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Scientists Map Gut-to-Brain Circuit That Cuts Appetite During Parasite Infection

The study reveals an epithelial relay that uses acetylcholine to trigger serotonin signaling to the brain.

Overview

  • UCSF-led researchers, whose peer-reviewed paper appeared Wednesday in Nature, traced a pathway from tuft cells to enterochromaffin cells to vagal nerves that lowers food intake.
  • Tuft cells sensed parasite-made metabolites such as succinate and released acetylcholine, which prompted nearby enterochromaffin cells to secrete serotonin that activates the vagus nerve.
  • The team found two acetylcholine phases from tuft cells, with an early burst followed by a sustained trickle that explains why appetite loss often appears days into infection.
  • In mouse tests, infected animals ate less when tuft-cell acetylcholine signaling was intact, while engineered mice without that machinery kept eating, confirming the pathway drives the behavior.
  • Tuft cells released acetylcholine without the usual neuronal release gear, revealing a non-neuronal route for gut–brain signaling that researchers say could inform future care for IBS and food intolerances.