Chronic Stress during Adolescence Alters Alcohol-Induced Conditioned Place Preference in Mice Selectively Bred for High Alcohol Preference but no Low Alcohol Preference

Chronic stress exposure during adolescence is associated with more long-lasting negative consequences than exposure during adulthood. Adolescent chronic stress exposure has long-lasting effects on physiology and behavior, including an increased risk of developing an alcohol use disorder (AUD) later in life. This relationship is particularly true in individuals with a familial history of AUDs. Recent research has shown that chronic stress in adolescent mice increased voluntary alcohol consumption in adulthood, but did not do so in adult mice. However, little is known about the mechanism of the relationship between adolescent chronic stress and increased alcohol consumption in adulthood. Evidence suggests that chronic stress exposure during adolescence has long-term effects on the developing brain, including areas important for sensitivity to the rewarding effects of alcohol. The over-arching aim of the current study was to explore the effects of adolescent chronic stress on sensitivity to the motivational effects of alcohol in adulthood. Three stress treatment groups were used, including subjects exposed to stress during adolescence, subjects exposed to stress during adulthood, and subjects not exposed to stress. Within each stress treatment group, high-alcohol preferring (HAP2) and low-alcohol preferring (LAP2) mice were represented, to mimic differences in familial AUD history. Thirty days after stress exposure, all subjects began a conditioned place preference (CPP) paradigm, a behavioral task that measures the sensitivity to alcohol\u27s rewarding effects. Since re-exposure to a stressor has been associated with an increased risk in relapse and other drug-seeking behaviors, half of the subjects in each stress treatment group were re-exposed to the original stressor (RS) before the CPP posttest. Overall, LAP2 mice showed greater CPP than HAP2 mice, which supports more recent literature suggesting that an inverse relationship between alcohol consumption and CPP expression may exist. In contrast to what was hypothesized, adolescent stress exposure decreased CPP expression in the HAP2 subjects during the first portion of testing. This finding may support an inverse relationship between alcohol consumption and CPP expression, when interpreted such that subjects exposed to stress during adolescence may drink more during adulthood because they are less sensitive to the rewarding effects of alcohol. In LAP2 subjects, there were no differences in CPP expression between the stress treatment groups, supporting past research suggesting that HAP2 mice are more sensitive to alterations in drug-related behaviors following stress exposure. RS did not produce alterations in CPP in either line. Overall, the findings of the current study suggest that one explanation for why individuals exposed to stress during adolescence may increase alcohol consumption during adulthood might be because more alcohol is required in order to reach the desired perceived rewarding effects of the drug, especially in those with a familial history of AUDs

Prenatal alcohol and tetrahydrocannabinol exposure: Effects on spatial and working memory

IntroductionAlcohol and cannabis are widely used recreational drugs that can negatively impact fetal development, leading to cognitive impairments. However, these drugs may be used simultaneously and the effects of combined exposure during the prenatal period are not well understood. Thus, this study used an animal model to investigate the effects of prenatal exposure to ethanol (EtOH), Δ-9-tetrahydrocannabinol (THC), or the combination on spatial and working memory.MethodsPregnant Sprague–Dawley rats were exposed to vaporized ethanol (EtOH; 68 ml/h), THC (100 mg/ml), the combination, or vehicle control during gestational days 5–20. Adolescent male and female offspring were evaluated using the Morris water maze task to assess spatial and working memory.ResultsPrenatal THC exposure impaired spatial learning and memory in female offspring, whereas prenatal EtOH exposure impaired working memory. The combination of THC and EtOH did not exacerbate the effects of either EtOH or THC, although subjects exposed to the combination were less thigmotaxic, which might represent an increase in risk-taking behavior.DiscussionOur results highlight the differential effects of prenatal exposure to THC and EtOH on cognitive and emotional development, with substance- and sex-specific patterns. These findings highlight the potential harm of THC and EtOH on fetal development and support public health policies aimed at reducing cannabis and alcohol use during pregnancy

The effects of choline on stress regulation in rats exposed to alcohol during development

Includes bibliographical references (p. 55-62).Prenatal alcohol exposure can damage the developing brain, adversely affecting cognitive and emotional development. Animal models indicate that perinatal supplementation with choline (an essential nutrient important for brain development) can reduce the severity of learning deficits associated with developmental alcohol exposure. In addition to altering cognitive systems, choline may also influence stress responses, which could further influence cognitive performance. In fact, prenatal alcohol exposure may cause abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis, a system that regulates stress responses, and recent evidence indicates that choline influences genes important in the regulation of stress. The present study examined if alcohol exposure during the 3rd trimester equivalent affected stress responses, and if any changes were modulated by postnatal choline supplementation. Using a rat model, the study included six treatment groups in a 3 (ethanol-exposed, sham control, non-intubated control) x 2 (choline, vehicle) design. Ethanol (5.25 g/kg/day) was delivered via intragastric intubation from postnatal days (PD) 4 through 9, a period equivalent to the human 3rd trimester. From PD 10-30, subjects were injected subcutaneously with either vehicle (saline) or choline chloride (100 mg/kg/day). On PD 31, subjects were placed on a platform, a mild stressor, in open space for 5 minutes and behaviors were recorded on video and subsequently coded by investigators blind to treatment condition. 100 uL of blood were collected before and after the stressor to determine levels of corticosterone (CORT), a stress hormone. On PD 36, subjects were also tested on an elevated plus maze (EPM), another task used to assess anxiety levels. It was hypothesized that alcohol would increase stress, whereas choline would reduce anxiety-related behaviors, particularly in alcohol-exposed subjects. Alcohol exposure did not significantly alter CORT levels or stress behaviors, suggesting that alcohol exposure during periods of late gestation does not alter stress responses. Moreover, although choline did reduce post-stress CORT levels in alcohol-exposed male subjects, overall, choline did not produce consistent effects on stress responses. These data suggest that choline selectively targets cognitive systems in the brain, and that choline's mitigation of fetal alcohol effects is not mediated by effects on stress

Choline Supplementation Modifies the Effects of Developmental Alcohol Exposure on Immune Responses in Adult Rats

Prenatal alcohol exposure can disrupt the development of numerous systems, including the immune system. Indeed, alterations in cytokine levels may contribute to the neuropathological, behavioral, and cognitive problems, and other adverse outcomes observed in individuals with fetal alcohol spectrum disorders. Importantly, supplementation with the essential nutrient choline can improve performance in hippocampal-dependent behaviors; thus, the present study examined the effects of choline on plasma and hippocampal cytokines in adult rats exposed to ethanol in early development. From postnatal day (PD) 4–9 (third trimester equivalent), pups received ethanol (5.25 g/kg/day) or Sham intubations. Subjects were treated with choline chloride (100 mg/kg/day) or saline from PD10–30. On PD60, plasma and hippocampal tissue was collected before and after an immune challenge (lipopolysaccharide (LPS); 50 ug/kg). Prior to the immune challenge, ethanol-exposed subjects showed an overall increase in hippocampal pro-inflammatory cytokines, an effect mitigated by choline supplementation. In contrast, in the plasma, choline reduced LPS-related increases in pro-inflammatory markers, particularly in ethanol-exposed subjects. Thus, early choline supplementation may modify both brain and peripheral inflammation. These results suggest that early choline can mitigate some long-term effects of ethanol exposure on hippocampal inflammation, which may contribute to improved hippocampal function, and could also influence peripheral immune responses that may impact overall health.Medicine, Faculty ofNon UBCCellular and Physiological Sciences, Department ofReviewedFacultyResearche

Effects of prenatal alcohol and delta-9-tetrahydrocannabinol exposure via electronic cigarettes on motor development.

BACKGROUND: Prenatal alcohol exposure can lead to a wide range of neurological and behavioral deficits, including alterations in motor domains. However, much less is known about the effects of prenatal cannabis exposure on motor development, despite cannabis being the most consumed illicit drug among women. Cannabis use among pregnant women has become increasingly popular given the widespread perception that consumption is safe during pregnancy. Moreover, alcohol and cannabis are commonly used together, even among pregnant women. Yet few studies have explored the potential consequences of combined prenatal exposure on behavioral domains. METHODS: Using our previously established model, during gestational days 5 to 20, four groups of pregnant Sprague-Dawley rats were exposed to vaporized alcohol, delta-9-Tetrahydrocannabinol (THC) via electronic (e-) cigarettes, the combination of alcohol and THC, or a vehicle. Following birth, offspring were tested on early sensorimotor development, adolescent motor coordination, and adolescent activity levels. RESULTS: Prenatal THC e-cigarette exposure delayed sensorimotor development early in life and impaired motor coordination later in early adolescence; combined prenatal alcohol and THC exposure did not have additive effects on sensorimotor development. However, combined prenatal exposure produced hyperactivity among male offspring. CONCLUSIONS: Prenatal cannabis exposure may lead to impaired motor skills throughout early development and combined exposure with alcohol during gestation may lead to hyperactivity in early adolescence. These findings have important implications for informing pregnant women of the risks to the fetus associated with prenatal cannabis exposure, with and without alcohol, and could influence public policy

Choline Supplementation Alters Hippocampal Cytokine Levels in Adolescence and Adulthood in an Animal Model of Fetal Alcohol Spectrum Disorders

Alcohol (ethanol) exposure during pregnancy can adversely affect development, with long-lasting consequences that include neuroimmune, cognitive, and behavioral dysfunction. Alcohol-induced alterations in cytokine levels in the hippocampus may contribute to abnormal cognitive and behavioral outcomes in individuals with fetal alcohol spectrum disorders (FASD). Nutritional intervention with the essential nutrient choline can improve hippocampal-dependent behavioral impairments and may also influence neuroimmune function. Thus, we examined the effects of choline supplementation on hippocampal cytokine levels in adolescent and adult rats exposed to alcohol early in development. From postnatal day (PD) 4–9 (third trimester-equivalent), Sprague–Dawley rat pups received ethanol (5.25 g/kg/day) or sham intubations and were treated with choline chloride (100 mg/kg/day) or saline from PD 10–30; hippocampi were collected at PD 35 or PD 60. Age-specific ethanol-induced increases in interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), and keratinocyte chemoattractant/human growth-regulated oncogene (KC/GRO) were identified in adulthood, but not adolescence, whereas persistent ethanol-induced increases of interleukin-6 (IL-6) levels were present at both ages. Interestingly, choline supplementation reduced age-related changes in interleukin-1 beta (IL-1β) and interleukin-5 (IL-5) as well as mitigating the long-lasting increase in IFN-γ in ethanol-exposed adults. Moreover, choline influenced inflammatory tone by modulating ratios of pro- to -anti-inflammatory cytokines. These results suggest that ethanol-induced changes in hippocampal cytokine levels are more evident during adulthood than adolescence, and that choline can mitigate some effects of ethanol exposure on long-lasting inflammatory tone

The functional and evolutionary impacts of human-specific deletions in conserved elements

Conserved genomic sequences disrupted in humans may underlie uniquely human phenotypic traits. We identified and characterized 10,032 human-specific conserved deletions (hCONDELs). These short (average 2.56 base pairs) deletions are enriched for human brain functions across genetic, epigenomic, and transcriptomic datasets. Using massively parallel reporter assays in six cell types, we discovered 800 hCONDELs conferring significant differences in regulatory activity, half of which enhance rather than disrupt regulatory function. We highlight several hCONDELs with putative human-specific effects on brain development, including HDAC5, CPEB4, and PPP2CA. Reverting an hCONDEL to the ancestral sequence alters the expression of LOXL2 and developmental genes involved in myelination and synaptic function. Our data provide a rich resource to investigate the evolutionary mechanisms driving new traits in humans and other species