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Seemiller LR, Garcia-Trevizo P, Novoa C, Goldberg LR, Murray S, Gould TJ. Adolescent intermittent alcohol exposure produces strain-specific cross-sensitization to nicotine and other behavioral adaptations in adulthood in C57BL/6J and DBA/2J mice. Pharmacol Biochem Behav 2023; 232:173655. [PMID: 37802393 PMCID: PMC10995114 DOI: 10.1016/j.pbb.2023.173655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/10/2023]
Abstract
Adolescent alcohol exposure is associated with lasting behavioral changes in humans and in mice. Prior work from our laboratory and others have demonstrated that C57BL/6J and DBA/2J mice differ in sensitivity to some effects of acute alcohol exposure during adolescence and adulthood. However, it is unknown if these strains differ in cognitive, anxiety-related, and addiction-related long-term consequences of adolescent intermittent alcohol exposure. This study examined the impact of a previously validated adolescent alcohol exposure paradigm (2-3 g/kg, i.p., every other day PND 30-44) in C57BL/6J and DBA/2J male and female mice on adult fear conditioning, anxiety-related behavior (elevated plus maze), and addiction-related phenotypes including nicotine sensitivity (hypothermia and locomotor depression) and alcohol sensitivity (loss of righting reflex; LORR). Both shared and strain-specific long-term consequences of adolescent alcohol exposure were found. Most notably, we found a strain-specific alcohol-induced increase in sensitivity to nicotine's hypothermic effects during adulthood in the DBA/2J strain but not in the C57BL/6J strain. Conversely, both strains demonstrated a robust increased latency to LORR during adulthood after adolescent alcohol exposure. Thus, we observed strain-dependent cross-sensitization to nicotine and strain-independent tolerance to alcohol due to adolescent alcohol exposure. Several strain and sex differences independent of adolescent alcohol treatment were also observed. These include increased sensitivity to nicotine-induced hypothermia in the C57BL/6J strain relative to the DBA/2J strain, in addition to DBA/2J mice showing more anxiety-like behaviors in the elevated plus maze relative to the C57BL/6J strain. Overall, these results suggest that adolescent alcohol exposure results in altered adult sensitivity to nicotine and alcohol with some phenotypes mediated by genetic background.
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Affiliation(s)
- Laurel R Seemiller
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | | | - Carlos Novoa
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Lisa R Goldberg
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Samantha Murray
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Thomas J Gould
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA.
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Rice RC, Baratta AM, Farris SP. Home-Cage Sipper Devices Reveal Age and Sex Differences in Ethanol Consumption Patterns. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.22.533844. [PMID: 36993453 PMCID: PMC10055331 DOI: 10.1101/2023.03.22.533844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Free-choice paradigms such as two-bottle choice (2BC) are commonly used to characterize ethanol consumption and preference of rodent models used to study alcohol use disorder (AUD). However, these assays are limited by low temporal resolution that misses finer patterns of drinking behavior, including circadian drinking patterns that are known to vary with age and sex and are affected in AUD pathogenesis. Modern, cost-effective tools are becoming widely available that could elucidate these patterns, including open-source, Arduino-based home-cage sipper devices. We hypothesized that adaptation of these home-cage sipper devices would uncover distinct age- and sex-related differences in temporal drinking patterns. To test this hypothesis, we used the sipper devices in a continuous 2BC paradigm using water and ethanol (10%; v/v) for 14 days to measure drinking patterns of male and female adolescent (3-week), young adult (6-week), and mature adult (18-week) C57BL/6J mice. Daily grams of fluid consumption were manually recorded at the beginning of the dark cycle, while home-cage sipper devices continuously recorded the number of sips. Consistent with prior studies, females consumed more ethanol than males, and adolescent mice consumed the most out of any age group. Correlation analyses of manually recorded fluid consumption versus home-cage sipper activity revealed a statistically significant prediction of fluid consumption across all experimental groups. Sipper activity was able to capture subtle circadian differences between experimental groups, as well as distinct individual variation in drinking behavior among animals. Blood ethanol concentrations were significantly correlated with sipper data, suggesting that home-cage sipper devices can accurately determine individual timing of ethanol consumption. Overall, our studies show that augmenting the 2BC drinking paradigm with automated home-cage sipper devices can accurately measure ethanol consumption across sexes and age groups, revealing individual differences and temporal patterns of ethanol drinking behavior. Future studies utilizing these home-cage sipper devices will further dissect circadian patterns for age and sex relevant to the pathogenesis of AUD, as well as underlying molecular mechanisms for patterns in ethanol consumption. Highlights Female mice consume more ethanol than males in a continuous access paradigmAdolescent male and female mice consume more ethanol than young or mature adult miceAutomated home-cage sipper devices accurately measure ethanol consumptionDevices reveal sex- and age-dependent differences in circadian drinking patternsDevices reveal distinct individual variation in circadian drinking patterns.
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Brocato ER, Wolstenholme JT. Adolescent binge ethanol impacts H3K36me3 regulation of synaptic genes. Front Mol Neurosci 2023; 16:1082104. [PMID: 36937047 PMCID: PMC10020663 DOI: 10.3389/fnmol.2023.1082104] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/10/2023] [Indexed: 03/06/2023] Open
Abstract
Adolescence is marked in part by the ongoing development of the prefrontal cortex (PFC). Binge ethanol use during this critical stage in neurodevelopment induces significant structural changes to the PFC, as well as cognitive and behavioral deficits that can last into adulthood. Previous studies showed that adolescent binge ethanol causes lasting deficits in working memory, decreases in the expression of chromatin remodeling genes responsible for the methylation of histone 3 lysine 36 (H3K36), and global decreases in H3K36 in the PFC. H3K36me3 is present within the coding region of actively-transcribed genes, and safeguards against aberrant, cryptic transcription by RNA Polymerase II. We hypothesize that altered methylation of H3K36 could play a role in adolescent binge ethanol-induced memory deficits. To investigate this at the molecular level, ethanol (4 g/kg, i.g.) or water was administered intermittently to adolescent mice. RNA-and ChIP-sequencing were then performed within the same tissue to determine gene expression changes and identify genes and loci where H3K36me3 was disrupted by ethanol. We further assessed ethanol-induced changes at the transcription level with differential exon-use and cryptic transcription analysis - a hallmark of decreased H3K36me3. Here, we found ethanol-induced changes to the gene expression and H3K36me3-regulation of synaptic-related genes in all our analyses. Notably, H3K36me3 was differentially trimethylated between ethanol and control conditions at synaptic-related genes, and Snap25 and Cplx1 showed evidence of cryptic transcription in males and females treated with ethanol during adolescence. Our results provide preliminary evidence that ethanol-induced changes to H3K36me3 during adolescent neurodevelopment may be linked to synaptic dysregulation at the transcriptional level, which may explain the reported ethanol-induced changes to PFC synaptic function.
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Affiliation(s)
- Emily R. Brocato
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Jennifer T. Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
- VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, VA, United States
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Seemiller LR, Goldberg LR, Garcia-Trevizo P, Gould TJ. Interstrain differences in adolescent fear conditioning after acute alcohol exposure. Brain Res Bull 2023; 194:35-44. [PMID: 36681252 PMCID: PMC10921434 DOI: 10.1016/j.brainresbull.2023.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/03/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023]
Abstract
Adolescent sensitivity to alcohol is a predictor of continued alcohol use and misuse later in life. Thus, it is important to understand the many factors that can impact alcohol sensitivity. Data from our laboratory suggested that susceptibility to alcohol-associated contextual fear learning deficits varied among adolescent and adult mice from two mouse strains. To investigate the extent of genetic background's influences on adolescent learning after alcohol exposure, we examined how 9 inbred mouse strains differed in vulnerability to alcohol-induced contextual and cued fear conditioning deficits. We demonstrated significant strain- and sex-dependent effects of acute alcohol exposure on adolescent fear learning, with alcohol having most pronounced effects on contextual fear learning. Female adolescents were more susceptible than males to alcohol-induced impairments in contextual, but not cued, fear learning, independent of genetic background. Heritability for contextual and cued fear learning after alcohol exposure was estimated to be 31 % and 18 %, respectively. Learning data were compared to Blood Ethanol Concentrations (BEC) to assess whether strain differences in alcohol metabolism contributed to strain differences in learning after alcohol exposure. There were no clear relationships between BEC and learning outcomes, suggesting that strains differed in learning outcomes for reasons other than strain differences in alcohol metabolism. Genetic analyses revealed polymorphisms across strains in notable genes, such as Chrna7, a promising genetic candidate for susceptibility to alcohol-induced fear conditioning deficits. These results are the first to demonstrate the impact of genetic background on alcohol-associated fear learning deficits during adolescence and suggest that the mechanisms underlying this sensitivity are distinct from alcohol metabolism.
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Affiliation(s)
- Laurel R Seemiller
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Lisa R Goldberg
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | | | - Thomas J Gould
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA.
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Seemiller LR, Logue SF, Gould TJ. Inbred mouse strain differences in alcohol and nicotine addiction-related phenotypes from adolescence to adulthood. Pharmacol Biochem Behav 2022; 218:173429. [PMID: 35820468 DOI: 10.1016/j.pbb.2022.173429] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 06/18/2022] [Accepted: 07/06/2022] [Indexed: 11/20/2022]
Abstract
Understanding the genetic basis of a predisposition for nicotine and alcohol use across the lifespan is important for public health efforts because genetic contributions may change with age. However, parsing apart subtle genetic contributions to complex human behaviors is a challenge. Animal models provide the opportunity to study the effects of genetic background and age on drug-related phenotypes, while controlling important experimental variables such as amount and timing of drug exposure. Addiction research in inbred, or isogenic, mouse lines has demonstrated genetic contributions to nicotine and alcohol abuse- and addiction-related behaviors. This review summarizes inbred mouse strain differences in alcohol and nicotine addiction-related phenotypes including voluntary consumption/self-administration, initial sensitivity to the drug as measured by sedative, hypothermic, and ataxic effects, locomotor effects, conditioned place preference or place aversion, drug metabolism, and severity of withdrawal symptoms. This review also discusses how these alcohol and nicotine addiction-related phenotypes change from adolescence to adulthood.
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Affiliation(s)
- Laurel R Seemiller
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Sheree F Logue
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA
| | - Thomas J Gould
- Department of Biobehavioral Health, Penn State University, University Park, PA, USA.
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Bogenpohl JW, Weston RM, Foreman TN, Kitchen KE, Miles MF. Chloride intracellular channel 4 (CLIC4) expression profile in the mouse medial prefrontal cortex and its regulation by ethanol. Alcohol Clin Exp Res 2022; 46:29-39. [PMID: 34839533 PMCID: PMC8799520 DOI: 10.1111/acer.14754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 11/12/2021] [Accepted: 11/22/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Chloride intracellular channel 4 (CLIC4) is a multifunctional metamorphic protein for which a growing body of evidence supports a major role in the brain's molecular and behavioral responses to ethanol (EtOH). Although key to understanding the functional biology underlying this role, little is known about the cellular and subcellular expression patterns of CLIC4 in brain and how they are affected by EtOH. METHODS We used qRT-PCR to assess Clic4 mRNA expression in the medial prefrontal cortex (mPFC) of C57BL/6J mice in the absence and presence of acute EtOH exposure. Two complementary immunohistochemical techniques were employed to assess the subcellular localization of the CLIC4 protein and its pattern of expression across brain cell types in the mPFC in the absence and presence of acute EtOH. RESULTS Through immunohistochemical and stereological techniques, we show that CLIC4 protein is robustly expressed by oligodendrocytes (most abundant), microglia, and astrocytes, with minimal expression in neurons. Following acute EtOH exposure, we observed a rapid increase in Clic4 mRNA expression in female but not male mice and an overall increase in the number of oligodendrocytes and astrocytes expressing the CLIC4 protein. CONCLUSIONS These findings suggest that Clic4 functions as an early response gene for acute EtOH in brain, which likely underlies its ability to modulate EtOH behavior. Our results also suggest that the role of CLIC4 in the brain's response to EtOH is mediated through oligodendrocytes.
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Affiliation(s)
- James W. Bogenpohl
- Department of Molecular Biology and Chemistry, Christopher
Newport University, Newport News, VA, USA,Corresponding author: Correspondence:
James Bogenpohl PhD; Christopher Newport University; Department of Molecular
Biology and Chemistry; 1 Avenue of the Arts, Newport News, VA 23606;
757-594-8289;
| | - Rory M. Weston
- Department of Pharmacology and Toxicology, Virginia
Commonwealth University, Richmond, VA, USA
| | - Taylor N. Foreman
- Department of Molecular Biology and Chemistry, Christopher
Newport University, Newport News, VA, USA
| | - Kaitlyn E. Kitchen
- Department of Molecular Biology and Chemistry, Christopher
Newport University, Newport News, VA, USA
| | - Michael F. Miles
- Department of Pharmacology and Toxicology, Virginia
Commonwealth University, Richmond, VA, USA,VCU Alcohol Research Center, Virginia Commonwealth
University, Richmond, VA, USA
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Brocato E, Wolstenholme JT. Neuroepigenetic consequences of adolescent ethanol exposure. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2021; 160:45-84. [PMID: 34696879 DOI: 10.1016/bs.irn.2021.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Adolescence is a critical developmental period characterized by ongoing brain maturation processes including myelination and synaptic pruning. Adolescents experience heightened reward sensitivity, sensation seeking, impulsivity, and diminished inhibitory self-control, which contribute to increased participation in risky behaviors, including the initiation of alcohol use. Ethanol exposure in adolescence alters memory and cognition, anxiety-like behavior, and ethanol sensitivity as well as brain myelination and dendritic spine morphology, with effects lasting into adulthood. Emerging evidence suggests that epigenetic modifications may explain these lasting effects. Focusing on the amygdala, prefrontal cortex and hippocampus, we review studies investigating the epigenetic consequences of adolescent ethanol exposure. Ethanol metabolism globally increases donor substrates for histone acetylation and histone and DNA methylation, and this chapter discusses how this can further impact epigenetic programming of the adolescent brain. Elucidation of the mechanisms through which ethanol can alter the epigenetic code at specific transcripts may provide therapeutic targets for intervention.
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Affiliation(s)
- Emily Brocato
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Jennifer T Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States; VCU-Alcohol Research Center, Virginia Commonwealth University, Richmond, VA, United States.
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Seemiller LR, Gould TJ. Adult and adolescent C57BL/6J and DBA/2J mice are differentially susceptible to fear learning deficits after acute ethanol or MK-801 treatment. Behav Brain Res 2021; 410:113351. [PMID: 33974921 PMCID: PMC8403488 DOI: 10.1016/j.bbr.2021.113351] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/19/2021] [Accepted: 05/06/2021] [Indexed: 12/31/2022]
Abstract
Ethanol and other drugs of abuse disrupt learning and memory processes, creating problems associated with drug use and addiction. Understanding individual factors that determine susceptibility to drug-induced cognitive deficits, such as genetic background, age, and sex, is important for prevention and treatment. Comparison of adolescent and adult mice of both sexes across inbred mouse strains can reveal age, sex, and genetic contributions to phenotypes. We treated adolescent and adult, male and female, C57BL/6J and DBA/2J inbred mice with ethanol (1 g/kg or 1.5 g/kg) or MK-801 (0.05 mg/kg or 0.1 mg/kg), an NMDA receptor antagonist, prior to fear conditioning training. Contextual and cued fear retention were tested one day and eight or nine days after training. After ethanol exposure, adult C57BL/6J mice experienced greater deficits in contextual learning than adult DBA/2J mice. C57BL/6 J adolescents were less susceptible to ethanol-induced contextual learning disruptions than C57BL/6J adults, and adolescent males of both strains exhibited greater ethanol-induced contextual learning deficits than adolescent females. After MK-801 exposure, adolescent C57BL/6J mice experienced more severe contextual learning deficits than adolescent DBA/2J mice. Both ethanol and MK-801 had greater effects on contextual learning than cued learning. Collectively, we demonstrate that genetic background contributes to contextual and cued learning outcomes after ethanol or MK-801 exposure. Further, we report age-dependent drug sensitivities that are strain-, sex-, and drug-specific, suggesting that age, sex, and genetic background interact to determine contextual and cued learning impairments after ethanol or MK-801 exposure.
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Affiliation(s)
- L R Seemiller
- Department of Biobehavioral Health, Penn State University, 219 Biobehavioral Health Building, University Park, PA, 16801, United States
| | - T J Gould
- Department of Biobehavioral Health, Penn State University, 219 Biobehavioral Health Building, University Park, PA, 16801, United States.
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Chronic Ethanol Exposure during Adolescence Increases Voluntary Ethanol Consumption in Adulthood in Female Sprague Dawley Rats. Brain Sci 2020; 10:brainsci10120900. [PMID: 33255234 PMCID: PMC7761054 DOI: 10.3390/brainsci10120900] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 11/24/2022] Open
Abstract
Early alcohol use is a major concern due to the dramatic rise in alcohol use during adolescence. In humans, adolescent males and females consume alcohol at equivalent rates; however, in adulthood males are more likely to consume harmful levels of alcohol. In animal models, the long-term dose-dependent and sex-dependent effects of alcohol exposure during adolescence have not been readily assessed relative to exposure that is initiated in adulthood. The purpose of the present set of experiments was to determine if adolescent exposure to chronic ethanol would predispose male and female rats to greater ethanol intake in adulthood when compared to animals that were not exposed to chronic ethanol exposure until early adulthood. Male and female rats were chronically administered 0.75 g/kg or 1.5 g/kg ethanol or saline for 21 days during adolescence (postnatal day (PND) 30–50) or adulthood (PND 60–80). All rats subsequently underwent 14-days of abstinence (PND 51–64 or PND 81–94, respectively). Finally, all rats were given 30-min daily access to saccharin-sweetened ethanol or saccharin alone from PND 65–80 for adolescent-exposed rats and PND 95–110 for adult-exposed rats. Exposure to 0.75 g/kg ethanol did not alter ethanol or saccharin intake in adolescent-exposed or adult-exposed rats, regardless of sex. In contrast, chronic exposure to the higher 1.5 g/kg dose during adolescence increased ethanol intake in adulthood in female rats. However, there was no change in saccharin intake in animals exposed to 1.5 g/kg ethanol during adolescence or adulthood, regardless of sex. Additionally, there were no clear age- and ethanol-dependent changes in duration of loss of righting reflex and blood ethanol concentrations to a challenge administration of a higher dose of ethanol. The results of the present set of experiments indicate chronic exposure to a high dose of ethanol during adolescence in female rats did indeed predispose rats to consume more ethanol in adulthood. Given that these effects were only observed in adolescent-exposed female rats, these results support a unique vulnerability to the long-term consequences of adolescent ethanol exposure in female rats, an effect that is not merely mediated by the sweetener used in the ethanol solution.
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10
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Carrara-Nascimento PF, Hoffmann LB, Flório JC, Planeta CS, Camarini R. Effects of Ethanol Exposure During Adolescence or Adulthood on Locomotor Sensitization and Dopamine Levels in the Reward System. Front Behav Neurosci 2020; 14:31. [PMID: 32210774 PMCID: PMC7067700 DOI: 10.3389/fnbeh.2020.00031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/13/2020] [Indexed: 12/02/2022] Open
Abstract
Behavioral sensitization is a process of neuroadaptation characterized by a gradual increase in motor behaviors. The major neural substrates involved in the behavioral sensitization lie on the dopaminergic mesocorticolimbic pathway, which is still under development during adolescence. To investigate age-differences in ethanol behavioral sensitization and dopamine levels in distinct brain regions of the reward system, adolescent and adult mice were repeatedly pretreated with saline or ethanol (2.0 g/kg i.p.) during 15 consecutive days and challenged with saline or ethanol 5 days after pretreatment. Dopamine and its metabolites were measured in tissue samples of the prefrontal cortex (PFC), nucleus accumbens (NAc) and striatum by HPLC analysis. While repeated ethanol administration resulted in the development of locomotor sensitization in both adult and adolescent mice, only the adults expressed sensitization to a subsequent ethanol challenge injection. Neurochemical results showed reduced dopamine levels in adolescents compared to adults. Specifically, mice pretreated with ethanol during adolescence displayed lower dopamine levels in the PFC compared to the respective adult group in response to an ethanol challenge injection, and preadolescent mice exhibited lower dopamine levels in the NAc following an acute ethanol treatment compared to adults. These findings suggest that adolescent mice are not only less sensitive to the expression of ethanol-induced sensitization than adults, but also show lower dopamine content after ethanol exposition in the PFC and NAc.
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Affiliation(s)
| | - Lucas Barbosa Hoffmann
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Jorge Camilo Flório
- Departmento de Patologia, Escola de Medicina Veterinária, Universidade de São Paulo, São Paulo, Brazil
| | - Cleopatra Silva Planeta
- Laboratório de Neuropsicofarmacologia, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, Araraquara, Brazil
| | - Rosana Camarini
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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Smoker MP, Hernandez M, Zhang Y, Boehm SL. Assessment of Acute Motor Effects and Tolerance Following Self-Administration of Alcohol and Edible ∆ 9 -Tetrahydrocannabinol in Adolescent Male Mice. Alcohol Clin Exp Res 2019; 43:2446-2457. [PMID: 31524960 DOI: 10.1111/acer.14197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 09/10/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Cannabinoids and their principle psychoactive target, the cannabinoid type 1 receptor (CB1R), impact a number of alcohol-related properties, and although alcohol and cannabis are often co-used, particularly in adolescence, few animal models of this phenomenon exist. We modeled the co-use of alcohol and ∆9 -tetrahydrocannabinol (THC) in adolescent mice using ingestive methods popular during this developmental period in humans, namely binge-drinking and edible THC. With this model, we assessed levels of use, acute effects, and tolerance to each substance. METHODS Adolescent male C57BL/6J mice had daily, limited access to 1 of 2 edible doughs (THC or control), to 1 of 2 fluids (ethanol (EtOH) or water), and in 1 of 2 orders (dough-fluid or fluid-dough). Home cage locomotor activity was recorded both during access and after access. On the day following the final access session, a subset of mice were assessed for functional and metabolic tolerance to alcohol using accelerating rotarod and blood EtOH concentrations, respectively. The remaining mice were assessed for tolerance to THC-induced hypothermia, and whole-brain CB1R expression was assessed in all mice. RESULTS EtOH intake was on par with levels previously reported in adolescent mice. Edible THC was well-consumed, but consumption decreased at the highest dose provided. Locomotor activity increased following EtOH intake and decreased following edible THC consumption, and edible THC increased fluid intake in general. The use of alcohol produced neither functional nor metabolic tolerance to an alcohol challenge. However, the use of edible THC impaired subsequent drug-free rotarod performance and was associated with a reduction in THC's hypothermic effect. CONCLUSIONS Adolescent mice self-administered both alcohol and edible THC to a degree sufficient to acutely impact locomotor activity. However, only edible THC consumption had lasting effects during short-term abstinence. Thus, this adolescent co-use model could be used to explore sex differences in self-administration and the impact substance co-use might have on other domains such as mood and cognition.
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Affiliation(s)
- Michael P Smoker
- From the, Department of Psychology, Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Maribel Hernandez
- From the, Department of Psychology, Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Yanping Zhang
- From the, Department of Psychology, Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Stephen L Boehm
- From the, Department of Psychology, Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
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12
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Ruby CL, Paye G, Fabi JL, Zhang J, Risinger MO, Palmer KN, Verbanes NM, D'Angelo A, Watts TM, Mabe L, Swartzwelder HS. Sex Differences in Photic Entrainment and Sensitivity to Ethanol-Induced Chronodisruption in Adult Mice After Adolescent Intermittent Ethanol Exposure. Alcohol Clin Exp Res 2018; 42:2144-2159. [PMID: 30102762 DOI: 10.1111/acer.13867] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/07/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Evidence supports a role for the circadian system in alcohol use disorders, but the impact of adolescent alcohol exposure on circadian timing later in life is unknown. Acute ethanol (EtOH) attenuates circadian photic phase-resetting in adult, but not adolescent, rodents. However, nearly all studies have focused on males and it is unknown whether this adolescent-typical insensitivity to EtOH persists into adulthood after adolescent drinking. METHODS Circadian activity was monitored in C57BL/6J mice receiving adolescent intermittent EtOH (AIE) exposure (15% EtOH and water every other day throughout adolescence) or water alone followed by 24 days wherein EtOH was not available (washout). Mice then received a challenge dose of EtOH (1.5 g/kg, intraperitoneal) or saline 15 minutes prior to a 30-minute phase-delaying light pulse and then were released into constant darkness (DD). To control for possible phase-shifting by EtOH challenge alone, a separate group of mice underwent AIE exposure (or water-only) and washout and then received an EtOH or saline injection, but did not receive a light pulse prior to DD. RESULTS Striking sex differences in nearly all measures of circadian photic entrainment were observed during adolescence but AIE effects were subtle and few. Only EtOH-naïve adult male mice showed attenuated photic phase-shifts with EtOH challenge, while all other groups showed normal phase-resetting responses to light. AIE-exposed females showed a persistent delay in activity offset. CONCLUSIONS Adult male AIE-exposed mice retained adolescent-like insensitivity to EtOH-induced suppression of photic phase-resetting, suggesting AIE-induced "lock-in" of an adolescent behavioral phenotype. Adult AIE-exposed females showed delayed initiation of the rest phase. Our results also indicate that intermittent EtOH drinking has subtle effects on circadian activity in mice during adolescence that differ from previously reported effects on adult males. The observed sex differences in circadian activity, EtOH consumption and preference, and responses to EtOH challenge merit future mechanistic study.
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Affiliation(s)
- Christina L Ruby
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Gerneleh Paye
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Jason L Fabi
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Jiawen Zhang
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Megan O Risinger
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Kaitlyn N Palmer
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Natalie M Verbanes
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Ariana D'Angelo
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Tia M Watts
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Lauren Mabe
- Department of Biology , Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - H Scott Swartzwelder
- Department of Psychiatry and Behavioral Sciences , Duke University, Durham, North Carolina
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13
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Effects of ethanol on negative phototaxis and motility in brown planarians (Dugesia tigrina). Neurosci Lett 2018; 685:102-108. [PMID: 30145368 DOI: 10.1016/j.neulet.2018.08.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/20/2018] [Accepted: 08/20/2018] [Indexed: 11/20/2022]
Abstract
The behavioral effects of ethanol in brown planarians were studied in four experiments. In the first two experiments, acute administrations of ethanol increased travel time in a dose-dependent fashion in individual planarians moving away from a light source. Orderly results were obtained using both within-subject and between-group designs. In a third experiment, ethanol dose was arranged by time rather than concentration. Ethanol increased travel time overall, but variability between subjects was considerable. In a final experiment, ethanol administration reduced motility and altered movement patterns in planarians in an open-field test. These experiments demonstrated that negative phototaxis by planarians may exhibit sufficient stability to allow for experimental determinations of dose-response curves utilizing both within-subject and between-subject designs.
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14
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Wolstenholme JT, Mahmood T, Harris GM, Abbas S, Miles MF. Intermittent Ethanol during Adolescence Leads to Lasting Behavioral Changes in Adulthood and Alters Gene Expression and Histone Methylation in the PFC. Front Mol Neurosci 2017; 10:307. [PMID: 29018328 PMCID: PMC5622951 DOI: 10.3389/fnmol.2017.00307] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/12/2017] [Indexed: 01/23/2023] Open
Abstract
Adolescents primarily consume alcohol in binges, which can be particularly harmful to the developing frontal cortex and increase risk for an adult alcohol use disorder. We conducted a study investigating immediate and long lasting changes to the prefrontal cortex (PFC) transcriptome to determine the molecular mechanisms underlying adult ethanol behavioral sensitivity following binge ethanol in adolescence. DBA/2J mice were orally dosed with 4 g/kg ethanol intermittently from day 29 to 42. Adolescent mice were tested for anxiety-like behavior and ethanol sensitivity using the loss of righting reflex task. As adults, mice were tested for cognitive changes using the novel object recognition task, ethanol-induced anxiolysis and ethanol sensitivity. Adolescent binge ethanol altered ethanol sensitivity in young mice and led to lasting memory deficits in the object recognition test and greater ethanol sensitivity in adulthood. Using genomic profiling of transcripts in the PFC, we found that binge ethanol reduced myelin-related gene expression and altered chromatin modifying genes involved in histone demethylation at H3K9 and H3K36. We hypothesize that ethanol's actions on histone methylation may be a switch for future transcriptional changes that underlie the behavioral changes lasting into adulthood.
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Affiliation(s)
- Jennifer T Wolstenholme
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States.,VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, VA, United States
| | - Tariq Mahmood
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Guy M Harris
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Shahroze Abbas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | - Michael F Miles
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States.,VCU Alcohol Research Center, Virginia Commonwealth University, Richmond, VA, United States.,Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, United States
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15
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Kamens HM, Silva C, Peck C, Miller CN. Varenicline modulates ethanol and saccharin consumption in adolescent male and female C57BL/6J mice. Brain Res Bull 2017; 138:20-25. [PMID: 28778837 DOI: 10.1016/j.brainresbull.2017.07.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/20/2017] [Accepted: 07/27/2017] [Indexed: 11/27/2022]
Abstract
Adolescence is a critical period in brain development that coincides with the initiation of alcohol use. Nicotinic acetylcholine receptors (nAChR) have been shown to modulate ethanol behaviors in adult humans and in animal models; however, the role of these receptors in adolescent ethanol behaviors has not been explored. Throughout adolescence, nAChR expression undergoes large-scale developmental changes which may alter behavioral responses to ethanol. Here we examined the effect of varenicline, a nAChR partial agonist, on ethanol consumption, ataxia, sedation, and metabolism in adolescent male and female C57BL/6J mice. The effect of varenicline on ethanol consumption was tested through the Drinking-in-the-Dark (DID) paradigm that models binge-like ethanol consumption. To ensure that results were specific for ethanol, we also tested the effect of varenicline on saccharin consumption. Additionally, varenicline was administered 30min prior to an acute injection of ethanol before being tested for ataxia on the balance beam, sedation using the loss of righting reflex, or ethanol metabolism. Varenicline dose dependently decreased ethanol consumption, but also influenced saccharin intake. Varenicline showed no significant effect on ethanol metabolism, ataxia, or sedation. Unlike its effects in adult animals, varenicline is able to reduce ethanol consumption without increasing the ataxic and sedative effects of ethanol. This work suggests that the neurobiological mechanisms of ethanol behaviors may change across the lifespan and highlights the need for more research on the role of nAChRs in ethanol behaviors throughout development.
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Affiliation(s)
- Helen M Kamens
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, 16802, United States.
| | - Constanza Silva
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Colette Peck
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, 16802, United States
| | - Carley N Miller
- Department of Biobehavioral Health, The Pennsylvania State University, University Park, PA, 16802, United States
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16
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Jury NJ, Pollack GA, Ward MJ, Bezek JL, Ng AJ, Pinard CR, Bergstrom HC, Holmes A. Chronic Ethanol During Adolescence Impacts Corticolimbic Dendritic Spines and Behavior. Alcohol Clin Exp Res 2017; 41:1298-1308. [PMID: 28614590 PMCID: PMC5509059 DOI: 10.1111/acer.13422] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 05/13/2017] [Indexed: 02/04/2023]
Abstract
BACKGROUND Risk for alcohol use disorders (AUDs) in adulthood is linked to alcohol drinking during adolescence, but understanding of the neural and behavioral consequences of alcohol exposure during adolescence remains incomplete. Here, we examined the neurobehavioral impact of adolescent chronic intermittent EtOH (CIE) vapor exposure in mice. METHODS C57BL/6J-background Thy1-EGFP mice were CIE-exposed during adolescence or adulthood and examined, as adults, for alterations in the density and morphology of dendritic spines in infralimbic (IL) cortex, prelimbic (PL) cortex, and basolateral amygdala (BLA). In parallel, adolescent- and adult-exposed C57BL/6J mice were tested as adults for 2-bottle EtOH drinking, sensitivity to EtOH intoxication (loss of righting reflex [LORR]), blood EtOH clearance, and measures of operant responding for food reward. RESULTS CIE during adolescence decreased IL neuronal spine density and increased the head width of relatively wide-head IL and BLA spines, whereas CIE decreased head width of relatively narrow-head BLA spines. Adolescents had higher EtOH consumption prior to CIE than adults, while CIE during adulthood, but not adolescence, increased EtOH consumption relative to pre-CIE baseline. CIE produced a tolerance-like decrease in LORR sensitivity to EtOH challenge, irrespective of the age at which mice received CIE exposure. Mice exposed to CIE during adolescence, but not adulthood, required more sessions than AIR controls to reliably respond for food reward on a fixed-ratio (FR) 1, but not subsequent FR3, reinforcement schedule. On a progressive ratio reinforcement schedule, break point responding was higher in the adolescent- than the adult-exposed mice, regardless of CIE. Finally, footshock punishment markedly suppressed responding for reward in all groups. CONCLUSIONS Exposure to CIE during adolescence altered dendritic spine density and morphology in IL and BLA neurons, in parallel with a limited set of behavioral alterations. Together, these data add to growing evidence that key corticolimbic circuits are vulnerable to the effects of alcohol during adolescence, with lasting, potentially detrimental, consequences for behavior.
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Affiliation(s)
- Nicholas J Jury
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Gabrielle A Pollack
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York
| | - Meredith J Ward
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York
| | - Jessica L Bezek
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York
| | - Alexandra J Ng
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York
| | - Courtney R Pinard
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
| | - Hadley C Bergstrom
- Department of Psychological Science, Program in Neuroscience and Behavior, Vassar College, Poughkeepsie, New York
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland
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17
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α6β2 nicotinic acetylcholine receptors influence locomotor activity and ethanol consumption. Alcohol 2017; 61:43-49. [PMID: 28457669 DOI: 10.1016/j.alcohol.2017.02.178] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 02/10/2017] [Accepted: 02/11/2017] [Indexed: 12/13/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) in the mesolimbic dopamine system have been implicated in ethanol behaviors. In particular, work in genetically engineered mice has demonstrated that α6-containing nAChRs are involved in ethanol consumption and sedation. A limitation of these studies is that the alteration in the receptor was present throughout development. The recently described α6β2 antagonist, N,N-decane-1,10-diyl-bis-3-picolinium diiodide (bPiDI), now makes it possible to test for the involvement of these receptors using a pharmacological approach. The aim of this study was to examine the role of α6β2 nAChRs in ethanol behaviors using a pharmacological approach. Adolescent C57BL/6J mice were treated with bPiDI 30 min prior to testing the mice for binge-like ethanol consumption in the drinking-in-the-dark (DID) test, ethanol-induced motor incoordination using the balance beam, and ethanol-induced sedation using the Loss of Righting Reflex (LORR) paradigm. Adolescent animals were chosen because they express a high amount of α6 mRNA relative to adult animals. Control studies were also performed to determine the effect of bPiDI on locomotor activity and ethanol metabolism. Female mice treated with 20 mg/kg bPiDI had reduced locomotor activity compared to saline-treated animals during the first 30 min following an acute injection. Pretreatment with the α6β2 antagonist reduced adolescent ethanol consumption but also reduced saccharin consumption. No significant effects were observed on ethanol-induced ataxia, sedation, or metabolism. This study provides evidence that α6β2 nAChRs are involved in locomotor activity as well as ethanol and saccharin consumption in adolescent animals.
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18
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Ruby CL, Palmer KN, Zhang J, Risinger MO, Butkowski MA, Swartzwelder HS. Differential Sensitivity to Ethanol-Induced Circadian Rhythm Disruption in Adolescent and Adult Mice. Alcohol Clin Exp Res 2016; 41:187-196. [PMID: 27997028 DOI: 10.1111/acer.13275] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/19/2016] [Indexed: 12/29/2022]
Abstract
BACKGROUND Growing evidence supports a central role for the circadian system in alcohol use disorders, but few studies have examined this relationship during adolescence. In mammals, circadian rhythms are regulated by the suprachiasmatic nucleus, a biological clock whose timing is synchronized (reset) to the environment primarily by light (photic) input. Alcohol (ethanol [EtOH]) disrupts circadian timing in part by attenuating photic phase-resetting responses in adult rodents. However, circadian rhythms change throughout life and it is not yet known whether EtOH has similar effects on circadian regulation during adolescence. METHODS General circadian locomotor activity was monitored in male C57BL6/J mice beginning in adolescence (P27) or adulthood (P61) in a 12-hour light, 12-hour dark photocycle for ~2 weeks to establish baseline circadian activity measures. On the day of the experiment, mice received an acute injection of EtOH (1.5 g/kg, i.p.) or equal volume saline 15 minutes prior to a 30-minute light pulse at Zeitgeber Time 14 (2 hours into the dark phase) and then were released into constant darkness (DD) for ~2 weeks to assess phase-resetting responses. Control mice of each age-group received injections but no light pulse prior to DD. RESULTS While adults showed the expected decrease in photic phase-delays induced by acute EtOH, this effect was absent in adolescent mice. Adolescents also showed baseline differences in circadian rhythmicity compared to adults, including advanced photocycle entrainment, larger photic phase-delays, a shorter free-running (endogenous) circadian period, and greater circadian rhythm amplitude. CONCLUSIONS Collectively, our results indicate that adolescent mice are less sensitive to the effect of EtOH on circadian photic phase-resetting and that their daily activity rhythms are markedly different than those of adults.
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Affiliation(s)
- Christina L Ruby
- Department of Biology, Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Kaitlyn N Palmer
- Department of Biology, Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Jiawen Zhang
- Department of Biology, Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Megan O Risinger
- Department of Biology, Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - Melissa A Butkowski
- Department of Biology, Indiana University of Pennsylvania, Indiana, Pennsylvania
| | - H Scott Swartzwelder
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, North Carolina.,Neurobiology Research Laboratory, VA Medical Center, Durham, North Carolina
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19
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Panksepp JB, Rodriguez ED, Ryabinin AE. Sweetened ethanol drinking during social isolation: enhanced intake, resistance to genetic heterogeneity and the emergence of a distinctive drinking pattern in adolescent mice. GENES BRAIN AND BEHAVIOR 2016; 16:369-383. [PMID: 27706910 DOI: 10.1111/gbb.12346] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/14/2016] [Accepted: 09/26/2016] [Indexed: 01/15/2023]
Abstract
With its ease of availability during adolescence, sweetened ethanol ('alcopops') is consumed within many contexts. We asked here whether genetically based differences in social motivation are associated with how the adolescent social environment impacts voluntary ethanol intake. Mice with previously described differences in sociability (BALB/cJ, C57BL/6J, FVB/NJ and MSM/MsJ strains) were weaned into isolation or same-sex pairs (postnatal day, PD, 21), and then given continuous access to two fluids on PDs 34-45: one containing water and the other containing an ascending series of saccharin-sweetened ethanol (3-6-10%). Prior to the introduction of ethanol (PDs 30-33), increased water and food intake was detected in some of the isolation-reared groups, and controls indicated that isolated mice also consumed more 'saccharin-only' solution. Voluntary drinking of 'ethanol-only' was also higher in a subset of the isolated groups on PDs 46-49. However, sweetened ethanol intake was increased in all isolated strain × sex combinations irrespective of genotype. Surprisingly, blood ethanol concentration (BEC) was not different between these isolate and socially housed groups 4 h into the dark phase. Using lickometer-based measures of intake in FVB mice, we identified that a predominance of increased drinking during isolation transpired outside of the typical circadian consumption peak, occurring ≈8.5 h into the dark phase, with an associated difference in BEC. These findings collectively indicate that isolate housing leads to increased consumption of rewarding substances in adolescent mice independent of their genotype, and that for ethanol this may be because of when individuals drink during the circadian cycle.
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Affiliation(s)
- J B Panksepp
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - E D Rodriguez
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - A E Ryabinin
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
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20
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Direct effects of ethanol on neuronal differentiation: An in vitro analysis of viability and morphology. Brain Res Bull 2016; 127:177-186. [PMID: 27679397 DOI: 10.1016/j.brainresbull.2016.09.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/22/2016] [Accepted: 09/23/2016] [Indexed: 12/29/2022]
Abstract
The deleterious effects of ethanol (EtOH) on the brain have been widely described, but its effects on the neuronal cytoskeleton during differentiation have not yet been firmly established. In this context, our aim was to investigate the direct effect of EtOH on cortical neurons during the period of differentiation. Primary cultures of cortical neurons obtained from 1-day-old rats were exposed to EtOH after 7days of culture, and viability and morphology were analyzed at structural and ultrastructural levels after 24-h EtOH exposure. EtOH caused a significant reduction of 73±7% in the viability of cultured cortical neurons, by preferentially inducing apoptotic cellular death. This effect was accompanied by an increase in caspase 3 and 9 expression. Furthermore, EtOH induced a reduction in total dendrite length and in the number of dendrites per cell. Ultrastructural studies showed that EtOH increased the number of lipidic vacuoles, lysosomes and multilamellar vesicles and induced a dilated endoplasmatic reticulum lumen and a disorganized Golgi apparatus with a ring-shape appearance. Microtubules showed a disorganized distribution. Apposition between pre- and postsynaptic membranes without a defined synaptic cleft and a delay in presynaptic vesicle organization were also observed. Synaptophysin and PSD95 expression, proteins pre- and postsynaptically located, were reduced in EtOH-exposed cultures. Overall, our study shows that EtOH induces neuronal apoptosis and changes in the cytoskeleton and membrane proteins related with the establishment of mature synapses. These direct effects of EtOH on neurons may partially explain its effects on brain development.
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21
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Kasten CR, Boehm SL. Preclinical Medication Development: New Targets and New Drugs. Alcohol Clin Exp Res 2016; 40:1418-24. [PMID: 27177689 PMCID: PMC4930385 DOI: 10.1111/acer.13105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/17/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Chelsea R. Kasten
- Department of Psychology and Indiana Alcohol Research Center, Indiana University – Purdue University of Indianapolis, Indianapolis, IN 46202
| | - Stephen L. Boehm
- Department of Psychology and Indiana Alcohol Research Center, Indiana University – Purdue University of Indianapolis, Indianapolis, IN 46202
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22
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Fritz BM, Quoilin C, Kasten CR, Smoker M, Boehm SL. Concomitant Caffeine Increases Binge Consumption of Ethanol in Adolescent and Adult Mice, But Produces Additive Motor Stimulation Only in Adolescent Animals. Alcohol Clin Exp Res 2016; 40:1351-60. [PMID: 27154344 DOI: 10.1111/acer.13089] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/30/2016] [Indexed: 02/01/2023]
Abstract
BACKGROUND Binge co-consumption of highly caffeinated energy drinks with alcohol (ethanol [EtOH]) has become a common practice among adolescents/young adults and has been associated with an increased incidence of hazardous behaviors. Animal models are critical in advancing our understanding the neurobehavioral consequences of this form of binge drinking. Surprisingly, virtually no work has explored caffeine and EtOH co-consumption or its long-term consequences in adolescent animals. The primary objective of the current study was to extend a previously established mouse model of voluntary binge caffeine and EtOH co-consumption to explore adolescent consumption and responses compared to adults. METHODS Adolescent and adult male C57BL/6J mice had daily limited access to caffeine (0.03% w/v), EtOH (20% v/v), a combined EtOH/caffeine solution, or water for 14 days via the binge-like drinking paradigm, drinking-in-the-dark (DID). Home cage locomotor activity was measured during DID in a subset of mice. Following DID, all mice rested for 18 days so that adolescents reached adulthood, whereupon all mice underwent 7 days of continuous access 2-bottle choice drinking for 10% (v/v) EtOH or water. RESULTS Co-consumption with caffeine significantly increased EtOH intake and resultant blood ethanol concentrations in both adolescent and adult mice. In addition, adolescent mice exhibited a uniquely robust locomotor stimulant response to caffeine and EtOH co-consumption. Later EtOH intake and preference was not influenced, however, by prior fluid consumption history via DID. CONCLUSIONS Together with findings from the human literature, our results suggest that caffeine co-consumption may positively influence binge alcohol consumption in adolescents/young adults. Importantly, this age group may be particularly sensitive to the additive stimulant effects of caffeinated alcohol consumption, an effect which may be related to the high incidence of associated negative outcomes in this population. These observations are particularly concerning considering the heightened plasticity of the adolescent brain.
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Affiliation(s)
- Brandon M Fritz
- Department of Psychology and Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Caroline Quoilin
- Department of Psychology and Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana.,Institute of Neuroscience, Université Catholique Louvain, Brussels, Belgium
| | - Chelsea R Kasten
- Department of Psychology and Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Michael Smoker
- Department of Psychology and Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Stephen L Boehm
- Department of Psychology and Indiana Alcohol Research Center, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
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23
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Tipps ME, Raybuck JD, Kozell LB, Lattal KM, Buck KJ. G Protein-Gated Inwardly Rectifying Potassium Channel Subunit 3 Knock-Out Mice Show Enhanced Ethanol Reward. Alcohol Clin Exp Res 2016; 40:857-64. [PMID: 27012303 PMCID: PMC4820358 DOI: 10.1111/acer.13012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 01/07/2016] [Indexed: 12/17/2022]
Abstract
BACKGROUND G protein-gated inwardly rectifying potassium (GIRK) channels contribute to the effects of a number of drugs of abuse, including ethanol. However, the roles of individual subunits in the rewarding effects of ethanol are poorly understood. METHODS We compare conditioned place preference (CPP) in GIRK3 subunit knock-out (GIRK3(-/-)), heterozygote (GIRK3(+/-)), and wild-type (WT) mice. In addition, the development of locomotor tolerance/sensitization and the effects of EtOH intoxication on associative learning (fear conditioning) are also assessed. RESULTS Our data show significant EtOH CPP in GIRK3(-/-) and GIRK3(+/-) mice, but not in the WT littermates. In addition, we demonstrate that these effects are not due to differences in EtOH metabolism, the development of EtOH tolerance/sensitivity, or associative learning abilities. While there were no consistent genotype differences in the fear conditioning assay, our data do show a selective sensitization of the impairing effects of EtOH intoxication on contextual learning, but no effect on cued learning. CONCLUSIONS These findings suggest that GIRK3 plays a role in EtOH reward. Furthermore, the selectivity of this effect suggests that GIRK channels could be an effective therapeutic target for the prevention and/or treatment of alcoholism.
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Affiliation(s)
- Megan E. Tipps
- Portland Alcohol Research Center; Portland VA Medical Center, 3710 SW US Veterans Hospital Rd., Bldg 104, Portland, OR 97239-3098, USA
- Department of Behavioral Neuroscience; Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239-3098, USA
| | - Jonathan D. Raybuck
- Department of Behavioral Neuroscience; Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239-3098, USA
| | - Laura B. Kozell
- Portland Alcohol Research Center; Portland VA Medical Center, 3710 SW US Veterans Hospital Rd., Bldg 104, Portland, OR 97239-3098, USA
- Department of Behavioral Neuroscience; Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239-3098, USA
| | - K. Matthew Lattal
- Department of Behavioral Neuroscience; Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239-3098, USA
| | - Kari J. Buck
- Portland Alcohol Research Center; Portland VA Medical Center, 3710 SW US Veterans Hospital Rd., Bldg 104, Portland, OR 97239-3098, USA
- Department of Behavioral Neuroscience; Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239-3098, USA
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24
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Quoilin C, Boehm SL. Involvement of the GABAA Receptor in Age-Dependent Differences in Binge-Like Ethanol Intake. Alcohol Clin Exp Res 2016; 40:408-17. [PMID: 26833274 DOI: 10.1111/acer.12953] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 11/04/2015] [Indexed: 11/27/2022]
Abstract
BACKGROUND Binge alcohol (ethanol [EtOH]) drinking is common during adolescence, a time characterized by many behavioral and neurobiological changes. Among them, the GABAA receptor system undergoes substantial modifications, including changes in the density, distribution, and subunit composition of the receptor. Based on its demonstrated role in EtOH consumption, this study aimed to investigate the effects of 2 different GABAA receptor agonists on binge-like EtOH intake in adolescent and adult mice using the Drinking-in-the-Dark model. METHODS Three hours into their dark cycle, adolescent (postnatal day 28 [P28]) and adult (P63) male C57BL/6J mice were given daily access to 20% EtOH for 2 hours during 8 consecutive days. Immediately before the access on day 8, mice (P35 and P70) were systemically injected with 1 of 2 different GABAergic drugs. The effects of muscimol, a full GABAA agonist, were assessed in a first experiment. The second experiment tested for the more specific involvement of δ-containing extrasynaptic GABAA receptors through the administration of THIP (4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol). RESULTS Adolescent mice consumed more EtOH than their adult counterparts. Following the administration of GABAA agonists, levels of EtOH intake were reduced at both ages. However, age-dependent differences were revealed following the administration of THIP, with adolescents exhibiting greater sensitivity to its suppressant effects, especially during the first 30 minutes of binge EtOH access. CONCLUSIONS This study adds to the existing literature demonstrating the crucial role of the GABAA receptor in alcohol consumption. In addition, it suggests that age differences in the GABAA receptor modulation of binge alcohol drinking might be more dependent on extrasynaptic GABAA receptors.
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Affiliation(s)
- Caroline Quoilin
- Addiction Neuroscience, Department of Psychology, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
| | - Stephen L Boehm
- Addiction Neuroscience, Department of Psychology, Indiana University - Purdue University Indianapolis, Indianapolis, Indiana
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25
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Valenza M, DiLeo A, Steardo L, Cottone P, Sabino V. Ethanol-related behaviors in mice lacking the sigma-1 receptor. Behav Brain Res 2016; 297:196-203. [PMID: 26462569 PMCID: PMC4679530 DOI: 10.1016/j.bbr.2015.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 01/01/2023]
Abstract
RATIONALE The Sigma-1 receptor (Sig-1R) is a chaperone protein that has been implicated in drug abuse and addiction. Multiple studies have characterized the role the Sig-1R plays in psychostimulant addiction; however, fewer studies have specifically investigated its role in alcohol addiction. We have previously shown that antagonism of the Sig-1R reduces excessive drinking and motivation to drink, whereas agonism induces binge-like drinking in rodents. OBJECTIVES The objectives of these studies were to investigate the impact of Sig-1R gene deletion in C57Bl/6J mice on ethanol drinking and other ethanol-related behaviors. METHODS We used an extensive panel of behavioral tests to examine ethanol actions in male, adult mice lacking Oprs1, the gene encoding the Sig-1R. To compare ethanol drinking behavior, Sig-1 knockout (KO) and wild type (WT) mice were subject to a two-bottle choice, continuous access paradigm with different concentrations of ethanol (3-20% v/v) vs. water. Consumption of sweet and bitter solutions was also assessed in Sig-1R KO and WT mice. Finally, motor stimulant sensitivity, taste aversion and ataxic effects of ethanol were assessed. RESULTS Sig-1R KO mice displayed higher ethanol intake compared to WT mice; the two genotypes did not differ in their sweet or bitter taste perception. Sig-1R KO mice showed lower sensitivity to ethanol stimulant effects, but greater sensitivity to its taste aversive effects. Ethanol-induced sedation was instead unaltered in the mutants. CONCLUSIONS Our results prove that the deletion of the Sig-1R increases ethanol consumption, likely by decreasing its rewarding effects, and therefore indicating that the Sig-1R is involved in modulation of the reinforcing effects of alcohol.
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Affiliation(s)
- Marta Valenza
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States; Department of Biomedical Sciences and Human Oncology, University of Bari "Aldo Moro", Bari, Italy
| | - Alyssa DiLeo
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Luca Steardo
- Department of Physiology and Pharmacology "V. Erspamer", Sapienza University, Rome, Italy
| | - Pietro Cottone
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States
| | - Valentina Sabino
- Laboratory of Addictive Disorders, Departments of Pharmacology and Psychiatry, Boston University School of Medicine, Boston, MA, United States.
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Pautassi RM, Godoy JC, Molina JC. Adolescent rats are resistant to the development of ethanol-induced chronic tolerance and ethanol-induced conditioned aversion. Pharmacol Biochem Behav 2015; 138:58-69. [PMID: 26388098 DOI: 10.1016/j.pbb.2015.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 08/17/2015] [Accepted: 09/15/2015] [Indexed: 01/11/2023]
Abstract
The analysis of chronic tolerance to ethanol in adult and adolescent rats has yielded mixed results. Tolerance to some effects of ethanol has been reported in adolescents, yet other studies found adults to exhibit greater tolerance than adolescents or comparable expression of the phenomena at both ages. Another unanswered question is how chronic ethanol exposure affects subsequent ethanol-mediated motivational learning at these ages. The present study examined the development of chronic tolerance to ethanol's hypothermic and motor stimulating effects, and subsequent acquisition of ethanol-mediated odor conditioning, in adolescent and adult male Wistar rats given every-other-day intragastric administrations of ethanol. Adolescent and adult rats exhibited lack of tolerance to the hypothermic effects of ethanol during an induction phase; whereas adults, but not adolescents, exhibited a trend towards a reduction in hypothermia at a challenge phase (Experiment 1). Adolescents, unlike adults, exhibited ethanol-induced motor activation after the first ethanol administration. Adults, but not adolescents, exhibited conditioned odor aversion by ethanol. Subsequent experiments conducted only in adolescents (Experiment 2, Experiment 3 and Experiment 4) manipulated the context, length and predictability of ethanol administration. These manipulations did not promote the expression of ethanol-induced tolerance. This study indicated that, when moderate ethanol doses are given every-other day for a relatively short period, adolescents are less likely than adults to develop chronic tolerance to ethanol-induced hypothermia. This resistance to tolerance development could limit long-term maintenance of ethanol intake. Adolescents, however, exhibited greater sensitivity than adults to the acute motor stimulating effects of ethanol and a blunted response to the aversive effects of ethanol. This pattern of response may put adolescents at risk for early initiation of ethanol intake.
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Affiliation(s)
- Ricardo Marcos Pautassi
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC - CONICET - Universidad Nacional de Córdoba), Córdoba C.P 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba C.P 5000, Argentina.
| | - Juan Carlos Godoy
- Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba C.P 5000, Argentina
| | - Juan Carlos Molina
- Instituto de Investigación Médica M. y M. Ferreyra (INIMEC - CONICET - Universidad Nacional de Córdoba), Córdoba C.P 5000, Argentina; Facultad de Psicología, Universidad Nacional de Córdoba, Córdoba C.P 5000, Argentina
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Sex differences in adult Wistar rats in the voluntary consumption of ethanol after pre-exposure to ethanol-induced flavor avoidance learning. Pharmacol Biochem Behav 2015. [PMID: 26216835 DOI: 10.1016/j.pbb.2015.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Vulnerability to ethanol abuse may be a function of the balance between the opposing (aversive and rewarding) motivational effects of the drug. The study of these effects is particularly important for understanding alcohol addiction. Research in this field seems to point out that ethanol effects are determined by a set of internal factors (sex, ethanol intake history, etc.), as well as by environmental conditions surrounding the individual (i.e., stress) and, of course, the interactions between all these factors. This work explores sex differences in sensitivity to aversive effects of ethanol using the procedure of flavor avoidance learning (FAL), as well as the effect of this learning experience on subsequent voluntary ethanol consumption, in adult rats. The results obtained indicated a slight sex based difference in the amount of FAL acquired in that females acquisition was weaker (experiment 1), and a differing influence of previous experience with the aversive effects of ethanol on the voluntary consumption of the drug for each sex (experiment 2). In particular, it was observed that female ethanol-naive rats showed a higher intake level and preference for ethanol than both ethanol-experienced female rats and ethanol-naive male rats. In contrast, the ethanol-experienced male rats showed a greater consumption of and preference for ethanol than ethanol-naive male rats and ethanol-experienced female rats. These data are discussed noting a range of possible explicative factors (sex hormones, hedonic processing, etc.), but further studies are warranted to elucidate the mechanisms by which ethanol pre-exposure influences the subsequent intake of ethanol differently by sex.
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Porcu P, Morrow AL. Divergent neuroactive steroid responses to stress and ethanol in rat and mouse strains: relevance for human studies. Psychopharmacology (Berl) 2014; 231:3257-72. [PMID: 24770626 PMCID: PMC4135033 DOI: 10.1007/s00213-014-3564-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/25/2014] [Indexed: 01/09/2023]
Abstract
RATIONALE Neuroactive steroids are endogenous or synthetic steroids that rapidly alter neuronal excitability via membrane receptors, primarily γ-aminobutyric acid type A (GABAA) receptors. Neuroactive steroids regulate many physiological processes including hypothalamic-pituitary-adrenal (HPA) axis function, ovarian cycle, pregnancy, aging, and reward. Moreover, alterations in neuroactive steroid synthesis are implicated in several neuropsychiatric disorders. OBJECTIVES This review will summarize the pharmacological properties and physiological regulation of neuroactive steroids, with a particular focus on divergent neuroactive steroid responses to stress and ethanol in rats, mice, and humans. RESULTS GABAergic neuroactive steroids exert a homeostatic regulation of the HPA axis in rats and humans, whereby the increase in neuroactive steroid levels following acute stress counteracts HPA axis hyperactivity and restores homeostasis. In contrast, in C57BL/6J mice, acute stress decreases neurosteroidogenesis and neuroactive steroids exert paradoxical excitatory effects upon the HPA axis. Rats, mice, and humans also differ in the neuroactive steroid responses to ethanol. Genetic variation in neurosteroidogenesis may explain the different neuroactive steroid responses to stress or ethanol. CONCLUSIONS Rats and mouse strains show divergent effects of stress and ethanol on neuroactive steroids in both plasma and brain. The study of genetic variation in the various processes that determine neuroactive steroids levels as well as their effects on cell signaling may underlie these differences and may play a relevant role for the potential therapeutic benefits of neuroactive steroids.
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Affiliation(s)
- Patrizia Porcu
- Neuroscience Institute, National Research Council of Italy (CNR), Cittadella Universitaria, 09042, Monserrato, Cagliari, Italy,
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Burkhardt JM, Adermark L. Locus of onset and subpopulation specificity of in vivo ethanol effect in the reciprocal ventral tegmental area-nucleus accumbens circuit. Neurochem Int 2014; 76:122-30. [PMID: 25058792 DOI: 10.1016/j.neuint.2014.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 12/13/2022]
Abstract
Elevated levels of dopamine in the nucleus accumbens (nAc) as a consequence of increased activation of dopaminergic neurons in the VTA are associated with the reinforcing properties of ethanol consumption, but whether the initiation of drug-response is connected to a direct activation of dopaminergic cell bodies in the VTA region or involves GABAergic neurons in VTA and/or the nAc is unclear. To this end, neuronal firing rate was recorded simultaneously in the VTA and nAc of awake and freely-moving C57BL6/J mice receiving an intraperitoneal (i.p.) injection of ethanol (0.75, 2.0, or 3.5g/kg) or saline. Recorded units were classified based on electrophysiological properties and the pharmacological response to the dopamine D2 receptor agonist quinpirole into putative dopaminergic (DA) neurons and fast-spiking or slow-spiking putative GABAergic neurons. Our data show that ethanol acutely decreases the firing frequency of GABAergic units in both the VTA and nAc in a dose-dependent manner, and enhances the firing rate of DA neurons. In order to define the onset of ethanol-induced rate changes normalized population vectors describing the collective firing rate of classes of neurons over time were generated and compared with saline-treatment. Population vectors of DA neurons in the VTA and GABAergic units in the nAc showed a significant deviation from the saline condition within 40s following ethanol-administration (2.0g/kg), while inhibition of GABAergic units in the VTA had a slower onset. In conclusion, the data presented here suggests that EtOH exerts a direct effect on DA firing frequency, but that decreased firing frequency of inhibitory neurons in VTA and nAc contributes to the dopamine-elevating properties of ethanol.
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Affiliation(s)
- John M Burkhardt
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, Oslo, Norway; Champalimaud Neuroscience Programme, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Louise Adermark
- Addiction Biology Unit, Institute of Neuroscience and Physiology, Gothenburg University, Sweden.
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Broadwater M, Spear LP. Consequences of adolescent or adult ethanol exposure on tone and context fear retention: effects of an acute ethanol challenge during conditioning. Alcohol Clin Exp Res 2014; 38:1454-60. [PMID: 24588350 DOI: 10.1111/acer.12382] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/08/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND An acute ethanol (EtOH) challenge prior to fear conditioning typically disrupts fear retention to contextual cues to a greater degree than fear retention to a discrete tone cue, and adolescent rats are less sensitive than adults to these EtOH-induced disruptions of context fear memory. Given that some research suggests that repeated EtOH exposure during adolescence may "lock-in" adolescent-typical EtOH sensitivity into adulthood, the purpose of this study was to determine whether adults exposed to EtOH as adolescents would be less sensitive to EtOH-induced disruptions of context fear. METHODS Male Sprague-Dawley rats were given 4 g/kg intragastric EtOH (25% v/v) or water every 48 hours for a total of 11 exposures during adolescence (postnatal day [P] 28 to 48) or adulthood (P70-90). After a 22-day non-EtOH period, animals were acutely challenged with 1 g/kg intraperitoneal EtOH or saline 10 minutes prior to tone or context (noncued) fear conditioning. Tone and context fear retention was subsequently examined. RESULTS Regardless of age or exposure history, typical deficits in context fear retention were evident after EtOH challenge during conditioning. Similarly, tone fear retention was disrupted in all animals that were trained in the presence of EtOH, which was somewhat surprising given the relative resistance of tone fear retention to an acute EtOH challenge. CONCLUSIONS These results do not support the notion of a "lock-in" of adolescent-typical EtOH sensitivity as there was no influence of exposure age on sensitivity to the disruptive effects of an acute EtOH challenge. Thus, it appears that not all adolescent-like EtOH sensitivities persist into adulthood after prior EtOH exposure during adolescence.
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Affiliation(s)
- Margaret Broadwater
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Porcu P, Locci A, Santoru F, Berretti R, Morrow AL, Concas A. Failure of acute ethanol administration to alter cerebrocortical and hippocampal allopregnanolone levels in C57BL/6J and DBA/2J mice. Alcohol Clin Exp Res 2014; 38:948-58. [PMID: 24428156 DOI: 10.1111/acer.12329] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/25/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Ethanol (EtOH) administration increases brain allopregnanolone levels in rats, and this increase contributes to sensitivity to EtOH's behavioral effects. However, EtOH's effects on allopregnanolone may differ across species. We investigated the effects of acute EtOH administration on allopregnanolone, progesterone, and corticosterone levels in cerebral cortex and hippocampus of C57BL/6J and DBA/2J mice, 2 inbred strains with different alcohol sensitivity. METHODS Naïve male C57BL/6J and DBA/2J mice received EtOH (1, 2, 3, or 4 g/kg, intraperitoneally [i.p.]) or saline and were euthanized 1 hour later. For the time-course study, mice received EtOH (2 g/kg, i.p.) and were euthanized 15, 30, 60, and 120 minutes later. Steroids were measured by radioimmunoassay. RESULTS Acute EtOH administration did not alter cerebrocortical and hippocampal levels of allopregnanolone and progesterone in these strains at any of the doses and time points examined. Acute EtOH dose-dependently increased cerebrocortical corticosterone levels by 319, 347, and 459% in C57BL/6J mice at the doses of 2, 3, and 4 g/kg, and by 371, 507, 533, and 692% in DBA/2J mice at the doses of 1, 2, 3, and 4 g/kg, respectively. Similar changes were observed in the hippocampus. EtOH's effects on cerebrocortical corticosterone levels were also time dependent in both strains. Moreover, acute EtOH administration time-dependently increased plasma levels of progesterone and corticosterone. Finally, morphine administration increased cerebrocortical allopregnanolone levels in C57BL/6J (+77, +93, and +88% at 5, 10, and 30 mg/kg, respectively) and DBA/2J mice (+81% at 5 mg/kg), suggesting that the impairment in brain neurosteroidogenesis may be specific to EtOH. CONCLUSIONS These results underline important species differences on EtOH-induced brain neurosteroidogenesis. Acute EtOH increases brain and plasma corticosterone levels but does not alter cerebrocortical and hippocampal concentrations of allopregnanolone and progesterone in naïve C57BL/6J and DBA/2J mice.
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Affiliation(s)
- Patrizia Porcu
- Institute of Neuroscience, National Research Council of Italy (CNR), Cagliari, Italy
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Bhorkar AA, Dandekar MP, Nakhate KT, Subhedar NK, Kokare DM. Involvement of the central melanocortin system in the effects of caffeine on anxiety-like behavior in mice. Life Sci 2013; 95:72-80. [PMID: 24361398 DOI: 10.1016/j.lfs.2013.12.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 12/07/2013] [Accepted: 12/10/2013] [Indexed: 12/12/2022]
Abstract
AIMS To investigate the role of the melanocortin (MC) system in the framework of the central nucleus of the amygdala (CeA) in the differential effects of the adenosine receptor blocker caffeine on anxiety-like behavior, using the social interaction (SI) test. MAIN METHODS Caffeine was injected intraperitoneally, alone or in combination with alpha-melanocyte stimulating hormone (α-MSH), the MC4 receptor agonist RO27-3225 or the antagonist HS014 via the intra-CeA route. The effects of chronic (21 days) caffeine, given alone or concurrently with α-MSH, or RO27-3225, were investigated. The effects of withdrawal of these treatments on SI time were also evaluated. Furthermore, the acute effects of HS014 were investigated in different sets of caffeine-withdrawn mice. KEY FINDINGS Acute injection of caffeine, RO27-3225, or α-MSH produced anxiety-like behavior. Prior treatment with α-MSH, or RO27-3225 potentiated the caffeine-induced anxiety-like behavior. Subchronic treatment with HS014 increased the SI time, which was attenuated by caffeine. Chronic administration of caffeine resulted in tolerance to caffeine's anxiogenic effect, while abrupt discontinuation of the treatment produced peak anxiety-like behavior at 72 h post-withdrawal. Concurrent administration of α-MSH, or RO27-3225 with chronic caffeine delayed the development of tolerance and prevented withdrawal-induced anxiety-like behavior. Moreover, acute treatment with HS014 at 72 h post-withdrawal attenuated the anxiety-like behavior. SIGNIFICANCE α-MSH, possibly via MC4 receptor in the neuroanatomical framework of the CeA, may contribute to the acute, chronic and withdrawal actions of caffeine associated with anxiety-like behavior in the neuroanatomical framework of the CeA.
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Affiliation(s)
- Amita A Bhorkar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India
| | - Manoj P Dandekar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India
| | - Kartik T Nakhate
- Rungta College of Pharmaceutical Sciences and Research, Rungta Educational Campus, Kohka-Kurud Road, Bhilai 490 024, Chhattisgarh, India
| | - Nishikant K Subhedar
- Indian Institute of Science Education and Research (IISER), Sai Trinity Building, Sutarwadi, Pashan, Pune 411 021, Maharashtra, India
| | - Dadasaheb M Kokare
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440 033, Maharashtra, India.
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Rose JH, Calipari ES, Mathews TA, Jones SR. Greater ethanol-induced locomotor activation in DBA/2J versus C57BL/6J mice is not predicted by presynaptic striatal dopamine dynamics. PLoS One 2013; 8:e83852. [PMID: 24349553 PMCID: PMC3861521 DOI: 10.1371/journal.pone.0083852] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 11/18/2013] [Indexed: 12/13/2022] Open
Abstract
A large body of research has aimed to determine the neurochemical factors driving differential sensitivity to ethanol between individuals in an attempt to find predictors of ethanol abuse vulnerability. Here we find that the locomotor activating effects of ethanol are markedly greater in DBA/2J compared to C57BL/6J mice, although it is unclear as to what neurochemical differences between strains mediate this behavior. Dopamine elevations in the nucleus accumbens and caudate-putamen regulate locomotor behavior for most drugs, including ethanol; thus, we aimed to determine if differences in these regions predict strain differences in ethanol-induced locomotor activity. Previous studies suggest that ethanol interacts with the dopamine transporter, potentially mediating its locomotor activating effects; however, we found that ethanol had no effects on dopamine uptake in either strain. Ex vivo voltammetry allows for the determination of ethanol effects on presynaptic dopamine terminals, independent of drug-induced changes in firing rates of afferent inputs from either dopamine neurons or other neurotransmitter systems. However, differences in striatal dopamine dynamics did not predict the locomotor-activating effects of ethanol, since the inhibitory effects of ethanol on dopamine release were similar between strains. There were differences in presynaptic dopamine function between strains, with faster dopamine clearance in the caudate-putamen of DBA/2J mice; however, it is unclear how this difference relates to locomotor behavior. Because of the role of the dopamine system in reinforcement and reward learning, differences in dopamine signaling between the strains could have implications for addiction-related behaviors that extend beyond ethanol effects in the striatum.
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Affiliation(s)
- Jamie H. Rose
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Erin S. Calipari
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Tiffany A. Mathews
- Department of Chemistry, Wayne State University, Detroit, Michigan, United States of America
| | - Sara R. Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
- * E-mail:
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Yorgason JT, Ferris MJ, Steffensen SC, Jones SR. Frequency-dependent effects of ethanol on dopamine release in the nucleus accumbens. Alcohol Clin Exp Res 2013; 38:438-47. [PMID: 24117706 DOI: 10.1111/acer.12287] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 07/30/2013] [Indexed: 01/19/2023]
Abstract
BACKGROUND Ethanol (EtOH) is known to have excitatory effects on dopamine (DA) release, with moderate-to-high doses (0.5 to 2.5 g/kg) of acute EtOH enhancing DA neuron firing rates in the ventral tegmental area (VTA) and DA levels in the nucleus accumbens (NAc). EtOH has also been shown to reduce DA activity, with moderate doses (1 to 2 g/kg) attenuating electrically evoked release, and higher doses (5 g/kg) decreasing NAc DA levels, demonstrating a biphasic effect of EtOH on DA release. The purpose of the current study was to evaluate EtOH's inhibitory effects on NAc DA terminal release under low- and high-frequency stimulation conditions. METHODS Using fast-scan cyclic voltammetry in NAc slices from C57BL/6J mice, we examined EtOH's (40 to 160 mM) effects on DA release under several different stimulation parameters, varying frequency (5 to 125 Hz), number of pulses (1 to 10), and stimulation intensity (50 to 350 μA). Additionally, calcium concentrations were manipulated under high-frequency stimulation conditions (20 Hz, 10 pulses, 350 μA) to determine whether EtOH's effects were dependent upon calcium concentration, and by extension, the amount of DA release. RESULTS Acute EtOH (40 to 160 mM) inhibited DA release to a greater extent under high-frequency, multiple-pulse stimulation conditions, with increased sensitivity at 5 and 10 pulses and frequencies of 20 Hz or higher. High-frequency, multiple-pulse stimulations also resulted in greater DA release compared with single-pulse release, which was controlled by reducing stimulation intensity. Under reduced DA conditions, high-frequency stimulations still showed increased EtOH sensitivity. Reducing calcium levels also decreased DA release at high-frequency stimulations, but did not affect EtOH sensitivity. CONCLUSIONS EtOH appears to inhibit DA release at NAc terminals under high-frequency stimulation conditions that are similar to release events observed during phasic burst firing in DAergic neurons, suggesting that EtOH may provide inhibition of DA terminals selectively during phasic signaling, while leaving tonic DA terminal activity unaffected.
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Affiliation(s)
- Jordan T Yorgason
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Quoilin C, Didone V, Tirelli E, Quertemont E. Chronic tolerance to ethanol-induced sedation: implication for age-related differences in locomotor sensitization. Alcohol 2013; 47:317-22. [PMID: 23566528 DOI: 10.1016/j.alcohol.2013.01.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/28/2013] [Accepted: 01/31/2013] [Indexed: 01/18/2023]
Abstract
The adolescent brain has been suggested to be particularly sensitive to ethanol-induced neuroadaptations, which in turn could increase the risk of youths for alcohol abuse and dependence. Sensitization to the locomotor stimulant effects of ethanol has often been used as an animal model of ethanol-induced neuroadaptations. Previously, we showed that young mice were more sensitive than adults to the locomotor sensitization induced by high ethanol doses. However, this effect could be due to age-related differences in chronic tolerance to the sedative effects of ethanol. The aim of the present study is to assess chronic tolerance to the sedative effects of ethanol in weaning 21-day-old (P21), adolescent 35-day-old (P35) and adult 63-day-old (P63) female Swiss mice. After a daily injection of saline or 4 g/kg ethanol during 6 consecutive days, all P21, P35 and P63 mice were injected with 4 g/kg ethanol and submitted to the loss of righting reflex procedure. Our results confirm that the sensitivity to the acute sedative effects of ethanol gradually increases with age. Although this schedule of ethanol injections induces significant age-related differences in ethanol sensitization, it did not reveal significant differences between P21, P35 and P63 mice in the development of a chronic ethanol tolerance to its sedative effects. The present results show that age-related differences in the development of ethanol sensitization cannot be explained by differences in chronic ethanol tolerance to its sedative effects. More broadly, they do not support the idea that ethanol-induced sensitization is a by-product of chronic ethanol tolerance.
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Moore EM, Forrest RD, Boehm SL. Genotype modulates age-related alterations in sensitivity to the aversive effects of ethanol: an eight inbred strain analysis of conditioned taste aversion. GENES, BRAIN, AND BEHAVIOR 2013; 12:70-7. [PMID: 23171343 PMCID: PMC3553292 DOI: 10.1111/gbb.12004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/18/2012] [Accepted: 11/15/2012] [Indexed: 02/04/2023]
Abstract
Adolescent individuals display altered behavioral sensitivity to ethanol, which may contribute to the increased ethanol consumption seen in this age-group. However, genetics also exert considerable influence on both ethanol intake and sensitivity. Currently there is little research assessing the combined influence of developmental and genetic alcohol sensitivities. Sensitivity to the aversive effects of ethanol using a conditioned taste aversion (CTA) procedure was measured during both adolescence (P30) and adulthood (P75) in eight inbred mouse strains (C57BL/6J, DBA/2J, 129S1/SvImJ, A/J, BALB/cByJ, BTBR T(+) tf/J, C3H/HeJ and FVB/NJ). Adolescent and adult mice were water deprived, and subsequently provided with access to 0.9% (v/v) NaCl solution for 1 h. Immediately following access mice were administered ethanol (0, 1.5, 2.25 and 3 g/kg, ip). This procedure was repeated in 72 h intervals for a total of five CTA trials. Sensitivity to the aversive effects of ethanol was highly dependent upon both strain and age. Within an inbred strain, adolescent animals were consistently less sensitive to the aversive effects of ethanol than their adult counterparts. However, the dose of ethanol required to produce an aversion response differed as a function of both age and strain.
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Affiliation(s)
- Eileen M. Moore
- Center for Development and Behavioral Neuroscience, Department of Psychology, Binghamton University – SUNY Binghamton, 4400 Vestal Parkway East, Binghamton, NY 13902, USA
- Indiana Alcohol Research Center, Psychobiology of Addictions, Department of Psychology, Purdue School of Science, IUPUI, 402 N. Blackford Street, LD 124, Indianapolis, IN 46202, USA
| | - Robert D. Forrest
- Indiana Alcohol Research Center, Psychobiology of Addictions, Department of Psychology, Purdue School of Science, IUPUI, 402 N. Blackford Street, LD 124, Indianapolis, IN 46202, USA
| | - Stephen L. Boehm
- Indiana Alcohol Research Center, Psychobiology of Addictions, Department of Psychology, Purdue School of Science, IUPUI, 402 N. Blackford Street, LD 124, Indianapolis, IN 46202, USA
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Melón LC, Wray KN, Moore EM, Boehm SL. Sex and age differences in heavy binge drinking and its effects on alcohol responsivity following abstinence. Pharmacol Biochem Behav 2013; 104:177-87. [PMID: 23333154 DOI: 10.1016/j.pbb.2013.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 12/30/2012] [Accepted: 01/01/2013] [Indexed: 01/14/2023]
Abstract
Binge drinking during adolescence may perturb the maturing neuroenvironment and increase susceptibility of developing an alcohol use disorder later in life. In the present series of experiments, we utilized a modified version of the drinking in the dark-multiple scheduled access (DID-MSA) procedure to study how heavy binge drinking during adolescence alters responsivity to ethanol later in adulthood. Adult and adolescent C57BL/6J (B6) and DBA/2J (D2) males and females were given access to a 20% ethanol solution for 3 hourly periods, each separated by 2h of free water access. B6 adults and adolescents consumed 2 to 3.5 g/kg ethanol an hour and displayed significant intoxication and binge-like blood ethanol concentrations. There was an interaction of sex and age, however, driven by high intakes in adult B6 females, who peaked at 11.01 g/kg. Adolescents of both sexes and adult males never consumed more than 9.3 g/kg. D2 mice consumed negligible amounts of alcohol and showed no evidence of intoxication. B6 mice were abstinent for one month and were retested on the balance beam 10 min following 1.75 g/kg ethanol challenge (20%v/v; i.p). They were also tested for changes in home cage locomotion immediately following the 1.75 g/kg dose (for 10 min prior to balance beam). Although there was no effect of age of exposure, all mice with a binge drinking history demonstrated a significantly dampened ataxic response to an ethanol challenge. Female mice that binge drank during adulthood showed a significantly augmented locomotor response to ethanol when compared to their water drinking controls. This alteration was not noted for males or for females that binge drank during adolescence. These results highlight the importance of biological sex, and its interaction with age, in the development of behavioral adaptation following binge drinking.
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Affiliation(s)
- Laverne C Melón
- Psychobiology of Addictions, Department of Psychology, Indiana University/Purdue University-Indianapolis, Indianapolis, IN 46202, USA.
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Carrara-Nascimento PF, Lopez MF, Becker HC, Olive MF, Camarini R. Similar ethanol drinking in adolescent and adult C57BL/6J mice after chronic ethanol exposure and withdrawal. Alcohol Clin Exp Res 2013; 37:961-8. [PMID: 23298188 DOI: 10.1111/acer.12056] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/11/2012] [Indexed: 01/04/2023]
Abstract
BACKGROUND Increasing evidence shows that excessive alcohol consumption during adolescence increases vulnerability to alcohol use disorders in adulthood. The aim of this study was to examine differences between adolescent and adult C57BL/6J mice in drinking behavior and blood ethanol (EtOH) concentrations (BECs) after chronic EtOH exposure and withdrawal. METHODS Male adolescent (PND = 28 to 30) and adult (PND = 70) C57BL/6J mice were allowed to consume EtOH in a 2-bottle choice paradigm (15% EtOH vs. water) for 3 weeks (Baseline drinking, Test 1, and Test 2), which were interspersed with 2 cycles (Cycles I and II) of chronic EtOH vapor or air inhalation (16 hours) and withdrawal (8 hours). BECs were determined during both cycles. RESULTS Chronic EtOH exposure led to increased EtOH intake during Test 1 and Test 2 in both adolescent and adult mice compared with air-exposed controls, and no differences between age groups were observed. During Cycle I adult mice showed higher BECs compared with adolescents. During Cycle II, BECs were lower in adult mice as compared to Cycle I, and BECs in adolescent mice did not change between the 2 cycles. CONCLUSIONS Chronic EtOH exposure followed by withdrawal periods increases EtOH consumption similarly in both adolescent and adult mice, despite differences in BECs.
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Huang C, Titus JA, Bell RL, Kapros T, Chen J, Huang R. A mouse model for adolescent alcohol abuse: stunted growth and effects in brain. Alcohol Clin Exp Res 2012; 36:1728-37. [PMID: 22433022 PMCID: PMC7723750 DOI: 10.1111/j.1530-0277.2012.01759.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2011] [Accepted: 01/14/2012] [Indexed: 12/26/2022]
Abstract
BACKGROUND Adolescent alcohol abuse remains a serious public health concern, with nearly a third of high school seniors reporting heavy drinking in the previous month. METHODS Using the high ethanol-consuming C57BL/6J mouse strain, we examined the effects of ethanol (3.75 g/kg, IP, daily for 45 days) on body weight and brain region mass (cerebral cortex, cerebellum, corpus callosum) during peri-adolescence (postnatal day [P]25 to 70) or adulthood (P180 to 225) of both males and females. RESULTS In control peri-adolescent animals, body weight gain was greater in males compared with females. In the peri-adolescent exposure group, ethanol significantly reduced body weight gain to a similar extent in both male and female mice (82 and 84% of controls, respectively). In adult animals, body weight gain was much less than that of the peri-adolescent mice, with ethanol having a small but significant effect in males but not females. Between the control peri-adolescent and adult cohorts (measurements taken at P70 and 225, respectively), there were no significant differences in the mass of the cerebral cortex or the cerebellum from either male or female mice, although the rostro-caudal length of the corpus callosum increased slightly but significantly (6.1%) between these time points. CONCLUSIONS Ethanol treatment significantly reduced the mass of the cerebral cortex in peri-adolescent (-3.1%), but not adult, treated mice. By contrast, ethanol significantly reduced the length of the corpus callosum in adult (-5.4%), but not peri-adolescent, treated mice. Future studies at the histological level may yield additional details concerning ethanol and the peri-adolescent brain.
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Affiliation(s)
- Chiming Huang
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO 64110, USA.
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Fritz BM, Grahame NJ, Boehm SL. Selection for high alcohol preference drinking in mice results in heightened sensitivity and rapid development of acute functional tolerance to alcohol's ataxic effects. GENES BRAIN AND BEHAVIOR 2012; 12:78-86. [PMID: 22853703 DOI: 10.1111/j.1601-183x.2012.00830.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 06/01/2012] [Accepted: 07/27/2012] [Indexed: 12/01/2022]
Abstract
Propensity to develop acute functional (or within session) tolerance to alcohol (ethanol) may influence the amount of alcohol consumed, with higher drinking associated with greater acute functional tolerance (AFT). The goal of this study was to assess this potential correlated response between alcohol preference and AFT in second and third replicate lines of mice selectively bred for high (HAP2 and HAP3) and low (LAP2 and LAP3) alcohol preference drinking. Male and female mice were tested for development of AFT on a static dowel task, which requires that animals maintain balance on a wooden dowel in order to prevent falling. On test day, each mouse received one (1.75 g/kg; Experiment 1) or two (1.75 and 2.0 g/kg; Experiment 2) injections of ethanol; an initial administration before being placed on the dowel and in Experiment 2, an additional administration after the first regain of balance on the dowel. Blood samples were taken immediately after loss of balance [when blood ethanol concentrations (BECs) were rising] and at recovery (during falling BECs) in Experiment 1, and after first and second recovery in Experiment 2. It was found that HAP mice fell from the dowel significantly earlier and at lower BECs than LAP mice following the initial injection of ethanol and were therefore more sensitive to its early effects. Furthermore, Experiment 1 detected significantly greater AFT development (BECfalling--BECrising) in HAP mice when compared with LAP mice, which occurred within ~30 min, supporting our hypothesis. However, AFT was not different between lines in Experiment 2, indicating that ~30-60 min following alcohol administration, AFT development was similar in both lines. These data show that high alcohol drinking genetically associates with both high initial sensitivity and very early tolerance to the ataxic effects of ethanol.
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Affiliation(s)
- B M Fritz
- Indiana Alcohol Research Center and Department of Psychology, Indiana University - Purdue University Indianapolis, Indianapolis, IN 46202, USA
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The α6 nicotinic acetylcholine receptor subunit influences ethanol-induced sedation. Alcohol 2012; 46:463-71. [PMID: 22572056 DOI: 10.1016/j.alcohol.2012.03.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2011] [Revised: 03/20/2012] [Accepted: 03/22/2012] [Indexed: 02/06/2023]
Abstract
Alcohol and nicotine are often co-used and data from human and animals studies have demonstrated that common genes underlie responses to these two drugs. Recently, the genes that code for the subunits of the nicotinic acetylcholine receptors have been implicated as a common genetic mediator for alcohol and nicotine responses. The mammalian genes that code for the α6 and β3 subunits of the nicotinic acetylcholine receptor (Chrna6 and Chrnb3, respectively) are located adjacent to each other on human and mouse chromosome 8. These subunits have gained attention as potential regulators of drug behaviors because of their expression in the striatum where they have been shown to modulate dopamine release. Human genetic studies have shown that variation in these genes is associated with alcohol phenotypes. In the current experiments, mice lacking the Chrna6 or Chrnb3 gene were tested for three ethanol behaviors: choice ethanol consumption, ataxia, and sedation. Wildtype (WT), heterozygous (HET), and knockout (KO) mice of each strain went through a standard 2-bottle choice drinking paradigm, the balance beam, and the Loss of Righting Reflex (LORR) paradigm. No genotypic effects on any of the 3 behavioral tasks were observed in Chrnb3 animals. While the Chrna6 gene did not significantly influence ethanol consumption (g/kg) or ataxia, mice lacking the α6 subunit took significantly longer to recover their righting reflex than WT animals. These data provide evidence that receptors containing this subunit modulate the sedative effects of ethanol. Further work examining other models of ethanol consumption and behavioral responses to ethanol is needed to fully characterize the role of these receptor subunits in modulating ethanol responses.
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Tarragon E, Baliño P, Aragon CMG. Dantrolene blockade of ryanodine receptor impairs ethanol-induced behavioral stimulation, ethanol intake and loss of righting reflex. Behav Brain Res 2012; 233:554-62. [PMID: 22677274 DOI: 10.1016/j.bbr.2012.05.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/22/2012] [Accepted: 05/26/2012] [Indexed: 12/21/2022]
Abstract
Calcium has been characterized as one of the most ubiquitous, universal and versatile intracellular signals. Among other substances with the ability to alter intracellular calcium levels, ethanol has been described as particularly relevant because of its social and economic impact. Ethanol effects on calcium distribution and flux in vitro have been widely studied, showing that acute ethanol administration can modulate intracellular calcium concentrations in a dose dependent manner. Intracellular calcium released from the endoplasmic reticulum plays a determinant role in several cellular processes. In this study, we aim to assess the effect of dantrolene, a ryanodine receptor antagonist, on three different ethanol-elicited behaviors: locomotor activity, loss of righting reflex and ethanol intake. Mice were challenged with an injection of dantrolene (0-5 mg/kg, i.p.) 30 min before ethanol (0-4 g/kg, i.p.) administration. Animals were immediately placed in an open field cylinder to monitor distance travelled horizontally or in a V-shaped trough to measure righting reflex recovery time. For ethanol intake, dantrolene (0-5mg/kg, i.p.) was administered 30 min before ethanol (20%, v/v) exposure, following a drinking in the dark paradigm. Our results showed that dantrolene selectively reduces ethanol-induced stimulation, loss of righting reflex, and ethanol intake in a dose dependent manner. Together, these data suggest that intracellular calcium released from the endoplasmic reticulum may play a critical role in behavioral effects caused by ethanol, and point to a calcium-dependent pathway as a possible cellular mechanism of action for ethanol.
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Affiliation(s)
- Ernesto Tarragon
- Area de Psicobiologia, Universitat Jaume I, 12071 Castellón, Spain
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Masso-Welch PA, Tobias ME, Vasantha Kumar SC, Bodziak M, Mashtare T, Tamburlin J, Koury ST. Folate exacerbates the effects of ethanol on peripubertal mouse mammary gland development. Alcohol 2012; 46:285-92. [PMID: 22440688 DOI: 10.1016/j.alcohol.2011.12.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 08/31/2011] [Accepted: 12/14/2011] [Indexed: 12/24/2022]
Abstract
Alcohol consumption is linked with increased breast cancer risk in women, even at low levels of ingestion. The proposed mechanisms whereby ethanol exerts its effects include decreased folate levels resulting in diminished DNA synthesis and repair, and/or acetaldehyde-generated DNA damage. Based on these proposed mechanisms, we hypothesized that ethanol would have increased deleterious effects during periods of rapid mammary gland epithelial proliferation, such as peripuberty, and that folate deficiency alone might mimic and/or exacerbate the effects of ethanol. To test this hypothesis, weight-matched 28-35 day old CD2F1 female mice were pair-fed liquid diets ±3.2% ethanol, ±0.1% folate for 4 weeks. Folate status was confirmed by assay of liver and kidney tissues. In folate deficient mice, no significant ethanol-induced changes to the mammary gland were observed. Folate replete mice fed ethanol had an increased number of ducts per section, due to an increased number of terminal short branches. Serum estrogen levels were increased by ethanol, but only in folate replete mice. These results demonstrate that folate deficiency alone does not mimic the effects of ethanol, and that folate deficiency in the presence of ethanol blocks proliferative effects of ethanol on the mammary ductal tree.
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Van Skike CE, Novier A, Diaz-Granados JL, Matthews DB. The effect of chronic intermittent ethanol exposure on spatial memory in adolescent rats: the dissociation of metabolic and cognitive tolerances. Brain Res 2012; 1453:34-9. [PMID: 22464184 DOI: 10.1016/j.brainres.2012.03.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 03/01/2012] [Accepted: 03/04/2012] [Indexed: 12/25/2022]
Abstract
Using a rapid chronic intermittent ethanol (CIE) vapor exposure paradigm, we demonstrate the dissociability of metabolic tolerance from cognitive tolerance in adolescent rats. Adolescent rats were trained to spatially navigate in the Morris Water Maze and then exposed to CIE vapor or air 16 h a day for 4 days. After a final 28 h withdrawal, all rats received a saline or ethanol challenge, followed by a test of spatial memory 30 min after administration. Results indicate that CIE vapor exposure did not significantly impair adolescent spatial memory. Although CIE-exposed rats developed metabolic tolerance to a subsequent ethanol administration, CIE exposure did not alter dose-dependent ethanol-induced spatial memory impairments. These data indicate that metabolic ethanol tolerance can be distinguished from cognitive ethanol tolerance during adolescence and suggest that blood alcohol levels alone do not fully explain ethanol-induced spatial memory impairments.
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Affiliation(s)
- Candice E Van Skike
- Department of Psychology and Neuroscience, Baylor University, Baylor Addiction Research Center, Waco, TX 76798, USA.
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Mukhopadhyay P, Brock G, Webb C, Pisano MM, Greene RM. Strain-specific modifier genes governing craniofacial phenotypes. ACTA ACUST UNITED AC 2012; 94:162-75. [PMID: 22371338 DOI: 10.1002/bdra.22890] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 01/06/2023]
Abstract
BACKGROUND The presence of strain-specific modifier genes is known to modulate the phenotype and pathophysiology of mice harboring genetically engineered mutations. Thus, identification of genetic modifier genes is requisite to understanding control of phenotypic expression. c-Ski is a transcriptional regulator. Ski(-/-) mice on a C57BL6J (B6) background exhibit facial clefting, while Ski(-/-) mice on a 129P3 (129) background present with exencephaly. METHODS In the present study, oligonucleotide-based gene expression profiling was used to identify potential strain-specific modifier gene candidates present in wild type mice of B6 and 129 genetic backgrounds. Changes in gene expression were verified by TaqMan quantitative real-time PCR. RESULTS Steady-state levels of 89 genes demonstrated a significantly higher level of expression, and those of 68 genes demonstrated a significantly lower level of expression in the developing neural tubes from embryonic day (E) 8.5, B6 embryos when compared to expression levels in neural tubes derived from E 8.5, 129 embryos. CONCLUSIONS Based on the results from the current comparative microarray study, and taking into consideration a number of relevant published reports, several potential strain-specific gene candidates, likely to modify the craniofacial phenotypes in various knockout mouse models have been identified.
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Affiliation(s)
- Partha Mukhopadhyay
- University of Louisville Birth Defects Center, Department of Molecular, Cellular and Craniofacial Biology, ULSD, University of Louisville, Louisville, Kentucky 40292, USA
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Spanos M, Besheer J, Hodge CW. Increased sensitivity to alcohol induced changes in ERK Map kinase phosphorylation and memory disruption in adolescent as compared to adult C57BL/6J mice. Behav Brain Res 2012; 230:158-66. [PMID: 22348893 DOI: 10.1016/j.bbr.2012.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Revised: 01/31/2012] [Accepted: 02/06/2012] [Indexed: 12/18/2022]
Abstract
Adolescence is a critical period of brain development that is accompanied by increased probability of risky behavior, such as alcohol use. Emerging research indicates that adolescents are differentially sensitive to the behavioral effects of acute ethanol as compared to adults but the neurobiological mechanisms of this effect remain to be fully elucidated. This study was designed to evaluate effects of acute ethanol on extracellular signal-regulated kinase phosphorylation (p-ERK1/2) in mesocorticolimbic brain regions. We also sought to determine if age-specific effects of ethanol on p-ERK1/2 are associated with ethanol-induced behavioral deficits on acquisition of the hippocampal-dependent novel object recognition (NOR) test. Adolescent and adult C57BL/6J mice were administered acute ethanol (0 0.5, 1, or 3g/kg, i.p.). Brains were removed 30-min post injection and processed for analysis of p-ERK1/2 immunoreactivity (IR). Additional groups of mice were administered ethanol (0 or 1g/kg) prior to the NOR test. Analysis of p-ERK1/2 IR showed that untreated adolescent mice had significantly higher levels of p-ERK1/2 IR in the nucleus accumbens shell, basolateral amygdala (BLA), central amygdala (CeA), and medial prefrontal cortex (mPFC) as compared to adults. Ethanol (1g/kg) selectively reduced p-ERK1/2 IR in the dentate gyrus and increased p-ERK1/2 IR in the BLA only in adolescent mice. Ethanol (3g/kg) produced the same effects on p-ERK1/2 IR in both age groups with increases in CeA and mPFC, but a decrease in the dentate gyrus, as compared to age-matched saline controls. Pretreatment with ethanol (1g/kg) disrupted performance on the NOR test specifically in adolescents, which corresponds with the ethanol-induced inhibition of p-ERK1/2 IR in the hippocampus. These data show that adolescent mice have differential expression of basal p-ERK1/2 IR in mesocorticolimbic brain regions. Acute ethanol produces a unique set of changes in ERK1/2 phosphorylation in the adolescent brain that are associated with disruption of hippocampal-dependent memory acquisition.
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Affiliation(s)
- Marina Spanos
- Neurobiology Curriculum, School of Medicine, University of North Carolina at Chapel Hill, Thurston-Bowles Building, CB #7178, Chapel Hill, NC 27599, United States
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Bhandari P, Hill JS, Farris SP, Costin B, Martin I, Chan CL, Alaimo JT, Bettinger JC, Davies AG, Miles MF, Grotewiel M. Chloride intracellular channels modulate acute ethanol behaviors in Drosophila, Caenorhabditis elegans and mice. GENES BRAIN AND BEHAVIOR 2012; 11:387-97. [PMID: 22239914 DOI: 10.1111/j.1601-183x.2012.00765.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Identifying genes that influence behavioral responses to alcohol is critical for understanding the molecular basis of alcoholism and ultimately developing therapeutic interventions for the disease. Using an integrated approach that combined the power of the Drosophila, Caenorhabditis elegans and mouse model systems with bioinformatics analyses, we established a novel, conserved role for chloride intracellular channels (CLICs) in alcohol-related behavior. CLIC proteins might have several biochemical functions including intracellular chloride channel activity, modulation of transforming growth factor (TGF)-β signaling, and regulation of ryanodine receptors and A-kinase anchoring proteins. We initially identified vertebrate Clic4 as a candidate ethanol-responsive gene via bioinformatic analysis of data from published microarray studies of mouse and human ethanol-related genes. We confirmed that Clic4 expression was increased by ethanol treatment in mouse prefrontal cortex and also uncovered a correlation between basal expression of Clic4 in prefrontal cortex and the locomotor activating and sedating properties of ethanol across the BXD mouse genetic reference panel. Furthermore, we found that disruption of the sole Clic Drosophila orthologue significantly blunted sensitivity to alcohol in flies, that mutations in two C. elegans Clic orthologues, exc-4 and exl-1, altered behavioral responses to acute ethanol in worms and that viral-mediated overexpression of Clic4 in mouse brain decreased the sedating properties of ethanol. Together, our studies demonstrate key roles for Clic genes in behavioral responses to acute alcohol in Drosophila, C. elegans and mice.
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Affiliation(s)
- P Bhandari
- Department of Human and Molecular Genetics, Department of Pharmacology and Toxicology, Virginia Commonwealth University Alcohol Research Center, Richmond, VA, USA
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Intracellular calcium chelation with BAPTA-AM modulates ethanol-induced behavioral effects in mice. Exp Neurol 2012; 234:446-53. [PMID: 22306018 DOI: 10.1016/j.expneurol.2012.01.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 01/11/2012] [Accepted: 01/16/2012] [Indexed: 11/23/2022]
Abstract
Calcium (Ca(2+)) has been characterized as one of the most ubiquitous, universal and versatile intracellular signaling molecules responsible for controlling numerous cellular processes. Ethanol-induced effects on Ca(2+) distribution and flux have been widely studied in vitro, showing that acute ethanol administration can modulate intracellular Ca(2+) concentrations in a dose dependent manner. In vivo, the relationship between Ca(2+) manipulation and the corresponding ethanol-induced behavioral effects have focused on Ca(2+) flux through voltage-gated Ca(2+) channels. The present study investigated the role of inward Ca(2+) currents in ethanol-induced psychomotor effects (stimulation and sedation) and ethanol intake. We studied the effects of the fast Ca(2+) chelator, BAPTA-AM, on ethanol-induced locomotor activity and the sedative effects of ethanol. Swiss (RjOrl) mice were pretreated with BAPTA-AM (0-10 mg/kg) 30 min before an ethanol (0-4 g/kg) challenge. Our results revealed that pretreatment with BAPTA-AM prevented locomotor stimulation produced by ethanol without altering basal locomotion. In contrast, BAPTA-AM reversed ethanol-induced hypnotic effects. In a second set of experiments, we investigated the effects of intracellular Ca(2+) chelation on ethanol intake. Following a drinking-in-the-dark methodology, male C57BL/6J mice were offered 20% v/v ethanol, tap water, or 0.1% sweetened water. The results of these experiments revealed that BAPTA-AM pretreatment (0-5 mg/kg) reduced ethanol consumption in a dose-dependent manner while leaving water and sweetened water intake unaffected. Our findings support the role of inward Ca(2+) currents in mediating different behavioral responses induced by ethanol. Our results are discussed together with data indicating that ethanol appears to be more sensitive to intracellular Ca(2+) manipulations than other psychoactive drugs.
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Silveri MM. Adolescent brain development and underage drinking in the United States: identifying risks of alcohol use in college populations. Harv Rev Psychiatry 2012; 20:189-200. [PMID: 22894728 PMCID: PMC4669962 DOI: 10.3109/10673229.2012.714642] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Alcohol use typically is initiated during adolescence, a period that coincides with critical structural and functional maturation of the brain. Brain maturation and associated improvements in decision making continue into the third decade of life, reaching a plateau within the period referred to as emerging adulthood (18-24 years). This particular period covers that of traditionally aged college students, and includes the age (21 years) when alcohol consumption becomes legal in the United States. This review highlights neurobiological evidence indicating the vulnerabilities of the emerging-adult brain to the effects of alcohol. Factors increasing the risks associated with underage alcohol use include the age group's reduced sensitivity to alcohol sedation and increased sensitivity to alcohol-related disruptions in memory. On the individual level, factors increasing those risks are a positive family history of alcoholism, which has a demonstrated effect on brain structure and function, and emerging comorbid psychiatric conditions. These vulnerabilities-of the age group, in general, as well as of particular individuals-likely contribute to excessive and unsupervised drinking in college students. Discouraging alcohol consumption until neurobiological adulthood is reached is important for minimizing alcohol-related disruptions in brain development and decision-making capacity, and for reducing the negative behavioral consequences associated with underage alcohol use.
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Affiliation(s)
- Marisa M. Silveri
- Neurodevelopmental Laboratory on Addictions and Mental Health, Brain Imaging Center, McLean Hospital, Belmont, Massachusetts, USA Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, USA
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Quoilin C, Didone V, Tirelli E, Quertemont E. Chronic ethanol exposure during adolescence alters the behavioral responsiveness to ethanol in adult mice. Behav Brain Res 2011; 229:1-9. [PMID: 22227505 DOI: 10.1016/j.bbr.2011.12.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/22/2011] [Accepted: 12/25/2011] [Indexed: 11/26/2022]
Abstract
Alcohol exposure during early adolescence is believed to durably alter the behavioral properties of ethanol, increasing the likelihood of later alcohol-related disorders. The aim of the present experiments was to characterize changes in the behavioral effects of ethanol in adult female Swiss mice after a chronic ethanol exposure during adolescence, extending from postnatal day 28 to postnatal day 42. After a chronic ethanol exposure during adolescence (daily injections of 0, 2.5 or 4 g/kg ethanol for 14 consecutive days), adult mice were tested at postnatal day 63. The locomotor stimulant effects of ethanol, together with ethanol sensitization were tested in experiment 1. In experiment 2, the sedative effects of ethanol were assessed with the loss of righting reflex procedure. Finally, in experiment 3, the anxiolytic effects of ethanol were tested with the light/dark box test. Adult mice chronically exposed to ethanol during adolescence showed a lower basal locomotor activity, but higher locomotor stimulant effects of ethanol than non-exposed mice. Additionally, these adult mice developed higher rates of ethanol sensitization after chronic re-exposure to ethanol in adulthood. Adult mice exposed to ethanol during adolescence also had a stronger tolerance to the sedative effects of high ethanol doses, although they showed no evidence of changes in the anxiolytic effects of ethanol. These results are in agreement with the thesis that chronic alcohol consumption during adolescence, especially in high amounts, increases the risk of later alcohol-related disorders.
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Affiliation(s)
- Caroline Quoilin
- Département Psychologie, Cognition et Comportement, Université de Liège, Belgium
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