Intravenous Alcohol Self-administration Research Articles

Initial evidence of delay discounting’s predictive utility for alcohol self-administration in ecologically valid contexts among young adults who drink heavily

BackgroundWhile delay discounting is robustly associated with alcohol use disorder, whether discounting predicts real-time alcohol use behaviors is unclear. Existing support comes from laboratory studies using intravenous alcohol self-administration methods, thus limiting ecological validity and generalizability. The present study evaluated whether delay discounting predicted real-time alcohol use in naturalistic settings with and without probabilistic negative consequences for consuming larger amounts of alcohol. MethodsThis secondary analysis utilized data from three laboratory alcohol self-administration studies with young adults who engaged in frequent heavy drinking (N=206, 45% female). Participants completed a delay discounting measure before an alcohol self-administration session in an actual or simulated bar with (n=187) or without (n=19) probabilistic negative consequences (compensation loss) tied to performance on cognitive and psychomotor tasks after alcohol self-administration. Bootstrapped (unstandardized) coefficient estimates and 95% confidence intervals were utilized due to the sample size discrepancy. ResultsMultiple regressions revealed that delay discounting did not significantly predict estimated blood alcohol concentration (eBAC) or number of drinks consumed when procedures included probabilistic negative consequences. Among participants who completed procedures without probabilistic negative consequences, delay discounting was positively associated with peak eBAC. ConclusionCounter to hypotheses, steeper delay discounting did not predict real-time alcohol use in contexts with probabilistic negative consequences, whereas preliminary evidence suggests that delay discounting predicts real-time alcohol use behaviors in contexts without probabilistic negative consequences. The specific discounting task may have impacted study findings, thus future research should consider how the sign (gain vs. loss), outcome certainty, and delay relate to alcohol consumption.

High-intensity sweet taste as a predictor of subjective alcohol responses to the ascending limb of an intravenous alcohol prime: an fMRI study.

High-intensity sweet-liking has been linked to alcohol use disorder (AUD) risk. However, the neural underpinning of this association is poorly understood. To find a biomarker predictive of AUD, 140 participants (social and heavy drinkers, ages 21-26) underwent functional magnetic resonance imaging (fMRI) during a monetary incentive delay (MID) task and stimulation with high (SucroseHigh)- and low-concentration sucrose, as well as viscosity-matched water. On another day after imaging, and just before free-access intravenous alcohol self-administration, participants experienced a 30 mg% alcohol prime (10 min ascent) using the Computerized Alcohol Infusion System. Principal component analysis (PCA) of subjective responses (SR) to the prime's ascending limb generated enjoyable (SRenjoy) and sedative (SRsed) intoxication components. Another PCA created one component reflective of self-administered alcohol exposure (AE) over 90 min. Component loadings were entered as regressors in a voxel-wise general linear fMRI model, with reward type as a fixed factor. By design, peak prime breath alcohol concentration was similar across participants (29 ± 3.4 mg%). SRenjoy on the prime's ascending limb correlated positively with [SucroseHigh > Water] in the supplementary motor area and right dorsal anterior insula, implicating the salience network. Neither SR component correlated with the brain's response to MID. AE was unrelated to brain reward activation. While these findings do not support a relationship between alcohol self-administration and (1) subjective liking of or (2) regional brain response to an intensely sweet taste, they show that alcohol's enjoyable intoxicating effects on the rising limb correspond with anterior insular and supplementary motor area responses to high-concentration sucrose taste. No such associations were observed with MID despite robust activation in those regions. Insula and supplementary motor area responses to intense sensations relate to a known risk factor for AUD in a way that is not apparent with a secondary (monetary) reward.

Free-access intravenous alcohol self-administration in social drinkers and individuals with alcohol use disorder: Evaluation of relationships with phosphatidylethanol and self-reported alcohol consumption.

The free-access (FA) intravenous alcohol self-administration (IV-ASA) paradigm is an experimental approach that can identify modulators of alcohol consumption in humans. Moreover, the outcome measures of IV-ASA paradigms are associated with self-reported alcohol intake using the timeline follow-back method (TLFB). To evaluate how FA IV-ASA reflects drinking in real life, we examined the relationship between an objective marker of recent alcohol intake, phosphatidylethanol in blood (B-PEth), and TLFB and measures obtained during IV-ASA in individuals with alcohol use disorder (AUD) and social drinkers (SD). We also explored the associations between these measures and gut-brain peptides involved in AUD pathophysiology. Thirty-eight participants completed a laboratory session in which they self-administered alcohol intravenously. The safety limit was 200 mg%, and main outcomes were mean and peak breath alcohol concentrations (BrAC). Blood samples were drawn prior to IV-ASA and subjective alcohol effects were rated during the experiment. The study sample comprised 24 SD and 14 participants with DSM-5 mild AUD. Although BrACs were not associated with B-PEth or TLFB in the full sample or AUD subgroup, there was an association with TLFB in SD. In both subgroups, BrACs were associated with alcohol craving but with differential timing. Total ghrelin levels were higher in AUD participants than in SD. No associations between B-PEth levels and achieved BrACs were observed in the mild AUD group, the SD group, or the full sample. The ability for FA IV-ASA to reflect recent drinking was confirmed only for TLFB in SD, whereas there were no associations within the smaller subsample of participants with mild AUD or in the full sample. Further studies that include a larger AUD sample are warranted. The association of BrACs with craving for alcohol suggests that the IV-ASA method may be useful for assessing interventions that target craving. This could be explored by using the FA IV-ASA model to evaluate the effects on craving of approved pharmacotherapies for AUD.

Modeling ability to resist alcohol in the human laboratory: A pilot study

BackgroundRoughly half of patients with alcohol use disorder prefer non-abstinence based approaches to treatment. However, only individuals who can limit their alcohol use after low-risk consumption are most likely to benefit from these approaches. This pilot study developed a laboratory-based intravenous alcohol self-administration paradigm to determine the characteristics of individuals who could successfully resist consuming alcohol after an initial exposure. MethodsSeventeen non-treatment seeking heavy drinkers completed two versions of an intravenous alcohol self-administration paradigm designed to assess impaired control over alcohol use. In the paradigm, participants received a priming dose of alcohol and then entered a 120-min resist phase, in which they received monetary rewards if they resisted self-administering alcohol. We used Cox proportional hazards regression to determine the impact of craving and Impaired Control Scale scores on rate of lapse. Results64.7% of participants across both versions of the paradigm were unable to resist alcohol for the duration of the session. Craving at baseline (HR = 1.07, 95% CI 1.01-1.13, p = 0.02) and following priming (HR = 1.08, 95% CI 1.02-1.15, p = 0.01) were associated with rate of lapse. Individuals who lapsed endorsed greater attempts to control their drinking over the prior six months compared to individuals who resisted. ConclusionsThis study provides preliminary evidence that craving may be predictive of risk of lapse in individuals who are trying to limit alcohol intake after consuming a small initial amount of alcohol. Future studies should test this paradigm in a larger and more diverse sample.

Binge and high-intensity drinking-Associations with intravenous alcohol self-administration and underlying risk factors.

Some styles of alcohol consumption are riskier than others. How the level and rate of alcohol exposure contribute to the increased risk of alcohol use disorder is unclear, but likely depends on the alcohol concentration time course. We hypothesized that the brain is sensitive to the alcohol concentration rate of change and that people at greater risk would self-administer faster. We developed a novel intravenous alcohol self-administration paradigm to allow participants direct and reproducible control over how quickly their breath alcohol concentration changes. We used drinking intensity and the density of biological family history of alcohol dependence as proxies for risk. Thirty-five alcohol drinking participants aged 21-28 years provided analytical data from a single, intravenous alcohol self-administration session using our computer-assisted alcohol infusion system rate control paradigm. A shorter time to reach 80 mg/dl was associated with increasing multiples of the binge drinking definition (p = 0.004), which was in turn related to higher density of family history of alcoholism (FHD, p = 0.04). Rate-dependent changes in subjective response (intoxication and stimulation) were also associated with FHD (each p = 0.001). Subsequently, given the limited sample size and FHD range, associations between multiples of the binge drinking definition and FHD were replicated and extended in analyses of the Collaborative Study on the Genetics of Alcoholism database. The rate control paradigm models binge and high-intensity drinking in the laboratory and provides a novel way to examine the relationship between the pharmacokinetics and pharmacodynamics of alcohol and potentially the risk for the development of alcohol use disorders.

Pharmacodynamic determinants of hangover: An intravenous alcohol self-administration study in non-dependent drinkers

Alcohol hangover refers to the combination of negative mental and physical symptoms that can be experienced after an episode of alcohol consumption, typically emerging as blood alcohol concentration (BAC) approaches zero. Hangover has been associated with heavy drinking and may be relevant in the transition to alcohol use disorder (AUD). Our aim was to examine hangover prevalence and associated symptoms following intravenous alcohol self-administration (IV-ASA), and to identify possible predictors of hangover in non-dependent drinkers.Ninety-five drinkers without AUD completed an IV-ASA session. Pharmacodynamic measures of alcohol consumption included peak and average breath alcohol concentrations. Subjective measures of alcohol response included the Drug Effects Questionnaire and Biphasic Effects of Alcohol Scale. The Alcohol Hangover Scale assessed hangover symptoms from the end of the session until the following morning.78% of participants endorsed at least one hangover symptom following IV-ASA. There was no association between hangover scores and IV-ASA measures of alcohol consumption. Additional mediation and moderation analysis revealed that self-reported intoxication was a significant mediator of the relationship between recent drinking and hangover symptoms.Hangover symptoms may be an early marker of the relationship between subjective response to alcohol and heavy drinking for those with no prior history of AUD. In particular, the effects of hangover go beyond exposure to alcohol and the individual’s subjective response to this exposure is associated with their experience of hangover. Future studies should further characterize the determinants of hangover across different populations of drinkers to better understand the risk for AUD and inform prevention methods.

The Motivation for Alcohol Reward: Predictors of Progressive-Ratio Intravenous Alcohol Self-Administration in Humans.

The Progressive Ratio (PR) self-administration paradigm is a common pre-clinical method used to examine the motivation for a drug attributed to a craving, reward, or the relief of negative affect. The Computer-assisted Alcohol Infusion System (CAIS) enables intravenous alcohol self-administration behavior in humans. This system provides the investigator with control over the trajectory of each incremental breath alcohol concentration (BrAC) reward and the maximum BrAC allowed in a session. This paradigm allows participants to earn these alcohol rewards using a sequence of button presses specified by the investigator. The system employs a physiologically-based pharmacokinetic model-based algorithm to achieve the same incremental BrAC exposure in every participant. Participants (n = 11) took part in two identical sessions to examine test-retest reliability, and an additional group (n = 73) completed a single session. Sessions began with a 25 min priming phase: participants were instructed to press a button an increasing number of times per reward, accumulating four standardized incremental BrAC trajectories. The second phase comprised an ad-lib, PR paradigm lasting 125 min. Each reward required an increasing number of button presses. Measures of self-administration included: average and peak BrAC, total rewards earned, total grams of ethanol consumed per unit of total body water, the total number of button presses, and the average rate of button pressing. Self-administration measures were highly correlated both between and within sessions, demonstrating test-retest reliability and internal consistency. Recent drinking history was strongly associated with self-administration measures; heavier drinkers chose greater alcohol self-administration. These results indicate the reliability and sensitivity of this progressive-ratio intravenous alcohol self-administration method for assessing the motivational properties of alcohol, with the potential for improved testing of the efficacy of new medications thought to reduce consumption of alcohol. This method can be used to understand the genetic and environmental determinants of alcohol self-administration in humans.

The Motivation for Alcohol Reward: Predictors of Progressive-Ratio Intravenous Alcohol Self-Administration in Humans

The Progressive Ratio (PR) self-administration paradigm is a common pre-clinical method used to examine the motivation for a drug attributed to a craving, reward, or the relief of negative affect. The Computer-assisted Alcohol Infusion System (CAIS) enables intravenous alcohol self-administration behavior in humans. This system provides the investigator with control over the trajectory of each incremental breath alcohol concentration (BrAC) reward and the maximum BrAC allowed in a session. This paradigm allows participants to earn these alcohol rewards using a sequence of button presses specified by the investigator. The system employs a physiologically-based pharmacokinetic model-based algorithm to achieve the same incremental BrAC exposure in every participant. Participants (n = 11) took part in two identical sessions to examine test-retest reliability, and an additional group (n = 73) completed a single session. Sessions began with a 25 min priming phase: participants were instructed to press a button an increasing number of times per reward, accumulating four standardized incremental BrAC trajectories. The second phase comprised an ad-lib, PR paradigm lasting 125 min. Each reward required an increasing number of button presses. Measures of self-administration included: average and peak BrAC, total rewards earned, total grams of ethanol consumed per unit of total body water, the total number of button presses, and the average rate of button pressing. Self-administration measures were highly correlated both between and within sessions, demonstrating test-retest reliability and internal consistency. Recent drinking history was strongly associated with self-administration measures; heavier drinkers chose greater alcohol self-administration. These results indicate the reliability and sensitivity of this progressive-ratio intravenous alcohol self-administration method for assessing the motivational properties of alcohol, with the potential for improved testing of the efficacy of new medications thought to reduce consumption of alcohol. This method can be used to understand the genetic and environmental determinants of alcohol self-administration in humans.

Effect of intravenous ghrelin administration, combined with alcohol, on circulating metabolome in heavy drinking individuals with alcohol use disorder.

Ghrelin may influence several alcohol-related behaviors in animals and humans by modulating central and/or peripheral biological pathways. The aim of this exploratory analysis was to investigate associations between ghrelin administration and the human circulating metabolome during alcohol exposure in nontreatment seeking, heavy drinking individuals with alcohol use disorder (AUD). We used serum samples from a randomized, crossover, double-blind, placebo-controlled human laboratory study with intravenous (IV) ghrelin or placebo infusion in two experiments. During each session, participants received a loading dose (3µg/kg) followed by continuous infusion (16.9ng/kg/min) of acyl ghrelin or placebo. The first experiment included an IV alcohol self-administration (IV-ASA) session and the second experiment included an IV alcohol clamp (IV-AC) session, both with the counterbalanced infusion of ghrelin or placebo. Serum metabolite profiles were analyzed from repeated blood samples collected during each session. In both experiments, ghrelin infusion was associated with an altered serum metabolite profile, including significantly increased levels of cortisol (IV-ASA q-value=0.0003 and IV-AC q<0.0001), corticosterone (IV-ASA q=0.0202 and IV-AC q<0.0001), and glycochenodeoxycholic acid (IV-ASA q=0.0375 and IV-AC q=0.0013). In the IV-ASA experiment, ghrelin infusion increased levels of cortisone (q=0.0352) and fatty acids 18:1 (q=0.0406) and 18:3 (q=0.0320). Moreover, in the IV-AC experiment, ghrelin infusion significantly increased levels of glycocholic acid (q<0.0001) and phenylalanine (q=0.0458). IV ghrelin infusion, combined with IV alcohol administration, was associated with increases in the circulating metabolite levels of corticosteroids and glycine-conjugated bile acids, among other changes. Further research is needed to understand the role that metabolomic changes play in the complex interaction between ghrelin and alcohol.

Exploring regulation and function of dopamine D3 receptors in alcohol use disorder. A PET [11C]-(+)-PHNO study.

Preclinical studies support an important role of dopamine D3 receptors (DRD3s) in alcohol use disorder (AUD). In animals, voluntary alcohol consumption increases DRD3 expression, and pharmacological blockade of DRD3s attenuates alcohol self-administration and reinstatement of alcohol seeking. However, these findings have yet to be translated in humans. This study used positron emission tomography (PET) and [11C]-(+)-PHNO to compare receptor levels in several dopamine D2 receptor (DRD2) and DRD3 regions of interest between AUD subjects in early abstinence (n = 17; 6.59 ± 4.14 days of abstinence) and healthy controls (n = 18). We recruited non-treatment seeking subjects meeting DSM-5 criteria for AUD. We examined the relationship between DRD2/3 levels and both alcohol craving and alcohol motivation/wanting, using a cue reactivity procedure and an intravenous alcohol self-administration (IVASA) paradigm, respectively. [11C]-(+)-PHNO binding levels in AUD subjects were significantly lower than binding in HCs when looking at all DRD2/3 ROIs jointly (Wilk’s Λ = .58, F(6,28) =3.33, p = 0.013, η2p = 0.42), however there were no region-specific differences. Binding values demonstrate −12.3% and −16.1% lower [11C]-(+)-PHNO binding in the SMST and SN respectively, though these differences did not withstand Bonferroni corrections. There was a positive association between [11C]-(+)-PHNO binding in the SN (almost exclusively reflective of DRD3) and alpha (lower values reflect higher alcohol demand) in the APT after Bonferroni corrections (r = 0.66, p = 0.0080). This demonstrates that AUD subjects with lower DRD3 levels in the SN exhibit increased demand for alcohol. These results replicate previous findings demonstrating reduced DRD2/3 levels while also supporting a lack of DRD3 upregulation and potential downregulation in early abstinent AUD. Furthermore, the finding that binding in the SN is associated with alcohol demand warrants further examination.

36344 Effect of CHRNA5 genetic variation and smoking on alcohol related phenotypes in healthy adult drinkers

ABSTRACT IMPACT: Understanding the influence of genetic variation and smoking on alcohol consumption helps in improving the treatment strategies for alcohol addiction OBJECTIVES/GOALS: Variation in the nicotinic receptor gene CHRNA5 (rs16969968) is associated with nicotine use and dependence, however its role in alcohol consumption is unclear. This study examined the effects of rs16969968 and smoking on alcohol related phenotypes in people without alcohol use disorder (AUD). METHODS/STUDY POPULATION: The study included 1,037 healthy adult drinkers without AUD (201 smokers, 836 non-smokers). A subset (n=161) participated in an Intravenous Alcohol Self-Administration (IV-ASA) laboratory session. Alcohol-related measures included Timeline Followback (TLFB), which measures drinking quantity and frequency in the past 90 days, and the Alcohol Use Disorders Identification Test (AUDIT), which measures alcohol use and consequences. IV-ASA measures included average and peak breath alcohol concentration (BrAC). The effect of rs16969968 was tested using a dominant model based on the presence of the A allele, and the influence of the rs16969968 polymorphism and smoking on alcohol phenotypes was assessed using t-tests and two-way ANOVA. RESULTS/ANTICIPATED RESULTS: There was a main effect of rs16969968 genotype with A-allele carriers (AA/AG) showing higher AUDIT-Dependence scores compared to the GG group. A main effect of smoking was observed on all the TLFB and AUDIT measures, with smokers showing greater alcohol consumption and problems compared to non-smokers. In the rs16969968 AA/AG group, smokers reported significantly more drinking days (p&lt;0.0001), and greater number of drinks (p&lt;0.0001), as well as higher AUDIT scores than non-smokers. IV-ASA measures did not show any difference between genotype groups or between smokers and non-smokers. DISCUSSION/SIGNIFICANCE OF FINDINGS: This study identifies both independent and interactive effects of CHRNA5 gene variation and smoking on alcohol drinking measures and provides strong evidence for the effect of smoking on alcohol drinking and its consequences.

Sensation seeking, impulsivity, and aggression moderate sex effects on adolescent laboratory binging.

Sex, comprising biological and gender-related distinctions, is a known risk factor for alcohol use disorders. Moreover, sensation seeking, impulsivity, and aggression have been found to predict binge drinking and to reflect behavioral disinhibition. We tested effects of these disinhibited traits on binging during intravenous alcohol self-administration (ivASA), a method that eliminates sex differences in the pharmacokinetics of alcohol. Eighty-five German social drinkers (49 men) completed 3 questionnaires assessing sensation seeking, impulsivity, and aggression, as well as an ivASA session at ages 18-19. Sixty-five of them were retested at ages 21-22. Participants reported real-life drinking problems and the number of binge days in the 45 days preceding lab testing. Analyses employed continuous data and median splits to examine associations between disinhibited traits and the portion of women and men in the sample who achieved a breath alcohol concentration of 80 mg% during ivASA ("binge fraction"). At ages 18-19, and only if scoring low on sensation seeking, impulsivity, or aggression, women had significantly lower binge fractions during ivASA than men. Further, low compared to high impulsivity or aggression predicted lower binge fractions in women but not in men. Neither first- nor second-wave disinhibited traits significantly predicted binge fractions at ages 21-22. We perceive that personality traits reflecting behavioral disinhibition might be a strong indicator of drinking problems, specifically among young women. Targeted brief interventions might therefore be used in educational or clinical settings to inform such women about their increased risk and the potential health and behavioral problems associated with binge drinking. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Translating preclinical models of alcohol seeking and consumption into the human laboratory using intravenous alcohol self-administration paradigms.

Preclinical models of alcohol use disorder (AUD) have advanced theoretical, mechanistic, and pharmacological study of the human condition. "Liking" and "wanting" behaviors reflect core processes underlying several models of AUD. However, the development and application of translational models of these preclinical approaches are at an incipient stage. The goal of this study was to examine how intravenous free-access and progressive-ratio, operant-response human alcohol self-administration paradigms can be used as translational human model parallels of preclinical "liking" and "wanting." Participants were 40 adults (mean age=23.7, SD=2.0; 45% female) of European descent who reported 12.6 drinking days (SD=5.2) out of the previous 30 (average=4.1 drinks per drinking day [SD=1.7]). Individuals diverged in their alcohol self-administration behavior, such that free-access and progressive-ratio paradigm outcomes were not significantly correlated (p=0.44). Free-access alcohol seeking was related to enjoying alcohol (p<0.001), but not craving (p=0.48), whereas progressive-ratio seeking at similar levels of alcohol exposure was related to craving (p=0.02), but not enjoying (p=0.30). Family history of alcoholism, venturesomeness traits, and disinhibition traits were unrelated (ps>0.70) to preferred level of breath alcohol concentration (BrAC) in the free-access session, a measure of liking alcohol. Family history of alcoholism, disinhibition traits, and recent drinking history were significantly related (ps<0.05) to alcohol seeking in the progressive-ratio paradigm, a measure of wanting alcohol. We conclude that intravenous alcohol self-administration paradigms show promise in modeling behaviors that characterize and parallel alcohol "liking" and "wanting" in preclinical models. These paradigms provide a translational link between preclinical methods and clinical trials.

Subjective alcohol responses in high- and low-risk adolescents: results from the Dresden Longitudinal Study on Alcohol Use in Young Adults.

Research shows that sensitivity to certain alcohol responses conveys risk for problem drinking. This study aimed to determine if high-risk adolescent drinkers infuse more alcohol and experience greater alcohol-induced stimulation and wanting and less sedation than low-risk adolescent drinkers. Ninety-two low- (n=38) and high-risk (n=54) adolescent drinkers, as determined by Alcohol Use Disorders Identification Test scores of <6 or ≥6, respectively, participated in the Dresden Longitudinal Study on Alcohol Use in Young Adults in which intravenous alcohol self-administration was examined in a mixed within- and between-subjects design. Technische Universität Dresden. Dresden, Germany. Predictors were drinking status (high- versus low-risk), time and their interactions. Outcomes were arterial blood alcohol concentration (aBAC); alcohol-induced stimulation, sedation and wanting assessed at baseline, 10 (alcohol prime), 45, 65, 85, 105, 125 and 145minutes. Covariates were family history of alcohol use disorder, sex and aBAC. The alcohol prime dose produced similar sharp increases in stimulation and sedation in high- and low-risk drinkers (time P < 0.001; group×time P > 0.05). During self-administration, high-risk drinkers reached higher aBACs (P=0.028) at a faster rate (group×time P<0.001), and experienced further increases in stimulation (group×time P=0.005) but with similar sedation (group×time P=0.794) than in low-risk drinkers. High-risk drinkers also exhibited greater tonic alcohol wanting (group P=0.003) throughout the session. High-risk adolescent drinkers appear to have heightened sensitivity to alcohol-induced stimulation and tonic high levels of wanting compared with low-risk adolescent drinkers.

4293 Relationship between recent drinking history, subjective response to alcohol, and sex in HRV in non-dependent drinkers

OBJECTIVES/GOALS: Previous research has shown acute and chronic alcohol effects on cardiac function, including elevated heart rate (HR) and lowered heart rate variability (HRV). This study aimed to examine the relationship between cardiac reactivity and subjective response following intravenous (IV) alcohol in non-dependent drinkers. METHODS/STUDY POPULATION: Non-dependent drinkers (N = 46, average age = 25.2) completed a human laboratory IV alcohol self-administration (IV-ASA) session. Subjective response to alcohol was assessed using the Drug Effects Questionnaire (DEQ) and Alcohol Urge Questionnaire (AUQ). Drinking behavior was assessed using the Alcohol Timeline Followback (TLFB) and Alcohol Use Disorders Identification Test (AUDIT). HR was recorded using the Polar Pro Heart Rate monitor throughout the session. HRV measures were calculated using guidelines determined by the Task Force of the European Society of Cardiology and The North American Society of Pacing and Electrophysiology. RESULTS/ANTICIPATED RESULTS: Recent drinking history as measured by the AUDIT and TLFB was not significantly different by sex. Results showed heavier drinking measures (AUDIT and TLFB) were positively associated with HRV measures (all p-values &lt; 0.02). Those who reported a greater increase in alcohol craving (AUQ score) and wanted more alcohol (DEQ) following an alcohol prime, showed a greater change in HRV (p &lt; 0.005). When examining HRV change from baseline throughout the priming session, there was a significant sex interaction for NN50 (p &lt; 0.03) and a trend for PNN50 (p-value &lt; 0.07). DISCUSSION/SIGNIFICANCE OF IMPACT: Acute IV alcohol alters cardiac reactivity measures in non-dependent drinkers. Future directions include examining the role of sex in HRV changes during alcohol consumption during IV-ASA. Understanding the effect of alcohol on cardiac reactivity and physiology may help characterize those at risk for alcohol use disorders.

Effects of exogenous ghrelin administration and ghrelin receptor blockade, in combination with alcohol, on peripheral inflammatory markers in heavy-drinking individuals: Results from two human laboratory studies

The ghrelin system has been garnering interest for its role in different neuropsychiatric disorders, including alcohol use disorder (AUD). Accordingly, targeting the ghrelin system is under investigation as a potential novel therapeutic approach. While alcohol provokes the immune system and inflammatory responses, ghrelin has potent immunomodulatory and anti-inflammatory properties. The present study aimed to shed light on the “crosstalk” between ghrelin and inflammation by examining the effects of exogenous ghrelin administration and ghrelin receptor blockade on peripheral inflammatory markers in the context of two human laboratory studies with alcohol administration. Non-treatment-seeking, heavy-drinking individuals with alcohol dependence, the majority of whom were African American males, were enrolled. In the first randomized, crossover, double-blind, placebo-controlled human laboratory study, participants underwent two experimental paradigms – an intravenous alcohol self-administration (IV-ASA) and an intravenous alcohol clamp (IV-AC) – each consisting of two counterbalanced sessions (ghrelin, placebo). A loading dose of intravenous ghrelin (3 mcg/kg) or placebo, followed by a continuous ghrelin (16.9 ng/kg/min) or placebo infusion was administered. In the second dose-escalating, single-blind, placebo-controlled human laboratory phase 1b study, participants were dosed with an oral ghrelin receptor blocker (PF-5190457) and underwent an oral alcohol challenge. Repeated blood samples were collected, and plasma concentrations of the following inflammatory markers were measured: C-reactive protein (CRP), interleukin (IL)-6, IL-10, IL-18, and tumor necrosis factor alpha (TNF-α). During the IV-ASA experiment, significant drug × time interaction effects were observed for IL-6 (F3,36 = 3.345, p = 0.030) and IL-10 (F3,53.2 = 4.638, p = 0.006), indicating that ghrelin, compared to placebo, significantly reduced blood concentrations of the proinflammatory cytokine IL-6, while increasing blood concentrations of the anti-inflammatory cytokine IL-10. No significant drug × time interaction effects were observed during the IV-AC experiment, possibly because of its much shorter duration and/or smaller sample. Treatment with PF-5190457, compared to placebo, had no significant effect on the inflammatory markers investigated. In conclusion, a supraphysiologic pharmacological challenge with exogenous ghrelin in heavy-drinking individuals produced anti-inflammatory effects in the context of intravenous alcohol administration. On the contrary, ghrelin receptor blockade did not lead to any change in the inflammatory markers included in this study. Mechanistic studies are required to better understand the interaction between ghrelin, alcohol, and inflammatory processes.

The relationship between impaired control, impulsivity, and alcohol self-administration in nondependent drinkers.

Impaired control over drinking is a significant marker of alcohol use disorder (AUD), and a potential target of intervention (Heather, Tebbutt, Mattick, & Zamir, 1993; Leeman, Toll, Taylor, & Volpicelli, 2009). Impaired control may be related to, but conceptually distinct from, impulsivity (Leeman, Patock-Peckham, & Potenza, 2012; Leeman, Ralevski, et al., 2014). However, the relationship between impaired control, impulsivity, and alcohol consumption, particularly in nondependent drinkers is less clear. This study aimed to characterize these relationships using a free-access intravenous alcohol self-administration (IV-ASA) paradigm in nondependent drinkers (N = 48). Results showed individuals with higher self-reported impaired control achieved higher blood alcohol concentrations (BAC) during the IV-ASA session and reported greater hedonic subjective responses to alcohol. Higher impaired control was also associated with greater positive urgency and reward sensitivity. Moderated-mediation analysis showed that the relationship between positive urgency and peak BAC was mediated by impaired control, and partially moderated by subjective alcohol response. These findings highlight the critical role of impaired control over drinking on alcohol consumption and subjective responses in nondependent drinkers. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Ghrelin: From a Gut Hormone to a Potential Therapeutic Target for Alcohol Addiction

Alcohol use disorder (AUD) is a chronic relapsing disease with significant medical, psychosocial, and economic burden. Pharmacological treatments for AUD are, however, limited in number and efficacy. Beyond classic neurotransmitter systems, there has been a growing interest in understanding the role of peripheral pathways (e.g., gut‐brain communications) in AUD, with the ultimate goal of identifying novel therapeutic targets. Ghrelin is an orexigenic peptide synthesized by enteroendocrine cells primarily located in the gastric mucosa. Ghrelin is known as the ‘hunger hormone’, given its role in stimulating both homeostatic and hedonic food intake. Ghrelin has also been shown to modulate alcohol seeking and consummatory behaviors, possibly through interactions with reward and stress pathways. Here we investigated whether and how pharmacological manipulation of the ghrelin system may affect biobehavioral correlates of alcohol use in heavy‐drinking alcohol‐dependent individuals. First, in a randomized, double‐blind, placebo‐controlled, human laboratory study, intravenous (IV) ghrelin/placebo was administered and two experiments were conducted: progressive‐ratio IV alcohol self‐administration (IV‐ASA) and brain functional magnetic resonance imaging (fMRI). Results showed that IV ghrelin, compared to placebo, significantly increased the number of alcohol infusions self‐administered (p=0.04) and reduced the time to initiate alcohol self‐administration (p=0.03). In addition, ghrelin increased the alcohol‐related signal in the amygdala (p=0.01) and modulated the food‐related signal in the medial orbitofrontal cortex (p=0.01) and nucleus accumbens (p=0.08). In the second study, we examined the effects of a novel ghrelin receptor inverse agonist (PF‐5190457) co‐administered with alcohol in both rodents and humans. No pharmacological interactions between alcohol and PF‐5190457 were found. PF‐5190457 did not interact with the effects of alcohol on locomotor activity or loss‐of‐righting reflex. In humans, PF‐5190457 was well tolerated, did not cause any significant side effect, and did not alter alcohol pharmacokinetics or alcohol‐induced subjective effects. As a secondary outcome, a cue‐reactivity procedure was also conducted in a bar‐like laboratory setting. Results showed that PF‐5190457, compared to placebo, reduced cue‐elicited craving for alcohol (p=0.05), as well as attention to alcohol cues (p=0.02). In conclusion, the ghrelin system seems to regulate both behavioral and neurobiological correlates of alcohol consumption and may represent a potential target for developing novel medications to treat AUD.Support or Funding InformationThis work was supported by A) NIH intramural funding ZIA‐AA000218 jointly supported by NIAAA and NIDA, and B) NCATS grant UH2/UH3‐TR000963. Development of the Computerized Alcohol Infusion System software was supported by the NIAAA‐funded Indiana Alcohol Research Center (AA007611). Pfizer provided the PF‐5190457 drug under the NCATS grant UH2/UH3‐TR000963 grant.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

3255 Association between dopaminergic genetic variants, COMTrs4680 and DRD2rs1076560, and alcohol consumption and reward behaviors in non-dependent drinkers

OBJECTIVES/SPECIFIC AIMS: The objective of this exploratory study is to evaluate the relationship between the individual genetic variants in COMTrs4680 and DRDrs1076560 and relevant alcohol use behaviors (i.e. alcohol consumption and reward processing behaviors) in non-dependent drinkers within experimentally controlled IV-ASA CAIS sessions. The overall goal of this study is to begin gathering data on the influence of individual genetic variants on alcohol consumption and other drinking-related behaviors. This will aid in the creation of a polygenic model of risk for AUD which will provide more insight into how the mesolimbic pathway is affected by alcohol use. METHODS/STUDY POPULATION: Study population: The sample included male and female non-dependent drinkers (N=149). Genotypes for functional polymorphisms in COMT (rs4680) and DRD2 (rs1076560) genes were determined for all subjects from blood samples obtained during screening. Alcohol consumption was assessed using the 90-day Timeline Followback Interviews (TLFB). Study population demographics: Self-reported gender (53.5% identified as male); Self-reported race (61.2% identified as white); Age ranged from 21-46 years old, with 22 years being the mode. Experiment: Free access (open-bar) intravenous alcohol self-administration (IV-ASA) using the computer-assisted alcohol infusion system (CAIS) paradigm; Subjects had the choice of pressing a button ad libitum for IV alcohol infusions during the session, neurobehavioral questionnaires were collected throughout the 2.5-hr alcohol infusion session. Primary outcome measures included: Total Rewards, Peak breath alcohol concentration (BrAC) achieved, and Total Ethanol consumed. Statistical Analyses: Conducted using SPSS IBM Statistics Versions 1.0.0-2482; non-dependent drinkers were organized into two groups based on their genotypes, minor allele carriers and major allele homozygotes. Outcome measures were compared between genotype groups using analysis of variance or non-parametric Mann-Whitney U-test as appropriate. RESULTS/ANTICIPATED RESULTS: -We expect the genetic makeup of the sample to be reflective of larger genome samples that are publically available (e.g. e!Ensembl) - Initial analysis for COMTrs4680 did not reveal significant effects on IV-ASA measures. Specifically, the majo DISCUSSION/SIGNIFICANCE OF IMPACT: Alcohol Use Disorder (AUD) affects millions of men and women globally. The heterogeneity within AUD individuals has made it difficult to identify biological and/or psychological factors that could be targeted for the development of treatments. By using the human laboratory model of free access IV-ASA, this study evaluated the relationship between dopaminergic genetic variants, COMTrs4680 and DRDrs1076560, and alcohol consumption in non-dependent drinkers within a controlled experimental environment. This study will begin to evaluate genetic and behavioral data that can be used to create a polygenic model of risk for AUD, which will provide more insight as to how the mesolimbic reward pathway is affected by alcohol use and contributes to risk for AUD.

3207 Relation between Dopamine Transporter (DAT1) polymorphism and subjective effects of alcohol among non-dependent drinkers

OBJECTIVES/SPECIFIC AIMS: Dopamine transporter (DAT1) gene variation is associated with reward-related phenotypes including alcohol response. There is also evidence for a potential moderating role for mu-opioid receptor (OPRM1) gene variation on the relationship between DAT1 variation and alcohol response measures. We aimed at studying the interaction between the DAT1 VNTR and OPRM1 A118G polymorphisms on alcohol consumption and subjective responses among non-dependent drinkers. METHODS/STUDY POPULATION: We employed a progressive ratio (PR) paradigm of intravenous alcohol self-administration (IV-ASA) using the Computer-Assisted Infusion System (CAIS) to assess the motivation for alcohol seeking and consumption in a sample of nondependent drinkers. We used the Drug Effects Questionnaire (DEQ) and Biphasic Alcohol Effects Questionnaire (BAES) to assess subjective response. IV-ASA measures included average breath alcohol concentration (BrAC) and total ethanol infused. Peripheral blood samples were collected for genotyping. Ethics approval was obtained from the NIH Addictions Institutional Review Board. RESULTS/ANTICIPATED RESULTS: Fifty participants completed the PR IV-ASA session after informed consent. There were significant interactions between the DAT1 and OPRM1 genotypes in subjective effects of alcohol. Simple main effects analysis showed that DAT1 10a allele carriers that were also OPRM1 G allele carriers had significantly higher scores for several measures: “feel the drug effects” (F (1,46)=6.573, P = 0.014), “feel intoxicated”(F(1,46)=8.613, P = 0.005) and “feeling high” (F(1,46)=10.889, P = 0.002) in DEQ and higher sedation (F(1,46)=4.575, P = 0.038) in BAES. The genotypes statistically significantly predicted average breath alcohol (F (1,61) =3.295, p=0.044) and total ethanol infused(F(1,61)=3.632, p=0.032. DAT1 VNTR and OPRM1 A118G polymorphisms taken together accounted for 6.9 and 7.8% of variations in average breath alcohol and total ethanol infused respectively. DISCUSSION/SIGNIFICANCE OF IMPACT: Polymorphic variations in DAT1 and OPRM1 interact with each other in determining subjective effects of alcohol in intravenous alcohol infusion assessing motivation for alcohol seeking and consumption in nondependent drinkers. These epistatic interactions in subjective effects of alcohol are salient in the context of predicting and understanding neurobiological effects of alcohol and thereby the therapeutic responses in treating alcohol use disorders.