NPY and in situ carcinoma: For example, XYS can effectively regulate expression of tyrosine hydroxyls (TrkB), neurotrophin 3 (NT-3), neurotrophic factor (BDNF), leptin receptor (ob-R), and neuropeptide Y (NPY) in the hippocampal, arcuate nucleus and frontal cortex in rats with CIS [18, 19].