Serotonergic neuron ADF modulates avoidance behaviors by inhibiting sensory neurons in C. elegans

Pflugers Arch. 2019 Feb;471(2):357-363. doi: 10.1007/s00424-018-2202-4. Epub 2018 Sep 11.


Serotonin plays an essential role in both the invertebrate and vertebrate nervous systems. ADF, an amphid neuron with dual ciliated sensory endings, is considered to be the only serotonergic sensory neuron in the hermaphroditic Caenorhabditis elegans. This neuron is known to be involved in a range of behaviors including pharyngeal pumping, dauer formation, sensory transduction, and memory. However, whether ADF neuron is directly activated by environmental cues and how it processes these information remains unknown. In this study, we found that ADF neuron responds reliably to noxious stimuli such as repulsive odors, copper, sodium dodecyl sulfonate (SDS), and mechanical perturbation. This response is mediated by cell-autonomous and non-cell autonomous mechanisms. Furthermore, we show that ADF can modulate avoidance behaviors by inhibiting ASH, an amphid neuron with single ciliated ending. This work greatly furthers our understanding of 5-HT's contributions to sensory information perception, processing, and the resulting behavioral responses.

Keywords: Avoidance behavior; Caenorhabditis elegans; Sensory information perception; Serotonergic neuron.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Avoidance Learning / physiology*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / metabolism
  • Copper / metabolism
  • Nervous System / metabolism
  • Nervous System / physiopathology
  • Sensory Receptor Cells / metabolism
  • Sensory Receptor Cells / physiology*
  • Serotonergic Neurons / metabolism
  • Serotonergic Neurons / physiology*
  • Serotonin / metabolism
  • Signal Transduction / physiology
  • Sodium Dodecyl Sulfate / metabolism


  • Caenorhabditis elegans Proteins
  • Serotonin
  • Sodium Dodecyl Sulfate
  • Copper