NGF and obesity due to melanocortin 4 receptor deficiency: Therefore, the studies that had observed changes of synaptic plasticity such as NGF, BDNF, p38MAPK, cAMP response element-binding protein (CREB) and synapsin 1 in rats with obesity triggered by the energy imbalance from high fat diet, are still scarce, and in particular, there is no study to this date implementing the use of regular exercise and dietary change in these obese models.