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Consequences of continuous social defeat stress on ethanol-induced corticosterone responses and brain monoamines
Abstracts / Alcohol 60 (2017) 203e243
assess the contribution of two key PAG subregions, the dorsal and ventral PAG, to emotional and behavioral changes stemming from alcohol dependence. To investigate this question, Gi-coupled designer receptors exclusively activated by designer drugs (Gi DREADDs) were expressed in ventral or dorsal PAG neurons under the control of a CamKIIɑ promotor in alcohol dependent and non-dependent Wistar rats. Approximately 45 min prior to testing to assess anxiety, alcohol self-administration, somatic withdrawal symptoms and compulsive alcohol drinking behavior, rats were injected subcutaneously with the synthetic ligand for Gi DREADDs, clonzapine-n-oxide (CNO; 1 mg/kg) or vehicle. Data shows that alcohol dependent rats were more anxious, self-administered greater amounts of alcohol, and displayed more signs of somatic withdrawal than nondependent rats, in agreement with past studies. Functional inhibition of the ventral PAG via Gi DREADD activation did not alter alcohol dependence-induced enhancements in alcohol self-administration or somatic withdrawal signs. However, preliminary evidence suggests that inhibition of the ventral PAG attenuated alcohol dependence-induced enhancements in anxiety. Experiments are underway to assess these behaviors following functional inhibition of the dorsal PAG. P171 WITHDRAWAL FROM CHRONIC INTERMITTENT ETHANOL ENGAGES A CIRCUIT IN THE BED NUCLEUS OF THE STRIA TERMINALIS THAT PROMOTES ANXIETY AND FEAR-RELATED BEHAVIOR Catherine A. Marcinkiewcz, Dipanwita Pati, Jeffrey F. Diberto, Thomas L. Kash. University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Alcohol dependence is a progressive brain disorder characterized by an increased sensitivity to the reinforcing properties of alcohol, compulsive and habitual use, and chronic relapse to alcohol drinking. Earlier studies from our lab have shown that acute withdrawal from chronic intermittent ethanol (CIE) vapor enhances anxiety-like behavior and serotonin2C (5HT2CR) signaling in the BNST. In a more recent study, we found that 5HT2CR signaling elicits anxiety and fear-related behavior by activating an inhibitory microcircuit in the BNST. The goal of the present study was to elucidate the role of inhibitory BNST microcircuits in anxiety and fearrelated behavior during alcohol withdrawal using an integrated circuitlevel approach, using genetic ‘reporter’ mice to isolate specific cells and choleratoxin labeling for retrograde tracing. We found non-projecting CRF neurons in the BNST were more excitable after withdrawal from CIE, while the frequency of sIPSCs was significantly heightened in non-CRF projection neurons. These data suggest that CIE may inhibit anxiolytic outputs of the BNST by increasing GABA release from local CRF neurons. We then used a chemogenetic approach to probe the role of CRF BNST neurons in anxiety and fear during CIE withdrawal. Our preliminary data suggests that chemogenetic silencing of CRF neurons in the BNST attenuates CIE-enhanced anxiety in the marble burying test and also reduces CIE-potentiated cued fear recall. Future studies will investigate the contribution of BNST projections to the VTA and LH to these alcohol-induced aversive behaviors. These experiments may dissociate differential roles of anxiety versus fearrelated behaviors during withdrawal from chronic alcohol. P172 CONSEQUENCES OF CONTINUOUS SOCIAL DEFEAT STRESS ON ETHANOL-INDUCED CORTICOSTERONE RESPONSES AND BRAIN MONOAMINES Isabel M. Hartmann-Quadros, Cristiane A. Favoretto, Yasmin C. Nunes, Giovana C. Macedo. Universidade Federal de S~ ao Paulo, UNIFESP, S~ ao Paulo, Brazil Introduction: Chronic exposure to stress may dysregulate the hypothalamic-pituitary-adrenal axis and brain monoamines, contributing to the
243
development of stress-related disorders, including drug and alcohol dependence. The present study assessed ethanol-induced corticosterone responses and brain monoamine levels in mice previously submitted to continuous social defeat stress. Methodology: Male Swiss mice were exposed to a 10-day continuous social defeat protocol, with daily confrontations with an aggressive male resident. Ten days after the final defeat, mice were tested for locomotor response to an ethanol injection (2.2g/kg; i.p.) or saline. Thirty minutes after the locomotor test, blood was collected for determination of plasmatic corticosterone, and brains were dissected for determination of tissue monoamines. Results: Socially stressed mice failed to show a stimulating locomotor response to ethanol, while controls displayed ethanol-induced stimulation (p<0.05). Ethanol administration induced increases in plasma corticosterone (p<0.05), but to a lesser extent in defeated mice (p<0.05). Monoamine levels were affected by defeat stress exposure, and also by ethanol, in different brain regions. In the hypothalamus, social stress promoted reduced levels of dopamine, noradrenaline and serotonin (p<0.05). In the frontal cortex, defeated mice presented reduced serotonin and dopamine levels (p<0.05). In the striatum, ethanol treatment increased dopamine levels in control mice (p<0.05), but failed to do so in defeated mice. Conclusion: Our results suggest that chronic exposure to continuous defeat stress blunted ethanolinduced locomotor stimulation, and also reduced ethanol-induced corticosterone secretion. Social stress promoted differential reductions in brain monoamine contents in the hypothalamus, frontal cortex and striatum. P173 YOUNG ALCOHOL BINGE DRINKERS SHOW IMMUNE/INFLAMMATORY ALTERATIONS WITH HIGHER SUSCEPTIBILITY IN WOMEN: CORRELATIONS WITH NEUROPSYCHOLOGICAL ABILITIES n, Inmaculada Concepcio n Rodríguez-Rojo, Angeles Laura Orío, María Anto Correas, Borja García-Bueno, Monserrat Corral, Fernando Rodríguez de Fonseca, Luis Miguel García-Moreno, Fernando Maestú, Fernando Cadaveira. Universidad Complutense, Madrid, Spain; Instituto de Salud Carlos III, Spain; Centre of Biomedical Technology, Madrid, Spain; Centro n Biome dica en Red de Salud Mental, Madrid, Spain; de Investigacio n Biome dica, Ma laga, Spain; University of Instituto de Investigacio Santiago de Compostela, Galicia, Spain Alcohol binge drinking is a pattern of heavy alcohol consumption increasingly used by adolescents and young adults. Evidence indicates that alcohol binge induces peripheral inflammation and an exacerbated neuroimmune response that may participate in the alcohol-induced cognitive/ behavioral dysfunctions. Here, we recruited 20 years old university students, identified as men and women binge drinkers for at least 2 years. Young alcohol binge drinkers had elevated levels of blood endotoxin compared with controls and an up-regulation of TLR4/NFkB inflammatory pathway in peripheral blood mononuclear cells, together with pro-inflammatory cytokine/chemokine release, oxidative stress and lipid peroxidation. These changes positively correlate with the estimated blood alcohol levels achieved during alcohol binge intoxication and negatively with the time elapsed from the last alcohol consumption. The immune/ inflammatory changes were more prominent in women drinkers, who showed elevations in alcohol danger-associated molecules, such as HMGB1, indicating that there are sex-differences in the peripheral inflammatory response to alcohol. By contrary, cortisol levels were decreased in alcohol binge drinkers. Finally, higher levels of inflammatory markers -mainly MCP-1, but also LPS, HMGB1, TLR4, IL-6, and COX-2correlated with worse episodic memory and executive functioning in women binge drinkers but not in men. These results emphasize possible risky consequences of alcohol use in binge episodes during the young period, and call attention to sex differences in the alcohol-induced immune/inflammatory and neurocognitive responses.
assess the contribution of two key PAG subregions, the dorsal and ventral PAG, to emotional and behavioral changes stemming from alcohol dependence. To investigate this question, Gi-coupled designer receptors exclusively activated by designer drugs (Gi DREADDs) were expressed in ventral or dorsal PAG neurons under the control of a CamKIIɑ promotor in alcohol dependent and non-dependent Wistar rats. Approximately 45 min prior to testing to assess anxiety, alcohol self-administration, somatic withdrawal symptoms and compulsive alcohol drinking behavior, rats were injected subcutaneously with the synthetic ligand for Gi DREADDs, clonzapine-n-oxide (CNO; 1 mg/kg) or vehicle. Data shows that alcohol dependent rats were more anxious, self-administered greater amounts of alcohol, and displayed more signs of somatic withdrawal than nondependent rats, in agreement with past studies. Functional inhibition of the ventral PAG via Gi DREADD activation did not alter alcohol dependence-induced enhancements in alcohol self-administration or somatic withdrawal signs. However, preliminary evidence suggests that inhibition of the ventral PAG attenuated alcohol dependence-induced enhancements in anxiety. Experiments are underway to assess these behaviors following functional inhibition of the dorsal PAG. P171 WITHDRAWAL FROM CHRONIC INTERMITTENT ETHANOL ENGAGES A CIRCUIT IN THE BED NUCLEUS OF THE STRIA TERMINALIS THAT PROMOTES ANXIETY AND FEAR-RELATED BEHAVIOR Catherine A. Marcinkiewcz, Dipanwita Pati, Jeffrey F. Diberto, Thomas L. Kash. University of North Carolina at Chapel Hill, Chapel Hill, NC, USA Alcohol dependence is a progressive brain disorder characterized by an increased sensitivity to the reinforcing properties of alcohol, compulsive and habitual use, and chronic relapse to alcohol drinking. Earlier studies from our lab have shown that acute withdrawal from chronic intermittent ethanol (CIE) vapor enhances anxiety-like behavior and serotonin2C (5HT2CR) signaling in the BNST. In a more recent study, we found that 5HT2CR signaling elicits anxiety and fear-related behavior by activating an inhibitory microcircuit in the BNST. The goal of the present study was to elucidate the role of inhibitory BNST microcircuits in anxiety and fearrelated behavior during alcohol withdrawal using an integrated circuitlevel approach, using genetic ‘reporter’ mice to isolate specific cells and choleratoxin labeling for retrograde tracing. We found non-projecting CRF neurons in the BNST were more excitable after withdrawal from CIE, while the frequency of sIPSCs was significantly heightened in non-CRF projection neurons. These data suggest that CIE may inhibit anxiolytic outputs of the BNST by increasing GABA release from local CRF neurons. We then used a chemogenetic approach to probe the role of CRF BNST neurons in anxiety and fear during CIE withdrawal. Our preliminary data suggests that chemogenetic silencing of CRF neurons in the BNST attenuates CIE-enhanced anxiety in the marble burying test and also reduces CIE-potentiated cued fear recall. Future studies will investigate the contribution of BNST projections to the VTA and LH to these alcohol-induced aversive behaviors. These experiments may dissociate differential roles of anxiety versus fearrelated behaviors during withdrawal from chronic alcohol. P172 CONSEQUENCES OF CONTINUOUS SOCIAL DEFEAT STRESS ON ETHANOL-INDUCED CORTICOSTERONE RESPONSES AND BRAIN MONOAMINES Isabel M. Hartmann-Quadros, Cristiane A. Favoretto, Yasmin C. Nunes, Giovana C. Macedo. Universidade Federal de S~ ao Paulo, UNIFESP, S~ ao Paulo, Brazil Introduction: Chronic exposure to stress may dysregulate the hypothalamic-pituitary-adrenal axis and brain monoamines, contributing to the
243
development of stress-related disorders, including drug and alcohol dependence. The present study assessed ethanol-induced corticosterone responses and brain monoamine levels in mice previously submitted to continuous social defeat stress. Methodology: Male Swiss mice were exposed to a 10-day continuous social defeat protocol, with daily confrontations with an aggressive male resident. Ten days after the final defeat, mice were tested for locomotor response to an ethanol injection (2.2g/kg; i.p.) or saline. Thirty minutes after the locomotor test, blood was collected for determination of plasmatic corticosterone, and brains were dissected for determination of tissue monoamines. Results: Socially stressed mice failed to show a stimulating locomotor response to ethanol, while controls displayed ethanol-induced stimulation (p<0.05). Ethanol administration induced increases in plasma corticosterone (p<0.05), but to a lesser extent in defeated mice (p<0.05). Monoamine levels were affected by defeat stress exposure, and also by ethanol, in different brain regions. In the hypothalamus, social stress promoted reduced levels of dopamine, noradrenaline and serotonin (p<0.05). In the frontal cortex, defeated mice presented reduced serotonin and dopamine levels (p<0.05). In the striatum, ethanol treatment increased dopamine levels in control mice (p<0.05), but failed to do so in defeated mice. Conclusion: Our results suggest that chronic exposure to continuous defeat stress blunted ethanolinduced locomotor stimulation, and also reduced ethanol-induced corticosterone secretion. Social stress promoted differential reductions in brain monoamine contents in the hypothalamus, frontal cortex and striatum. P173 YOUNG ALCOHOL BINGE DRINKERS SHOW IMMUNE/INFLAMMATORY ALTERATIONS WITH HIGHER SUSCEPTIBILITY IN WOMEN: CORRELATIONS WITH NEUROPSYCHOLOGICAL ABILITIES n, Inmaculada Concepcio n Rodríguez-Rojo, Angeles Laura Orío, María Anto Correas, Borja García-Bueno, Monserrat Corral, Fernando Rodríguez de Fonseca, Luis Miguel García-Moreno, Fernando Maestú, Fernando Cadaveira. Universidad Complutense, Madrid, Spain; Instituto de Salud Carlos III, Spain; Centre of Biomedical Technology, Madrid, Spain; Centro n Biome dica en Red de Salud Mental, Madrid, Spain; de Investigacio n Biome dica, Ma laga, Spain; University of Instituto de Investigacio Santiago de Compostela, Galicia, Spain Alcohol binge drinking is a pattern of heavy alcohol consumption increasingly used by adolescents and young adults. Evidence indicates that alcohol binge induces peripheral inflammation and an exacerbated neuroimmune response that may participate in the alcohol-induced cognitive/ behavioral dysfunctions. Here, we recruited 20 years old university students, identified as men and women binge drinkers for at least 2 years. Young alcohol binge drinkers had elevated levels of blood endotoxin compared with controls and an up-regulation of TLR4/NFkB inflammatory pathway in peripheral blood mononuclear cells, together with pro-inflammatory cytokine/chemokine release, oxidative stress and lipid peroxidation. These changes positively correlate with the estimated blood alcohol levels achieved during alcohol binge intoxication and negatively with the time elapsed from the last alcohol consumption. The immune/ inflammatory changes were more prominent in women drinkers, who showed elevations in alcohol danger-associated molecules, such as HMGB1, indicating that there are sex-differences in the peripheral inflammatory response to alcohol. By contrary, cortisol levels were decreased in alcohol binge drinkers. Finally, higher levels of inflammatory markers -mainly MCP-1, but also LPS, HMGB1, TLR4, IL-6, and COX-2correlated with worse episodic memory and executive functioning in women binge drinkers but not in men. These results emphasize possible risky consequences of alcohol use in binge episodes during the young period, and call attention to sex differences in the alcohol-induced immune/inflammatory and neurocognitive responses.