From binge eating to binge drinking: A new and robust paradigm for assessing binge ethanol self-administration in male rats

Animal models of alcohol (ethanol) self-administration are crucial to dissect the neurobiological mechanisms underlying alcohol dependence, yet only a few of these induce pharmacologically relevant levels of alcohol consumption and rarely the alcohol self-administration co-occurs with other addictive behaviours. The present study aims to validate a novel model of voluntary ethanol consumption in male Wistar rats, in which ethanol access follows a binge eating experience. Over 10 sessions, Wistar rats were exposed to binge or control eating (i.e., the ingestion of 11.66 and 0.97 kcal/3 min, respectively, derived from a highly palatable food), immediately followed by two-bottle choice intake tests (2%, 6%, 10% or 14% w/w ethanol vs. water). Rats exposed to binge eating drank significantly more 6% or 10% (w/w) ethanol than control peers, reaching up to 6.3 g(EtOH)/kg. Rats stimulated with 2%, 6%, 10% or 14% ethanol after binge eating, but not those given those ethanol concentrations after control eating, exhibited significant within-group increases in ethanol drinking. This ethanol consumption was not altered by quinine adulteration (up to 0.1 g/L), and it was blocked by naltrexone (10 mg/kg), administered immediately before binge eating. Blood ethanol levels significantly correlated with ethanol consumption; and the more ethanol consumed, the greater the distance travelled in an open field test conducted after the two-bottle choice test. Altogether, this self-administration model seems a valid and robust alternative with remarkable potential for research on different stages of the alcohol addiction and, particularly, to assess interactions between alcohol consumption and others addictive-like behaviours.

Automated summary

The present study validates a novel model of voluntary ethanol consumption in male Wistar rats, in which ethanol access follows binge eating, and demonstrates a significant increase in ethanol consumption after binge eating compared to control eating. This model shows remarkable potential for research on different stages of alcohol addiction and assessing interactions between alcohol consumption and other addictive-like behaviors.