Mixture and concentration effects on odorant receptor response patterns in vivo

Timothy S. McClintock, Qiang Wang, Tomoko Sengoku, William B. Titlow, Patrick Breheny

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Natural odors are mixtures of volatile chemicals (odorants). Odors are encoded as responses of distinct subsets of the hundreds of odorant receptors and trace amine-associated receptors expressed monogenically by olfactory sensory neurons. This is an elegantly simple mechanism for differentially encoding odors but it is susceptible to complex dose-response relationships and interactions between odorants at receptors, which may help explain olfactory phenomena, such as mixture suppression, synthetic versus elemental odor processing, and poorly predictable perceptual outcomes of new odor mixtures. In this study, in vivo tests in freely behaving mice confirm evidence of a characteristic receptor response pattern consisting of a few receptors with strong responses and a greater number of weakly responding receptors. Odorant receptors responsive to an odor are often unrelated and widely divergent in sequence, even when the odor consists of a single species of odorant. Odorant receptor response patterns to a citrus odor broaden with concentration. Some highly sensitive receptors respond only to a low concentration but others respond in proportion to concentration, a feature that may be critical for concentration-invariant perception. Other tests find evidence of interactions between odorants in vivo. All of the odorant receptor responses to a moderate concentration of the fecal malodor indole are suppressed by a high concentration of the floral odorant, α-ionone. Such suppressive effects are consistent with prior evidence that odorant interactions at individual odorant receptors are common.

Original languageEnglish
Pages (from-to)429-438
Number of pages10
JournalChemical Senses
Volume45
Issue number6
DOIs
StatePublished - Jul 7 2020

Bibliographical note

Publisher Copyright:
© The Author(s) 2020. Published by Oxford University Press. All rights reserved.

Keywords

  • Citrus
  • G protein-coupled receptor
  • Malodor
  • Sensory neuroscience
  • Smell

ASJC Scopus subject areas

  • Physiology
  • Sensory Systems
  • Physiology (medical)
  • Behavioral Neuroscience

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