When we suppressed elevations in cAMP in PVHMC4R neurons in a previous study using selective expression of a modified phosphodiesterase (PDE), mice developed massive obesity accompanied by a lower frequency of spontaneous activity and spontaneous postsynaptic potentials in PVHMC4R neurons in vitro5. This evidence concerns the gene ALDH7A1 and obesity due to melanocortin 4 receptor deficiency.