Arcuate Nucleus

2022-01-25 links: Neuroanatomy reference:

Arcuate Nucleus (Infundibular Nucleus) #

There’s actually two of them: in the Hypothalamus and the Medulla.

• The only neurons known to release melanocortins.

Appetite Signaling #

https://www.cellbiol.net/ste/alpobesity2.php

• [Participation of the central melanocortin system in metabolic regulation and energy homeostasis]
  • 
    • It is the Vagus Nerve that carries leptin, ghrelin, PYY, and cholecystokinin.
  • Leptin receptors work via the JAK2-STAT3 pathway:
  • The first-order neurons receive:
    • Peptide YY: from the colon and ileum.
      • Anorexigenic
    • Leptin: from adipose (long-term/homeostatically?) and stomach (short-term)
      • Anorexigenic
    • Cholecystokinin: from the duodenum of the small intestine
      • Anorexigenic, secreting early satiety. Stimulates digestive enzymes from the pancreas, and Bile.
    • Insulin: from the pancreas.
      • Anorexigenic
    • Ghrelin: from the stomach. Might be secreted by hypothalamic neurons, too?
      • Orexigenic
    • Endocannabinoids like anandamide, which are produced in the small intestines.
  • Thse second-order neurons are:
    • Synthesized in the ‘anabolic neurons’ are Agouti-related protein (in Neuropeptide Y-containing/releasing cell bodies in the ventromedial part. - NPY is the other component).
    • ‘Catabolic neurons’ project to Proopiomelanocortin neurons, acting on the appetite-controling neurons’ Melanocortin Receptors.
      • These melanocortin neurons also apparently release CART .