Poster Presentation ANZOS-Breakthrough Discoveries Joint Annual Scientific Meeting 2018

Bingeing on sweet drinks: Persistent elevated intakes in rats (#238)

Simone Rehn 1 , Robert A Boakes 1
  1. University of Sydney, Camperdown, NSW, Australia

Several existing animal models have examined the overlap between binge-like consumption of high-sugar foods or drinks and addiction given the prevalence of comorbidity between human binge eating disorder and substance use disorder. However, findings from these existing models suffer from methodological weaknesses. We have addressed these issues using a new rat model of bingeing (Eikelboom & Hewitt, 2016).  Two experiments tested whether bingeing may be analogous to substance abuse in its potential to produce addiction-like behaviours.  During the 4-week Phase 1 of Experiment 1 rats were given either no access (Chow group), daily access (Unrestricted group) or access on every fourth day (Binge group) to a 4% sucrose solution.  Intermittent access resulted in escalating sucrose intakes in the Binge group to double the daily intakes in the Unrestricted group.  Critically, in Phase 2, when both Binge and Unrestricted groups were given identical alternate-day sucrose access, the Binge group maintained elevated sucrose intakes.  This suggests that Binge rats undergo a long-term change in sucrose consumption that resembles tolerance for addictive drugs.  However, several measures failed to find elevated ‘withdrawal’ or ‘craving’ in the Binge relative to the Unrestricted group, suggesting that binge-like consumption of sucrose does not elicit addiction-like behaviours more so than prolonged sucrose consumption.  Experiment 2 assessed whether bingeing in this model was hedonically reinforced by replacing sucrose from Experiment 1 with a non-caloric sweetener, saccharin, and a hyperpalatable glucose-saccharin mixture.  Both Saccharin Binge and Glucose-Saccharin Binge groups exhibited persistent elevated intakes relative to the Unrestricted groups and replicated the binge effect found in Experiment 1.  Yet, there were again no differences in ‘craving’ or ‘withdrawal’ between Binge and Unrestricted groups.  Altogether, bingeing in this model appears to be hedonically motivated, reflecting the nature of human bingeing, but binge-like consumption itself may not produce an addiction-like profile.