Figure 8.

Schematic illustration showing the flow in the suppressive action of amphetamine (AMPH). Amphetamine treatment activates dopamine release in the brain, which may in turn activate hypothalamic POMC expression, inhibit hypothalamic NPY expression and finally decrease food intake. The activation of POMC neurons, which is partly due to the disinhibition of NPY neurons, may result in the increased expression of pERK1/2, pCREB, POMC and MC₃ receptor (MC3R). Finally, the decrease in NPY or the increase in MC₃ receptors may contribute to the reduction of food intake. The thinner arrows indicate the flow of amphetamine treatment in the induction of anorexia. The solid black arrow indicates the activation, the dotted arrows indicate the inhibition and the dashed arrow represents the disinhibition (or activation). The upward and downward arrows in the squares indicate the responses of increase and decrease.