Sugar withdrawal and differential reinforcement of low rate (DRL) performance in rats

Sugar consumption is assumed to induce a behavioral state that is similar to the one provoked by addictive substances. Drug withdrawal increases impulsivity, assessed by differential reinforcement of low rate (DRL) performance. The present study investigated the effect of withdrawal from a prolonged period of sugar consumption on DRL performance. Water-deprived rats were trained under a DRL 20s (DRL 20) schedule. The animals were allowed to choose between plain water and a sucrose solution (E group) or water only (C group) for 30 days. The sucrose solution was then removed, and measures of DRL 20 performance were obtained on 3 consecutive days. Results showed that DRL performance in the C group improved after sugar withdrawal, whereas performance in the E group led to the loss of reinforcers. An analysis of variance-type analysis showed that the E group had higher response rates per reinforcer, lower IRTs, and greater differences between baseline and abstinence than the C group after 3 days of sugar withdrawal. Thus, sugar abstinence after a relatively long consumption period resulted in impairment of DRL performance, confirming the parallel effects of addictive drugs and sugar and suggesting an increase in impulsivity as a consequence of sugar deprivation.