The Actions of Caenorhabditis elegans Neuropeptide-Like Peptides (NLPs) on Body Wall Muscle of Ascaris suum and Pharyngeal Muscle of C. elegans


The actions of six Neuropeptide-like Peptides (NLPs) were investigated on Ascaris suum dorsal body wall muscle and Caenorhabditis elegans pharyngeal muscle. The NLPs tested on A. suum muscle, viz, NLP-1A, NLP-2A and B, had no direct effect on the muscle but all reversibly reduced acetylcholine (ACh)-induced contractions of the muscle, NLP-2A being the most potent, with an IC50 value of 78 μM. NLP-2A also reversibly reduced ACh-induced depolarizations of A. suum muscle resting membrane potential. NLP-1A, NLP-2A, NLP-3C and NLP-10A all increased pharyngeal pumping in C. elegans, NLP-8A weakly inhibited pumping while NLP-2B was inactive. NLP-10A induced a concentrationdependent increase in pumping activity with a threshold of 10–100 nM. Since genes encoding NLPs (nlp genes) are expressed in C. elegans pharyngeal neurons it is likely these peptides play a role in feeding behaviour.


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Papaioannou, S., Holden-Dye, L. & Walker, R.J. The Actions of Caenorhabditis elegans Neuropeptide-Like Peptides (NLPs) on Body Wall Muscle of Ascaris suum and Pharyngeal Muscle of C. elegans. BIOLOGIA FUTURA 59, 189–197 (2008).

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  • Ascaris suum
  • Caenorhabditis elegans
  • neuropeptide-like peptides
  • pharynx
  • body wall muscle