Wistar-Kyoto Female Rats Are More Susceptible to Develop Sugar Binging: A Comparison with Wistar Rats

Abstract

The hedonic component of the feeding behavior involves the mesolimbic reward system and resembles addictions. Nowadays, the excessive consumption of sucrose is considered addictive. The Wistar-Kyoto (WKY) rat strain is prone to develop anxiety and addiction-like behavior; nevertheless, a lack of information regarding their vulnerability to develop sugar binging-like behavior (SBLB) and how it affects the reward system persist. Therefore, the first aim of the present study was to compare the different predisposition of two rat strains, Wistar (W) and WKY to develop the SBLB in female and male rats. Also, we studied if the SBLB-inducing protocol produces changes in anxiety-like behavior using the plus-maze test (PMT) and, analyzed serotonin (5-HT) and noradrenaline (NA) concentrations in brain areas related to anxiety and ingestive behavior (brain stem, hypothalamus, nucleus accumbens, and amygdala). Finally, we evaluated whether fluoxetine, a drug that has been effective in reducing the binge-eating frequency, body weight, and severity of binge eating disorder, could also block this behavior. Briefly, WKY and W female rats were exposed to 30% sucrose solution (2 h, 3 days/week for 4 weeks), and fed up ad libitum. PMT was performed between the last two test periods. Immediately after the last test where sucrose access was available, rats were decapitated and brain areas extracted for high-performance liquid chromatography analysis. The results showed that both W and WKY female and male rats developed the SBLB. WKY rats consumed more calories and ingested a bigger amount of sucrose solution than their W counterpart. This behavior was reversed by using fluoxetine, rats exposed to the SBLB-inducing protocol presented a rebound effect during the washout period. On female rats, the SBLB-inducing protocol induced changes in NA concentrations on WKY, but not on W rats. No changes were found in 5-HT levels. Finally, animals that developed SBLB showed increased anxiety-like behavior in the PMT. In conclusion, WKY female rats can be considered as a more susceptible rat strain to develop SBLB.

Sex differences in sucrose reinforcement in Long-Evans rats

“…Sex differences in binging of fat or a palatable mixture (fat + sugar) have been described, with females binging more than males [ 14 , 15 ]. With sucrose alone as the reinforcer, females binged slightly more than males [ 13 ] and females binged more than males but this effect was observed only in Wistar-Kyoto, but not Wistar rats [ 16 ].…”

Wistar Kyoto Rats Display Anhedonia In Consumption but Retain Some Sensitivity to the Anticipation of Palatable Solutions

“…When bodyweight is corrected for, the differences between WKY and Wistar rats were removed or greatly reduced. Previous findings have been somewhat mixed here, where for instance marked increases in sucrose consumption have been observed in WKY rats (Papacostas-Quintanilla et al, 2017). Other previous studies have not included a comparator strain as a control (e.g., Tacchi et al, 2008), while others have found increased bodyweight of WKY rats compared to Wistars (Dommett and Rostron, 2013).…”

“…Differential sex effects can also be observed concerning stress vulnerability (Bangasser and Valentino, 2014;Bangasser and Wicks, 2017;Bangasser and Wiersielis, 2018;Wellman et al, 2018) and thereby the potential ability of stress to modulate ongoing depressive symptoms. In animal studies, sex is an important variable in the expression of sucrose binging-like behavior in WKY rats (Papacostas-Quintanilla et al, 2017). Other work suggests that female WKY rats exhibit less anhedonia than male WKY rats (Burke et al, 2016), although direct non-consumptive measures of anhedonia were not employed in this study.…”

Intra-accumbens Raclopride Administration Prevents Behavioral Changes Induced by Intermittent Access to Sucrose Solution

“…The discrepancy between these results may be explained considering methodological differences including sex, strain, and diet composition, since Lardeux et al, used male Long–Evans rats and a mixture of carbohydrates and fat to induce binge-like behavior. Especially sex of the subjects is relevant, for instance, it has been shown that female Wistar-Kyoto rats developed a more stable and significant binge-like behavior than male rats (Papacostas-Quintanilla et al, 2017 ); and mice expressing DRD2S and lacking DRD2L drink more ethanol than wild-type subjects (both sexes), and interestingly this genotype is associated with excessive intake of sucrose solution in female mice (Bulwa et al, 2011 ). Furthermore, it was reported that intra-NAcS administration of sulpiride dose-dependently attenuated reinstatement of drug seeking induced by a cocaine priming injection (Anderson et al, 2006 ).…”