Differential covariation in taste responsiveness to bitter stimuli in rats

Susan M. Brasser, Khyobeni Mozhui, David V. Smith

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Variation exists in the sensitivity of individual rodents and humans to different bitter tastants. An absence of uniform correlation in responsiveness to different bitter substances across individuals within a species suggests heterogeneity in the mechanisms underlying stimulus processing within this taste modality. Here, we examined taste responsiveness of individual rats to three bitter compounds (quinine hydrochloride, denatonium benzoate, and cycloheximide) in short-term lick tests to determine the magnitude of covariation among responses to these stimuli and infer commonalities in their receptor and neural mechanisms. Rats were tested with a given pair of bitter stimuli during three sessions comprising randomized trial blocks of six concentrations of each stimulus + deionized water. Psychophysical functions were generated for individual rats for respective stimulus pairs, and concentrations of each stimulus that produced equivalent lick suppression relative to water were correlated across animals. Behavioral taste responsiveness to quinine hydrochloride strongly covaried with responsiveness to denatonium benzoate (r = +0.82). Lick responsiveness to quinine was less robustly correlated with that to cycloheximide (r = +0.44), and denatonium and cycloheximide responses failed to correlate. These results imply substantial overlap in the bitter taste coding mechanisms for quinine and denatonium but some degree of independence in the mechanisms responsible for gustatory processing of cycloheximide. More generally, these data reinforce the notion that bitter taste processing is not a homogeneous event.

Original languageEnglish (US)
Pages (from-to)793-799
Number of pages7
JournalChemical Senses
Volume30
Issue number9
DOIs
StatePublished - Nov 1 2005

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Quinine
Cycloheximide
Water
Sensory Receptor Cells
Rodentia
denatonium benzoate

All Science Journal Classification (ASJC) codes

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

Cite this

Differential covariation in taste responsiveness to bitter stimuli in rats. / Brasser, Susan M.; Mozhui, Khyobeni; Smith, David V.

In: Chemical Senses, Vol. 30, No. 9, 01.11.2005, p. 793-799.

Research output: Contribution to journalArticle

Brasser, Susan M. ; Mozhui, Khyobeni ; Smith, David V. / Differential covariation in taste responsiveness to bitter stimuli in rats. In: Chemical Senses. 2005 ; Vol. 30, No. 9. pp. 793-799.
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