Ionotropic receptors (IRs): chemosensory ionotropic glutamate receptors in Drosophila and beyond

Insect Biochem Mol Biol. 2013 Sep;43(9):888-97. doi: 10.1016/j.ibmb.2013.02.007. Epub 2013 Mar 1.


Ionotropic Receptors (IRs) are a recently characterized family of olfactory receptors in the fruit fly, Drosophila melanogaster. IRs are not related to insect Odorant Receptors (ORs), but rather have evolved from ionotropic glutamate receptors (iGluRs), a conserved family of synaptic ligand-gated ion channels. Here, we review the expression and function of IRs in Drosophila, highlighting similarities and differences with iGluRs. We also briefly describe the organization of the neuronal circuits in which IRs function, comparing and contrasting them with the sensory pathways expressing ORs. Finally, we summarize the bioinformatic identification and initial characterization of IRs in other species, which imply an evolutionarily conserved role for these receptors in chemosensation in insects and other protostomes.

Keywords: Chemosensation; Drosophila melanogaster; Evolution; Gustation; Ionotropic glutamate receptor; Olfaction.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Evolution, Molecular
  • Insecta / genetics*
  • Insecta / metabolism
  • Olfactory Receptor Neurons / metabolism
  • Receptors, Ionotropic Glutamate / genetics
  • Receptors, Ionotropic Glutamate / metabolism*


  • Drosophila Proteins
  • Receptors, Ionotropic Glutamate