Answer is b. Decreasing ; increasing
Neuropeptides are a class of messenger molecules present in central nervous system of many mammalian brain. About 100 different neuropeptides made and release from the hypothalamus of mammalian brain. A neuropeptide, after release may diffuse in the blood to exert its action on sleep, alertness, anxiety. Thus, neuropeptides play key roles in modulating neuronal activity.