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Background: Functional MRI (fMRI) task-related analyses rely on an estimate of the brain's hemodynamic response function (HRF) to model the brain's response to events. Although changes in the HRF have been found after acute alcohol administration, the effects of heavy chronic alcohol consumption on the HRF have not been explored, and the potential benefits or pitfalls of estimating each individual's HRF on fMRI analyses of chronic alcohol use disorder (AUD) are not known., Methods: Participants with AUD and controls (CTL) received structural, functional, and vascular scans. During fMRI, participants were cued to tap their fingers, and averaged responses were extracted from the motor cortex. Curve fitting on these HRFs modeled them as a difference between 2 gamma distributions, and the temporal occurrence of the main peak and undershoot of the HRF was computed from the mean of the first and second gamma distributions, respectively., Results: ANOVA and regression analyses found that the timing of the HRF undershoot increased significantly as a function of total lifetime drinking. Although gray matter volume in the motor cortex decreased with lifetime drinking, this was not sufficient to explain undershoot timing shifts, and vascular factors measured in the motor cortex did not differ among groups. Comparison of random-effects analyses using custom-fitted and canonical HRFs for CTL and AUD groups showed better results throughout the brain for custom-fitted versus canonical HRFs for CTL subjects. For AUD subjects, the same was true except for the basal ganglia., Conclusions: These findings suggest that excessive alcohol consumption is associated with changes in the HRF undershoot. HRF changes could provide a possible biomarker for the effects of lifetime drinking on brain function. Changes in HRF topography affect fMRI activation measures, and subject-specific HRFs generally improve fMRI activation results., (© 2020 by the Research Society on Alcoholism.)

Although epidemiological research has shown an increase in drinking following stressors and trauma, limited paradigms have been validated to study the relationship between stress and drinking in the human laboratory. The current study developed a progressive ratio (PR) operant procedure to examine the effects of psychosocial stress on alcohol craving and several alcohol-motivated behaviors in persons with alcohol use disorder. Current heavy, nontreatment-seeking drinkers (N = 30) were media-recruited and completed a comprehensive assessment of recent drinking, mood and health. Participants were admitted to the clinical research unit and underwent 4-day, physician-monitored alcohol abstinence. On days 4 and 5, participants underwent the Trier Social Stress Test or a neutral session in random order followed by the alcohol-motivated response (AMR) procedure in which subjects worked for money or alcohol under a PR operant procedure. Subjects received earned money vouchers or alcohol at the conclusion of the session. The Trier Social Stress Test increased alcohol craving and rate of responding and decreased the number of changeovers between alcohol versus money reinforcers on the PR schedule. There was a positive relationship between alcohol craving and drinks earned during the stress session. This novel paradigm provides an experimental platform to examine motivation to drink without confounding by actual alcohol ingestion during the work session, thereby setting the stage for future studies of alcohol interventions., (© 2017 The Authors.Addiction Biology published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

During the critical developmental periods of childhood when neural plasticity is high, exposure to early life stress (ELS) or trauma may lead to enduring changes in physiological stress systems and enhanced vulnerability for psychopathological conditions such as post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) in adulthood. Clinical and preclinical studies have sought to understand the possible mechanisms linking ELS, PTSD, and AUD. Preclinical studies have employed animal models of stress to recapitulate PTSD-like behavioral deficits and alcohol dependence, providing a basic framework for identifying common physiological mechanisms that may underlie these disorders. Clinical studies have documented ELS-related endocrine dysregulation and genetic variations associated with PTSD and AUD, as well as disruption in crucial neural circuitry throughout the corticomesolimbic region. Despite limitations and challenges, both types of studies have implicated three interrelated mechanisms: hypothalamic pituitary adrenal (HPA) axis and glucocorticoid signaling dysregulation, genetics, and epigenetics. ELS exposure leads to disruption of HPA axis function and glucocorticoid signaling, both of which affect homeostatic cortisol levels. However, individual response to ELS depends on genetic variations at specific genes that moderate HPA axis and brain function, thus influencing susceptibility or resilience to psychopathologies. Epigenetic-influenced pathways also are emerging as a powerful force in helping to create the PTSD and AUD phenotypes. Dysregulation of the HPA axis has an epigenetic effect on genes that regulate the HPA axis itself, as well as on brain-specific processes such as neurodevelopment and neurotransmitter regulation. These studies are only beginning to elucidate the underpinnings of ELS, PTSD, and AUD. Larger human cohorts, identification of additional genetic determinants, and better animal models capable of recapitulating the symptoms of PTSD and AUD are needed., Competing Interests: Financial Disclosure The authors declare that they have no competing financial interests.

The aim of this study was to examine the relationship between family history of alcohol use disorder and striatal dopamine using positron emission tomography imaging. Participants were 84 healthy, 18- to 30-year-old, social drinkers recruited via fliers and newspaper advertisements. At assessment, participants completed measures of lifetime personal and family substance use and psychiatric symptoms. Participants underwent two consecutive positron emission tomography scans using the D 2 /D 3 dopamine receptor radioligand [ 11 C]raclopride. Scans were preceded by intravenous saline and amphetamine 0.3 mg/kg, providing measures of baseline [ 11 C]raclopride binding potential (BP ND ) and change in [ 11 C]raclopride (ΔBP ND ). Subjective ratings of stimulant drug effects were collected during scans. Subjects were classified as family history positive (FHP) if they reported any first-degree relative with alcohol use disorder (AUD) and family history negative (FHN) if no first-degree relatives had history of AUD. Participants were predominantly White (69.0 percent) and male (62.1 percent). Baseline [ 11 C]raclopride BP ND was generally higher in FHP compared with FHN subjects across striatal subdivisions. There were no differences in ΔBP ND across regions. Negative subjective drug effects were more pronounced in FHP than in FHN subjects. While FHN subjects evidenced the expected positive relationship between ΔBP ND and positive subjective drug effects, this relationship was disrupted in FHP subjects. There are key differences in dopamine status and subjective stimulant drug experiences as a function of family AUD history. These findings have important implications for understanding risk for AUD development in FHP offspring., Competing Interests: Drs. Alvanzo, Kuwabara, McCaul, and Xu reported no biomedical financial interests or potential conflicts of interest., (© 2015 Society for the Study of Addiction.)

Persons with a history of alcohol dependence are more likely to use tobacco and to meet criteria for nicotine dependence compared with social drinkers or non-drinkers. The high levels of comorbidity of nicotine and alcohol use and dependence are thought to be related to interactions between nicotinic, opioid and dopamine receptors in mesolimbic regions. The current study examined whether individual differences in regional μ-opioid receptor (MOR) availability were associated with tobacco use, nicotine dependence and level of nicotine craving in 25 alcohol-dependent (AD) subjects. AD subjects completed an inpatient protocol, which included medically supervised alcohol withdrawal, monitored alcohol abstinence, transdermal nicotine maintenance (21 mg/day) and Positron Emission Tomography (PET) imaging using the MOR agonist [(11) C]-carfentanil (CFN) before (basal scan) and during treatment with 50 mg/day naltrexone (naltrexone scan). Subjects who had higher scores on the Fagerström Nicotine Dependence Test had significantly lower basal scan binding potential (BPND ) across mesolimbic regions, including the amygdala, cingulate, globus pallidus, thalamus and insula. Likewise, the number of cigarettes per day was negatively associated with basal scan BPND in mesolimbic regions. Higher nicotine craving was significantly associated with lower BPND in amygdala, globus pallidus, putamen, thalamus and ventral striatum. Although blunted during naltrexone treatment, the negative association was maintained for nicotine dependence and cigarettes per day, but not for nicotine craving. These findings suggest that intensity of cigarette smoking and severity of nicotine dependence symptoms are systematically related to reduced BPND across multiple brain regions in AD subjects., (© 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.)

Individual differences in subjective responses (SRs) to alcohol are moderated by genetic variants and may be risk factors for the development of alcohol use disorders. Variation in the GABA(A) α2 receptor subunit gene (GABRA2) has been associated with alcohol dependence (AD). Therefore, we examined whether individual differences in SRs, which reflect sensitivity to the effects of alcohol, are associated with variation in GABRA2. Sixty-nine healthy subjects (21-30 years) underwent a laboratory-based within-session cumulative oral alcohol dosing procedure, achieving a mean peak blood alcohol level of 100.4 mg/dl (standard error = 2.5). Subjective assessments were obtained throughout the session, including ascending and descending limbs of the alcohol curve. We genotyped single nucleotide polymorphisms (SNPs) across the chromosome 4 region spanning GABRA2 and analyzed the effect of genotype and haplotypes on subjective responses to alcohol. Population substructure was characterized through the use of ancestry informative markers. Individual SNP analysis demonstrated that carriers of the minor alleles for SNPs rs279858, rs279844, rs279845, rs279826, rs279828 and rs279836 had lower 'Negative' alcohol effects scores than individuals homozygous for the common allele at each SNP (P = 0.0060, P = 0.0035, P = 0.0045, P = 0.0043, P = 0.0037 and P = 0.0061, respectively). Haplotype effects of block 1 showed concordant results with SNPs in this block (P = 0.0492 and P = 0.0150 for haplotypes 1 and 4, respectively). The minor alleles for several of these SNPs have previously been associated with AD. Our findings provide further evidence that variation within GABRA2 is associated with attenuated negative responses to alcohol, a known risk factor for vulnerability to alcohol use disorders., (Published 2012. This article is a U.S. Government work and is in the public domain in the USA.)

Hypothalamic-pituitary-adrenal (HPA) axis responses following naloxone administration have been assumed to provide a measure of opioid receptor activity. Employing positron emission tomography (PET) using the mu opioid receptor (MOR) selective ligand [(11)C] carfentanil (CFN), we demonstrated that cortisol responses to naloxone administration were negatively correlated with MOR availability. In this study, we examined whether naloxone-induced cortisol and adrenocorticotropin (ACTH) responses in 15 healthy control and 20 recently detoxified alcohol-dependent subjects correlated with delta opioid receptor (DOR) availability in 15 brain regions using the DOR-selective ligand [(11)C] methyl-naltrindole (MeNTL) and PET imaging. The day after the scan, cortisol responses to cumulative doses of naloxone were determined. Peak cortisol and ACTH levels and area under the cortisol and ACTH curve did not differ by group. There were negative relationships between cortisol area under curve to naloxone and [(11)C] MeNTL-binding potential (BP(ND)) in the ventral striatum, anterior cingulate, fusiform cortices, temporal cortex, putamen and a trend in the hypothalamus of healthy control subjects. However, in alcohol-dependent subjects, cortisol responses did not correlate with [(11)C]MeNTL BP(ND) in any brain region. Plasma ACTH levels did not correlate with [(11)C]MeNTL BP(ND) in either group. The study demonstrates that naloxone provides information about individual differences in DOR availability in several mesolimbic structures. The data also show that the HPA axis is intimately connected with mesolimbic stress pathways through opioidergic neurotransmission in healthy subjects but this relationship is disrupted during early abstinence in alcohol-dependent subjects., (© 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.)

The mu opioid receptor system is altered in alcohol dependent (AD) subjects. Cortisol responses to opioid receptor antagonists are assumed to impart information about opioid receptor activity. In the present study we examined naloxone-induced cortisol responses in 18 healthy control (HC) and 25 recently detoxified AD subjects and then correlated the cortisol response with mu opioid receptor availability across 15 brain regions using positron emission tomography (PET) and the mu opioid receptor selective ligand [(11)C] Carfentanil (CFN). On average the AD subjects required twice the dose of naloxone to induce a peak cortisol response compared to the HC subjects. Using the rising slope of the cortisol curve (placebo to peak) as a metric we then went on to examine the relationship between cortisol responses to naloxone and [(11)C]CFN BP(ND). There were significant negative relationships between cortisol and [(11)C]CFN binding potential (BP(ND)) in multiple brain regions of HC subjects. However, cortisol responses did not correlate with [(11)C]CFN BP(ND) across any brain region in AD subjects. In summary, naloxone imparts information about individual differences in mu opioid receptor availability throughout the mesolimbic system in healthy individuals. However pathways governing the relationship between naloxone-induced cortisol and mu opioid receptor availability are disrupted during early abstinence in AD subjects., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: The endogenous opioid system plays a significant role in alcohol dependence. The goal of the current study was to investigate regional brain mu-opioid receptor (MOR) and delta-opioid receptor (DOR) availability in recently abstinent alcohol-dependent and age-matched healthy control men and women with positron emission tomography (PET) imaging., Methods: Alcohol-dependent subjects completed an inpatient protocol, which included medically supervised withdrawal and PET imaging on day 5 of abstinence. Control subjects completed PET imaging following an overnight stay. PET scans with the MOR-selective ligand [(11)C]carfentanil (CFN) were completed in 25 alcohol-dependent and 30 control subjects. Most of these same subjects (20 alcohol-dependent subjects and 18 controls) also completed PET scans with the DOR-selective ligand [(11)C]methylnaltrindole (MeNTL)., Results: Volumes of interest and statistical parametric mapping analyses indicated that alcohol-dependent subjects had significantly higher [(11)C]CFN binding potential (BP(ND) ) than healthy controls in multiple brain regions including the ventral striatum when adjusting for age, gender, and smoking status. There was an inverse relationship between [(11)C]CFN BP(ND) and craving in several brain regions in alcohol-dependent subjects. Groups did not differ in [(11)C]MeNTL BP(ND) ; however, [(11)C]MeNTL BP(ND) in caudate was positively correlated with recent alcohol drinking in alcohol-dependent subjects., Conclusions: Our observation of higher [(11)C]CFN BP(ND) in alcohol-dependent subjects can result from up-regulation of MOR and/or reduction in endogenous opioid peptides following long-term alcohol consumption, dependence, and/or withdrawal. Alternatively, the higher [(11)C]CFN BP(ND) in alcohol-dependent subjects may be an etiological difference that predisposed these individuals to alcohol dependence or may have developed as a result of increased exposure to childhood adversity, stress, and other environmental factors known to increase MOR. Although the direction of group differences in [(11)C]MeNTL BP(ND) was similar in many brain regions, differences did not achieve statistical significance, perhaps as a result of our limited sample size. Additional research is needed to further clarify these relationships. The finding that alcohol-dependent subjects had higher [(11)C]CFN BP(ND) is consistent with a prominent role of the MOR in alcohol dependence., (Copyright © 2011 by the Research Society on Alcoholism.)

A challenging question that continues unanswered in the field of addiction is why some individuals are more vulnerable to substance use disorders than others. Numerous risk factors for alcohol and other drugs of abuse, including exposure to various forms of stress, have been identified in clinical studies. However, the neurobiological mechanisms that underlie this relationship remain unclear. Critical neurotransmitters, hormones and neurobiological sites have been recognized, which may provide the substrates that convey individual differences in vulnerability to addiction. With the advent of more sophisticated measures of brain function in humans, such as functional imaging technology, the mechanisms and neural pathways involved in the interactions between drugs of abuse, the mesocorticolimbic dopamine system and stress systems are beginning to be characterized. This review provides a neuroadaptive perspective regarding the role of the hormonal and brain stress systems in drug addiction with a focus on the changes that occur during the transition from occasional drug use to drug dependence. We also review factors that contribute to different levels of hormonal/brain stress activation, which has implications for understanding individual vulnerability to drug dependence. Ultimately, these efforts may improve our chances of designing treatment strategies that target addiction at the core of the disorder.

Blockade of brain mu-opioid receptor (mu-OR) and delta-opioid receptor (delta-OR) was investigated in recently abstinent alcohol-dependent subjects (N=21) maintained on naltrexone. Subjects completed a 19-day inpatient protocol, which included alcohol abstinence followed by naltrexone treatment (50 mg) on days 15-19. Blood samples were collected after the first administration of naltrexone to evaluate serum levels of naltrexone and 6-beta-naltrexol. Regional brain mu-OR binding potential (BP) and delta-OR Ki was measured using [11C]carfentanil (CAR) positron emission tomography (PET) and [11C]methyl naltrindole ([11C]MeNTI) PET, respectively, before (day 5) and during naltrexone treatment (day 18). Naltrexone inhibition of [11C]CAR BP was near maximal across all brain regions of interest with little variability across subjects (mean+SD% inhibition=94.9+4.9%). Naltrexone only partially inhibited the [11C]MeNTI Ki and there was more variability across subjects (mean+SD% inhibition=21.1+14.49%). Peak serum levels of naltrexone were positively correlated with % inhibition of delta-OR Ki in neocortex and basal ganglia. Peak serum levels of naltrexone were not correlated with % inhibition of mu-OR BP. Peak levels of 6-beta-naltrexol were not significantly correlated with % inhibition of mu-OR BP or delta-OR Ki. Thus, the FDA recommended therapeutic dose of naltrexone was sufficient to produce near complete inhibition of the mu-OR in recently abstinent alcohol dependent subjects. The lower percent inhibition of delta-OR and greater variability in delta-OR blockade by naltrexone across subjects may contribute to individual differences in treatment outcomes to naltrexone. Further investigations on the relationship between individual differences in delta-OR blockade by naltrexone and clinical outcomes should be explored.

The present study was designed to determine whether stress hormones and subjective responses to a psychological stressor were different in nonalcoholic offspring from families with a history of alcohol dependence (family history positive, FHP) than in nonalcoholic offspring without a family history of alcohol dependence (family history negative, FHN). Forty-five healthy subjects (17 FHP, 28 FHN), between the ages of 18 and 29 years, completed the Trier Social Stress Test (TSST). The TSST consisted of 5 min of public speaking followed by 5 min of mental arithmetic. Three baseline and five post-TSST blood samples were drawn. Pre- and post-TSST self-report measures of anxiety were obtained. Cortisol, adrenocorticotropin (ACTH), and prolactin significantly increased in response to the TSST in the entire study sample (F(1,187)=70.22, p<0.001, F(1,143)=33, p<0.001, and F(1,134)=14.37, p<0.001, respectively). Cortisol responses were influenced by an interaction between racial composition and family history of alcoholism (F(1,57)=4.50, p=0.038). Among Caucasian subjects, FHP subjects had greater cortisol response to the TSST compared to FHN subjects (F(1,57)=4.45, p=0.039). No family history effect was identified in African-American subjects. Adrenocorticotropin responses did not differ between FHP and FHN subjects. Adrenocorticotropin response was positively associated with baseline ACTH levels in FHN subjects (t=5.02, p=or<0.001), but not in FHP subjects. Prolactin responses did not differ between FHP and FHN subjects. Anxiety response scores (post-TSST scores minus pre-TSST scores) were higher in FHP subjects compared with FHN subjects (z=-2.67, p=0.007). In addition, anxiety response scores were positively associated with cortisol response levels to the TSST in FHN subjects (t=4.52, p<0.001). In contrast, anxiety responses were negatively associated with cortisol responses in FHP subjects (t=-2.30, p=0.024). Our findings are consistent with theories that greater reactivity to stress is associated with greater risks for alcoholism. Furthermore, the findings suggest that the association between the hypothalamic-pituitary-adrenal axis hormonal response and the subjective perception of stress might be deranged in offspring of alcoholics.

Background: The offspring of alcohol-dependent individuals are at increased risk for alcoholism. The present study was designed to determine whether mesolimbic dopamine binding potential (BP), dopamine release, stress hormones, and subjective responses to intravenous amphetamine are different in nonalcoholic offspring from families with a history of alcohol dependence [family history positive (FHP)] than in nonalcoholic offspring without a family history of alcohol dependence [family history negative (FHN)]., Methods: Participants were 41 healthy men and women (11 FHP, 30 FHN; age range 18-29). After completing baseline psychiatric symptom and personality measures, striatal D2/D3 dopamine BP and dopamine release in response to an amphetamine challenge were measured with positron emission tomography (PET) using the D2/D3 dopamine (DA) receptor radioligand [11C]raclopride. Binding potential was defined as Bmax/KD, percent change in BP from baseline defined dopamine release. During the scans, subjects rated the degree to which they were experiencing each of 10 possible drug effects. Plasma cortisol and growth hormone (GH) were also measured at scheduled intervals during the scans., Results: Neither baseline BP nor dopamine release differed by family history. Similarly, subjective responses to amphetamine did not differ by a family history of alcoholism. Although both cortisol and GH increased following administration of amphetamine, these increases did not differ between family history groups., Conclusions: Using amphetamine to provoke mesolimbic dopamine, we did not show significant differences in dopamine release, subjective responses, or stress hormone measures as a function of family history of alcoholism.

Background: Previous studies have described blunted stress hormone responses after pharmacological activation of the hypothalamic-pituitary-adrenal (HPA) axis in sober alcoholics. The aim of the present study was to compare ACTH, cortisol, and prolactin responses to a psychological stressor in abstinent alcohol-dependent subjects matched to healthy control subjects., Methods: Individuals who met DSM-IV diagnostic criteria for a history of alcohol dependence but not for other axis I disorders were included in the study (n = 18; mean duration of abstinence +/- SEM, 3.5 +/- 5.7 years). Social drinkers (n = 23) served as control subjects. The sober alcohol-dependent and control subjects were matched for demographic measures including levels of stress symptoms. All subjects underwent the Trier Social Stress Test (TSST), a laboratory-based psychological stressor. Prestress and poststress plasma ACTH, cortisol, and prolactin levels, as well as a self-report measure of anxiety (State-Trait Anxiety Inventory), were obtained., Results: Nondepressed, abstinent alcoholics and control subjects did not differ with regard to age, racial composition, or baseline or poststress ratings of anxiety. Whereas ACTH and cortisol levels increased in response to the TSST, prolactin levels did not. Stress hormone response curves for the three hormones did not differ between the alcoholics and control subjects., Conclusions: When matched for levels of stress, a laboratory-based psychological stress test did not induce differential hormone response curves for abstinent alcoholics and control subjects.

Although far from conclusive, evidence implicating the endogenous opioid system in the development and maintenance of alcoholism is growing. Currently available data suggest that ethanol increases opioid neurotransmission and that this activation is part of the mechanism responsible for its reinforcing effects. Findings from preclinical research indicate that ethanol consumption and ethanol-induced dopamine (DA) release are both reduced by opioid antagonists. Individual differences in endogenous opioid activity have been linked to inherited risks for alcoholism in studies comparing ethanol-preferring and nonpreferring rats, as well as in studies using targeted gene mutation (knockout) strategies. To a large extent, findings from human studies have paralleled those from the preclinical work. Persons who differ in family history of alcoholism have been shown to also differ in basal beta-endorphin activity, beta-endorphin response to alcohol, and subjective and HPA axis hormonal response to opioid antagonists. Findings from clinical trials indicate that opioid antagonists may reduce ethanol consumption in alcoholics, particularly in persons who have resumed drinking. Nevertheless, many questions remain unanswered about the use of opioid antagonists in alcoholism treatment and about the exact role of the opioid system in ethanol preference and reward. The progression of knowledge in this field suggests that many of these questions are imminently answerable, as our ability to characterize relationships between opioid activity and human behavior continues to develop. This paper summarizes both the progress that has been made and the gaps that remain in our understanding of the interactions between the endogenous opioid system and risk for alcoholism., (Copyright 2004 Elsevier Inc.)

Background: The endogenous opioid system has been linked to alcohol dependence through animal and human studies. We investigated the relationship between alcohol craving and brain mu opioid receptors (mu-OR) in alcohol-dependent subjects., Methods: Regional brain mu-OR binding potential (BP) was measured using [(11)C]carfentanil positron emission tomography in eight male alcohol-dependent subjects undergoing alcohol withdrawal and eight matched control subjects. Self-reported alcohol craving, withdrawal, and mood were measured., Results: Lower mu-OR BP was associated with higher craving in the right dorsal lateral prefrontal cortex, the right anterior frontal cortex, and right parietal cortex. In these regions, alcoholics showed lower mean mu-OR BP compared with control subjects. Mu-OR BP in four other brain regions also correlated with craving, but there were no group differences in receptor binding potential. Mu-OR BP also correlated with depressive symptoms in five brain regions, three of which were identified in the craving analyses., Conclusions: Results show a strong functional relationship between alcohol craving, mood, and mu-OR binding in specific brain regions of recently abstinent, alcohol-dependent men.

Background: There is strong evidence for the role of the endogenous opioid system in alcohol reinforcement and consumption; however, recent human laboratory studies and clinical trials have reported mixed effects of naltrexone (a nonselective opioid antagonist) on alcohol-related behaviors. This paper reports a secondary data analysis of a human laboratory study that examines the relationship between serum levels of 6-beta-naltrexol, the major, biologically active metabolite of naltrexone, and subjective effects of alcohol., Methods: The study used a within-subjects design to examine the effects of naltrexone (0, 50, and 100 mg/day) on subjective responses to alcohol (none, moderate, and high dose) in heavy drinkers (n = 23). Each subject received three doses of naltrexone in random order; each naltrexone dose was administered over an 8 day period on an inpatient unit, with a 1 week outpatient washout between doses. After stabilization at each of the naltrexone doses, subjects participated in three alcohol challenge sessions (none, moderate, and high dose) in random order; thus, each subject participated in a total of nine alcohol administration sessions., Results: Doubling the naltrexone dose (50 vs. 100 mg/day) doubled the mean serum 6-beta-naltrexol levels. At each naltrexone dose, there was a 4-fold range in 6-beta-naltrexol levels across subjects. Before alcohol administration, higher 6-beta-naltrexol levels were associated with higher ratings of sedation. After high-dose alcohol administration, higher 6-beta-naltrexol levels were associated with significantly lower ratings of liking and best effects., Conclusions: These findings provide further evidence of the involvement of the opioid system in the modulation of alcohol effects and suggest that serum 6-beta-naltrexol concentrations may be important in predicting therapeutic response to naltrexone.

Endogenous opioid activity has been associated with the regulation of mood and inhibition of the hypothalamic-pituitary-adrenal (HPA) axis. We assessed differences in psychological symptomology and naloxone sensitivity in non-alcoholic males and females with a family history of alcoholism (FHP) and without a family history of alcoholism (FHN). This was followed by assessment of the association between naloxone sensitivity and psychological symptomology. Psychological symptomology was measured using the Revised Symptom Checklist (SCL-90-R) during enrollment. Adrenocorticotropin was measured following intravenous administration of naloxone/placebo. FHP males reported more obsessive-compulsive symptomology as well as increased sensitivity to naloxone relative to other groups. A positive association was observed between degree of obsessive-compulsive symptomology and naloxone sensitivity, and the association was strongest among FHP males. These findings suggest that the increased risk of alcoholism in FHP subjects (especially males) may be associated with altered opioid activity, which is expressed through an elevated level of obsessive compulsive symptomology.

Background: This study was designed to assess whether nonalcoholic offspring from families with a high density of alcohol-dependent individuals have altered hypothalamic-pituitary-adrenal (HPA) axis dynamics compared with nonalcoholic subjects without a family history of alcohol dependence., Methods: Seventy-eight nonalcoholic subjects aged 18 to 25 were enrolled in the protocol. Thirty-nine subjects were offspring from families with a high density of alcohol dependence and were designated as family history-positive (FHP) subjects. Thirty-nine subjects were biological offspring of nonalcohol-dependent parents and were designated as family history-negative (FHN) subjects. Subjects received naloxone hydrochloride (0 and 125 microg/kg) and cosyntropin (0, 0.25 microg, and 250 microg) in double-blind, randomized order and cortisol was monitored. A subset of subjects (11 FHP, 11 FHN) was admitted to the General Clinical Research Center to measure serum cortisol levels every 30 min for 24 hr., Results: FHP subjects had an increased cortisol response to opioid receptor blockade induced by naloxone. However, no group differences in cortisol were uncovered during administration of cosyntropin or during monitoring of the cortisol circadian profile., Conclusion: These observations suggest that differences in the cortisol dynamics between FHP and FHN subjects are unmasked by opioid receptor blockade directed at the hypothalamus, but not when cortisol levels are directly provoked at the level of the adrenal gland. In addition, unprovoked cortisol secretion monitored over a 24-hr interval cannot distinguish FHP from FHN subjects.

The endogenous opioid system is part of a neural circuitry functionally related to alcohol-seeking behaviors. A family history of alcoholism is the strongest predictor of future development of alcohol dependence. This study was designed to evaluate ACTH responses to opioid receptor blockade as a function of family history for alcohol dependence. The nonselective opioid antagonist naloxone stimulates ACTH secretion by blocking opioidergic input on paraventricular corticotropin-releasing factor neurons, thereby providing a methodology for comparing hypothalamic opioid tone between study groups. Sixty nonalcoholic subjects, aged 18-25 yr, were enrolled in a protocol to measure the ACTH response to naloxone. Thirty-two subjects were offspring from families with a high density of alcohol dependence and were designated as family history-positive subjects. Twenty-eight subjects were offspring of nonalcohol-dependent parents and were designated family history-negative subjects. Subjects received naloxone (125 microg/kg) or placebo (0.9% saline) in double blind, randomized order. Plasma ACTH was monitored. Family history-positive men had increased ACTH response to naloxone compared to 1) family history-positive women, 2) family history-negative men, and 3) family history-negative women. Despite differences in plasma ACTH levels after naloxone administration, plasma naloxone concentrations did not differ between study groups. This finding suggests that nonalcoholic male offspring of alcohol-dependent men have altered endogenous opioid activity directed at hypothalamic corticotropin-releasing factor neurons.

Background: This study was designed to assess whether nonalcoholic offspring from families with a high density of alcohol-dependent individuals have altered endogenous central nervous system opioid activity. Naloxone hydrochloride stimulates plasma cortisol by blocking opioidergic input on the corticotropin-releasing factor neuron, thereby providing a noninvasive method for measuring hypothalamic opioid tone., Methods: Forty-eight nonalcoholic subjects aged 18 to 25 years were enrolled in a protocol to measure endogenous opioid activity by inducing opioid receptor blockade with the receptor antagonist, naloxone. Twenty-six subjects were offspring from families with a high density of alcohol dependence and were designated as family history-positive subjects. Twenty-two subjects were biological offspring of nonalcohol-dependent parents and designated as family history-negative subjects. Subjects received naloxone hydrochloride (0, 125, and 375 microg/kg) in double-blind, randomized order. Serum cortisol levels were monitored., Results: Family history-negative subjects had a graded cortisol response to each dose of naloxone. In contrast, family history-positive subjects achieved a maximal cortisol response to the 125-microg/kg dose of naloxone hydrochloride with no further increase in cortisol levels observed following the 375-microg/kg dose. Family history-negative subjects had a diminished cortisol response to the 125-microg/kg dose compared with the family history-positive subjects. Plasma naloxone concentrations did not differ between family history groups., Conclusions: Individuals from families with a high density of alcohol dependence are more sensitive to naloxone compared with offspring of nonalcohol-dependent parents. This implies that individuals with a family history of alcohol dependence have diminished endogenous hypothalamic opioid activity.

This study examined influences of ethanol exposure on phosphorylation of cAMP response element-binding protein (CREB) and CRE-binding activity in the striatum of rats. The phosphorylated form of CREB increased 180% during acute intoxication, compared to sham conditions. After chronic ethanol exposure, induction of CREB phosphorylation by an acute ethanol challenge was markedly attenuated (50%) compared with acute ethanol exposure in the pair-fed condition. Gel retardation assays with oligomers encoding the rat proenkephalin CRE-1 and CRE-2 were performed to determine the effects of ethanol on CRE-binding activity. Supershift experiments demonstrated that striatal nuclear protein contains CREB and CEBPPbeta (CCAAT/enhancer-binding protein) and that both transcription factors are involved in specifically binding to the DNA sequence. Rechallenging rats that had been chronically exposed to ethanol with an acute ethanol challenge reduced the CRE/nuclear protein complexes. However, supershift analyses did not show that chronic ethanol exposure altered the dimerization patterns of CREB and CEBPbeta within the complexes. Associated with these impairments in CREB binding and CREB phosphorylation was a significant reduction in two CREB-modulated factors, proenkephalin and c-fos expression. In summary, acute ethanol exposure activates the phosphorylation of CREB. Neuroadaptation to chronic ethanol exposure includes alterations in CREB physiology that may impair genes that are dependent upon CREB for transcriptional activation.

We evaluated G-proteins that are components of adenylyl cyclase (AC) signal transduction in erythrocyte and lymphocyte membranes from 26 family history positive (FHP) non-alcoholic and 26 family history negative (FHN) nonalcoholic subjects. Subjects were classified as FHP if their father met criteria for alcohol dependence; as FHN, if there was no history of alcoholism in any first or second degree relatives. Immunoblot analysis indicated that levels of erythrocyte membrane Gs alpha from FHP subjects were greater than levels in FHN subjects (171 +/- 11 vs 100 +/- 6, P < 0.001). To confirm the results of the immunoblot analysis, Gs alpha was quantitated by cholera toxin-dependent [32P]ADP-ribosylation. Levels of erythrocyte [32P]ADP-ribose-Gs alpha from FHP subjects were greater than levels in FHN subjects (236 +/- 28 vs 100 +/- 14, P < 0.001). Gs alpha levels did not correlate with age or alcohol consumption. By contrast to differences in Gs alpha, immunoblot analysis showed similar levels of Gi(2)alpha and Gi(3)alpha in erythrocyte membranes of FHP and FHN subjects. Pertussis toxin-catalyzed [32P]ADP-ribosylation of Gi-like G-proteins confirmed the immunoblot observations. Lastly, compared to FHN subjects, FHP subjects had enhanced Gs alpha expression in lymphocyte membranes as well (138 +/- 11 vs 100 +/- 5.5; P < 0.02). In summary, compared to FHN nonalcoholic men, FHP nonalcoholic men had greater levels of the stimulatory G-protein, Gs alpha, in erythrocyte and lymphocyte membranes. Enhanced expression of Gs alpha may be a marker of increased risk for the future development of alcoholism.

Alcoholism is a familial disorder with both genetic and environmental determinants. The sons of alcoholic fathers have been documented to have alterations in several neuroendocrine measures. We investigated the ACTH/cortisol response to ovine corticotropin-releasing hormone (oCRH) and ethanol in men with and without a family history of alcoholism. Men were defined as family history positive (FHP) (n = 7) if their father was alcoholic; as family history negative (FHN) (n = 16), if their father was nonalcoholic. Ethanol (0.75 g/kg) or placebo was ingested over 15 min, 1 microgram/kg oCRH was administered, and plasma ACTH/cortisol levels were determined at -20, 0, 15, 30, 60, and 90 min after oCRH. Following placebo, FHP men had lower peak ACTH response to oCRH than did FHN men (12 +/- 2 vs 20 +/- 2 pmol/liter, P = 0.04). In FHN men, plasma ACTH response to oCRH was blunted during the ethanol session compared to the placebo session (13 +/- 1 vs 20 +/- 2 pmol/liter; P = 0.006). In contrast, FHP men had similar ACTH responses to oCRH during ethanol and placebo sessions. Cortisol responses to oCRH were similar in both groups during both sessions. In summary, FHP and FHN nonalcoholic men had different plasma ACTH responses following the administration of oCRH.

Ethanol exposure alters signal transduction through the adenylyl cyclase (AC) system. To elucidate the basis for this effect, we investigated the AC system in peripheral lymphocytes from abstinent alcoholic men (n = 22), actively drinking alcoholic men (n = 41), and nonalcoholic control men (n = 16). Immunoblot analysis of lymphocyte membranes from abstinent alcoholics demonstrated a 3.0-fold increase in the level of Gi2 alpha protein (p < 0.05) compared with controls. However, levels of Gs alpha protein were similar in both groups. Abstinent alcoholics had a 2.9-fold increase in Gi2 alpha mRNA (p < 0.001) and a 2.7-fold increase in Gs alpha mRNA (p < 0.03) compared with lymphocytes from control subjects. Actively drinking alcoholics, in contrast, had unaltered Gs alpha protein, Gi2 alpha protein, and Gi2 alpha mRNA levels compared with control subjects, but did have a 1.8-fold increase (p < 0.01) in Gs alpha mRNA. Consistent with enhanced Gi2 alpha expression, lymphocyte membranes from abstinent alcoholics had decreased basal, prostaglandin E1-, guanosine 5'-0-(3-thiotriphosphate)-gamma S-, and forskolin-stimulated AC activity compared with both controls and actively drinking alcoholics (p < 0.05). We conclude that lymphocyte AC is reduced during abstinence from alcohol and enhanced expression of the inhibitory G-protein, Gi2 alpha, may account for this change.

The impact of chronic alcohol abuse on the hypothalamic-pituitary-adrenal (HPA) axis was investigated in actively drinking, nondepressed alcoholics with no evidence of liver disease. Fourteen male alcoholics and 13 matched nonalcoholics were studied. Although alcoholics and controls had similar decrements in cortisol levels after metyrapone blockade, plasma ACTH and 11-deoxycortisol levels in alcoholics were 60% (P less than 0.05) and 40% (P less than 0.05), respectively, of control values. To further clarify defects in the HPA axis of the alcoholic group, each subject underwent a CRH stimulation test. Compared to control subjects, alcoholics had a significantly blunted plasma ACTH response to CRH stimulation (P less than 0.05). Timing of the peak plasma ACTH response was altered in alcoholics. Whereas all control subjects had a peak plasma ACTH response 30 min after CRH administration, 50% of alcoholics demonstrated a peak plasma ACTH response 60 min after CRH administration, and 50% demonstrated a peak plasma ACTH response 30 min after CRH. To determine if adrenal function was also impaired, alcoholics and controls underwent a standard (250 micrograms) and a submaximal (0.250 micrograms) Cortrosyn stimulation test. Controls demonstrated a significant cortisol response to both standard and low dose Cortrosyn. Although alcoholics had a cortisol response similar to that of controls after the standard dose of Cortrosyn, they did not have a statistically significant rise in cortisol after the submaximal dose of Cortrosyn. Twenty-four-hour urinary free cortisol levels were 2-fold higher in alcoholics compared to controls. In summary, although a subset of alcoholics demonstrated enhanced basal production of cortisol, most alcoholics had a blunted response to acute intervening stress, including CRH, low dose ACTH-(1-24), and metyrapone blockade. These data suggest that alcoholics have ethanol-induced HPA axis injury, resulting in an inappropriately reduced response to nonethanol-induced stress.