Lisdexamfetamine suppresses instrumental and consummatory behaviorssupported by foods with varying degrees of palatability: Exploration of abinge-like eating model

Diets high in sugar or fat are associated with multiple health conditions, including binge eating disorder (BED). BED affects approximately 2% of the US adult population, and occurs more frequently in females. It is important to develop animal models of palatable food consumption and food seeking that may have relevance for BED and other conditions associated with excessive food intake. The catecholamine uptake blocker and d-amphetamine prodrug lisdexamfetamine is used to treat BED. The present experiments studied the effect of lisdexamfetamine on food intake and food-reinforced effort-based choice in female Wistar rats. Three groups of rats received different food exposure conditions in the home cage randomly spread over several weeks: a chocolate exposure group (CE; brief access of chocolate and additional lab chow, n = 15), a lab chow exposure (LChE) group given additional access to lab chow (n = 8), and a third group given empty food dishes (n = 7). In tests of food intake under non-restricted conditions, lisdexamfetamine (0.1875–1.5 mg/kg IP) significantly reduced intake of both chocolate and chow in the CE group. In the LChE group, there was a trend towards reduced chow intake induced by lisdexamfetamine. All rats were trained on a Progressive Ratio/chow feeding choice task, in which they had a choice between working for high carbohydrate chocolate flavored pellets by lever pressing vs. approaching and consuming a concurrently available lab chow. The LChE group and the empty food dish group were combined to create one control group (n = 15). There was a significant overall dose-related suppressive effect of lisdexamfetamine on lever pressing but no group difference, and no dose x group interaction. Lisdexamfetamine significantly decreased chow intake in the CE group, but not in the control group. In conclusion, lisdexamfetamine affected both food intake and food-reinforced operant behavior, with larger effects seen in the group exposed to chocolate