DRD2 and obesity due to melanocortin 4 receptor deficiency: Given the significant impact of disrupted D2R function on the neural circuitry modulating food reward, additional research into the molecular mechanisms and cellular processes that cause underlying receptor desensitization and downregulation, in the context of high-fat diets and obesity, is necessary to develop potential therapeutic solutions to resensitize D2Rs and restore normal D2R-mediated inhibition.