For instance, earlier studies using rats that were selectively bred as obesity‐prone (OP) or obesity resistant (OR, based on weight gain profiles following exposure to a high fat diet) (Levin et al., 1997), indicated that OR rats show enhanced intrinsic SPA, and orexin‐induced SPA as compared with that of control and OP rats (Teske et al., 2006). The gene discussed is HCRT; the disease is obesity due to melanocortin 4 receptor deficiency.