LEP and obesity due to melanocortin 4 receptor deficiency: Recently, it was also demonstrated that RAS in the brain selectively facilitates renal and brown adipose tissue sympathetic nerve responses to leptin while sparing effects on food intake [45] and that hypothalamic arcuate nucleus plays an important role in mediating the sympathetic nerve responses to leptin and in the adverse sympathoexcitatory effects of leptin in obesity [46].