Chronic Daily Ethanol and Withdrawal: 1. Long-Term Changes in the Hypothalamo-Pituitary-Adrenal Axis

Alcohol-induced hormonal and metabolic alterations in plasma and erythrocytes-a gender-based study

PURPOSE

This study aimed to understand the gender-specific alcohol-induced biochemical changes and TBARS association with the endocrine system.

METHODS

Human male and female subjects ranging from 35 ± 10 years old with an 8-10-year drinking history were included in the study.

RESULTS

The results demonstrated that testosterone levels were lower in male alcoholics and higher in female alcoholics, as well as higher estrogen and cortisol levels in both genders. In addition, we found lower T3, T4, and thyroid-stimulating hormone (TSH) levels in alcoholics of both sexes. Furthermore, plasma TBARS, protein carbonyls, nitrite, and nitrate levels increased significantly with concomitant decrease in reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in both male and female alcoholics. Furthermore, erythrocyte lysate nitrite and nitrate levels membrane total cholesterol, phospholipid and cholesterol/phospholipid (C/P) ratio with lower total membrane proteins in both genders of alcoholics. SDS-PAGE analysis of erythrocyte membrane proteins revealed increased density of band 3, protein 4.1, 4.2, 4.9 and glycophorins, whereas decreases in spectrin (α and β) were observed in both genders of alcoholics. Besides, alcoholics of both sexes had a lower ability to resist osmotic hemolysis. Plasma TBARS was negatively correlated with testosterone, TSH, T3 and T4 in male alcoholics, moreover, estradiol and cortisol were positively correlated in males and females respectively.

CONCLUSION

Female alcoholics may be more susceptible to osmotic hemolysis due to increased erythrocyte membrane lipid peroxidation with decreased antioxidant status, which results in an altered membrane C/P ratio and membrane protein composition.

The oxytocin receptor rs2254298 polymorphism and alcohol withdrawal symptoms: a gene-environment interaction in mood disorders

Objective

Alcohol use disorder (AUD) is a common mental disorder characterized by repeated withdrawal episodes. Negative emotions during withdrawal are the primary factors affecting successful abstinence. Oxytocin is a critical modulator of emotions. OXTR, the oxytocin receptor, may also be a promising candidate for treating alcohol withdrawal symptoms. Previous studies indicated that people with different genotypes of OXTR rs2254298 were reported to suffer from more significant depressive or heightened anxiety symptoms when experiencing early adversity. The present study aims to explore the modulatory role of the polymorphism OXTR rs2254298 on mood disorders during alcohol withdrawal and to help researchers better understand and develop effective relapse prevention and interventions for alcohol use disorders.

Methods

We recruited 265 adult Chinese Han men with AUD. Anxiety and depressive symptoms were measured using the Self-Rating Anxiety Scale and Self-Rating Depression Scale. Alcohol dependence levels were measured using Michigan Alcoholism Screening Test. Genomic DNA extraction and genotyping from participants' peripheral blood samples.

Result

First, a multiple linear regression was used to set the alcohol dependence level, OXTR.rs2254298, interaction terms as the primary predictor variable, and depression or anxiety as an outcome; age and educational years were covariates. There was a significant interaction between OXTR rs2254298 and alcohol dependence level on anxiety (B = 0.23, 95% confidence interval [CI]: 0.01-0.45) but not on depression (B = -0.06, 95% CI: -0.30 - 0.18). The significance region test showed that alcohol-dependent men who are GG homozygous were more likely to experience anxiety symptoms than subjects with the A allele (A allele: β = 0.27, p < 0.001; GG homozygote: β = 0.50, p < 0.001). Finally, re-parameterized regression analysis demonstrated that this gene-environment interaction of OXTR rs2254298 and alcohol dependence on anxiety fits the weak differential susceptibility model (R² = 0.17, F (5,259) = 13.46, p < 0.001).

Conclusion

This study reveals a gene-environment interactive effect between OXTR rs2254298 and alcohol withdrawal on anxiety but not depression. From the perspective of gene-environment interactions, this interaction fits the differential susceptibility model; OXTR rs2254298 GG homozygote carriers are susceptible to the environment and are likely to experience anxiety symptoms of alcohol withdrawal.

Impacts of maternal separation stress on ethanol-related responses, anxiety- and depressive-like behaviors in adolescent mice

The present work evaluated the consequences of chronic maternal separation (MS), an animal model of early-life stress, on ethanol intake and striatal Fos expression induced by ethanol consumption. Furthermore, we analyzed MS impacts on anxiety- and depressive-like behaviors and on locomotor and plasma corticosterone responses to intraperitoneal treatment with ethanol in adolescent mice. For that, male and female C57BL/6J mice were exposed or not to MS stress, for 3 h per day, from postnatal day (PND) 1 to 14, and submitted to behavioral tests from PND 28. In Experiment 1, MS and control groups of mice were submitted to an involuntary ethanol intake protocol, and striatal Fos expression following ethanol exposure was analyzed. In Experiment 2, mice behavior was assessed in elevated plus-maze, sucrose splash, saccharin preference, and open field tests. Locomotor and plasma corticosterone responses induced by a systemic dose of ethanol (1.75 g/kg) were also evaluated. Our results demonstrated that MS increased ethanol intake only in an acute manner and did not impact ethanol-induced Fos expression in the dorsal striatum and nucleus accumbens (NAc) core and shell subregions. MS did not change the parameters analyzed during elevated plus-maze, sucrose splash, preference for saccharin, and open field tests. MS did not affect locomotor activity following ethanol injection nor plasma corticosterone response to the drug. Thus, our data showed that MS transiently increased ethanol intake. However, early-life stress did not impact Fos, locomotor, or plasma corticosterone responses to the drug. In addition, MS did not affect anxiety- and depressive-like behaviors in adolescent mice.

Theoretical Frameworks and Mechanistic Aspects of Alcohol Addiction: Alcohol Addiction as a Reward Deficit/Stress Surfeit Disorder

Alcohol use disorder (AUD) can be defined by a compulsion to seek and take alcohol, the loss of control in limiting intake, and the emergence of a negative emotional state when access to alcohol is prevented. Alcohol use disorder impacts multiple motivational mechanisms and can be conceptualized as a disorder that includes a progression from impulsivity (positive reinforcement) to compulsivity (negative reinforcement). Compulsive drug seeking that is associated with AUD can be derived from multiple neuroadaptations, but the thesis argued herein is that a key component involves the construct of negative reinforcement. Negative reinforcement is defined as drug taking that alleviates a negative emotional state. The negative emotional state that drives such negative reinforcement is hypothesized to derive from the dysregulation of specific neurochemical elements that are involved in reward and stress within basal forebrain structures that involve the ventral striatum and extended amygdala, respectively. Specific neurochemical elements in these structures include decreases in reward neurotransmission (e.g., decreases in dopamine and opioid peptide function in the ventral striatum) and the recruitment of brain stress systems (e.g., corticotropin-releasing factor [CRF]) in the extended amygdala, which contributes to hyperkatifeia and greater alcohol intake that is associated with dependence. Glucocorticoids and mineralocorticoids may play a role in sensitizing the extended amygdala CRF system. Other components of brain stress systems in the extended amygdala that may contribute to the negative motivational state of withdrawal include norepinephrine in the bed nucleus of the stria terminalis, dynorphin in the nucleus accumbens, hypocretin and vasopressin in the central nucleus of the amygdala, and neuroimmune modulation. Decreases in the activity of neuropeptide Y, nociception, endocannabinoids, and oxytocin in the extended amygdala may also contribute to hyperkatifeia that is associated with alcohol withdrawal. Such dysregulation of emotional processing may also significantly contribute to pain that is associated with alcohol withdrawal and negative urgency (i.e., impulsivity that is associated with hyperkatifeia during hyperkatifeia). Thus, an overactive brain stress response system is hypothesized to be activated by acute excessive drug intake, to be sensitized during repeated withdrawal, to persist into protracted abstinence, and to contribute to the compulsivity of AUD. The combination of the loss of reward function and recruitment of brain stress systems provides a powerful neurochemical basis for a negative emotional state that is responsible for the negative reinforcement that at least partially drives the compulsivity of AUD.

The Impacts of Supervised Exercise Intervention on Tobacco Withdrawal Symptoms

This study examined a supervised moderate-intensity aerobic exercise programme's effectiveness in regulating the Tobacco Withdrawal Symptoms (TWS) during temporary abstinence. This was a single group, pre and post-quasi intervention study. Thirty daily smokers participated in an 8-week supervised moderate-intensity aerobic exercise programme. We assessed the TWS, smoking urge, mood and stress-pleasure related hormonal variables after the aerobic exercise intervention. The measurements were conducted after overnight abstinence at baseline, post-intervention (at week-8) and post-detraining (at week-10). TWS components, smoking urge and mood were found to improve. For hormonal variables, cortisol and beta-endorphin except adrenaline showed insignificant changes at post-intervention and de-training. The findings suggest moderate-intensity exercise might help in reducing withdrawal symptoms and its adverse effects. Thus, exercise is an effective adjunct treatment in a smoking cessation programme.

Could Alcohol Abuse and Dependence on Junk Foods Inducing Obesity and/or Illicit Drug Use Represent Danger to Liver in Young People with Altered Psychological/Relational Spheres or Emotional Problems?

Recent data show that young people, mainly due to the pressure of some risk factors or due to disrupted interpersonal relationships, utilise greater reward value and display greater sensitivity to the reinforcing properties of “pleasurable stimuli”, specifically in those situations in which an enhanced dopamine release is present. Alcoholic beverages, foods rich in sugar and fat, and illicit drug use are pleasurable feelings associated with rewards. Research shows that there is a link between substance abuse and obesity in brain functioning. Still, alcohol excess is central in leading to obesity and obesity-related morbidities, such as hepatic steatosis, mainly when associated with illicit drug dependence and negative eating behaviours in young people. It is ascertained that long-term drinking causes mental damage, similarly to drug abuse, but also affects liver function. Indeed, beyond the pharmacokinetic interactions of alcohol with drugs, occurring in the liver due to the same metabolic enzymes, there are also pharmacodynamic interactions of both substances in the CNS. To complicate matters, an important noxious effect of junk foods consists of inducing obesity and obesity-related NAFLD. In this review, we focus on some key mechanisms underlying the impact of these addictions on the liver, as well as those on the CNS.

Sex differences in stress-induced alcohol intake: a review of preclinical studies focused on amygdala and inflammatory pathways

Clinical studies suggest that women are more likely than men to relapse to alcohol drinking in response to stress; however, the mechanisms underlying this sex difference are not well understood. A number of preclinical behavioral models have been used to study stress-induced alcohol intake. Here, we review paradigms used to study effects of stress on alcohol intake in rodents, focusing on findings relevant to sex differences. To date, studies of sex differences in stress-induced alcohol drinking have been somewhat limited; however, there is evidence that amygdala-centered circuits contribute to effects of stress on alcohol seeking. In addition, we present an overview of inflammatory pathways leading to microglial activation that may contribute to alcohol-dependent behaviors. We propose that sex differences in neuronal function and inflammatory signaling in circuits centered on the amygdala are involved in sex-dependent effects on stress-induced alcohol seeking and suggest that this is an important area for future studies.

The Omnipresence of Autonomic Modulation in Health and Disease

The Autonomic Nervous System (ANS) is a critical part of the homeostatic machinery with both central and peripheral components. However, little is known about the integration of these components and their joint role in the maintenance of health and in allostatic derailments leading to somatic and/or neuropsychiatric (co)morbidity. Based on a comprehensive literature search on the ANS neuroanatomy we dissect the complex integration of the ANS: (1) First we summarize Stress and Homeostatic Equilibrium - elucidating the responsivity of the ANS to stressors; (2) Second we describe the overall process of how the ANS is involved in Adaptation and Maladaptation to Stress; (3) In the third section the ANS is hierarchically partitioned into the peripheral/spinal, brainstem, subcortical and cortical components of the nervous system. We utilize this anatomical basis to define a model of autonomic integration. (4) Finally, we deploy the model to describe human ANS involvement in (a) Hypofunctional and (b) Hyperfunctional states providing examples in the healthy state and in clinical conditions.

Preventive Effects of Baclofen but Not Diazepam on Hippocampal Memory and Glucocorticoid Alterations After Prolonged Alcohol Withdrawal in Mice

Our study aims at comparing in C57/Bl male mice, the impact of repeated injections of baclofen (an agonist of GABAB receptor) or diazepam (a benzodiazepine acting through a positive allosteric modulation of GABAA receptor) administered during the alcohol-withdrawal period on hippocampus-dependent memory impairments and brain regional glucocorticoid dysfunction after a short (1-week) or a long (4-week) abstinence. Hence, mice were submitted to a 6-month alcohol consumption (12%v/v) and were progressively withdrawn to water. Then, after a 1- or 4-weeks abstinence, they were submitted to a contextual memory task followed by measurements of corticosterone concentrations in the dorsal hippocampus (dHPC), the ventral hippocampus (vHPC) and the prefrontal cortex (PFC). Results showed that 1- and 4-week withdrawn mice exhibited a severe memory deficit and a significant abnormal rise of the test-induced increase of corticosterone (TICC) in the dHPC, as compared to water-controls or to mice still under alcohol consumption. Repeated daily systemic administrations of decreasing doses of diazepam (ranged from 0.5 to 0.12 mg/kg) or baclofen (ranged from 1.5 to 0.37 mg/kg) during the last 15 days of the withdrawal period, normalized both memory and TICC scores in the dHPC in 1-week withdrawn animals; in contrast, only baclofen-withdrawn mice showed both normal memory performance and TICC scores in the dHPC after a 4-week withdrawal period. In conclusion, the memory improvement observed in 4-week withdrawn mice administered with baclofen stem from the protracted normalization of glucocorticoid activity in the dHPC, a phenomenon encountered only transitorily in diazepam-treated withdrawn mice.

Imipramine attenuates anxiety- and depressive-like effects of acute and prolonged ethanol-abstinence in male rats by modulating SERT and GR expression in the dorsal hippocampus

AIMS

Considering that serotoninergic agents attenuate symptoms of anxiety and are used to treat depression, we investigated whether subchronic treatment with imipramine, a serotonin/noradrenaline reuptake inhibitor, would prevent the anxiogenic-like behaviour induced by acute and/or chronic ethanol withdrawal. We also investigated whether those changes were related to the disfunctioning of hypothalamic-pituitary-adrenal (HPA) axis and serotonergic neurotransmission.

MAIN METHODS

264 Male Wistar rats were treated with ethanol 6% (vol./vol.) for 21 days. Acute ethanol withdrawal was induced by abrupt discontinuation of treatment and sustained for 48 h. Protracted abstinence was sustained for an additional period of 21 days. Behavioural tests included the Elevated Plus Maze (EPM) or Light/Dark Box (LDB) after acute abstinence, and the Forced Swim Test (FST) after protracted abstinence. Imipramine (15 mg/kg, i.p.) was administered 24, 19 and 1 h before EPM or LDB tests.

KEY FINDINGS

Acute abstinence decreased exploration of the open arms of the EPM, without changing exploration of LDB. Additionally, chronic abstinent rats displayed more time immobile in the FST, when compared to control animals. These effects were attenuated by imipramine treatment, without changing basal response. Imipramine prevented protracted abstinence -induced decrease in glucocorticoid receptor (GR) and serotonin transporter (SERT) expression in the dorsal hippocampus.

SIGNIFICANCE

Our findings indicate that chronic ethanol withdrawal affects the hippocampal serotonergic system by decreasing serotonin transporter expression. It also disturbs the HPA axis functioning through an imbalance on GR and mineralocorticoid (MR) expression.

The Role of Melanocortin Plasticity in Pain-Related Outcomes After Alcohol Exposure

The global COVID-19 pandemic has shone a light on the rates and dangers of alcohol misuse in adults and adolescents in the US and globally. Alcohol exposure during adolescence causes persistent molecular, cellular, and behavioral changes that increase the risk of alcohol use disorder (AUD) into adulthood. It is established that alcohol abuse in adulthood increases the likelihood of pain hypersensitivity and the genesis of chronic pain, and humans report drinking alcohol to relieve pain symptoms. However, the longitudinal effects of alcohol exposure on pain and the underlying CNS signaling that mediates it are understudied. Specific brain regions mediate pain effects, alcohol effects, and pain-alcohol interactions, and neural signaling in those brain regions is modulated by neuropeptides. The CNS melanocortin system is sensitive to alcohol and modulates pain sensitivity, but this system is understudied in the context of pain-alcohol interactions. In this review, we focus on the role of melanocortin signaling in brain regions sensitive to alcohol and pain, in particular the amygdala. We also discuss interactions of melanocortins with other peptide systems, including the opioid system, as potential mediators of pain-alcohol interactions. Therapeutic strategies that target the melanocortin system may mitigate the negative consequences of alcohol misuse during adolescence and/or adulthood, including effects on pain-related outcomes.

Serum β-endorphin levels are associated with addiction to suicidal behavior: A pilot study

The literature provides partial support for the hypothesis that some suicide attempters develop a behavioral addiction to suicidal behavior (SB). We hypothesized that major suicide repeaters (MR) (≥5 lifetime suicide attempts) are addicted to suicide attempts as measured by modified DSM-IV criteria for substance dependence. In this cross-sectional study with 13 psychiatric controls (PC), 55 non-major suicide attempters (NMR), and 9 MR we found that MR are characterized by emotional abuse and neglect, as well as higher scores on the Personality and Life Event scale (short version). The levels of 8 AM serum ACTH, cortisol and β-endorphin were elevated in all three groups. Serum β-endorphin (pg/mL) was particularly high in PC diagnosed with schizophrenia 220.34 (±56.30). The level of 8 AM serum β-endorphin rose with increased numbers of criteria met for addiction to SB from 130.31 (±88.16) (≥ 3 criteria met for addiction to SB) to 174.84 (±114.93) (≥ 6 criteria met for addiction to SB) whereas serum ACTH and cortisol did not change. SB addicts (≥ 6 criteria) displayed higher serum β-endorphin concentrations than non-addicts (174.84 ± 114.93 vs. 116.93 ± 61.70, FET p = 0.09). The present study brings some support to the addictive hypothesis of SB. Our results delineate β-endorphin as a promising biomarker of SB addiction, and offer a good basis for future studies that test whether buprenorphine can be used to prevent repetitive suicide attempts, non-suicidal-self-injury (NSSI), and the development of an addiction to SB.

Epigenetic landscape of stress surfeit disorders: Key role for DNA methylation dynamics

Chronic exposure to stress throughout lifespan alters brain structure and function, inducing a maladaptive response to environmental stimuli, that can contribute to the development of a pathological phenotype. Studies have shown that hypothalamic-pituitary-adrenal (HPA) axis dysfunction is associated with various neuropsychiatric disorders, including major depressive, alcohol use and post-traumatic stress disorders. Downstream actors of the HPA axis, glucocorticoids are critical mediators of the stress response and exert their function through specific receptors, i.e., the glucocorticoid receptor (GR), highly expressed in stress/reward-integrative pathways. GRs are ligand-activated transcription factors that recruit epigenetic actors to regulate gene expression via DNA methylation, altering chromatin structure and thus shaping the response to stress. The dynamic interplay between stress response and epigenetic modifiers suggest DNA methylation plays a key role in the development of stress surfeit disorders.

Plasma glucocorticogenic activity, race/ethnicity and alcohol intake among San Francisco Bay Area women

Racial and ethnic minorities are at higher risk for a variety of diseases. While sociodemographic and lifestyle factors contribute to racial/ethnic health disparities, the biological processes underlying these associations remain poorly understood. Stress and its biological consequences through the glucocorticoid receptor (GR) have been hypothesized to mediate adverse disease outcomes. In fasting morning samples of 503 control women from the San Francisco Bay Area Breast Cancer Study, we used a sensitive Chemical-Activated LUciferase gene eXpression (CALUX) assay to examine the association of sociodemographic and lifestyle factors with plasma glucocorticogenic (G) activity in three racial/ethnic groups. The G activity is a sensitive measure that reflects biological activity of total plasma glucocorticoids including cortisol and glucocorticoid-like compounds. Associations between G activity and sociodemographic and lifestyle factors were examined using multivariable linear regression models. Latina and non-Latina Black (NLB) women had 9% (P = 0.053) and 14% (P = 0.008) lower morning G activity than non-Latina White (NLW) women, respectively. Additionally, we replicated a previously reported association between G activity and alcohol intake (women who drank >10gms had 19% higher G activity than non-drinkers, P = 0.004) in Latina and NLB women. Further research should assess the association between G activity and health outcomes in a prospective cohort so as to characterize the relationship between total plasma G activity in pre-disease state and disease outcomes across different racial/ethnic populations.

Effects of Prazosin on Provoked Alcohol Craving and Autonomic and Neuroendocrine Response to Stress in Alcohol Use Disorder

BACKGROUND

Chronic alcohol use results in changes to stress biology and autonomic arousal contributing to acute alcohol withdrawal symptoms, neuroendocrine tolerance of the hypothalamic-pituitary-adrenal axis responses, high stress-induced craving, and risk of alcohol relapse. Thus, stress coping and recovery from alcohol during early abstinence may be jeopardized by such stress system dysfunction. Significant preclinical evidence suggests that noradrenergic disruption may contribute to these alcohol-related stress arousal changes and that alpha-1 adrenergic antagonists, such as prazosin, may normalize these stress system adaptations and reduce alcohol intake. Thus, we hypothesized that prazosin would reduce stress-induced craving and improve neuroendocrine and autonomic response to stress and alcohol cue exposure during early abstinence. We secondarily also assessed the role of lifetime anxiety disorders on these prazosin effects.

METHODS

Forty inpatient treatment-seeking alcohol-dependent individuals were randomly assigned to receive placebo (n = 18) or 16 mg/d, T.I.D., prazosin (n = 22) in a double-blind manner, titrated over 2 weeks. In weeks 3 to 4 after achieving full dose, patients were exposed to 3 5-minute personalized guided imagery conditions (stress cue, alcohol cue, neutral/relaxing cue), on 3 consecutive days in a random, counterbalanced order. Alcohol craving, anxiety, heart rate, cortisol, and adrenocorticotropic hormone (ACTH) levels were assessed at baseline, following imagery and at repeated recovery timepoints.

RESULTS

Prazosin reduced stress cue-induced alcohol craving (p < 0.05) and stress- and alcohol cue-induced anxiety (p < 0.05) and increased heart rate responses in all imagery conditions (p < 0.05). Prazosin lowered basal cortisol and ACTH (p's < 0.05) and attenuated stress cue-induced rises in cortisol (p < 0.05) versus placebo. Finally, in those without lifetime anxiety disorder, the placebo group showed stress- and alcohol cue-induced increases in cortisol (p's < 0.05), while the prazosin group did not.

CONCLUSIONS

Prazosin may attenuate stress cue-induced alcohol craving and anxiety during early abstinence while improving adrenergic and stress system function, effects which are independent of a history of lifetime anxiety disorders.

Chronic social defeat stress: Impacts on ethanol-induced stimulation, corticosterone response, and brain monoamine levels

BACKGROUND

Chronic exposure to stress may dysregulate the hypothalamic-pituitary-adrenal axis and brain monoamine levels, contributing to the development of ethanol dependence. Exposure to chronic social defeat stress may impact ethanol-related effects, neural, and endocrine functions.

AIM

This study assessed ethanol-induced locomotor activity, corticosterone responses, and brain monoamine levels in Swiss albino mice 10 days post-exposure to chronic social defeat stress.

METHODS

During a period of 10 days, male Swiss mice were exposed to daily defeat episodes, followed by housing with an aggressive mouse for 24 h. Control mice were housed in pairs and rotated every 24 h. Ten days post-stress, locomotor behavior was recorded after a challenge with ethanol (2.2 g/kg; intraperitoneal) or saline. After the test, blood and brain samples were collected for determination of plasma corticosterone and brain monoamines across different brain areas through high-performance liquid chromatography.

RESULTS

Defeated mice failed to show a stimulant locomotor response to ethanol, while controls displayed the expected ethanol-induced stimulation. Ethanol increased plasma corticosterone levels, with lower corticosterone secretion in defeated mice. Brain monoamines were affected by social defeat and ethanol, varying in different brain regions. Social stress reduced levels of dopamine, noradrenaline, and serotonin in the hypothalamus. Defeated mice presented reduced serotonin and dopamine levels in the frontal cortex. In the striatum, ethanol treatment increased dopamine levels in controls, but failed to do so in defeated mice.

CONCLUSIONS

Our results suggest that chronic exposure to social defeat blunted ethanol-induced locomotor stimulation, and reduced ethanol-induced corticosterone secretion. Social stress promoted differential reductions in brain monoamine levels in the hypothalamus and frontal cortex and blunted ethanol-induced dopamine increases in the striatum.

The effect of pre-existing alcohol use disorder on the risk of developing posttraumatic stress disorder: results from a longitudinal national representative sample

Background: There is inconsistent evidence in the literature as to whether or not Alcohol Use Disorder (AUD) is a risk factor for Post-Traumatic Stress Disorder (PTSD).Objectives: We evaluated the risk of developing PTSD after trauma exposure in individuals with AUD. As a secondary analysis, we also tested if alcohol dependence or alcohol abuse separately increased the risk of PTSD development. We also explored the effect of AUD on exposure to various traumas.Methods: Longitudinal data was obtained from 30,180 individuals with and without AUD from National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) waves I and II. Using propensity score methods, we matched individuals with AUD (alcohol abuse and/or dependence using DSM-IV criteria) to those without AUD at baseline on demographic, familial, and clinical factors to estimate the risk of PTSD development after trauma exposure. Data were adjusted for complex survey methods.Results: Individuals with AUD had an increased risk of being exposed to various traumas between wave I and II (60.6% vs. 48.3% of controls). Among individuals exposed to trauma between the two waves (N = 14,107), AUD had no effect on subsequent PTSD development after matching and controlling for covariates (OR: 1.00; 95%CI: 0.72-1.39; p = .99). However, those with alcohol dependence only did have an effect on subsequent PTSD development (OR: 1.76; 95%CI: 1.05-2.95; p = .03).Conclusion: In individuals with alcohol dependence the experience of trauma increases the risk of developing PTSD. These findings suggest that prevention methods from PTSD after trauma exposure for individuals with alcohol dependence are needed.

Individual Differences in Ethanol Drinking and Seeking Behaviors in Rats Exposed to Chronic Intermittent Ethanol Vapor Exposure is Associated with Altered CaMKII Autophosphorylation in the Nucleus Accumbens Shell

Chronic intermittent ethanol vapor exposure (CIE) in rodents produces reliable and high blood ethanol concentration and behavioral symptoms associated with moderate to severe alcohol use disorder (AUD)—for example, escalation of operant ethanol self-administration, a feature suggestive of transition from recreational to addictive use, is a widely replicated behavior in rats that experience CIE. Herein, we present evidence from a subset of rats that do not demonstrate escalation of ethanol self-administration following seven weeks of CIE. These low responders (LR) maintain low ethanol self-administration during CIE, demonstrate lower relapse to drinking during abstinence and reduced reinstatement of ethanol seeking triggered by ethanol cues when compared with high responders (HR). We examined the blood ethanol levels in LR and HR rats during CIE and show higher levels in LR compared with HR. We also examined peak corticosterone levels during CIE and show that LR rats have higher levels compared with HR rats. Lastly, we evaluated the levels of Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) in the nucleus accumbens shell and reveal that the activity of CaMKII, which is autophosphorylated at site Tyr-286, is significantly reduced in HR rats compared with LR rats. These findings demonstrate that dysregulation of the hypothalamic–pituitary–adrenal axis activity and plasticity-related proteins regulating molecular memory in the nucleus accumbens shell are associated with higher ethanol-drinking and -seeking in HR rats. Future mechanistic studies should evaluate CaMKII autophosphorylation-dependent remodeling of glutamatergic synapses in the ventral striatum as a plausible mechanism for the CIE-induced enhanced ethanol drinking and seeking behaviors.

Sex differences in binge-like EtOH drinking, corticotropin-releasing hormone and corticosterone: effects of β-endorphin

Binge drinking is an increasingly common pattern of risky use associated with numerous health problems, including alcohol use disorders. Because low basal plasma levels of β‐endorphin (β‐E) and an increased β‐E response to alcohol are evident in genetically at‐risk human populations, this peptide is thought to contribute to the susceptibility for disordered drinking. Animal models suggest that the effect of β‐E on consumption may be sex‐dependent. Here, we studied binge‐like EtOH consumption in transgenic mice possessing varying levels of β‐E: wild‐type controls with 100% of the peptide (β‐E +/+), heterozygous mice constitutively modified to possess 50% of wild‐type levels (β‐E +/−) and mice entirely lacking the capacity to synthesize β‐E (−/−). These three genotypes and both sexes were evaluated in a 4‐day, two‐bottle choice, drinking in the dark paradigm with limited access to 20% EtOH. β‐E deficiency determined sexually divergent patterns of drinking in that β‐E −/− female mice drank more than their wild‐type counterparts, an effect not observed in male mice. β‐E −/− female mice also displayed elevated basal anxiety, plasma corticosterone and corticotropin‐releasing hormone mRNA in the extended amygdala, and all of these were normalized by EtOH self‐administration. These data suggest that a heightened risk for excessive EtOH consumption in female mice is related to the drug's ability to ameliorate an overactive anxiety/stress‐like state. Taken together, our study highlights a critical impact of sex on neuropeptide regulation of EtOH consumption.

Gender-Specific Association between Alcohol Consumption and Stress Perception, Depressed Mood, and Suicidal Ideation: The 2010-2015 KNHANES

OBJECTIVE

Alcohol drinking can cause various psychiatric and medical diseases. Although women generally consume less alcohol than men, they may be at a greater risk for alcohol-related psychological distress. The aim of the current study is to evaluate whether the association between alcohol consumption and psychological distress, including stress, depressed mood, and suicidal ideation and the risks of psychological distress differ based on gender.

METHODS

The cross-sectional study included 31,657 participants (17,915 women and 13,742 men) from the 2010-2013 and 2015 Korea National Health and Nutrition Examination Survey. Alcohol drinking and Alcohol Use Disorders Identification Test (AUDIT) levels were assessed for evaluating the amount of alcohol intake and alcohol-related problems. Self-perception of stress, depressed mood, and suicidal ideation were assessed for evaluating psychological distress. Odds ratio and 95% confidence intervals for psychological distress were calculated using multiple logistic regression models.

RESULTS

The risks of psychological distress were not significantly associated with drinking level in both sexes. However, the risks of psychological distress were associated with an increase in AUDIT levels, and there were gender differences in the psychological consequences of alcohol-related problems. The association was more drastic in women, and women showed a significant association even though the severity of drinking problem was low with the exception of stress perception.

CONCLUSION

The risks of psychological distress were associated with the severity of alcohol-related problems and women were more likely to be susceptible. Therefore, it is recommended that women even at low-risk for problematic drinking should be screened for psychological distress.

Baclofen but Not Diazepam Alleviates Alcohol-Seeking Behavior and Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Stressed Withdrawn Mice

This study compares the impact of repeated injections of baclofen (an agonist of GABA_B receptors) or diazepam (a benzodiazepine having an agonist action on GABA_A receptors) given during the alcohol-withdrawal period on the stress-induced restoration of alcohol-seeking behavior and hypothalamic-pituitary-adrenal (HPA) axis dysfunction after a long (4 weeks) abstinence. Thus, C57BL/6 mice were submitted to a 6-month alcohol consumption [12% volume/volume (v/v)] and were progressively withdrawn to water before testing. Diazepam (Valium^®, Roche) and baclofen (Baclofen^®, Mylan) were administered intraperitoneally for 15 consecutive days (1 injection/day) during the withdrawal period at decreasing doses ranging from 1.0 mg/kg (Day 15) to 0.25 mg/kg (Day 1) for diazepam and from 1.5 mg/kg (Day 15) to 0.37 mg/kg (Day 1) for baclofen. Alcohol-seeking behavior was evaluated by alcohol-place preference in an odor recognition task. In the stress condition, mice received three electric footshocks 45 min before behavioral testing. Blood was sampled immediately after behavioral testing, and plasma corticosterone concentrations were measured by commercial enzyme immunoassay kits. Results showed that non-stressed withdrawn mice did not exhibit alcohol-place preference or alteration of plasma corticosterone concentrations relative to water controls. After stress, however, withdrawn mice exhibited a significant alcohol-place preference and higher circulating corticosterone concentrations as compared to stressed water controls. Interestingly, repeated administration during the withdrawal phase of baclofen but not diazepam suppressed both the alcohol-place preference and normalized corticosterone levels in stressed withdrawn animals. In conclusion, this study evidences that a pre-treatment with baclofen but not with diazepam during the withdrawal phase normalized, even after a long period of abstinence, the HPA axis response to stress, which contributes to the long-term preventing effects of this compound on alcohol-seeking behavior.

Targeting the Glucocorticoid Receptors During Alcohol Withdrawal to Reduce Protracted Neurocognitive Disorders

Persistent regional glucocorticoid (GC) dysregulation in alcohol-withdrawn subjects emerges as a key factor responsible for protracted molecular and neural alterations associated with long-term cognitive dysfunction. Regional brain concentrations of corticosterone vary independently from plasma concentrations in alcohol-withdrawn subjects, which may account for the treatment of alcohol withdrawal-induced persistent pathology. Thus, from a pharmacological point of view, a main issue remains to determine the relative efficacy of compounds targeting the GC receptors to attenuate or suppress the long-lasting persistence of brain regional GC dysfunctions in abstinent alcoholics, as well as persistent changes of neural plasticity. Data from animal research show that acting directly on GC receptors during the withdrawal period, via selective antagonists, can significantly counteract the development and persistence of cognitive and neural plasticity disorders during protracted abstinence. A critical remaining issue is to better assess the relative long-term efficacy of GC antagonists and other compounds targeting the corticotropic axis activity such as gamma-aminobutyric acid A (GABA_A) and GABA_B agonists. Indeed, benzodiazepines (acting indirectly on GABA_A receptors) and baclofen (agonist of the GABA_B receptor) are the compounds most widely used to reduce alcohol dependence. Clinical and preclinical data suggest that baclofen exerts an effective and more powerful counteracting action on such persistent cognitive and endocrine dysfunctions as compared to diazepam, even though its potential negative effects on memory processes, particularly at high doses, should be better taken into account.

Individual differences in the neuropsychopathology of addiction

Drug addiction or substance-use disorder is a chronically relapsing disorder that progresses through binge/intoxication, withdrawal/negative affect and preoccupation/anticipation stages. These stages represent diverse neurobiological mechanisms that are differentially involved in the transition from recreational to compulsive drug use and from positive to negative reinforcement. The progression from recreational to compulsive substance use is associated with downregulation of the brain reward systems and upregulation of the brain stress systems. Individual differences in the neurobiological systems that underlie the processing of reward, incentive salience, habits, stress, pain, and executive function may explain (i) the vulnerability to substance-use disorder; (ii) the diversity of emotional, motivational, and cognitive profiles of individuals with substance-use disorders; and (iii) heterogeneous responses to cognitive and pharmacological treatments. Characterization of the neuropsychological mechanisms that underlie individual differences in addiction-like behaviors is the key to understanding the mechanisms of addiction and development of personalized pharmacotherapy.

Stress, Motivation, and the Gut-Brain Axis: A Focus on the Ghrelin System and Alcohol Use Disorder

Since its discovery, the gut hormone, ghrelin, has been implicated in diverse functional roles in the central nervous system. Central and peripheral interactions between ghrelin and other hormones, including the stress-response hormone cortisol, govern complex behavioral responses to external cues and internal states. By acting at ventral tegmental area dopaminergic projections and other areas involved in reward processing, ghrelin can induce both general and directed motivation for rewards, including craving for alcohol and other alcohol-seeking behaviors. Stress-induced increases in cortisol seem to increase ghrelin in the periphery, suggesting a pathway by which ghrelin influences how stressful life events trigger motivation for rewards. However, in some states, ghrelin may be protective against the anxiogenic effects of stressors. This critical review brings together a dynamic and growing literature, that is, at times inconsistent, on the relationships between ghrelin, central reward-motivation pathways, and central and peripheral stress responses, with a special focus on its emerging role in the context of alcohol use disorder.

Advancing Pharmacotherapy Development from Preclinical Animal Studies

Animal models provide rapid, inexpensive assessments of an investigational drug's therapeutic potential. Ideally, they support the plausibility of therapeutic efficacy and provide a rationale for further investigation. Here, I discuss how the absence of clear effective-ineffective categories for alcohol use disorder (AUD) medications and biases in the clinical and preclinical literature affect the development of predictive preclinical alcohol dependence (AD) models. Invoking the analogical argument concept from the philosophy of science field, I discuss how models of excessive alcohol drinking support the plausibility of clinical pharmacotherapy effects. Even though these models are not likely be completely discriminative, they are sensitive to clinically effective medications and have revealed dozens of novel medication targets. In that context, I discuss recent preclinical work on GLP-1 receptor agonists, phosphodiesterase inhibitors, glucocorticoid receptor antagonists, nociception agonists and antagonists, and CRF1 antagonists. Clinically approved medications are available for each of these drug classes. I conclude by advocating a translational approach in which drugs are evaluated highly congruent preclinical models and human laboratory studies. Once translation is established, I suggest the burden is to develop hypothesis-based therapeutic interventions maximizing the impact of the confirmed pharmacotherapeutic effects in the context of additional variables falling outside the model.

Threat Response System: Parallel Brain Processes in Pain vis-à-vis Fear and Anxiety

Pain is essential for avoidance of tissue damage and for promotion of healing. Notwithstanding the survival value, pain brings about emotional suffering reflected in fear and anxiety, which in turn augment pain thus giving rise to a self-sustaining feedforward loop. Given such reciprocal relationships, the present article uses neuroscientific conceptualizations of fear and anxiety as a theoretical framework for hitherto insufficiently understood pathophysiological mechanisms underlying chronic pain. To that end, searches of PubMed-indexed journals were performed using the following Medical Subject Headings' terms: pain and nociception plus amygdala, anxiety, cognitive, fear, sensory, and unconscious. Recursive sets of scientific and clinical evidence extracted from this literature review were summarized within the following key areas: (1) parallelism between acute pain and fear and between chronic pain and anxiety; (2) all are related to the evasion of sensory-perceived threats and are subserved by subcortical circuits mediating automatic threat-induced physiologic responses and defensive actions in conjunction with higher order corticolimbic networks (e.g., thalamocortical, thalamo-striato-cortical and amygdalo-cortical) generating conscious representations and valuation-based adaptive behaviors; (3) some instances of chronic pain and anxiety conditions are driven by the failure to diminish or block respective nociceptive information or unconscious treats from reaching conscious awareness; and (4) the neural correlates of pain-related conscious states and cognitions may become autonomous (i.e., dissociated) from the subcortical activity/function leading to the eventual chronicity. Identifying relative contributions of the diverse neuroanatomical sources, thus, offers prospects for the development of novel preventive, diagnostic, and therapeutic strategies in chronic pain patients.

Abstinence from prolonged ethanol exposure affects plasma corticosterone, glucocorticoid receptor signaling and stress-related behaviors

Alcohol dependence is linked to dysregulation of the hypothalamic-pituitary-adrenal axis. Here, we investigated effects of repeated ethanol intoxication-withdrawal cycles (using chronic intermittent ethanol vapor inhalation; CIE) and abstinence from CIE on peak and nadir plasma corticosterone (CORT) levels. Irritability- and anxiety-like behaviors as well as glucocorticoid receptors (GR) in the medial prefrontal cortex (mPFC) were assessed at various intervals (2h-28d) after cessation of CIE. Results show that peak CORT increased during CIE, transiently decreased during early abstinence (1-11d), and returned to pre-abstinence levels during protracted abstinence (17-27d). Acute withdrawal from CIE enhanced aggression- and anxiety-like behaviors. Early abstinence from CIE reduced anxiety-like behavior. mPFC-GR signaling (indexed by relative phosphorylation of GR at Ser211) was transiently decreased when measured at time points during early and protracted abstinence. Further, voluntary ethanol drinking in CIE (CIE-ED) and CIE-naïve (ED) rats, and effects of CIE-ED and ED on peak CORT levels and mPFC-GR were investigated during acute withdrawal (8h) and protracted abstinence (28d). CIE-ED and ED increased peak CORT during drinking. CIE-ED and ED decreased expression and signaling of mPFC-GR during acute withdrawal, an effect that was reversed by systemic mifepristone treatment. CIE-ED and ED demonstrate robust reinstatement of ethanol seeking during protracted abstinence and show increases in mPFC-GR expression. Collectively, the data demonstrate that acute withdrawal from CIE produces robust alterations in GR signaling, CORT and negative affect symptoms which could facilitate excessive drinking. The findings also show that CIE-ED and ED demonstrate enhanced relapse vulnerability triggered by ethanol cues and these changes are partially mediated by altered GR expression in the mPFC. Taken together, transition to alcohol dependence could be accompanied by alterations in mPFC stress-related pathways that may increase negative emotional symptoms and increase vulnerability to relapse.

Corticotropin-Releasing Factor (CRF) and Addictive Behaviors

Drug addiction is a complex disorder that is characterized by compulsivity to seek and take the drug, loss of control in limiting intake of the drug, and emergence of a withdrawal syndrome in the absence of the drug. The transition from casual drug use to dependence is mediated by changes in reward and brain stress functions and has been linked to a shift from positive reinforcement to negative reinforcement. The recruitment of brain stress systems mediates the negative emotional state produced by dependence that drives drug seeking through negative reinforcement mechanisms, defined as the "dark side" of addiction. In this chapter we focus on behavioral and cellular neuropharmacological studies that have implicated brain stress systems (i.e., corticotropin-releasing factor [CRF]) in the transition to addiction and the predominant brain regions involved. We also discuss the implication of CRF recruitment in compulsive eating disorders.

Influence of stress associated with chronic alcohol exposure on drinking

Stress is commonly regarded as an important trigger for relapse and a significant factor that promotes increased motivation to drink in some individuals. However, the relationship between stress and alcohol is complex, likely changing in form during the transition from early moderated alcohol use to more heavy uncontrolled alcohol intake. A growing body of evidence indicates that prolonged excessive alcohol consumption serves as a potent stressor, producing persistent dysregulation of brain reward and stress systems beyond normal homeostatic limits. This progressive dysfunctional (allostatic) state is characterized by changes in neuroendocrine and brain stress pathways that underlie expression of withdrawal symptoms that reflect a negative affective state (dysphoria, anxiety), as well as increased motivation to self-administer alcohol. This review highlights literature supportive of this theoretical framework for alcohol addiction. In particular, evidence for stress-related neural, physiological, and behavioral changes associated with chronic alcohol exposure and withdrawal experience is presented. Additionally, this review focuses on the effects of chronic alcohol-induced changes in several pro-stress neuropeptides (corticotropin-releasing factor, dynorphin) and anti-stress neuropeptide systems (nocicepton, neuropeptide Y, oxytocin) in contributing to the stress, negative emotional, and motivational consequences of chronic alcohol exposure. Studies involving use of animal models have significantly increased our understanding of the dynamic stress-related physiological mechanisms and psychological underpinnings of alcohol addiction. This, in turn, is crucial for developing new and more effective therapeutics for treating excessive, harmful drinking, particularly stress-enhanced alcohol consumption. This article is part of the Special Issue entitled "Alcoholism".

Antireward, compulsivity, and addiction: seminal contributions of Dr. Athina Markou to motivational dysregulation in addiction

RATIONALE AND OBJECTIVES

Addiction is defined as a chronically relapsing disorder characterized by compulsive drug seeking that is hypothesized to derive from multiple sources of motivational dysregulation.

METHODS AND RESULTS

Dr. Athina Markou made seminal contributions to our understanding of the neurobiology of addiction with her studies on the dysregulation of reward function using animal models with construct validity. Repeated overstimulation of the reward systems with drugs of abuse decreases reward function, characterized by brain stimulation reward and presumbably reflecting dysphoria-like states. The construct of negative reinforcement, defined as drug taking that alleviates a negative emotional state that is created by drug abstinence, is particularly relevant as a driving force in both the withdrawal/negative affect and preoccupation/anticipation stages of the addiction cycle.

CONCLUSIONS

The negative emotional state that drives such negative reinforcement is hypothesized to derive from the dysregulation of key neurochemical circuits that drive incentive-salience/reward systems (dopamine, opioid peptides) in the ventral striatum and from the recruitment of brain stress systems (corticotropin-releasing factor, dynorphin) within the extended amygdala. As drug taking becomes compulsive-like, the factors that motivate behavior are hypothesized to shift to drug-seeking behavior that is driven not only by positive reinforcement but also by negative reinforcement. This shift in motivation is hypothesized to reflect the allostatic misregulation of hedonic tone such that drug taking makes the hedonic negative emotional state worse during the process of seeking temporary relief with compulsive drug taking.

Effects of chronic alcohol consumption on neuronal function in the non-human primate BNST

Alterations in hypothalamic-pituitary-adrenal axis function contribute to many of the adverse behavioral effects of chronic voluntary alcohol drinking, including alcohol dependence and mood disorders; limbic brain structures such as the bed nucleus of the stria terminalis (BNST) may be key sites for these effects. Here, we measured circulating levels of several steroid hormones and performed whole-cell electrophysiological recordings from acutely prepared BNST slices of male rhesus monkeys allowed to self-administer alcohol for 12 months or a control solution. Initial comparisons revealed that BNST neurons in alcohol-drinking monkeys had decreased membrane resistance, increased frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) with no change in spontaneous excitatory postsynaptic currents (sEPSCs). We then used a combined variable cluster analysis and linear mixed model statistical approach to determine whether specific factors including stress and sex hormones, age and measures of alcohol consumption and intoxication are related to these BNST measures. Modeling results showed that specific measures of alcohol consumption and stress-related hormone levels predicted differences in membrane conductance in BNST neurons. Distinct groups of adrenal stress hormones were negatively associated with the frequency of sIPSCs and sEPSCs, and alcohol drinking measures and basal neuronal membrane properties were additional positive predictors of inhibitory, but not excitatory, PSCs. The amplitude of sEPSCs was highly positively correlated with age, independent of other variables. Together, these results suggest that chronic voluntary alcohol consumption strongly influences limbic function in non-human primates, potentially via interactions with or modulation by other physiological variables, including stress steroid hormones and age.

Serotonin's Complex Role in Alcoholism: Implications for Treatment and Future Research

Current pharmacological treatments for alcohol dependence have focused on reducing alcohol consumption, but to date there are few treatments that also address the negative affective symptoms during acute and protracted alcohol withdrawal which are often exacerbated in people with comorbid anxiety and depression. Selective serotonin reuptake inhibitors (SSRIs) are sometimes prescribed to ameliorate these symptoms but can exacerbate anxiety and cravings in a select group of patients. In this critical review, we discuss recent literature describing an association between alcohol dependence, the SERT linked polymorphic region (5-HTTLPR), and pharmacological response to SSRIs. Given the heterogeneity in responsiveness to serotonergic drugs across the spectrum of alcoholic subtypes, we assess the contribution of specific 5-HT circuits to discrete endophenotypes of alcohol dependence. 5-HT circuits play a distinctive role in reward, stress, and executive function which may account for the variation in response to serotonergic drugs. New optogenetic and chemogenetic methods for dissecting 5-HT circuits in alcohol dependence may provide clues leading to more effective pharmacotherapies. Although our current understanding of the role of 5-HT systems in alcohol dependence is incomplete, there is some evidence to suggest that 5-HT3 receptor antagonists are effective in people with the L/L genotype of the 5-HTTLPR polymorphism while SSRIs may be more beneficial to people with the S/L or S/S genotype. Studies that assess the impact of serotonin transporter polymorphisms on 5-HT circuit function and the subsequent development of alcohol use disorders will be an important step forward in treating alcohol dependence.

Predator-scent stress, ethanol consumption and the opioid system in an animal model of PTSD

Emerging literature points to stress exposure as a potential contributor to the development of alcohol abuse, but animal models have yielded inconsistent results. Converging experimental data indicate that the endogenous opioid system modulates alcohol consumption and stress regulation. The aim of the present study is to examine the interplay between stress exposure, behavioral stress responses, ethanol (EtOH) consumption and the endogenous opioid system in an animal model of posttraumatic stress disorder. Rats were exposed to stress and then tested in a two-bottle free choice (TBC) assay or in a conditioned place preference paradigm. In some experiments, the endogenous opioid system was pharmacologically manipulated prior to stress exposure. The behavioral outcomes of stress exposure were assessed in an elevated plus-maze, with the acoustic startle response, and by monitoring the freezing response to trauma reminder. Immunoreactivity of phosphorylated opioid receptors in hippocampal subregions was also measured. Stress significantly increased the consumption of EtOH in the TBC assay. The severity of the behavioral response to stress was associated with EtOH consumption, cue-triggered freezing response to a trauma reminder, and endogenous levels of phosphorylated opioid receptors in the hippocampus. Pharmacologically manipulating the endogenous opioid system prior to stress exposure attenuated trauma cue-triggered freezing responses and blocked predator scent stress-induced potentiation of EtOH consumption. These data demonstrate a stress-induced potentiation of EtOH self-administration and reveal a clear association between individual patterns of the behavioral response to stress and alcohol preference, while indicating a role for the endogenous opioid system in the neurobiological response to stress.

Chronic Intermittent Ethanol Exposure Alters Stress Effects on (3α,5α)-3-hydroxy-pregnan-20-one (3α,5α-THP) Immunolabeling of Amygdala Neurons in C57BL/6J Mice

The GABAergic neuroactive steroid (3α,5α)-3-hydroxy-pregnan-20-one (3α,5α-THP, allopregnanolone) is decreased in various brain regions of C57BL/6J mice following exposure to an acute stressor or chronic intermittent ethanol (CIE) exposure and withdrawal. It is well established that there are complex interactions between stress and ethanol drinking, with mixed literature regarding the effects of stress on ethanol intake. However, there is little research examining how chronic ethanol exposure alters stress responses. The present work examined the impact of CIE exposure and withdrawal on changes in brain levels of 3α,5α-THP, as well as hormonal and behavioral responses to forced swim stress (FSS). Adult male C57BL/6J mice were exposed to four cycles of CIE to induce ethanol dependence. Following 8 h or 72 h withdrawal, mice were subjected to FSS for 10 min, and 50 min later brains were collected for immunohistochemical analysis of cellular 3α,5α-THP. Behavioral and circulating corticosterone responses to FSS were quantified. Following 8 h withdrawal, ethanol exposure potentiated the corticosterone response to FSS. Following 72 h withdrawal, this difference was no longer observed. Following 8 h withdrawal, stress-exposed mice showed no differences in immobility, swimming or struggling behavior. However, following 72 h withdrawal, ethanol-exposed mice showed less immobility and greater swimming behavior compared to air-exposed mice. Interestingly, cellular 3α,5α-THP levels were increased in the lateral amygdala 8 h and 72 h post-withdrawal in stressed ethanol-exposed mice compared to ethanol-exposed/non-stressed mice. In the paraventricular nucleus of the hypothalamus, stress exposure decreased 3α,5α-THP levels compared to controls following 72 h withdrawal, but no differences were observed 8 h post-withdrawal. There were no differences in cellular 3α,5α-THP levels in the nucleus accumbens shell at either withdrawal time point. These data suggest that there are different mechanisms mediating hormonal, behavioral, and brain responses to stress following CIE exposure. The lateral amygdala appears to be an extremely sensitive brain region exhibiting changes in cellular 3α,5α-THP levels following CIE and exposure to swim stress. It is likely that these changes in cellular 3α,5α-THP levels in the lateral amygdala contribute to the behavioral effects observed following 72 h withdrawal.

11β-hydroxysteroid dehydrogenase inhibition as a new potential therapeutic target for alcohol abuse

The identification of new and more effective treatments for alcohol abuse remains a priority. Alcohol intake activates glucocorticoids, which have a key role in alcohol's reinforcing properties. Glucocorticoid effects are modulated in part by the activity of 11β-hydroxysteroid dehydrogenases (11β-HSD) acting as pre-receptors. Here, we tested the effects on alcohol intake of the 11β-HSD inhibitor carbenoxolone (CBX, 18β-glycyrrhetinic acid 3β-O-hemisuccinate), which has been extensively used in the clinic for the treatment of gastritis and peptic ulcer and is active on both 11β-HSD1 and 11β-HSD2 isoforms. We observed that CBX reduces both baseline and excessive drinking in rats and mice. The CBX diastereomer 18α-glycyrrhetinic acid 3β-O-hemisuccinate (αCBX), which we found to be selective for 11β-HSD2, was also effective in reducing alcohol drinking in mice. Thus, 11β-HSD inhibitors may be a promising new class of candidate alcohol abuse medications, and existing 11β-HSD inhibitor drugs may be potentially re-purposed for alcohol abuse treatment.

Behavioral Neuroadaptation to Alcohol: From Glucocorticoids to Histone Acetylation

A prime mechanism that contributes to the development and maintenance of alcoholism is the dysregulation of the hypothalamic-pituitary-adrenal axis activity and the release of glucocorticoids (cortisol in humans and primates, corticosterone in rodents) from the adrenal glands. In the brain, sustained, local elevation of glucocorticoid concentration even long after cessation of chronic alcohol consumption compromises functional integrity of a circuit, including the prefrontal cortex (PFC), the hippocampus (HPC), and the amygdala (AMG). These structures are implicated in learning and memory processes as well as in orchestrating neuroadaptive responses to stress and anxiety responses. Thus, potentiation of anxiety-related neuroadaptation by alcohol is characterized by an abnormally AMG hyperactivity coupled with a hypofunction of the PFC and the HPC. This review describes research on molecular and epigenetic mechanisms by which alcohol causes distinct region-specific adaptive changes in gene expression patterns and ultimately leads to a variety of cognitive and behavioral impairments on prefrontal- and hippocampal-based tasks. Alcohol-induced neuroadaptations involve the dysregulation of numerous signaling cascades, leading to long-term changes in transcriptional profiles of genes, through the actions of transcription factors such as [cAMP response element-binding protein (CREB)] and chromatin remodeling due to posttranslational modifications of histone proteins. We describe the role of prefrontal-HPC-AMG circuit in mediating the effects of acute and chronic alcohol on learning and memory, and region-specific molecular and epigenetic mechanisms involved in this process. This review first discusses the importance of brain region-specific dysregulation of glucocorticoid concentration in the development of alcohol dependence and describes how persistently increased glucocorticoid levels in PFC may be involved in mediating working memory impairments and neuroadaptive changes during withdrawal from chronic alcohol intake. It then highlights the role of cAMP-PKA-CREB signaling cascade and histone acetylation within the PFC and limbic structures in alcohol-induced anxiety and behavioral impairments, and how an understanding of functional alterations of these pathways might lead to better treatments for neuropsychiatric disorders.

Preclinical evidence implicating corticotropin-releasing factor signaling in ethanol consumption and neuroadaptation

The results of many studies support the influence of the corticotropin-releasing factor (CRF) system on ethanol (EtOH) consumption and EtOH-induced neuroadaptations that are critical in the addiction process. This review summarizes the preclinical data in this area after first providing an overview of the components of the CRF system. This complex system involves hypothalamic and extra-hypothalamic mechanisms that play a role in the central and peripheral consequences of stressors, including EtOH and other drugs of abuse. In addition, several endogenous ligands and targets make up this system and show differences in their involvement in EtOH drinking and in the effects of chronic or repeated EtOH treatment. In general, genetic and pharmacological approaches paint a consistent picture of the importance of CRF signaling via type 1 CRF receptors (CRF(1)) in EtOH-induced neuroadaptations that result in higher levels of intake, encourage alcohol seeking during abstinence and alter EtOH sensitivity. Furthermore, genetic findings in rodents, non-human primates and humans have provided some evidence of associations of genetic polymorphisms in CRF-related genes with EtOH drinking, although additional data are needed. These results suggest that CRF(1) antagonists have potential as pharmacotherapeutics for alcohol use disorders. However, given the broad and important role of these receptors in adaptation to environmental and other challenges, full antagonist effects may be too profound and consideration should be given to treatments with modulatory effects.

Anxiety Symptoms During Adolescence Predicts Salivary Cortisol in Early Adulthood Among Blacks; Sex differences

BACKGROUND

Although the link between psychological distress and altered cortisol level has been already shown; very limited information exists about this association among Black youth.

OBJECTIVES

We tested sex differences in predictive role of symptoms of anxiety during adolescence on annual decline in morning salivary cortisol levels in early adulthood among Black youth.

PATIENTS AND METHODS

Data came from wave 1 (year 1994), wave 6 (year 2000), and wave 7 (year 2001) of the Flint adolescent study. In this study 176 Black youth (85 males and 91 females) were followed for 7 years from mean age of 15 at baseline to 22 at the end of follow up. Linear regression was used for data analysis with change in salivary cortisol from 2000 to 2001 as the dependent variable, symptoms of anxiety, at 1994 as independent variable, age, number of employed parents, depressive symptoms and alcohol use at 1994 as controls, and sex as the moderator.

RESULTS

Higher level of anxiety symptoms at 1994 was predictive of a higher decline in morning salivary cortisol from 2000 to 2001 for all youths, while the effects of baseline socio-economics, depressive symptoms, and alcohol use were controlled. Among female participants, anxiety symptoms at 1994 were predictive of a greater decline in morning salivary cortisol level from 2000 to 2001. The association was not found among males.

CONCLUSIONS

Our findings suggest sex differences in the predictive role of anxiety symptoms during adolescence on the annual decline in cortisol level during early adulthood. While most research on this topic is among White middle class individuals, our findings shed more light on the longitudinal links between psychological distress and the hypothalamus-pituitary-adrenal (HPA) axis function among Black youth.

Acute oral administration of the novel, competitive and selective glucocorticoid receptor antagonist ORG 34517 reduces the severity of ethanol withdrawal and related hypothalamic-pituitary-adrenal axis activation

BACKGROUND

The development of ethanol dependence is associated with alterations in hypothalamic-pituitary-adrenal (HPA) axis and activation of type II glucocorticoid receptors (GR). These effects may contribute to withdrawal-associated anxiety, craving and relapse to drinking. The present studies examined acute and oral administration of the novel, selective and competitive GR antagonist ORG 34517 on the severity of ethanol withdrawal.

METHODS

Adult, male Sprague-Dawley rats were administered ethanol (4g/kg/i.g.) twice daily for 5 days followed by 2 days of withdrawal for 1, 2 or 3 consecutive cycles. Blood ethanol levels (BELs) were determined at 0930 on Day 4 of each week, while blood corticosterone levels (BCLs) were obtained at 11:00hours on the first day of each ethanol withdrawal. During early withdrawal, subjects received oral administration of ORG 345617 (60mg/kg/i.g.) or a placebo and withdrawal was monitored.

RESULTS

Peak BELs of 225.52mg/dl were observed during the third week. Withdrawal from three cycles of the regimen produced marked behavioral abnormalities (e.g., aggression, rigidity, and hypoactivity) and significant increases in BCLs of ethanol-dependent subjects. Acute, oral administration of ORG 34517 during early withdrawal significantly reduced both the severity of ethanol withdrawal, as reflected in reduced rigidity, aggression, and hypoactivity, and elevations in BCL without producing any sedative-like effects.

CONCLUSIONS

The present findings demonstrate that repeated ethanol exposure and withdrawal is associated with significant behavioral abnormalities and dysregulation of HPA axis activation. Further these data suggest that selective GR antagonists should be further considered as putative pharmacotherapies for treatment of ethanol dependence.

Brain pathways to recovery from alcohol dependence

This article highlights the research presentations at the satellite symposium on "Brain Pathways to Recovery from Alcohol Dependence" held at the 2013 Society for Neuroscience Annual Meeting. The purpose of this symposium was to provide an up to date overview of research efforts focusing on understanding brain mechanisms that contribute to recovery from alcohol dependence. A panel of scientists from the alcohol and addiction research field presented their insights and perspectives on brain mechanisms that may underlie both recovery and lack of recovery from alcohol dependence. The four sessions of the symposium encompassed multilevel studies exploring mechanisms underlying relapse and craving associated with sustained alcohol abstinence, cognitive function deficit and recovery, and translational studies on preventing relapse and promoting recovery. Gaps in our knowledge and research opportunities were also discussed.

The dark side of emotion: the addiction perspective

Emotions are "feeling" states and classic physiological emotive responses that are interpreted based on the history of the organism and the context. Motivation is a persistent state that leads to organized activity. Both are intervening variables and intimately related and have neural representations in the brain. The present thesis is that drugs of abuse elicit powerful emotions that can be interwoven conceptually into this framework. Such emotions range from pronounced euphoria to a devastating negative emotional state that in the extreme can create a break with homeostasis and thus an allostatic hedonic state that has been considered key to the etiology and maintenance of the pathophysiology of addiction. Drug addiction can be defined as a three-stage cycle-binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation-that involves allostatic changes in the brain reward and stress systems. Two primary sources of reinforcement, positive and negative reinforcement, have been hypothesized to play a role in this allostatic process. The negative emotional state that drives negative reinforcement is hypothesized to derive from dysregulation of key neurochemical elements involved in the brain incentive salience and stress systems. Specific neurochemical elements in these structures include not only decreases in incentive salience system function in the ventral striatum (within-system opponent processes) but also recruitment of the brain stress systems mediated by corticotropin-releasing factor (CRF), dynorphin-κ opioid systems, and norepinephrine, vasopressin, hypocretin, and substance P in the extended amygdala (between-system opponent processes). Neuropeptide Y, a powerful anti-stress neurotransmitter, has a profile of action on compulsive-like responding for drugs similar to a CRF1 receptor antagonist. Other stress buffers include nociceptin and endocannabinoids, which may also work through interactions with the extended amygdala. The thesis argued here is that the brain has specific neurochemical neurocircuitry coded by the hedonic extremes of pleasant and unpleasant emotions that have been identified through the study of opponent processes in the domain of addiction. These neurochemical systems need to be considered in the context of the framework that emotions involve the specific brain regions now identified to differentially interpreting emotive physiological expression.

Modulation of proopiomelanocortin gene expression by ethanol in mouse anterior pituitary corticotrope tumor cell AtT20

In humans, alcoholism is associated with a decrease in basal ACTH and cortisol levels, and blunted pituitary ACTH responses to administered corticotropin-releasing hormone (CRH) during active drinking and after long-term abstinence. Preclinical studies indicate that a persistent decrease in pituitary activation after chronic exposure to ethanol is due to a direct effect of ethanol on the corticotrope of the anterior pituitary. The present studies were undertaken to determine if ethanol has effects on proopiomelanocortin (POMC) gene transcription activity in mouse anterior pituitary corticotrope tumor cell AtT20. We measured the levels of the POMC primary nuclear RNA transcript (PT), processing intermediate, and mature mRNA in the nucleus and the levels of the POMC mRNA in the cytoplasm after treatment of AtT20 cells with 5-15 mM concentrations of ethanol. After 15 mM ethanol for 60 to 120 min, the POMC PT levels were significantly decreased. This decreased POMC gene transcription activity was coupled with a significant reduction of the POMC cytoplasmic mRNA levels. After ethanol for 4h, however, both the decreases were no longer observed. After 8h, a decrease in the ACTH secretion in the medium was found. We further investigated if CRH or glutamate modulates the effects of ethanol on the POMC gene transcription activity. CRH at 10nM after 60 min increased the POMC PT levels, and 15mM ethanol attenuated the effect of CRH on the nuclear transcription activity. Glutamate receptor proteins, including NMDA receptor subtype NR1 (but not NR2A or NR2B) and GluR2, were identified by Western immunoblot analysis in AtT20 cells, with similar sizes to those in mouse hypothalamus. The inhibitory effect of 60 min ethanol at 5 to 15 mM on the POMC PT levels was attenuated by 50 μM L-glutamate. Together, our data showed that: (1) ethanol treatment in intoxicate doses significantly inhibited POMC gene transcription activity in a dose- and time-dependent manner in AtT20 cells, and (2) the POMC gene transcription activity in response to CRH or glutamate was altered by ethanol. Our results suggest that ethanol has an inhibitory effect on the POMC gene transcription activity in the anterior pituitary corticotrope, which may contribute to the persistent decrease in pituitary activation after chronic ethanol exposure.

Alcohol, stress hormones, and the prefrontal cortex: a proposed pathway to the dark side of addiction

Chronic exposure to alcohol produces changes in the prefrontal cortex that are thought to contribute to the development and maintenance of alcoholism. A large body of literature suggests that stress hormones play a critical role in this process. Here we review the bi-directional relationship between alcohol and stress hormones, and discuss how alcohol acutely stimulates the release of glucocorticoids and induces enduring modifications to neuroendocrine stress circuits during the transition from non-dependent drinking to alcohol dependence. We propose a pathway by which alcohol and stress hormones elicit neuroadaptive changes in prefrontal circuitry that could contribute functionally to a dampened neuroendocrine state and the increased propensity to relapse-a spiraling trajectory that could eventually lead to dependence.

Intermittent access ethanol consumption dysregulates CRF function in the hypothalamus and is attenuated by the CRF-R1 antagonist, CP-376395

Corticotrophin-releasing factor (CRF) is a mediator of stress responses and a key modulator of ethanol-mediated behaviors. We report here that the CRF receptor 1 (CRF-R1) antagonist, CP-376395 reduces 20% ethanol consumption in animals trained to consume ethanol on an intermittent, but not a continuous, schedule. Furthermore, using [(35) S]GTPγS binding assays, we demonstrate that CRF-mediated G-protein signaling in the hypothalamus of the intermittent drinkers is decreased when compared to controls suggesting that the effects of CP-376395 are mediated by extrahypothalamic mechanisms. The present study provides further support for the use of CRF-R1 antagonists for the treatment of alcohol use disorders and suggests that ethanol consumption dysregulates CRF function in the hypothalamus.

Role of hypothalamic corticotropin-releasing factor in mediating alcohol-induced activation of the rat hypothalamic-pituitary-adrenal axis

Alcohol stimulates the hypothalamic-pituitary-adrenal (HPA) axis through brain-based mechanisms in which endogenous corticotropin-releasing factor (CRF) plays a major role. This review first discusses the evidence for this role, as well as the possible importance of intermediates such as vasopressin, nitric oxide and catecholamines. We then illustrate the long-term influence exerted by alcohol on the HPA axis, such as the ability of a first exposure to this drug during adolescence, to permanently blunt neuroendocrine responses to subsequent exposure of the drug. In view of the role played by CRF in addiction, it is likely that a better understanding of the mechanisms through which this drug stimulates the HPA axis may lead to the development of new therapies used in the treatment of alcohol abuse, including clinically relevant CRF antagonists.

Addiction as a stress surfeit disorder

Drug addiction has been conceptualized as a chronically relapsing disorder of compulsive drug seeking and taking that progresses through three stages: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. Drug addiction impacts multiple motivational mechanisms and can be conceptualized as a disorder that progresses from positive reinforcement (binge/intoxication stage) to negative reinforcement (withdrawal/negative affect stage). The construct of negative reinforcement is defined as drug taking that alleviates a negative emotional state. Our hypothesis is that the negative emotional state that drives such negative reinforcement is derived from dysregulation of key neurochemical elements involved in the brain stress systems within the frontal cortex, ventral striatum, and extended amygdala. Specific neurochemical elements in these structures include not only recruitment of the classic stress axis mediated by corticotropin-releasing factor (CRF) in the extended amygdala as previously hypothesized but also recruitment of dynorphin-κ opioid aversive systems in the ventral striatum and extended amygdala. Additionally, we hypothesized that these brain stress systems may be engaged in the frontal cortex early in the addiction process. Excessive drug taking engages activation of CRF not only in the extended amygdala, accompanied by anxiety-like states, but also in the medial prefrontal cortex, accompanied by deficits in executive function that may facilitate the transition to compulsive-like responding. Excessive activation of the nucleus accumbens via the release of mesocorticolimbic dopamine or activation of opioid receptors has long been hypothesized to subsequently activate the dynorphin-κ opioid system, which in turn can decrease dopaminergic activity in the mesocorticolimbic dopamine system. Blockade of the κ opioid system can also block anxiety-like and reward deficits associated with withdrawal from drugs of abuse and block the development of compulsive-like responding during extended access to drugs of abuse, suggesting another powerful brain stress/anti-reward system that contributes to compulsive drug seeking. Thus, brain stress response systems are hypothesized to be activated by acute excessive drug intake, to be sensitized during repeated withdrawal, to persist into protracted abstinence, and to contribute to the development and persistence of addiction. The recruitment of anti-reward systems provides a powerful neurochemical basis for the negative emotional states that are responsible for the dark side of addiction. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.