Chemical Senses Advance Access originally published online on June 14, 2007
Chemical Senses 2007 32(7):711-719; doi:10.1093/chemse/bjm038
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A Quantitative Structure–Activity Analysis on the Relative Sensitivity of the Olfactory and the Nasal Trigeminal Chemosensory Systems
1 Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK 2 Chemosensory Perception Laboratory, Department of Surgery (Otolaryngology), University of California, San Diego, La Jolla, CA 92093-0957, USA
Correspondence to be sent to: Michael H. Abraham, Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ, UK. e-mail: m.h.abraham{at}ucl.ac.uk
| Abstract |
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We have applied a quantitative structure–activity relationship (QSAR) approach to analyze the chemical parameters that determine the relative sensitivity of olfaction and nasal chemesthesis to a common set of volatile organic compounds (VOCs). We used previously reported data on odor detection thresholds (ODTs) and nasal pungency thresholds (NPTs) from 64 VOCs belonging to 7 chemical series (acetate esters, carboxylic acids, alcohols, aliphatic aldehydes, alkylbenzenes, ketones, and terpenes). The analysis tested whether NPTs could be used to separate out "selective" chemosensory effects (i.e., those resting on the transfer of VOCs from the gas phase to the receptor phase) from "specific" chemosensory effects in ODTs. Previous work showed that selective effects overwhelmingly dominate chemesthetic potency whereas both selective and specific effects control olfactory potency. We conclude that it is indeed possible to use NPTs to separate out selective from specific effects in ODTs. Among the series studied, aldehydes and acids, except for formic acid, show clear specific effects in their olfactory potency. Furthermore, for VOCs whose odor potency rests mainly on selective effects, we have developed a QSAR equation that can predict their ODTs based on their NPTs.
Key words: chemesthetic QSAR, mechanism of biological activity, nasal chemosensory sensitivity, nasal irritation thresholds, odor detection thresholds, olfactory QSAR, VOCs
Accepted 20 April 2007