Chemical Senses Advance Access originally published online on July 16, 2009
Chemical Senses 2009 34(7):559-563; doi:10.1093/chemse/bjp036
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Discrimination of "Odorless" Mineral Oils Alone and as Diluents by Behaviorally Trained Mice
1 Department of Psychology, University of Florida, Gainesville, FL 32611, USA 2 The Center for Smell and Taste, University of Florida, Gainesville, FL 32611, USA
Correspondence to be sent to: David W. Smith, Department of Psychology, University of Florida, Gainesville, FL 32611, USA. e-mail: dwsmith{at}ufl.edu
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Abstract |
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Odorant diluents are generally chosen because of their odorless qualities, allowing them to dilute a target odorant without otherwise altering its perception. Unpublished observations from our laboratory, however, suggest that mineral oil (MO), a common diluent for oil-based odorants, may possess a distinct odor when used in the behavioral testing of mice. To test this, mice were trained to discriminate between 4 brands of MO, using a commercial, liquid-dilution olfactometer and a 2-odorant discrimination task. The results demonstrate that mice were able to detect MOs and to discriminate between MO pairs obtained from different sources. Additionally, we sought to determine if mice could discriminate different MOs when used as a diluent for suprathreshold levels of cineole. Mice were required to discriminate between bottles containing identical concentrations of cineole diluted in different brands of MO. The results showed that the mice readily discriminated each cineole/MO pairing. These data demonstrate that mice are able to detect and discriminate MOs obtained from different sources, both when presented alone and in mixtures. The results also indicate that MO is not an odorless diluent and should be used with caution in olfactory experiments, as the perception of odors being diluted may be unintentionally altered.
Key words: odor diluent, odorant, odorant discrimination, odorant mixtures, olfaction, olfactometer
Accepted 3 June 2009