Behavioral Traits Predicting Alcohol Drinking in Outbred Rats: An Investigation of Anxiety, Novelty Seeking, and Cognitive Flexibility

Centre for Neuroscience Studies, Queen's University, Kingston, ON, Canada.
Alcoholism Clinical and Experimental Research (Impact Factor: 3.21). 10/2011; 36(4):594-603. DOI: 10.1111/j.1530-0277.2011.01668.x
Source: PubMed


Most adults in Western society consume alcohol regularly without negative consequences. For a small subpopulation, however, drinking can quickly progress to excessive and chronic intake. Given the dangers associated with alcohol abuse, it is critical to identify traits that may place an individual at risk for developing these behaviors. To that end, we used a rat model to determine whether anxiety-related behaviors, novelty seeking, or cognitive flexibility predict excessive alcohol drinking under both limited and continuous access conditions.
Adult male rats were assessed in a series of behavioral tasks (elevated plus maze [EPM], locomotor activity, and discrimination/reversal learning in a Y-maze) followed by 6 weeks of daily, 1-hour access to alcohol in a free-choice, 2-bottle paradigm (10% alcohol vs. tap water). Next, subjects were given the opportunity to consume alcohol for 72 hours in drinking chambers that permit separate measures of each drinking bout. Half of the animals experienced a 2-week deprivation period between the limited and continuous access sessions.
Time spent on the open arms of the EPM, but not novelty seeking or discrimination/reversal learning, predicted alcohol consumption during limited, 1-h/d access sessions to alcohol. Anxiety-related behavior also predicted the escalation of intake when animals were given 72 hours of continuous access to alcohol. Bout size, but not frequency, was responsible for the increased consumption by high-anxiety subjects during this period. Finally, intake during limited access sessions predicted intake during continuous access, but only in subjects with low intake during limited access.
These findings confirm that preexisting anxiety-related behavior predicts alcohol intake under several schedules of alcohol access. Moreover, when access is unlimited, the high-anxiety-related group exhibited an increase in bout size, but not frequency, of drinking. In addition, we show that modest intake when alcohol is restricted may or may not progress to excessive intake when the drug is freely available.

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    • "Experimental animal models are critical for understanding the genetic, environmental and neurobiological underpinnings of AUD. One of the most consistent findings is that animals showing a high anxiety-like behavior also show higher alcohol intake [9] [10] [11] [12], but contrasting results have also been reported indicating on the complexity [13] [14] [15]. In most studies on this topic forced administration paradigms are used, where the animal is administrated http://dx.doi. "
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    ABSTRACT: Experimental animal models are critical for understanding the genetic, environmental and neurobiological underpinnings of alcohol use disorders. Limited studies investigate alcohol-induced effects on behavior using free-choice paradigms. The aims of the present experiment were to study voluntary alcohol intake using a modified intermittent access paradigm, investigate the effects of voluntary alcohol intake on behavioral profiles in water- and alcohol-drinking rats, and select extreme low- and high-drinking animals for a more detailed behavioral characterization. Sixty outbred male Wistar rats were randomized into water and alcohol groups. Behavioral profiles in the multivariate concentric square field™ (MCSF) test were assessed prior to and after voluntary alcohol intake. The animals had intermittent access to 20% alcohol and water for three consecutive days per week for seven weeks. The results revealed increased alcohol intake over time. No major alcohol-induced differences on behavior profiles were found when comparing water- and alcohol-drinking animals. The high-drinking animals displayed an alcohol deprivation effect, which was not found in the low-drinking animals. High-drinking rats had lower risk-taking behavior prior to alcohol access and lower anxiety-like behavior after voluntary alcohol intake compared to low-drinking rats. In conclusion, the modified intermittent access paradigm may be useful for pharmacological manipulation of alcohol intake. With regard to behavior, the present findings highlights the importance of studying subgroup-dependent differences and add to the complexity of individual differences in behavioral traits of relevance to the vulnerability for excessive alcohol intake.
    Full-text · Article · Sep 2014 · Behavioural Brain Research
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    • "A possible explanation for the day 2 withdrawal-induced preference for light is that ethanol is an appetitive stimulus for many animals, including zebrafish [24], [42], [43]. Additionally, rodents exposed to ethanol have been shown to search actively for ethanol and consume it freely if it is found [44], [45]. This may be due, in part, to an increase in glutamatergic neurotransmission that increases alcohol craving [3]. "
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    ABSTRACT: Alcohol abuse can lead to severe psychological and physiological damage. Little is known, however, about the relative impact of a small, daily dose of alcohol (daily-moderate schedule) versus a large, once per week dose (weekly-binge schedule). In this study, we examined the effect of each of these schedules on behavioural measures of anxiety in zebrafish (Danio rerio). Adult wild-type zebrafish were administered either 0.2% ethanol on a daily-moderate schedule or 1.4% ethanol on a weekly-binge schedule for a period of 21 days, and then tested for scototaxis (preference for darkness) during withdrawal. Compared to a control group with no alcohol exposure, the daily-moderate group spent significantly more time on the light side of the arena (indicative of decreased anxiety) on day two of withdrawal, but not day 9 of withdrawal. The weekly-binge group was not significantly different from the control group on either day of withdrawal and showed no preference for either the light or dark zones. Our results indicate that even a small dose of alcohol on a daily basis can cause significant, though reversible, changes in behaviour.
    Full-text · Article · May 2013 · PLoS ONE
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    • "Our findings of initial differences in anxiety-like behavior in the EPM test are in agreement with previous papers that have demonstrated innate behavioral discrepancy differences among outbred laboratory animals. This has been reported for both rats (Hayton et al., 2011; Liebsch et al., 1998; Prasad et al., 1996, 1997 and mice (Kaliste et al., 2006; Painsipp et al., 2007; Pelloux et al., 2009; Rodgers et al., 2002; Xu et al., 2006). We have shown that, compared to LAM, HAM consumed more alcohol and expressed greater preference for ethanol. "
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    ABSTRACT: Psychiatric illnesses, such as anxiety, are highly comorbid with drug use disorders in general and alcohol abuse in particular. Unfortunately, the causal role of anxiety in ethanol addiction is still unclear. We asked the question whether high anxiety predicts predilection of mice to voluntarily consume more alcohol than water. In the current study, we used the voluntary alcohol intake in two bottle choice drinking paradigm to explore whether high anxiety predicts higher alcohol preference and intake in outbred Tuck-Ordinary "TO" mice. To this end, mice were tested for their anxiety-like behavior using the elevated plus maze, open field and the marble burying test prior to voluntary continuous access to increasing concentrations of alcohol solutions. To assess their taste discrimination, mice had access to saccharin and quinine solutions. Results showed that compared to low-anxious mice (LAM), high-anxious mice (HAM) showed greater consumption and preference for ethanol but not for saccharin and quinine suggesting alterations in the rewarding effects of alcohol. Taken together, these findings suggest a correlative link between trait anxiety and the behavioral responses to ethanol.
    Full-text · Article · Feb 2013 · Pharmacology Biochemistry and Behavior
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