PD) 90, rats from all treatment groups were given saline, 0.3mg/kg, 3.0mg/kg, or 10.0mg/kg cocaine pairings with a specific context in the conditioned place preference (CPP) paradigm. While control animals of both sexes showed cocaine CPP at the 3.0 and 10.0mg/kg doses, ET females also showed cocaine CPP at 0.3mg/kg. This was accompanied by a decrease in c-Fos/GAD₆₇ cells in the nucleus accumbens (NAc) shell and GAD₆₇-only cells in the NAc shell and PFC at this 0.3mg/kg dose. ET males failed to show cocaine CPP at the 3.0mg/kg dose. This was associated with an increase in c-Fos only-labeled cells in the NAc core and PFC at this 3.0mg/kg dose. These results suggest that developmental alcohol exposure has a sexually-dimorphic effect on cocaine's conditioning effects in adulthood and the NAc.

Long-Term Effects of the Periconception Period on Embryo Epigenetic Profile and Phenotype: The Role of Stress and How This Effect Is Mediated

Stress represents an unavoidable aspect of human life, and pathologies associated with dysregulation of stress mechanisms - particularly psychiatric disorders - represent a significant global health problem. While it has long been observed that levels of stress experienced in the periconception period may greatly affect the offspring's risk of psychiatric disorders, the mechanisms underlying these associations are not yet comprehensively understood. In order to address this question, this chapter will take a 'top-down' approach, by first defining stress and associated concepts, before exploring the mechanistic basis of the stress response in the form of the hypothalamic-pituitary-adrenal (HPA) axis, and how dysregulation of the HPA axis can impede our mental and physical health, primarily via imbalances in glucocorticoids (GCs) and their corresponding receptors (GRs) in the brain. The current extent of knowledge pertaining to the impact of stress on developmental programming and epigenetic inheritance is then extensively discussed, including the role of chromatin remodelling associated with specific HPA axis-related genes and the possible role of regulatory RNAs as messengers of environmental stress both in the intrauterine environment and across the germ line. Furthering our understanding of the role of stress on embryonic development is crucial if we are to increase our predictive power of disease risk and devise-effective treatments and intervention strategies.

Prenatal alcohol exposure selectively enhances young adult perceived pleasantness of alcohol odors

Prenatal alcohol exposure (PAE) can lead to life-long neurobehavioral and social problems that can include a greater likelihood of early use and/or abuse of alcohol compared to older teens and young adults without PAE. Basic research in animals demonstrates that PAE influences later postnatal responses to chemosensory cues (i.e., odor & taste) associated with alcohol. We hypothesized that PAE would be related to poorer abilities to identify odors of alcohol-containing beverages, and would alter perceived alcohol odor intensity and pleasantness. To address this hypothesis we examined responses to alcohol and other odors in a small sample of young adults with detailed prenatal histories of exposure to alcohol and other drugs. The key finding from our controlled analyses is that higher levels of PAE were related to higher relative ratings of pleasantness for alcohol odors. As far as we are aware, this is the first published study to report the influence of PAE on responses to alcohol beverage odors in young adults. These findings are consistent with the hypothesis that positive associations (i.e., "pleasantness") to the chemosensory properties of alcohol (i.e., odor) are acquired prenatally and are retained for many years despite myriad interceding postnatal experiences. Alternate hypotheses may also be supported by the results. There are potential implications of altered alcohol odor responses for understanding individual differences in initiation of drinking, and alcohol seeking and high-risk alcohol-related behaviors in young adults.

The effects of postnatal alcohol exposure and galantamine on the context pre-exposure facilitation effect and acetylcholine efflux using in vivo microdialysis

Fetal alcohol spectrum disorders (FASD) are characterized by damage to multiple brain regions, including the hippocampus, which is involved in learning and memory. The acetylcholine neurotransmitter system provides major input to the hippocampus and is a possible target of developmental alcohol exposure. Alcohol (3.0 g/kg/day) was administered via intubation to male rat pups (postnatal day [PD] 2-10; ethanol-treated [ET]). Controls received a sham intubation (IC) or no treatment (NC). Acetylcholine efflux was measured using in vivo microdialysis (PD 32-35). ET animals were not different at baseline, but had decreased K(+)/Ca(2+)-induced acetylcholine efflux compared to NC animals and an enhanced acetylcholine response to galantamine (acetylcholinesterase inhibitor; 2.0 mg/kg) compared to both control groups. A separate cohort of animals was tested in the context pre-exposure facilitation effect task (CPFE; PD 30-32) following postnatal alcohol exposure and administration of galantamine (2.0 mg/kg; PD 11-30). Neither chronic galantamine nor postnatal alcohol exposure influenced performance in the CPFE task. Using immunohistochemistry, we found that neither alcohol exposure nor behavioral testing significantly altered the density of vesicular acetylcholine transporter or alpha7 nicotinic acetylcholine receptor in the ventral hippocampus (CA1). In the medial septum, the average number of choline acetyltransferase (ChAT+) cells was increased in ET animals that displayed the context-shock association; there were no changes in IC and NC animals that learned the context-shock association or in any animals that were in the control task that entailed no learning. Taken together, these results indicate that the hippocampal acetylcholine system is significantly disrupted under conditions of pharmacological manipulations (e.g., galantamine) in alcohol-exposed animals. Furthermore, ChAT was up‑regulated in ET animals that learned the CPFE, which may account for their ability to perform this task. In sum, developmental alcohol exposure may disrupt learning and memory in adolescence via a cholinergic mechanism.

Prenatal alcohol exposure and adolescent stress increase sensitivity to stress and gonadal hormone influences on cognition in adult female rats

Abnormal activity of stress hormone (hypothalamic-pituitary-adrenal [HPA]), and gonadal hormone (hypothalamic-pituitary-gonadal [HPG]) systems is reported following prenatal alcohol exposure (PAE). PAE increases vulnerability of brain regions involved in regulation of these systems to stressors or challenges during sensitive periods of development, such as adolescence. In addition, HPA and HPG functions are linked to higher order functions such as executive function (EF), with dysregulation of either system adversely affecting EF processes, including attention and response inhibition, that influence cognition. However, how HPA and HPG systems interact to influence cognitive performance in individuals with an FASD is not fully understood. To investigate, we used a rat model of moderate PAE. Adolescent female PAE and control offspring were exposed to 10days of chronic mild stress (CMS) and cognitive function was assessed on the radial arm maze (RAM) in adulthood. On the final test day, animals were sacrificed, with blood collected for hormone analyses, and vaginal smears taken to assess estrus stage at the time of termination. Analyses showed that adolescent CMS significantly increased levels of CORT and RAM errors during proestrus in adult PAE but not control females. Moreover, CORT levels were correlated with estradiol levels and with RAM errors, but only in PAE females, with outcome dependent on adolescent CMS condition. These results suggest that PAE increases sensitivity to the influences of stress and gonadal hormones on cognition, and thus, in turn, that HPA and HPG dysregulation may underlie some of the deficits in executive function described previously in PAE females.

The utility of zebrafish to study the mechanisms by which ethanol affects social behavior and anxiety during early brain development

Exposure to moderate levels of ethanol during brain development has a number of effects on social behavior but the molecular mechanisms that mediate this are not well understood. Gaining a better understanding of these factors may help to develop therapeutic interventions in the future. Zebrafish offer a potentially useful model in this regard. Here, we introduce a zebrafish model of moderate prenatal ethanol exposure. Embryos were exposed to 20mM ethanol for seven days (48hpf-9dpf) and tested as adults for individual social behavior and shoaling. We also tested their basal anxiety with the novel tank diving test. We found that the ethanol-exposed fish displayed reductions in social approach and shoaling, and an increase in anxiety in the novel tank test. These behavioral differences corresponded to differences in hrt1aa, slc6a4 and oxtr expression. Namely, acute ethanol caused a spike in oxtr and ht1aa mRNA expression, which was followed by down-regulation at 7dpf, and an up-regulation in slc6a4 at 72hpf. This study confirms the utility of zebrafish as a model system for studying the molecular basis of developmental ethanol exposure. Furthermore, it proposes a putative developmental mechanism characterized by ethanol-induced OT inhibition leading to suppression of 5-HT and up-regulation of 5-HT1A, which leads, in turn, to possible homeostatic up-regulation of 5-HTT at 72hpf and subsequent imbalance of the 5-HT system.

Neonatal handling: an overview of the positive and negative effects

As one of the first rodent models designed to investigate the effects of early-life experiences, the neonatal handling paradigm has helped us better understand how subtle changes in the infant environment can powerfully drive neurodevelopment of the immature brain in typical or atypical trajectories. Here, we review data from more than 50 years demonstrating the compelling effects of neonatal handling on behavior, physiology, and neural function across the lifespan. Moreover, we present data that challenge the classical view of neonatal handling as an animal model that results only in positive/beneficial outcomes. Indeed, the overall goal of this review is to offer the suggestion that the effects of early-life experiences-including neonatal handling-are nuanced rather than unidirectional. Both beneficial and negative outcomes may occur, depending on the parameters of testing, sex of the subject, and neurobehavioral system analyzed.

Prenatal ethanol exposure delays the onset of spermatogenesis in the rat

BACKGROUND

During late prenatal and early postnatal life, the reproductive system in males undergoes an extensive series of physiological and morphological changes. Prenatal ethanol (EtOH) exposure has marked effects on the development of the reproductive system, with long-term effects on function in adulthood. The present study tested the hypothesis that prenatal EtOH exposure will delay the onset of spermatogenesis.

METHODS

Development of the seminiferous tubules and the onset of spermatogenesis were examined utilizing a rat model of fetal alcohol spectrum disorder (FASD). Male offspring from ad libitum-fed control (C), pair-fed (PF), and EtOH-fed (prenatal alcohol exposure [PAE]) dams were terminated on postnatal (PN) days 5, 15, 18, 20, 25, 35, 45, and 55, to investigate morphological changes through morphometric analysis of the testes from early neonatal life through young adulthood.

RESULTS

PAE males had lower relative (adjusted for body weight) testis weights compared with PF and/or C males from PN15 through puberty (PN45). In addition, fewer gonocytes (primordial germ cells) were located on the basal lamina on PN5, while more of those touching the basal lamina were dividing in PAE compared with PF and C males, suggesting delayed cell division and migration processes. As well, the percentage of tubules with open lumena was lower in PAE compared with PF and C males on PN18 and 20, and PAE males had fewer primary spermatocytes per tubule on PN18 and round spermatids per tubule on PN25 compared with C males. Finally, the percentage of tubules at stages VII and VIII, when mature spermatids move to the apex of the epithelium and are released, was lower in PAE compared with PF and/or C males in young adulthood (PN55).

CONCLUSIONS

Maternal EtOH consumption appears to delay both reproductive development and the onset of spermatogenesis in male offspring, with effects persisting at least until young adulthood.

From research to practice: an integrative framework for the development of interventions for children with fetal alcohol spectrum disorders

Since fetal alcohol syndrome was first described over 35 years ago, considerable progress has been made in the delineation of the neurocognitive profile in children with prenatal alcohol exposure. Preclinical investigators have made impressive strides in elucidating the mechanisms of alcohol teratogenesis and in testing the effectiveness of pharmacological agents and dietary supplementation in the amelioration of alcohol-induced deficits. Despite these advances, only limited progress has been made in the development of evidence-based comprehensive interventions for functional impairment in alcohol-exposed children. Having performed a search in PubMed and PsycINFO using key words, interventions, treatment, fetal alcohol syndrome, prenatal alcohol exposure, and fetal alcohol spectrum disorders, we found only 12 papers on empirically-based interventions. Only two of these interventions had been replicated and none met the criteria of "well-established," as defined by Chambless and Hollon (Journal of Consulting and Clinical Psychology 66(1):7-18, 1998). There has been only limited cross-fertilization of ideas between preclinical and clinical research with regard to the development of interventions. Therefore, we propose a framework that allows integrating data from preclinical and clinical investigations to develop comprehensive intervention programs for children with fetal alcohol spectrum disorders. This framework underscores the importance of multi-level evaluations and interventions.

Cognitive and behavioral effects of prenatal alcohol exposure

Children exposed to substantial amounts of alcohol prenatally are known to display a range of physical and cognitive anomalies, referred to as fetal alcohol spectrum disorders (FASDs). Animal models and neuroimaging studies of FASDs have consistently demonstrated that specific regions of the brain (e.g., midline structures) are more vulnerable to the teratogenic effects of alcohol than other regions. The main aim of this article is to assess whether findings from cognitive–behavioral studies of FASDs yield a profile that maps onto the pattern of damage revealed by neuroanatomical investigations. To achieve this aim, the findings from studies that have investigated elementary functions (e.g., associative learning), general functions (e.g., intellectual abilities), specific functions (e.g., language and memory) and behavior in children and adults with FASDs are examined. The cognitive–behavioral profile emerging from the data is defined as a generalized deficit in processing and integrating complex information. It is proposed that slow processing of information mainly contributes to this deficit. The clinical implications of the above characterization of the cognitive–behavioral profile in FASDs are discussed.

Challenges to maternal wellbeing during pregnancy impact temperament, attention, and neuromotor responses in the infant rhesus monkey

The relative maturity, alertness, and reactivity of an infant at birth are sensitive indices of the neonate's health, the quality of the pregnancy, and the mother's wellbeing. Even when fetal growth and gestation length have been normal, the maturing fetus can still be adversely impacted by both physical events and psychological challenges to the mother during the prenatal period. The following research evaluated 413 rhesus monkeys from 7 different types of pregnancies to determine which conditions significantly influenced the behavioral responsiveness and state of the young infant. A standardized test battery modeled after the Neonatal Behavioral Assessment Scale for human newborns was employed. The largest impairments in orientation and increases in infant emotional reactivity were seen when female monkeys drank alcohol, even though consumed at only moderate levels during part of the pregnancy. The infants' ability to focus and attend to visual and auditory cues was also affected when the gravid female's adrenal hormones were transiently elevated for 2 weeks by ACTH administration. In addition, responses to tactile and vestibular stimulation were altered by both this ACTH treatment and psychological disturbance during gestation. Conversely, a 2-day course of antenatal corticosteroids 1 month before term resulted in infants with lower motor activity and reactivity. These findings highlight several pregnancy conditions that can affect a young infant's neurobehavioral status, even when otherwise healthy, and demonstrate that alterations or deficits are specific to the type of insult experienced by the mother and fetus.

A neurodevelopmental framework for the development of interventions for children with fetal alcohol spectrum disorders

Despite considerable data published on cognitive and behavioral disabilities in children with fetal alcohol spectrum disorders (FASD), relatively little information is available on behavioral or pharmacological interventions for alcohol-affected children. The main goals of this article, therefore, are to summarize published intervention studies of FASD and to present a neurodevelopmental framework, based on recent findings from a number of disciplines, for designing new therapies for alcohol-affected children. This framework assumes a neuroconstructionist view, which posits that reciprocal interactions between neural activity and the brain's hardware lead to the progressive formation of intra- and interregional neural connections. In this view, behavioral interventions can be conceptualized as a series of guided experiences that are designed to produce neural activation. Based on evidence from cognitive neuroscience, it is hypothesized that specific interventions targeting executive attention and self-regulation may produce greater generalizable results than those aimed at domain-specific skills in children with FASD. In view of reciprocal interactions between environmental effects and neural structures, the proposed framework suggests that the maximum effects of interventions can eventually be achieved by optimally combining behavioral methods and cognition-enhancing drugs.

Animal models of fetal alcohol spectrum disorders: impact of the social environment

Animal models of fetal alcohol spectrum disorder (FASD) have been used to demonstrate the specificity of alcohol's teratogenic effects and some of the underlying changes in the central nervous system (CNS) and, more recently, to explore ways to ameliorate the effects of alcohol. The main point of this review is to highlight research findings from the animal literature which point to the impact of the social context or social behavior on the effect(s) of alcohol exposure during development, and also to point to research questions about the social environment and effects of prenatal alcohol exposure that remain to be answered. Alcohol exposure during early development alters maternal responding to the exposed pup in a variety of ways and the alteration in maternal responding could alter later stress responsivity and adult maternal and social behavior of the exposed offspring. Environmental enrichment and voluntary exercise have been shown to ameliorate some of alcohol's impact during development, but the roles of enhanced social interactions in the case of enrichment and of social housing during voluntary exercise need to be more fully delineated. Similarly, the role of social context across the lifespan, such as social housing, social experiences, and contact with siblings, needs further study. Because of findings that alcohol during development alters DNA methylation patterns and that there are alterations in the maternal care of the alcohol-exposed offspring, epigenetic effects and their relationship to social behavior in animal models of FASD are likely to become a fruitful area of research. Because of the simpler social behavior and the short lifespan of rodents, animal models of FASD can be useful in determining how the social context impacts the effects of alcohol exposure during development.

Social enrichment during postnatal development induces transgenerational effects on emotional and reproductive behavior in mice

Across species there is evidence that the quality of the early social environment can have a profound impact on neurobiology and behavior. In the present study we explore the effect of communal rearing conditions (three dams with three litters per cage) during the postnatal period on offspring (F1) and grand-offspring (F2) anxiety-like and maternal behavior in Balb/c mice. Females rearing pups in communal nests exhibited increased levels of postpartum maternal care and communal rearing was found to abolish sex-differences in weaning weights. In adulthood, communally reared offspring were observed to display reduced anxiety-like behavior when placed in a novel environment. When rearing their own offspring under standard conditions, communally reared females demonstrated higher levels of motivation to retrieve pups, built higher quality nests, and exhibited higher levels of postpartum care compared to standard reared females. When exposed to an intruder male, communally reared females were more subordinate and less aggressive. F2 offspring of communally reared females were observed to engage in reduced anxiety-like behavior, have larger litter sizes and an increased frequency of nursing on PND 1. Analysis of neuropeptide receptor levels suggest that a communal rearing environment may exert sustained effects on behavior through modification of oxytocin and vasopressin (V1a) receptor densities. Though Balb-C mice are often considered "socially-incompetent" and high in anxiety-like behavior, our findings suggest that through enrichment of the postnatal environment, these behavioral and neuroendocrine deficits may be attenuated both within and across generations.

Voluntary exercise influences behavioral development in rats exposed to alcohol during the neonatal brain growth spurt

Children exposed to alcohol prenatally may suffer from severe brain damage, expressed as a variety of behavioral problems, including hyperactivity and learning deficits. There is a critical need to identify effective treatments for fetal alcohol effects. Physical exercise enhances cognitive ability and increases neurogenesis in the hippocampus, a brain area important for learning and memory. Thus, the present study examined whether physical exercise might reduce the severity of alcohol-induced behavioral alterations. Sprague-Dawley rats were intubated with 5.25 g/kg/day ethanol during the third trimester equivalent (postnatal days [PDs] 4-9). Intubated sham control and nontreated controls were included. From PD 21 to PD 51, half of the subjects were given access to running wheels. On PD 52, subjects were tested on the Morris water maze, and on PD 60, open field activity levels were measured. Morris maze performance was significantly impaired among ethanol-exposed subjects; exercise significantly improved performance of all groups. Similarly, ethanol-exposed subjects were overactive in the open field, an effect attenuated with exercise. In sum, these data suggest that exercise may increase neuronal plasticity not only in controls, but also in subjects exposed to alcohol during development.

Moderate level fetal alcohol exposure and serotonin transporter gene promoter polymorphism affect neonatal temperament and limbic-hypothalamic-pituitary-adrenal axis regulation in monkeys

BACKGROUND

A length polymorphism in the serotonin (5-HT) transporter gene promoter region in humans and rhesus monkeys affects functional characteristics of the brain 5-HT system. Prenatal alcohol exposure (FA-exposure) can have an impact on brain and psychosocial development that could interact with genetic endowment. This study determined whether moderate FA-exposure interacts with polymorphism in the 5-HT transporter gene to increase the incidence or severity of fetal alcohol effects in rhesus monkeys.

METHODS

The offspring of monkeys who did or did not consume moderate amounts of alcohol during pregnancy were assessed for temperament as neonates and adrenocorticotropic hormone (ACTH) and cortisol (CORT) in response to mother-infant separation at 6 months of age. Serotonin promoter region genotypes (homozygous s/s or heterozygous s/l versus homozygous l/l) were determined.

RESULTS

Prenatal alcohol exposed carriers of the s allele exhibited increased neonatal irritability and increased ACTH and CORT compared with FA-exposed monkeys homozygous for the l allele and monkeys that were not FA-exposed regardless of genotype.

CONCLUSIONS

The s allele of the 5-HT transporter increases the probability of neonatal irritability and increased stress responsiveness in FA-exposed monkeys, and this gene-environment interaction may affect psychosocial development. It is probable that FA-exposure contributes to 5-HT transporter gene-environment interactions in humans.

Effect of maternal ethanol consumption during pregnancy and lactation on kinetic parameters of folic acid intestinal transport in suckling rats

Ethanol ingestion is known to interfere with folate absorption and metabolism. A fostering/crossfostering analysis of maternal ethanol exposure effects on jejunum and ileum kinetic parameters in vivo of offspring rat folic acid absorption at 21 days postpartum was carried out. The rats were divided into four groups: CP, control pups; GP, pups exposed to ethanol only during gestation; LP, pups exposed to ethanol only during lactation; GLP, pups exposed to ethanol during gestation and lactation. Jejunal and ileal loop transport studies were performed using in vivo perfusion at a flow rate of 3 ml/min for 5 min. Folic acid concentrations of 0.25, 0.5, 1, 1.5 and 2.5 microM: were used. Jejunal and ileal absorption values were determined by the difference between the initial and the final amounts of substrate in the perfusate and expressed as picomoles per square centimeter of intestinal surface every 5 min. The results indicated that ethanol consumption by the dams during gestation and/or lactation led to significant changes in V(max), with no significant changes in apparent K(m). These findings suggest that exposure to ethanol during gestational and suckling periods leads to a general delay in postnatal body weight and that intestinal folate absorption appears to be upregulated in suckling rats, this effect being higher in the LP group.

The communicative functions of touch in humans, nonhuman primates, and rats: a review and synthesis of the empirical research

Although touch is one of the most neglected modalities of communication, several lines of research bear on the important communicative functions served by the modality. The authors highlighted the importance of touch by reviewing and synthesizing the literatures pertaining to the communicative functions served by touch among humans, nonhuman primates, and rats. In humans, the authors focused on the role that touch plays in emotional communication, attachment, bonding, compliance, power, intimacy, hedonics, and liking. In nonhuman primates, the authors examined the relations among touch and status, stress, reconciliation, sexual relations, and attachment. In rats, the authors focused on the role that touch plays in emotion, learning and memory, novelty seeking, stress, and attachment. The authors also highlighted the potential phylogenetic and ontogenetic continuities and discussed suggestions for future research.

Differential effects of neonatal handling on early life infection-induced alterations in cognition in adulthood

We have previously demonstrated that bacterial infection (Escherichia coli) in neonatal rats is associated with impaired memory in a fear-conditioning task in adulthood. This impairment, however, is only observed if a peripheral immune challenge (lipopolysaccharide; LPS) is administered around the time of learning. We used a brief separation/handling paradigm to determine if the adult memory impairment associated with neonatal-infection could be prevented. Naturally occurring variations in maternal care promote striking variations in offspring cognitive development, and handling paradigms are used to manipulate the quality and quantity of maternal care. Rats were injected on post natal (P) day 4 with E. coli or PBS, and half from each group were handled for 15 min/day from P4 to 20. All rats were then tested in adulthood. Neonatal handling of rats infected as neonates prevented the increase in microglial cell marker reactivity within the hippocampus, and the exaggerated brain IL-1beta production to LPS normally produced by the infection. Thus, these neural processes were now comparable to levels of non-infected PBS controls. Furthermore, handling completely prevented LPS-induced memory impairment in a context-fear task in adult rats infected as neonates. Finally, neonatal handling dramatically improved spatial learning and memory and decreased anxiety in rats treated early with PBS, but had no beneficial effect on these measures in rats infected as neonates. Taken together, these data suggest that maternal care may profoundly influence neuroinflammatory processes in adulthood, and that infection may also prevent maternal care influences on cognition later in life.

Infant stress reactivity and prenatal alcohol exposure

BACKGROUND

Animal studies have shown that prenatal alcohol exposure (PAE) is linked to alterations in the stress response systems. To date, little is known about the impact of PAE on stress systems in human infants. The current study examined PAE effects on the stress response, as evidenced by the activation of the limbic-hypothalamic-pituitary-adrenal (L-HPA) axis and autonomic system and changes in negative affect during a social-emotional challenge in human infants. We also examined whether the effects of PAE on infant responsiveness differed in boys and girls.

METHODS

Measures of cortisol, heart rate, and negative affect were obtained during a modified version of Tronick's still-face procedure, a standardized developmental paradigm used to study emotion and stress regulation. Our sample included fifty-five 5- to 7-month-old infants whose mothers were enrolled in an alcohol intervention study. Measures of maternal alcohol consumption during pregnancy and after delivery were obtained using Timeline Followback interviewing methods. Relationships between prenatal alcohol consumption and infant outcomes were examined. In addition, mothers were divided into high and low-frequency drinkers, based on the mean percent of prenatal drinking days (PDD) to facilitate between-group comparisons of infant stress measures.

RESULTS

Mothers enrolled in our study reported significant reductions in alcohol consumption after learning of their pregnancies. Nevertheless, PDD from conception to pregnancy recognition was related to increases in cortisol reactivity, elevated heart rate, and negative affect in their infants. The effects of PAE on infant responsiveness were significant after controlling for the effects of maternal depression and annual income. In addition, the effects of PAE on cortisol reactivity differed for boys and girls.

CONCLUSIONS

Greater PAE was related to greater activation of stress response systems. Our findings suggest that PAE affects the development of infant stress systems and that these effects differ in boys and girls. This work supports the possibility that PAE is related to alterations in infant stress systems, which could underlie problems in cognitive and social-emotional functioning that are common among persons exposed prenatally to alcohol.

Early adversity and alcohol availability persistently modify serotonin and hypothalamic–pituitary–adrenal-axis metabolism and related behavior: What experimental research on rodents and primates can tell us

Early experiences have profound influences on individual developmental trajectories. For example alcohol exposure during central nervous system development relates to a number of pathological consequences in adulthood. An increased risk of developing psychiatric disorders, like major depression and impulse-control-related pathologies is associated with alcohol exposure during fetal life and/or during adolescence. Additionally, adverse life experiences occurring early in development may exacerbate these consequences, while impinging on the same neural systems affected by precocious alcohol exposure. Conversely, a protective and/or stimulating environment may mitigate these alcohol-related negative outcomes. Experimental research in animal models constitutes a primary source of information in understanding both functional and dysfunctional human adaptations to these events. In this review, a selection of rodent and primate studies shows that developmental ethanol exposure on the one hand, and environmental treatments aimed at modifying the mother-offspring interaction on the other hand, independently modulate similar neuro-endocrine systems. In particular, we discuss the effects that the above-mentioned independent variables exert on the hypothalamic-pituitary-adrenal (HPA)-axis and on brain serotonergic pathways. Experimental evidence indicates that pathological adaptations of these systems are valuable predictors of human neuro-behavioral abnormalities like depression, impaired impulse control and alcohol abuse. Finally, a working hypothesis is proposed, which combines primate and rodent studies aimed: (i) at studying functional and pathological individual development following early ethanol consumption, and (ii) at heading towards a better definition of potential intervention strategies.

Prenatal ethanol exposure alters the effects of gonadectomy on hypothalamic-pituitary-adrenal activity in male rats

Prenatal ethanol exposure has marked effects on development of the hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes. In adulthood, ethanol-treated rats show altered gonadal hormone responses and reproductive function, and increased HPA responsiveness to stressors. Importantly, prenatal ethanol differentially alters stress responsiveness in adult males and females, raising the possibility that the gonadal hormones play a role in mediating prenatal ethanol effects on HPA function. To examine a possible testicular influence on HPA activity in males, we compared the effects of gonadectomy on HPA stress responses of adult male offspring from ethanol, pair-fed (PF) and ad libitum-fed control dams. Intact ethanol-treated rats showed increased adrenocorticotrophic hormone (ACTH) but blunted testosterone and luteinising hormone (LH) responses to restraint stress, and no stress-induced elevation in arginine vasopressin (AVP) mRNA levels compared to those observed in PF and/or control rats. Gonadectomy: (i) significantly increased ACTH responses to stress in control but not ethanol-treated and PF males; (ii) eliminated differences among groups in plasma ACTH and AVP mRNA levels; and (iii) altered LH and gonadotrophin-releasing hormone responses in ethanol-treated males. Taken together, these findings suggest that central regulation of both the HPA and HPG axes are altered by prenatal ethanol exposure, with normal testicular influences on HPA function markedly reduced in ethanol-treated animals. A decreased sensitivity to inhibitory effects of androgens could contribute to the HPA hyperresponsiveness typically observed in ethanol-treated males.

Postnatal environmental or experiential amelioration of neurobehavioral effects of perinatal alcohol exposure in rats

Fetal alcohol spectrum disorders (FASDs) in children are characterized by life-long compromises in learning, memory, and adaptive responses. To date, there are no clinical remedies for the treatment of global fetal alcohol effects, although interventions for specific outcomes are available. Here we review basic research in animal models of perinatal alcohol exposure to assess the potential of global environmental manipulations to ameliorate the neurobehavioral effects associated with FASD. Enhancement of the postnatal environment via neonatal handling, environmental enrichment, or rehabilitative or "therapeutic" motor training, can improve behavioral performance and ameliorate or even eliminate some deficits in perinatal alcohol-exposed rats and mice. While neuroanatomical changes associated with the behavioral improvements have been reported in some models, there generally appears to be a persistent impairment in neuronal plasticity. Such research suggests that it may be possible to manage the postnatal environment or experience of children with FASDs to improve function. It is, however, necessary to consider the difficulties in translating findings from research in animals to the clinic, school or home because sex-, postnatal age- and species-specific differences are critical factors in how specific environments may influence brain development. Continued study of the potential ameliorative effects of neonatal handling, environmental enrichment, and rehabilitative training as "therapies" in animal models will remain a valuable source of information for eventually devising treatments for children with FASDs.

Moderate iron deficiency in infancy: Biology and behavior in young rats

Iron deficiency anemia in early childhood is associated with developmental delays and perhaps, irreversible alterations in neurological functioning. The goals were to determine if dietary induced gestational and lactational iron deficiency alters brain monoamine metabolism and behaviors dependent on that neurotransmitter system. Young pregnant rats were provided iron deficient or control diets from early in gestation through to weaning of pups and brain iron concentration, regional monoamine variables and achievement of specific developmental milestones were determined throughout lactation. Despite anemia during lactation, most brain iron concentrations did not fall significantly until P25, and well after significant changes in monoamine levels, transporter levels, and D2R density changed in terminal fields. The changes in D2R density were far smaller than previously observed models that utilized severe dietary restriction during lactation or after weaning. Iron deficient pups had normal birth weight, but were delayed in the attainment of a number of milestones (bar holding, vibrissae-evoked forelimb placing). This approach of iron deficiency in utero and during lactation sufficient to cause moderate anemia but not stunt growth demonstrates that monaminergic metabolism changes occur prior to profound declines in brain iron concentration and is associated with developmental delays. Similar developmental delays in iron deficient human infants suggest to us that alterations in iron status during this developmental period likely affects developing brain monaminergic systems in these infants.

Spatial learning deficits induced by chronic prenatal ethanol exposure can be overcome by non-spatial pre-training

This study tested the hypothesis that behavioural intervention, in the form of non-spatial pre-training, mitigates the deficits in spatial learning tasks induced in guinea pig offspring by chronic prenatal ethanol exposure (CPEE). Timed, pregnant guinea pigs were treated with ethanol (4 g/kg maternal body weight/day), isocaloric-sucrose/pair-feeding, or water throughout gestation. Offspring received non-spatial pre-training, in which animals were exposed to the procedural requirements of the water maze in the absence of distal spatial cues, and then were tested in both stationary-platform and moving-platform tasks with spatial cues. Saliva cortisol was quantified in non-trained and pre-trained animals before and after exposure to the water maze.

RESULTS

CPEE offspring exhibited performance deficits in the stationary-platform task, and non-spatial pre-training improved performance of CPEE offspring to control levels. In contrast, non-spatial pre-training had no effect on the impaired performance of CPEE offspring in the moving-platform task. Non-trained CPEE offspring had elevated saliva cortisol concentration after water-maze exposure compared to control offspring. Moreover, pre-trained control animals exhibited a sensitization of the cortisol response after repeated exposure to the water maze, and this was not evident in pre-trained CPEE offspring.

CONCLUSIONS

These data demonstrate that CPEE produced deficits in spatial learning and memory processes that were partially overcome by non-spatial pre-training; however, more difficult tasks continued to reveal cognitive deficits. For repeated exposure to the water maze, CPEE offspring achieved a level of performance that was not different from control offspring, suggesting that it is the initial rate of acquisition of new learning, rather than the overall ability to learn, that is most adversely affected by CPEE.

Frequency of recent cocaine and alcohol use affects drug craving and associated responses to stress and drug-related cues

RATIONALE

Stress is known to increase drug craving, associated physiological arousal and risk of relapse in drug dependent individuals. However, it is unclear whether these responses are altered by recent frequency of drug use. The current study examined whether frequency of cocaine and alcohol abuse alters drug craving and associated arousal with laboratory exposure to stress and to drug related cues.

METHODS

Fifty-four recently abstinent treatment-seeking cocaine abusers who were part of a study on stress and drug craving were categorized into high- and low-frequency users on the basis of their recent cocaine use. The high use cocaine group also consumed significantly more alcohol than the low use cocaine group. Participants were exposed to a brief 5-min guided imagery procedure that involved imagining a recent personal stressful situation, a personal drug-related situation and a neutral-relaxing situation, one imagery session on separate days presented in random order. Subjective (craving and anxiety), cardiovascular (heart rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP)) and biochemical (adrenocorticotropic hormone (ACTH), cortisol, prolactin) measures were assessed.

RESULTS

High-frequency abusers demonstrated a significantly greater drug craving, anxiety and associated cardiovascular and hypothalamic-pituitary-adrenal (HPA) response to both stress and drug-cue exposure as compared to low-frequency abusers.

CONCLUSIONS

Increased frequency of recent cocaine and alcohol use is associated with an enhanced stress and cue-induced drug craving and arousal response that appears to be similar to the effects of cocaine, and one that may increase the vulnerability to drug-seeking behavior and relapse in drug dependent individuals.

Postnatal handling does not normalize hypothalamic corticotropin-releasing factor mRNA levels in animals prenatally exposed to ethanol

Postnatal handling has been shown to attenuate some of the deficits in developmental outcome observed following prenatal ethanol exposure (E) although it appears to be ineffective at ameliorating the hypothalamic-pituitary-adrenal (HPA) hyperresponsiveness to stressors that has been observed in adult E animals. However, the effects of postnatal handling on central regulation of HPA activity in E animals, particularly with regard to alterations in steady-state hypothalamic corticotropin-releasing factor (CRF) activity, have not been examined. In the present study, offspring from E, pair-fed (PF), and ad-libitum-fed control (C) groups were exposed to daily handling during the first 2 weeks of life (H) or were left entirely undisturbed until weaning (NH). Basal CRF and arginine vasopressin (AVP) mRNA in the parvocellular portion of the paraventricular nucleus (pPVN) of the hypothalamus were assessed at 90-110 days of age. Prenatal ethanol exposure resulted in elevated basal pPVN CRF mRNA levels compared to those in ad-libitum-fed controls. Handling altered CRF mRNA levels in a sex-specific and prenatal treatment-specific manner. Females showed no significant effects of handling. In contrast, handling decreased CRF mRNA levels in PF and C but not E males compared to their NH counterparts. There were no effects of prenatal ethanol or postnatal handling on AVP mRNA levels. These findings indicate that prenatal ethanol exposure results in elevated basal CRF mRNA levels in adulthood and that handling appears to be ineffective in normalizing those elevations, supporting the suggestion that altered basal HPA regulation in E animals may, at least in part, underlie their HPA hyperresponsiveness to stressors.

Fetal or Infantile Exposure to Ethanol Promotes Ethanol Ingestion in Adolescence and Adulthood: A Theoretical Review

BACKGROUND

Despite good evidence that ethanol abuse in adulthood is more likely the earlier human adolescents begin drinking, it is unclear why the early onset of drinking occurs in the first place. A review of experimental studies with animals complemented by clinical, epidemiologic and experimental studies with humans supports the idea that precipitating conditions for ethanol abuse occur well before adolescence, in terms of very early exposure to ethanol as a fetus or infant. Experimental studies with animals indicate, accordingly, that ethanol intake during adolescence or adulthood is potentiated by much earlier exposure to ethanol as a fetus or infant.

METHODS

Two broad theoretical frameworks are suggested to explain the increase in affinity for ethanol that follows very early exposure to ethanol, one based on effects of mere exposure and the other on associative conditioning. Studied for 50 years or more in several areas of psychology, "effects of mere exposure" refers to enhanced preference expressed for flavors, or just about any stimuli, that are relatively familiar. An alternative framework, in terms of associative conditioning, is guided by this working hypothesis: During ethanol exposure the fetus or infant acquires an association between ethanol's orosensory (odor/taste) and pharmacological consequences, causing the animal subsequently to seek out ethanol's odor and taste.

RESULTS AND CONCLUSIONS

The implication that ethanol has rewarding consequences for the fetus or young infant is supported by recent evidence with perinatal rats. Paradoxically, several studies have shown that such early exposure to ethanol may in some circumstances make the infant treat ethanol-related events as aversive, and yet enhanced intake of ethanol in adolescence is nevertheless a consequence. Alternative interpretations of this paradox are considered among the varied circumstances of early ethanol exposure that lead subsequently to increased affinity for ethanol.

Moderate level alcohol during pregnancy, prenatal stress, or both and limbic-hypothalamic-pituitary-adrenocortical axis response to stress in rhesus monkeys

This study examined the relationship between moderate-level prenatal alcohol exposure, prenatal stress, and postnatal response to a challenging event in 6-month-old rhesus monkeys. Forty-one rhesus monkey (Macaca mulatta) infants were exposed prenatally to moderate level alcohol, maternal stress, or both. Offspring plasma cortisol and adrenocorticotrophic hormone (ACTH) were determined from blood samples before maternal separation and after separation. Behavioral observations were made repeatedly across separation. Moderate-level prenatal alcohol exposure was associated with significantly higher plasma ACTH response to maternal separation. Offspring exposed to prenatal alcohol, prenatal stress, and prenatal alcohol and stress showed reduced behavioral adaptation to stress compared with controls. Baseline, 2-hr, and 26-hr plasma ACTH levels were intercorrelated and predicted behavior during separation.

Partial reversal of the effect of maternal care on cognitive function through environmental enrichment

Maternal care influences hippocampal development in the rat. The offspring of mothers that exhibit increased levels of pup licking/grooming and arched-back nursing (High LG-ABN mothers) show increased hippocampal N-methyl-D-aspartate (NMDA) receptor binding and enhanced hippocampal-dependent spatial learning. In these studies we examined whether environmental enrichment from days 22-70 of life might reverse the effects of low maternal care. Environmental enrichment eliminated the differences between the offspring of High and Low LG-ABN mothers in both Morris water maze learning and object recognition. However, enrichment did not reverse the effect of maternal care on long-term potentiation in the dentate gyrus or on hippocampal NMDA receptor binding. In contrast, peripubertal enrichment did reverse the effects of maternal care on hippocampal alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor binding. These findings provide evidence for the reversal of the effects of reduced maternal investment in early life on cognitive function in adulthood. Such effects might involve compensatory changes associated with peripubertal enrichment.

Enriched early experiences of mice underexpressing the beta-amyloid precursor protein restore spatial learning capabilities but not normal openfield behavior of adult animals

We have previously reported severely impaired spatial learning in mutant mice underexpressing a shortened variant of the beta-amyloid precursor protein (beta-APPtheta/theta). This targeted mutation is functionally equivalent to a null mutation. It also disturbs behavioral and neurological maturation with deficits emerging mainly between postnatal day (pd) 11 and 19. Such early tested mice exhibited almost no genotype-related difference in Morris water maze learning, raising the possibility that early handling might have compensated for genetic deficits. To verify this effect, we compared watermaze learning and open field behavior of 66 adult mutant and wildtype mice having been handled during pd 3-27 with that of 70 non-handled mutant and wildtype mice. Neurological testing during pd 3-27 markedly reduced time near wall and improved spatial retention of adult mutants, restoring their learning capabilities to wildtype levels. Early handling did not cure the mutation associated activity deficit in the open field, but mainly increased center field exploration in both mutants and wildtypes. In a follow-up experiment we analyzed whether an early (pd 3-10, n = 22) or middle (pd 11-19, n = 24) period of handling in form of neurological testing had differential effects on adult behavior. Mice handled during pd 11-19 had slightly shorter escape times than mice handled during pd 3-10 but were not significantly different in other behavioral measures. There were no sex related differences. Correlational and factor analysis showed that both the mutation and early handling had pleiotropic behavioral effects, resulting in differentially impaired mutants depending on the test situation. Likewise, early handling affected not only thigmotactic tendencies but also, more subtly, other behavioral components underlying water maze learning. We conclude that early postnatal stimulation can prevent mutation induced learning deficits in adult mice, but probably through other developmental mechanisms than those affected by the mutation. This implies that some behavioral impairments related to beta-APP malfunction may be corrected through simple treatments.

Postnatal stress of early weaning exacerbates behavioral outcome in prenatal alcohol-exposed juvenile rats

Some of the behavioral deficits caused by prenatal or postnatal alcohol exposure have been demonstrated to be ameliorated by environmental manipulations such as handling or environmental enrichment. This experiment, in contrast, investigated whether behavioral deficits due to prenatal alcohol exposure could be exacerbated by a stressful experience, early weaning. Pregnant dams were given either a liquid diet with 35% of the calories derived from alcohol, a liquid diet without alcohol to control for any effects of the liquid diet administration, or ad libitum food and water. Half of each litter were weaned at 15 days of age (early weaning) and half were weaned at 21 days of age (normally weaned). Offspring were weighed, tested for activity in an open field at 18 days of age, and trained to find a hidden platform in the Morris water maze at 22-24 days of age. Alcohol-exposed subjects who were weaned early were more impaired in spatial navigation ability than any other group. Similarly, the combination of early weaning and prenatal alcohol exposure caused the slowest growth. All subjects exposed to alcohol, regardless of weaning condition, had greater latencies to find the platform than those from the two control groups. There was no synergistic effect of alcohol and stress on activity levels, but all early-weaned females were more active than normally weaned females; males did not show this effect. Thus, environmental stressors such as early weaning can compound detrimental symptoms of prenatal alcohol exposure. These results have implications for the understanding of the effects of the environment on neuronal plasticity.

Therapeutic effects of complex motor training on motor performance deficits induced by neonatal binge-like alcohol exposure in rats: II. A quantitative stereological study of synaptic plasticity in female rat cerebellum

Twenty days of complex motor skill training in adult rats was previously demonstrated to rehabilitate motor performance deficits induced by binge alcohol exposure in neonatal rats. This follow-up study evaluated morphological plasticity in the paramedian lobule of the cerebellum (PML) using the same treatment and training regimens. On postnatal days (PD) 4-9, female Long-Evans rats were given either alcohol (Alcohol Exposure - AE, 4.5 g/kg/day via artificial rearing), exposure to gastrostomy control (GC) artificial rearing procedures, or reared normally as suckle controls (SC). After weaning, all rats were housed two to three per cage. At 180 days old, rats were randomly assigned either to a rehabilitation condition (RC: given 20 days of complex motor skill training), or to an inactive condition (IC: remained in their home cage). The AE rats were delayed in acquiring the training, but there were no group differences in performance over the last 2 weeks of training. Unbiased stereological techniques were used to evaluate PML volume, Purkinje cell and parallel fiber synapse density. Although total volume of PML was significantly reduced in the AE rats, complex motor skill training resulted in a significant increase in the PML molecular layer in all three postnatal treatment groups. The RC animals from the SC and AE groups had more parallel fiber synapses per Purkinje cell than corresponding IC animals. These data support the hypothesis that 'rehabilitative' motor training stimulates synaptogenesis in the PML, and that Purkinje neurons that survive the early postnatal alcohol insult are capable of substantial experience-induced plasticity.

Prenatal ethanol exposure and spatial navigation: effects of postnatal handling and aging

Prenatal ethanol exposure results in spatial navigation deficits in young and mid-aged animals. In contrast, postnatal handling attenuates spatial deficits that emerge with age in animals that are not handled. Therefore, we investigated the ability of handling to attenuate spatial deficits in animals prenatally exposed to ethanol (E). Sprague-Dawley male offspring from E, pair-fed (PF), and control (C) groups were handled (H) or nonhandled (NH) from 1 to 15 days of age and tested on the Morris water maze at 2 or 13 to 14 months of age. In young animals, H-E males had longer latencies to locate the submerged platform, and E animals, across handling conditions, showed altered search patterns compared to their PF and C counterparts. Mid-aged animals had longer latencies than young animals, with no differences among E, PF, and C animals. However, corticosterone levels were higher in mid-aged E than in C males. Handling did not attenuate impairments associated with either prenatal ethanol exposure or aging.

The impact of prenatal stress, fetal alcohol exposure, or both on development: perspectives from a primate model

The question of whether psychosocial stress during pregnancy (alone or in combination with fetal alcohol exposure) has negative consequences for offspring has not been clearly established in human studies. In this article, we present an overview of three prospective longitudinal studies. Using rhesus monkeys as subjects, a noise or hormone stressor, alone or in combination with moderate level alcohol solution, was presented daily during different stages of pregnancy. Prenatal stress resulted in lighter birth weights in two of three studies, and males from the alcohol plus noise stress condition had reduced birth weights. There were no significant effects of any of the prenatal treatments on gestation duration. Both prenatal stress and moderate fetal alcohol exposure reduced attention span and neuromotor capabilities of offspring during the first month of life, while early gestation prenatal stress, during the period of neuronal migration, emerged as a period of enhanced vulnerability for these effects. Under conditions of challenge, prenatally stressed monkeys showed more disturbance behaviors and reduced locomotion and exploration as well as altered hypothalamic-pituitary-adrenal (HPA) axis reactivity to stress. Fetal alcohol exposed monkeys also showed increased HPA axis activity in response to stressful conditions. Finally, altered patterns of alcohol consumption during adolescence were associated with prenatal stress.

Prenatal stress alters early neurobehavior, stress reactivity and learning in non-human primates: a brief review

In this paper we review three prospective longitudinal studies from our laboratory examining the effects of prenatal stress on early neuro behavior, stress reactivity and learning performance in rhesus monkeys. Either a noise stressor or ACTH treatment was administered to pregnant monkeys during specific periods of pregnancy and offspring were examined repeatedly across development. In all three studies, the prenatally stressed monkeys showed reduced attention and impaired neuromotor functioning during the first month of life compared to controls from undisturbed pregnancies. When the monkeys were separated from their mothers or peers at 6-8 months of age, prenatally stressed monkeys exhibited more disturbance behavior and showed hypothalamic-pituitary-adrenal axis dysregulation. During adolescence, they exhibited impairments in learning, compared to controls.

Behavioral/environmental intervention improves learning after cerebral hypoxia-ischemia in rats

BACKGROUND AND PURPOSE

In premature infants, many of whom experience ischemic brain insults, the environment of rearing influences cognitive outcome. We developed a model to evaluate the effect of rearing conditions on learning after unilateral cerebral hypoxia-ischemia (HI) in 7-day-old (P7) rats. We hypothesized that neonatal handling would benefit rats recovering from an episode of HI.

METHODS

Seventeen litters of P7 Long-Evans rats underwent either HI (right carotid ligation followed by 1.5 hours in 8% O(2)) or control procedures. From P8 to P14, randomized litters were either handled (15 minutes of separation from dam per day) or nonhandled. After P55, learning was tested in the Morris water maze. To evaluate injury severity, hippocampal, cortical, and striatal volumes were measured.

RESULTS

In water-maze performance, ANCOVA revealed an interaction between handling and severity of hippocampal damage. Among HI rats, handled rats learned faster when hippocampal damage was moderate (P<0.01, repeated-measures ANOVA), with no benefit when damage was mild or severe.

CONCLUSIONS

These observations suggest the beneficial cognitive effect of neonatal handling was limited to animals with moderate damage. Neonatal handling in post-HI rats may be a useful model in which to study mechanisms underlying the benefits of post-HI developmental intervention.

Effects of prenatal ethanol exposure and postnatal handling on conditioned taste aversion

Studies have shown that animals prenatally exposed to ethanol (E) exhibit deficits in conditioned taste aversion as well as displaying hypothalamic-pituitary-adrenal (HPA) hyperresponsiveness during exposure to stressors. In contrast, postnatal handling has been shown to attenuate both emotional and HPA reactivity under certain conditions. The present study tested the hypothesis that handling could attenuate adverse effects of prenatal ethanol exposure on consummatory behavior and HPA activity in a conditioned taste aversion task. We found that both prenatal ethanol exposure and handling independently increased saccharin consumption over 5 days of pretoxicosis exposure, suggesting that neophobia decreased at a faster rate in these animals. When conditioned aversion was assessed in handled animals under nondeprived conditions, E animals showed increased consumption compared to controls. Furthermore, across prenatal groups, lower corticosterone (CORT) levels were found in handled compared to nonhandled animals during reexposure under food-deprived conditions, emphasizing the importance of assessing both behavior and HPA function when examining an animal's response to a task and indicating that handling may not be effective at attenuating some deficits in E animals.

Influence of psychological variables on the activity of the hypothalamic-pituitary-adrenal axis

Psychobiology is the discipline that attempts to integrate the impact of environmental and psychological variables on biological systems. This paper focuses on the psychobiology of the hypothalamic-pituitary-adrenal (HPA) axis and illustrates several processes that influence the response of the HPA axis. The interaction of the developing rodent or primate with their primary care giver has permanent long-term effects on the HPA axis. Manipulations that alter maternal behavior during critical periods of development permanently modify the HPA axis. The HPA axis can be programmed to be hypo-responsive or hyper-responsive as a function of time and length of maternal separation. In the adult organism, the HPA response to stress is highly dependent on specific psychological factors such as control, predictability, and feedback. In primates, social variables have been shown to diminish or exacerbate the HPA stress response. During the post-natal period of development, the mother appears to actively inhibit the pups' HPA axis. Different aspects of maternal behavior regulate different components of the HPA system.