GHSR and obesity due to melanocortin 4 receptor deficiency: These studies, demonstrating 5-HT2CR antagonism results in a long-lasting orexigenic effect, indicate that therapeutic targeting of heterodimers may be useful to increase appetite and food intake, and could potentially be used in the treatment of anorexia nervosa; while conversely, combinations of 5-HT2CR agonists with GHSR1a antagonists could reduce appetite, with possible utility for anti-obesity therapies.