The neuropeptide NLP-22 regulates a sleep-like state in Caenorhabditis elegans

Nat Commun. 2013;4:2846. doi: 10.1038/ncomms3846.


Neuropeptides have central roles in the regulation of homoeostatic behaviours such as sleep and feeding. Caenorhabditis elegans displays sleep-like quiescence of locomotion and feeding during a larval transition stage called lethargus and feeds during active larval and adult stages. Here we show that the neuropeptide NLP-22 is a regulator of Caenorhabditis elegans sleep-like quiescence observed during lethargus. nlp-22 shows cyclical mRNA expression in synchrony with lethargus; it is regulated by LIN-42, an orthologue of the core circadian protein PERIOD; and it is expressed solely in the two RIA interneurons. nlp-22 and the RIA interneurons are required for normal lethargus quiescence, and forced expression of nlp-22 during active stages causes anachronistic locomotion and feeding quiescence. Optogenetic stimulation of the RIA interneurons has a movement-promoting effect, demonstrating functional complexity in a single-neuron type. Our work defines a quiescence-regulating role for NLP-22 and expands our knowledge of the neural circuitry controlling Caenorhabditis elegans behavioural quiescence.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans / physiology*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Feeding Behavior
  • Interneurons / metabolism
  • Larva / genetics
  • Larva / growth & development
  • Larva / physiology
  • Locomotion
  • Neuropeptides / genetics
  • Neuropeptides / metabolism*
  • Sleep
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Caenorhabditis elegans Proteins
  • LIN-42 protein, C elegans
  • NLP-22 protein, C elegans
  • Neuropeptides
  • Transcription Factors