Drug-paired environments can act as stimuli that elicit drug craving. In humans, drug craving is influenced by the amount of time abstinent, number of past periods of abstinence, and inadvertent exposure to the previously abused drug. The current experiments were designed to determine the effects of (i) the duration of abstinence on expression of ethanol (EtOH)-seeking; (ii) EtOH priming following a short and long abstinence period; and (iii) repeated deprivation cycles on relapse drinking and EtOH-seeking.Methods:
Rats were allowed to self-administer 15% EtOH, processed through extinction training, maintained in a home cage for a designated EtOH-free period, and then reintroduced to the operant context in the absence of EtOH. The experiments examined the effects of: (i) various home-cage duration periods (1 to 8 weeks), (ii) priming injections of EtOH in the Pavlovian spontaneous recovery (PSR; 14 days after extinction) and reinstatement of responding (RoR; 1 day after extinction) models, and (iii) exposure to repeated cycles of EtOH access-deprivation on relapse drinking and EtOH-seeking behavior.Results:
Highest expression of EtOH-seeking was observed following 6 weeks of home-cage maintenance. Priming injections of EtOH were more efficacious at stimulating/enhancing EtOH-seeking in the PSR than RoR model. Exposure to repeated cycles of EtOH deprivation and access enhanced and prolonged relapse drinking and the expression of EtOH-seeking (318 ± 22 responses), which was not observed in rats given equivalent consistent exposure to EtOH (66 ± 11 responses).Conclusions:
Overall, the data indicated that the PSR model has ecological validity; factors that enhance EtOH craving in humans enhance the expression of EtOH-seeking in the PSR test. The data also detail factors that need to be examined to determine the biological basis of EtOH-seeking (e.g., neuroadaptations that occur during the incubation period and following repeated cycles of EtOH drinking and abstinence).
Alcohol craving in humans can lead to alcohol relapse. Factors influencing alcohol craving include time from last drink, the number of cycles of alcohol abuse and abstinence, and unintentional exposure to alcohol. This research examined human factors in a rodent model of alcohol craving. The data indicated that alcohol craving in rats is greatest during the 6th week of abstinence, is enhanced in rats given multiple cycles of alcohol abuse and abstinence, and that priming with alcohol increases alcohol craving. Depicts the expression of alcohol craving during 1-, 2-, 4-, 6- or 8-weeks of abstinence. Alcohol craving in rats was enhanced during 2-, 4-, 6- and 8-weeks of abstinence and the expression of alcohol craving was the greatest during the 6th week of abstinence. In addition, the expression of alcohol craving remains elevated on the 2nd test day during 4- and 6-weeks of abstinence.