Neurohormones, rikkunshito and hypothalamic neurons interactively control appetite and anorexia.
Ghrelin is the orexigenic peptide produced in the periphery, and its plasma level shows remarkable pre/postprandial changes. Ghrelin is considered a pivotal signal to the brain to stimulate feeding. Hence, characterizing the target neurons for ghrelin in the hypothalamic feeding center and the signaling cascade in the target neurons are essential for understanding the mechanisms regulating appetite. Anorexia and cachexia associated with gastric surgery, stress-related diseases, and use of anti-cancer drugs cause the health problems, markedly deteriorating the quality of life. The anorexia involves several neurotransmitters and neuropeptides in the hypothalamic feeding center, in which corticotropin-releasing hormone (CRH), urocortine, serotonin (5HT) and brain-derived neurotrophic factor (BDNF) play a pivotal role. A Japanese herbal medicine, rikkunshito, has been reported to ameliorate the anorexia by promoting the appetite. This review describes 1) the interaction of ghrelin with the orexigenic neuropeptide Y (NPY) neurons in the hypothalamic arcuate nucleus (ARC) and underlying signaling cascade in NPY neurons, 2) the anorectic pathway driven by BDNF-CRH/urocortine and 5HTCRH/ urocortine pathways, 3) the effect of rikkunshito on the interaction of ghrelin and NPY neurons in ARC, and 4) the effect of rikkunshito on the interaction of 5HT on CRH neurons in paraventricular nucleus (PVN).
Division of Integrative Physiology, Department of Physiology, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan. tyada@jichi.ac.jp
Toshihiko
T
Yada
Daisuke
D
Kohno
Yuko
Y
Maejima
Udval
U
Sedbazar
Takeshi
T
Arai
Masako
M
Toriya
Fumihiko
F
Maekawa
Hedeharu
H
Kurita
Akira
A
Niijima
Koji
K
Yakabi
D000818:Animals; D000855:Anorexia / Q000188:drug therapy* / Q000378:metabolism; D001069:Appetite Regulation / Q000187:drug effects*; D019167:Appetite Stimulants / Q000494:pharmacology / Q000627:therapeutic use*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D002149:Energy Intake / Q000187:drug effects; D054439:Ghrelin / Q000819:agonists / Q000378:metabolism; D006801:Humans; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D050356:Lipid Metabolism / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000494:pharmacology / Q000627:therapeutic use*; D015398:Signal Transduction / Q000187:drug effects
D019167:Appetite Stimulants; D004365:Drugs, Chinese Herbal; C515349:GHRL protein, human; D054439:Ghrelin; D009478:Neuropeptide Y; D018377:Neurotransmitter Agents; C084136:liu-jun-zi-tang