Effects Of Prenatal Ethanol Research Articles

Consequences of low or moderate prenatal ethanol exposures during gastrulation or neurulation for open field activity and emotionality in mice

In a previous study we used a mouse model for ethanol exposure during gastrulation or neurulation to investigate the effects of modest and occasional human drinking during the 3rd or 4th week of pregnancy (Schambra et al., 2015). Pregnant C57Bl/6J mice were treated by gavage during gastrulation on gestational day (GD) 7 or neurulation on GD8 with 2 doses 4h apart of either 2.4 or 2.9g ethanol/kg body weight, resulting in peak blood ethanol concentrations (BECs) of 104 and 177mg/dl, respectively. We found that mice exposed to the low dose on either day were significantly delayed in their neonatal sensorimotor development. In the present study, we tested the same cohort of mice in an open field as juveniles on postnatal day (PD) 23–25 and as young adults on PD65–67 for prenatal ethanol effects on exploration and emotionality with measures of activity, rearing, grooming and defecation. We evaluated the effects of dose, sex, day of treatment and day of birth by multiple regression analyses.We found that, compared to the respective gavage controls, juvenile mice that had been prenatally exposed to the low BEC on either GD7 or GD8 were significantly hypoactive on the first 2 test days, reared significantly more on the last 2 test days, and groomed and defecated significantly more on all 3 test days. Only mice that had been treated on GD7 remained hypoactive as adults. Juvenile mice prenatally exposed to the moderate BEC on GD7 groomed significantly more, while those exposed on GD8 reared and defecated significantly more. Sex differences were highly significant in adult control mice, with control males less active and more emotional than females. Similar, but smaller, sex differences were also evident in adults exposed to ethanol prenatally. Persistence into later life of a deleterious effect of premature birth (i.e., birth on GD19 rather than GD20) on weight and behavior was not consistently supported by these data.Importantly, mice shown previously to be delayed in sensorimotor development as neonates, in the present study demonstrated hypoactivity and increased emotionality in open field behaviors as juveniles, and those mice exposed during gastrulation remained hypoactive as adults. Thus, we propose that the delayed motor development, hypoactivity and emotionality we observed in mice exposed to a low BEC during gastrulation or neurulation may relate to an attention deficit–activity disorder in humans, possibly the inattentive subtype, or Sluggish Cognitive Tempo (SCT). We further discuss concerns about occasional light or moderate alcohol consumption during the 3rd or 4th week of human pregnancy.

Fetal alcohol exposure alters proopiomelanocortin gene expression and hypothalamic-pituitary-adrenal axis function via increasing MeCP2 expression in the hypothalamus.

Proopiomelanocortin (POMC) is a precursor gene of the neuropeptide β-endorphin in the hypothalamus and is known to regulate various physiological functions including stress response. Several recent reports showed that fetal alcohol exposure programs the hypothalamus to produce lower levels of POMC gene transcripts and to elevate the hypothalamic-pituitary-adrenal (HPA) axis response to stressful stimuli. We investigated the role of methyl CpG binding protein (MeCP2) in the effects of prenatal ethanol on POMC gene expression and hypothalamic-pituitary-adrenal (HPA) axis function. Pregnant Sprague Dawley rats were fed between GD 7 and 21 with a liquid diet containing 6.7% alcohol, pair-fed with isocaloric liquid diet, or fed ad libitum with rat chow, and their male offsprings were used at 60 days after birth in this study. Fetal alcohol exposure reduced the level of POMC mRNA, but increased the level of DNA methylation of this gene in the arcuate nucleus (ARC) of the hypothalamus where the POMC neuronal cell bodies are located. Fetal alcohol exposed rats showed a significant increase in MeCP2 protein levels in POMC cells, MeCP2 gene transcript levels as well as increased MeCP2 protein binding on the POMC promoter in the arcuate nucleus. Lentiviral delivery of MeCP2 shRNA into the third ventricle efficiently reduced MeCP2 expression and prevented the effect of prenatal ethanol on POMC gene expression in the arcuate nucleus. MeCP2-shRNA treatment also normalized the prenatal ethanol-induced increase in corticotropin releasing hormone (CRH) gene expression in the hypothalamus and elevated plasma adrenocorticotrophic hormone (ACTH) and corticosterone hormone responses to lipopolysaccharide (LPS) challenge. These results suggest that fetal alcohol programming of POMC gene may involve recruitment of MeCP2 on to the methylated promoter of the POMC gene to suppress POMC transcript levels and contribute to HPA axis dysregulation.

Intergenerational effects of prenatal ethanol on glucose tolerance and insulin response

Consequences of prenatal exposure to ethanol (E) include morphological, physiological, and cognitive deficits and are collectively classified as fetal alcohol spectrum disorders. Adult prenatal E exposed offspring show insulin resistance, and given that in utero hyperglycemic environment can cause metabolic disorders in subsequent generations; we investigated the effects of grandmaternal E on functional glucose and insulin responses of the second generation. Sprague-Dawley (S) rat dams, mated with S males, received E-containing liquid diet and two different control diets between gestational days 8 and 20. Additionally, because prenatal E-induced behavioral deficits can be reversed by simultaneous thyroxine (T4) treatment, another group of dams received 0.3 mg/l T4 in their E diet. Their first-generation (F1) offspring were mated with control Brown Norway (B) males or females to produce SB and BS F2 progeny. Dams consuming E during pregnancy were hyperglycemic, and their F1 offspring showed insulin resistance in the glucose tolerance test (GTT). However, F2 responses to GTT varied based on the sex of prenatal E-exposed parent. BS F2 females, and both male and female SB F2 progeny, displayed hypoglycemic and hyperinsulinemic GTT response patterns. Although administering T4 to E dams normalized thyroid function of the F1 generation, it did not reverse their prenatal E-induced metabolic dysfunction. In contrast, administration of T4 to the alcohol-consuming grandmother reversed or alleviated the aberrant GTT responses of the F2 progeny. Prenatal E-induced dysregulation of glucose metabolism can affect the next generation, possibly via ethanol effects on the germline of the F1 fetus.

Effects of exposure to moderate levels of ethanol during prenatal brain development on dendritic length, branching, and spine density in the nucleus accumbens and dorsal striatum of adult rats

Reductions in measures of dendritic morphology in the agranular insular cortex have been identified as consequences of prenatal exposure to moderate levels of ethanol in the rat. Motivated by the strong connectivity between this region of frontal cortex and the striatum and a growing body of data linking specific components of the mesocortical/limbic system to effects of ethanol and ethanol self-administration, the current study investigated the effects of moderate fetal ethanol exposure on the dendritic morphology of medium spiny neurons (MSNs) in several regions of the striatum. Throughout gestation, pregnant rat dams either consumed a saccharin solution (control) or achieved average daily blood ethanol concentrations of 84 mg% via voluntary consumption of a 5% ethanol solution. The brains of adult male offspring were extracted and processed for Golgi-Cox staining. MSNs from the dorsomedial striatum, dorsolateral striatum and the nucleus accumbens core and shell were sampled for analysis. Relative to saccharin controls, robust reductions in dendritic length and branching, but not spine density, were observed in the shell of the nucleus accumbens in fetal-ethanol-exposed rats. No significant prenatal ethanol effects were found in the other regions of the striatum. These findings suggest that exposure to moderate levels of ethanol in utero can have profound effects on brain regions related to reward processing and provide possible clues relevant to understanding increased self-administration of drugs of abuse in animals exposed to ethanol during brain development.

Quantitative Trait Locus Mapping for Ethanol Teratogenesis in BXD Recombinant Inbred Mice

Individual differences in susceptibility to the detrimental effects of prenatal ethanol (EtOH) exposure have been demonstrated. Many factors, including genetics, play a role in susceptibility and resistance. We have previously shown that C57BL/6J (B6) mice display a number of morphological malformations following an acute dose of EtOH in utero, while DBA/2J (D2) mice are relatively resistant. Here, we present the results of quantitative trait locus (QTL) mapping for EtOH teratogenesis in recombinant inbred strains derived from a cross between B6 and D2 (BXD RIs). Pregnant dams were intubated with either maltose-dextrin or 5.8 g/kg EtOH on day 9 of gestation (GD9). On GD 18, dams were sacrificed and fetuses and placentae were removed. Placentae and fetuses were weighed; fetuses were sexed and examined for gross morphological malformations. Fetuses were then either placed in Bouin's fixative for subsequent soft-tissue analyses or eviscerated and placed in EtOH for subsequent skeletal examinations. QTL mapping for maternal weight gain (MWG), prenatal mortality, fetal weight (FW) at c-section, placental weight (PW), and several morphological malformations was performed using WebQTL. Heritability for our traits ranged from 0.06 for PW to 0.39 for MWG. We found suggestive QTLs mediating all phenotypes and significant QTLs for FW and digit and rib malformations. While most QTL regions are large, several intriguing candidate genes emerged based on polymorphisms between B6 and D2 and gene function. In this first mapping study for EtOH teratogenesis, several QTLs were identified. Future studies will further characterize these regions. Identification of genes and epigenetic modifications mediating susceptibility to the teratogenic effects of alcohol in mice will provide targets to examine in human populations.

Role of testosterone in mediating prenatal ethanol effects on hypothalamic–pituitary–adrenal activity in male rats

Prenatal ethanol (E) exposure programs the fetal hypothalamic-pituitary-adrenal (HPA) and -gonadal (HPG) axes such that E rats show HPA hyperresponsiveness to stressors and altered HPG and reproductive function in adulthood. Importantly, prenatal ethanol may differentially alter stress responsiveness in adult male and female offspring compared to their control counterparts. To test the hypothesis that alterations in HPA activity in E males are mediated, at least in part, by ethanol-induced changes in the capacity of testosterone to regulate HPA activity, we explored dose-related effects of testosterone on HPA and HPG function in adult male offspring from prenatal E, pair-fed (PF) and ad libitum-fed control (C) dams. Our data suggest that E males show changes in both HPA and HPG regulation, as well as altered sensitivity to the inhibitory effects of testosterone. While gonadectomy (GDX) reduced weight gain in all animals, low testosterone replacement restored body weights in PF and C but not E males. Further, sensitivity of the thymus and adrenal to circulating testosterone was reduced in E rats. In addition, stress-induced corticosterone (CORT) levels were increased in PF and C but not E males following GDX, and while low dose testosterone replacement restored CORT levels for PF and C, high testosterone levels were needed to normalize CORT levels for E males. A negative correlation between pre-stress testosterone and post-stress CORT levels in C but not in E and PF males further supports the finding of reduced sensitivity to testosterone. Importantly, testosterone appeared to have reduced effects on central corticotrophin releasing hormone (CRH) pathways in E, but greater effects on central arginine vasopressin (AVP) pathways in E and/or PF compared to C males. Testosterone also had less of an inhibitory effect on stress-induced luteinizing hormone increases in E than in PF and C males following GDX. In addition, androgen receptor mRNA levels in the medial preoptic nucleus and the principal nucleus of posterior bed nucleus of the stria terminalis were lower in E and PF compared to C males under intact conditions. Together, these data support our previous work suggesting altered sensitivity to testosterone in E males. Furthermore, differential effects of testosterone on the complex balance between central CRH and central AVP pathways may play a role in the HPA alterations observed. That some findings were similar in E and PF males suggest that nutritional effects of diet may have played a role in mediating at least some of the changes seen in E animals.

Effect of gestational ethanol exposure on long-term memory formation in newborn chicks

Fetal alcohol syndrome (FAS), a condition occurring in some children of mothers who have consumed alcohol during pregnancy, is characterized by craniofacial malformations, and physical and mental retardation. It is significant that even children with history of gestational ethanol exposure but relatively unaffected overall IQ performance, often exhibit learning difficulties and behavioral problems, suggestive of impaired memory formation. Hence, the specific aim of this study was to examine memory formation in chicks exposed to ethanol during early gestation toward the understanding of neurobehavioral disturbances in FAS. Chicks were exposed to alcohol on gestational days 1–3 by injection of ethanol into the airspace of freshly fertilized eggs. The effects of prenatal ethanol on physical growth and development, and memory formation were studied. The one-trial passive avoidance learning paradigm in 1-day-old chicks was used to study memory formation in these chicks. It was observed that chick embryos exposed to 10% ethanol on gestational days 1–3 had significant reduction in all body parameters when compared with appropriate controls. Further, ethanol-exposed chick embryos had significantly impaired ( P < .05) long-term memory (LTM) formation after training, though short-term or intermediate-term memory formation was unimpaired. Thus, the findings of the current study demonstrate the detrimental effects of ethanol exposure during early pregnancy on developing chick embryos in general and on memory formation in particular. Hence, it is suggested that impairment in LTM could be a fundamental mechanism for learning disorders and neurobehavioral abnormalities observed in FAS.

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.

Fetal alcohol syndrome, fetal alcohol exposure and neuro–endocrine–immune interactions

Human and animals studies have established that fetal alcohol exposure (FAE) is associated with significant impairments in cellular immune functions and marked disturbances in the interactions between the nervous, endocrine and immune systems. These observations have important clinical implications suggesting that FAE may lead to profound impairments in those aspects of the immune response that are most crucial for initiating, regulating, and sustaining immune surveillance against minor as well as lethal infectious agents, and against malignancies. FAE is a prenatal intervention, with effects on maternal and fetal glucocorticoids and long-term effects on neuro–endocrine–immune outcomes The marked effects of FAE upon neuro-endocrine–immune function that mediate many of the host's defense responses to infections in animal models are the subject of this review. Specifically FAE attenuates central nervous system (CNS)-mediated responses to immune challenges such as lipopolysaccharide (LPS) and interleukin (IL)-1-beta, including sympathetic outflow to the spleen, thermoregulatory and neuroendocrine processes and sickness behavior. Ethanol may have significant effects on the fetus either by a direct toxic effect during critical periods of development or because of the stress response it induces in the pregnant female. Maternal adrenalectomy in Sprague–Dawley rats or genetic impairment of hypothalamic–pituitary–adrenal (HPA) function, as in Lewis rats, were found to reverse the effects of prenatal ethanol on neuro–endocrine–immune responses in the offspring. These experimental studies suggest that activation of the maternal HPA axis may play a role in the developmental and long-term effects of ethanol.

Effects of Prenatal Ethanol and Choline on Urinary Vasopressin Excretion in the Rat

Prenatal ethanol (PE) exposure in rats increases water turnover and reduces arginine vasopressin (AVP) synthesis, storage, and release. Supplemental choline (SC) fed to pregnant rats while consuming alcohol normalizes water balance and AVP of offspring. Markers of fetal alcohol exposure are needed for people with mild symptoms. Lowered urinary AVP excretion (U[AVP]V) could provide a noninvasive diagnostic marker and SC should normalize the reduced U[AVP]V. Pregnant rats were fed one of four liquid diets; a control or an ethanol diet (35% of calories from ethanol) from day (D)7–21 of pregnancy with half of the rats fed SC (223 mg/100 ml liquid diet) from D10–21. At 8 weeks of age the offspring were placed in metabolic cages for 4 days. U[AVP]V was measured on D4. Increased water turnover in PE exposed rats was not accompanied by reduced U[AVP]V, but SC nearly doubled the U[AVP]V regardless of the PE exposure, and normalized water turnover. While these results in rats do not support the use of U[AVP]V as marker for PE exposure, they suggest an AVP mediated mechanism of SC correction of the polydipsia and polyuria. Supported in part by a Research Centers in Minority Institutions award, P20 RR11091.

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.

In utero ethanol suppresses cerebellar activator protein-1 and nuclear factor-kappa B transcriptional activation in a rat fetal alcohol syndrome model.

A model of fetal alcohol syndrome was used to investigate prenatal ethanol effects on cerebellar transcription factors. Pregnant Sprague-Dawley rats were divided into three treatment groups: ethanol-exposed (E), calorically matched pair-fed (PF), and freely fed ad libitum (AL) groups. Ethanol exposure was stopped 2 days before parturition. The DNA binding in neonatal cerebella of the redox-sensitive transcription factors nuclear factor-kappa B (NF-kappa B) and activator protein-1 (AP-1) were determined by electrophoretic mobility shift assays. On the first postnatal day (PD1), there was decreased activation of these transcription factors in the E group relative to the control groups. The PD1 transcriptional effects were reversed as the neonate underwent development without further ethanol exposure. Western blot studies showed no corresponding decreases in protein amounts of both AP-1 and NF-kappa B components on PD1. Postnatal glutathione levels and catalase activity, as measures of oxidative stress hypothesized to be a probable cause of the transcriptional effects, showed no statistically significant effects attributable to ethanol. Examination of prenatal cerebella on embryonic day 20 (EM20), a time during ethanol exposure, showed DNA-binding trends similar to those of PD1. EM20 Western blot studies showed decreases in the levels of the active form of glycogen synthase kinase-3 (GSK-3). GSK-3 inhibition was reversed by PD1. Blocking of GSK-3 activity with gestational dietary lithium diminished both AP-1 and NF-kappa B DNA binding. Thus, prenatal ethanol exposure has the effect of diminishing pro-survival transcriptional activation, an effect possibly mediated by changes in GSK-3 activity.

Prenatal Ethanol Reduces the Activity of Adult Midbrain Dopamine Neurons

Prenatal ethanol exposure has been demonstrated to reduce dopamine (DA) neurotransmission in the forebrain area, which could be contributed by altered electrical activity in midbrain DA neurons. This hypothesis was tested in the present study. The effects of prenatal ethanol exposure on the spontaneous activity of DA neurons in the substantia nigra and ventral tegmental area were investigated with extracellular single-unit recording techniques in adult male rats. Pregnant rats were administered single daily doses of 0, 3, or 5 g/kg ethanol via intragastric intubation from gestation day 8 through 20. An additional control group did not receive the intubation procedure. Prenatal ethanol treatment significantly reduced the number of spontaneously active DA neurons in the substantia nigra and ventral tegmental area in 3- to 5-month-old male offspring. The firing rate and firing pattern of the remaining spontaneously active DA neurons were not altered. There were no differences in the spontaneous activity of DA neurons between the nonintubated and 0 g/kg control groups, indicating possible intubation-induced stress did not influence the activity of DA neurons in adult offspring. Similar prenatal ethanol effects were also determined from older animals (14-16 months old), suggesting that the reduction in the spontaneous activity of DA neurons is a persistent phenomenon in adulthood after prenatal ethanol exposure. Furthermore, the reduction in the number of spontaneously active DA neurons was not the result of a loss in DA neurons per se, as revealed by the results of tyrosine hydroxylase immunohistochemistry. The prenatal ethanol exposure-induced reduction in DA neuronal activity may result from depolarization inactivation, because systemically administered apomorphine (20 microg) increased the spontaneous activity of DA neurons. Prenatal ethanol exposure induced a long-lasting reduction in the activity of midbrain DA neurons in adult animals. The effect was not the result of cell loss but possible changes in the electrical properties of DA neurons. The decreased electrical activity in midbrain DA neurons could contribute to the prenatal ethanol exposure-induced reduction in DA content and metabolites observed in previous studies and the attention/hyperactivity problems reported in children with fetal alcohol effects/fetal alcohol syndrome.

Prenatal ethanol effects on NGF level, NPY and ChAT immunoreactivity in mouse entorhinal cortex: a preliminary study.

It has been reported that maternal ethanol consumption leads to deficits in the limbic areas involved in cognitive functions and interferes with synthesis and utilization of neurotrophins. In the present study, it was hypothesized that prenatal alcohol intake might induce neuroanatomical alterations in the entorhinal cortex (EC). We also investigated the possible EC involvement of brain nerve growth factor (NGF), the first neurotrophin to be isolated, during such pathological events. To test this hypothesis, we used pregnant mice exposed to ethanol during EC neurogenesis (starting about gestational day 8). Our data show that prenatal alcohol intake in male mice alters the EC neuronal growth and differentiation. These morphological alterations are accompanied by an altered NGF level in the EC of prenatal alcohol-treated mice. We also found a decrease in choline acetyltransferase- and neuropeptide Y-immunopositive neurons in the EC of alcohol-exposed mice. However, the relationship between neuronal damage induced in the EC by ethanol, low presence of NGF, and the possible functional and behavioral consequences remains to be elucidated.

The Effect of Cold Stress on Lymphocyte Proliferation in Fetal Ethanol‐Exposed Rats

Prenatal ethanol exposure and stress have each been shown to have significant effects on the immune system. This study examined the possible interactive effects of prenatal ethanol exposure and exposure to stress later in life on the immune system. Differential vulnerability to these challenges in female and male offspring was assessed. At 5 to 6 months of age, female and male offspring from prenatal ethanol-exposed (E), pair-red (PF), and ad libitum-fed control (C) conditions were exposed to 0, 1 or 3 days of cold (4 degrees C). At the end of the cold period, the proliferative response of splenic lymphocytes to the mitogens concanavalin A (Con A) and pokeweed mitogen (PWM) was assessed. The data demonstrate a significant interactive effect between prenatal ethanol exposure and cold stress in female offspring. After 1 day of cold stress, E females had significantly increased PWM-induced lymphocyte proliferation compared with PF and C females, and significantly increased Con A-induced lymphocyte proliferation compared with PF females. There were no differences in PWM or Con A-induced lymphocyte proliferation among E, PF, and C females after 0 or 3 days of cold stress, nor among E, PF, and C males on any test day. Regardless of prenatal treatment, females exposed to 1 or 3 days of cold had significantly greater basal plasma corticosterone levels than females not exposed to cold. In contrast, only E males exposed to 1 or 3 days of cold had significantly increased basal plasma corticosterone levels, compared with E males not exposed to cold; PF and C males showed no significant change in basal corticosterone after cold stress. These data demonstrate that, in response to the challenge of cold stress, changes in lymphocyte proliferation to PWM and Con A may occur selectively in E females. Moreover, the interactive effects of prenatal ethanol and cold stress may result in enhanced rather than suppressed immune responsiveness.

Effects of prenatal maternal ethanol on male offspring progressive-ratio performance and response to amphetamine.

This study was designed to further explore the nature of our previously reported reduction in the efficacy of food reinforces for prenatal ethanol-exposed mice. We determined the effect of prenatal ethanol exposure on responding for food delivered on a progressive-ratio (PR) reinforcement schedule, which has been shown to be sensitive to changes in motivation and/or value of reinforcers, and we assessed the effects of amphetamine on responding maintained by the PR schedule. Subjects were adult (12 months old) male offspring of C57BL/6J mice fed liquid diets containing either ethanol (25% ethanol-derived calories, N = 12) or sucrose (25% sucrose-derived calories, N = 9) during gestation days 5-17. Prenatal ethanol-exposed mice differed from controls by having lower response rates and a greater disruption of responding following amphetamine injections. The reduced responding for food reward on the PR schedule supports our previously advanced hypothesis that prenatal ethanol reduces the efficacy of food reinforcers. The enhanced effects of amphetamine found in these adult mice is in agreement with previous reports on young rats. Although either of the effects of prenatal ethanol exposure observed in the present study are suggestive of altered DA systems, current neurochemical studies on either rats or mice provide no support for the hypothesis.

Effects of prenatal ethanol exposure and stress in adulthood on lymphocyte populations in rats.

The present study was undertaken to assess the possible interactive effects of prenatal ethanol exposure and stress in adulthood on lymphocyte populations in rat offspring, and to examine differential vulnerability of males and females to these challenges. Male and female offspring from prenatal ethanol-exposed (E), pair-fed, and ad libitum-fed control conditions were exposed to a 3-week chronic intermittent stress regimen in adulthood. Animals were exposed to two of six different stressors daily, one each at random times in the morning and afternoon, with the same pair of stressors being repeated every 4 days. Following the 3-week stress period, lymphocytes from four compartments (peripheral blood, spleen, thymus, and cervical lymph nodes) were analyzed for expression of differentiation antigens. Data demonstrate that, whereas a number of the effects of prenatal ethanol on lymphocyte populations appeared to be nutritionally mediated, the additional challenge of exposure to stressors differentially affected animals exposed to ethanol prenatally and appeared to have effects primarily in male offspring. Stressed E males had a greater reduction in the number of pan T-cells in the thymus and peripheral blood, compared with nonstressed E males, but showed an increased peripheral blood pan T-antigen expression. Stressed E males also had reduced numbers of peripheral blood CD4+ T cells compared to nonstressed E males [corrected].(ABSTRACT TRUNCATED AT 250 WORDS)

Prenatal ethanol effects and dopamine systems of adult C57 male mice

Behavioral, pharmacological, and neurochemical studies indicate that prenatal ethanol exposure can alter dopamine (DA) systems of developing rats. In addition, some of the behavioral changes described for prenatal-ethanol-exposed rats and mice (e.g., reduced responding for food and other rewards) as well as their response to various psychoactive drugs (e.g., amphetamines, methylphenidate, haloperidol) suggest that the DA system changes might extend into adulthood. Neurochemical studies on the effects of prenatal ethanol on DA systems of adults have not been reported for either species. The present study provides a neurochemical assessment of prenatal ethanol effects on DA systems of fully mature mice. Compared to chow and sucrose controls, adult offspring of mice fed a diet containing 25% ethanol derived calories had preadolescent growth deficits as observed in previous studies which also showed long-term behavioral deficits. Prenatal ethanol exposure in the present study, however, did not alter the concentration of DA or dihydroxyphenylacetic acid (DOPAC) nor the progressive decline in the concentration of these compounds in either striatum or nucleus accumbens of mature mice at intervals after synthesis inhibition by α-methyl-DL-p-tyrosine. Thus, the present study provides no neurochemical confirmation of altered DA systems resulting from prenatal ethanol exposure under conditions previously observed to alter adult behavior.

Prenatal ethanol effects on reward efficacy for adult mice are gestation stage specific

We previously reported that adult mice exposed to ethanol throughout gestation (G5-17) responded slower than controls on reinforcement schedules which required large numbers of responses per unit of food, i.e., high fixed ratio (FR) schedules. The primary finding of the present study was that ethanol exposure during the last 5 days of gestation (G12-17) is sufficient to produce this effect whereas a similar exposure early in gestation (G5-10) is not. Both male and female mice exposed to ethanol late in gestation responded slower than either lab chow or pair-fed controls, and the effect was similar to that of mice exposed to ethanol throughout gestation (G5-17) in our earlier study. Thus, developmental events occurring late in gestation are important for the reduced reinforcing efficacy of food for prenatal-ethanol-exposed mice. In addition, the present experiment established the comparability of the sucrose and lab chow controls on this task. The results of the present study and our previous report are compatible with the hypothesis that the reduced responding on high FR schedules exhibited by prenatal-ethanol-exposed mice reflects a reduction in the efficacy of food reward. It is possible that the reduction in reward efficacy is due to altered development of neuronal systems functionally related to reward which develop late in gestation.

Prenatal ethanol effects: Sex differences in offspring stress responsiveness

Previous studies have shown that offspring prenatally exposed to ethanol are hyperresponsive to stressors in adulthood, and have suggested that females are typically more affected than males. The present study was undertaken to investigate further this apparent sex difference in prenatal ethanol effects on stress responsiveness. Male and female offspring from prenatal ethanol-exposed (E), pair-fed (PF), and ad lib-fed control (C) conditions were tested in adulthood to determine adrenocortical responses to a prolonged (4-h) restraint stress. There were no significant differences in corticoid responsiveness among females from the three treatment groups. All females showed a marked increase in plasma corticosterone at 30 min, and corticoid levels remained elevated through 150-min restraint. By 180 min, all females showed a significant corticoid decrease, although corticosterone remained elevated over basal levels throughout the 240-min stress period. For males, in contrast, there were significant differences among groups. All males showed a significant corticoid increase over basal levels at 30 min, and corticoids remained significantly elevated through 90-min restraint. By 120 min, PF and C males showed a significant corticoid decrease although corticoids never returned to basal levels during the 240-min restraint period. E males, however, showed no significant decrease from peak corticosterone levels throughout the 240-min restraint stress. These data indicate that pituitary-adrenal hyperresponsiveness is not limited to fetal ethanol-exposed females, but may be demonstrated in fetal ethanol-exposed males under appropriate conditions. The parameters of the test situation, including the nature and intensity of the stressor and the time course of the response during stress or recovery from stress that is measured, appear to be critical in revealing differential effects of prenatal ethanol exposure on males and females.