Nonredundant function of two highly homologous octopamine receptors in food-deprivation-mediated signaling in Caenorhabditis elegans

J Neurosci Res. 2014 May;92(5):671-8. doi: 10.1002/jnr.23345. Epub 2014 Jan 21.


It is common for neurotransmitters to possess multiple receptors that couple to the same intracellular signaling molecules. This study analyzes two highly homologous G-protein-coupled octopamine receptors using the model animal Caenorhabditis elegans. In C. elegans, the amine neurotransmitter octopamine induces activation of cAMP response element-binding protein (CREB) in the cholinergic SIA neurons in the absence of food through activation of the Gq-coupled octopamine receptor SER-3 in these neurons. We also analyzed another Gq-coupled octopamine receptor, SER-6, that is highly homologous to SER-3. As seen in ser-3 deletion mutants, octopamine- and food-deprivation-mediated CREB activation was decreased in ser-6 deletion mutants compared with wild-type animals, suggesting that both SER-3 and SER-6 are required for signal transduction. Cell-specific expression of SER-6 in the SIA neurons was sufficient to restore CREB activation in the ser-6 mutants, indicating that SER-6, like SER-3, functions in these neurons. Taken together, these results demonstrate that two similar G-protein-coupled receptors, SER-3 and SER-6, function in the same cells in a nonredundant manner.

Keywords: C. elegans; CREB; G-protein-coupled receptor; food deprivation; octopamine.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adrenergic alpha-Agonists / pharmacology
  • Animals
  • Animals, Genetically Modified
  • CREB-Binding Protein / metabolism
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / genetics
  • Food Deprivation / physiology*
  • Mutation / genetics
  • Neurons / metabolism*
  • Octopamine / pharmacology
  • Phylogeny
  • Receptors, Biogenic Amine / metabolism*
  • Receptors, Serotonin / genetics
  • Receptors, Serotonin / metabolism*
  • Receptors, Serotonin, 5-HT3 / genetics
  • Receptors, Serotonin, 5-HT3 / metabolism*
  • Transcriptome / drug effects
  • Transcriptome / physiology*


  • Adrenergic alpha-Agonists
  • Caenorhabditis elegans Proteins
  • Receptors, Biogenic Amine
  • Receptors, Serotonin
  • Receptors, Serotonin, 5-HT3
  • norsynephrine receptor
  • serotonin 6 receptor
  • Octopamine
  • CREB-Binding Protein