Deletion of Melanin Concentrating Hormone Receptor-1 disrupts overeating in the presence of food cues

Exposure to environmental cues associated with food can evoke eating behavior in the absence of hunger. This capacity for reward cues to promote feeding behaviors under sated conditions can be examined in the laboratory using cue-potentiated feeding (CPF). The orexigenic neuropeptide Melanin Concentrating Hormone (MCH) is expressed throughout brain circuitry critical for CPF. We examined whether deletion of the MCH receptor, MCH-1R, would in KO mice disrupt overeating in the presence of a Pavlovian CS + associated with sucrose delivery. While both wild-type controls and KO mice showed comparable food magazine approach responses during the CPF test, MCH-1R deletion significantly impaired the ability of the CS + to evoke overeating of sucrose under satiety. Through the use of a refined analysis of meal intake, it was revealed that this disruption to overeating behavior in KO mice reflected a reduction in the capacity for the CS + to initiate and maintain bursts of licking behavior. These findings suggest that overeating during CPF requires intact MCH-1R signaling and may be due to an influence of the CS + on the palatability of food and on regulatory mechanisms of peripheral control. Thus, disruptions to MCH-1R signaling may be a useful pharmacological tool to inhibit this form of overeating behavior.