From the results of this study, it is indicated that the protein activations of BDNF, NGF and p38MAPK in the hippocampus of rats with high fat diet-induced obesity were inhibited resulting in significant reduction of such activations, and in addition, from the level of mRNA, the reduction tendency of TrkA, TrkB, MAPK1, CREB and Synapsin1 had been presented. The gene discussed is NTRK2; the disease is obesity due to melanocortin 4 receptor deficiency.