The Experts below are selected from a list of 375 Experts worldwide ranked by ideXlab platform
William S. Cain - One of the best experts on this subject based on the ideXlab platform.
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2007b) A quantitative structure-activity analysis on the relative sensitivity of the olfactory and the nasal trigeminal chemosensory systems
2016Co-Authors: Michael H. Abraham, Enrique J. Cometto-muñiz, William S. CainAbstract: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 ter-penes). 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, VOC
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Nasal Chemosensory Irritation in Humans
Toxicology of the Nose and Upper Airways, 2016Co-Authors: J. Enrique Cometto-mun˜iz, William S. Cain, Michael H. Abraham, Ricardo Sa´nchez-moreno, Javier Gil-lostesAbstract:Author(s): Cometto-Muniz, J. Enrique; Cain, William S.; Abraham, Michael H.; Sanchez-Moreno, Ricardo; Gil-Lostes, Javier | Abstract: Nasal chemosensory irritation (i.e., Chemesthesis) in humans results form stimulation of the trigeminal nerve. Almost all chemical vapors that produce odor can evoke nasal Chemesthesis at higher concentrations, although there is a cut-off point along homologous series beyond which larger homologs fail to be detected by Chemesthesis. The failure seems to rest on some aspect of molecular structure or dimensions rather than on a low vapor concentration. In turn, almost all irritants can also elicit an odor with the arguable exception of carbon dioxide (CO2). To separate the trigeminal from the olfactory response of the nose, investigators have tested subjects lacking olfaction (i.e., anosmics) and have measured nasal lateralization thresholds, i.e., the ability to localize whether a vapor entered the right or the left nostril when air enters the contralateral nostril. Such ability rests on trigeminal, not olfactory input. Detection of nasal Chemesthesis from chemical mixtures reveals additive effects among constituents, particularly at low levels of detectability (but still above chance detection). As a rule, increases in time of exposure decrease chemesthetic thresholds (i.e., enhances sensitivity) and produce higher ratings of irritation intensity. Nasal Chemesthesis can produce alterations in respiration, including a reflex, transitory apnea, and reductions in the duration and volume of nasal inhalations. Relative consistency has been found for irritation thresholds among two of three anatomical structures subsumed within “sensory irritation” – i.e., the nose and eye. Thus for predictive toxicology and risk assessment purposes, an argument can be made that measurements using one system can often be extrapolated to the other.
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A Quantitative Structure–Activity Analysis on the Relative Sensitivity of the Olfactory and the Nasal Trigeminal Chemosensory Systems
2015Co-Authors: Michael H. Abraham, Enrique J. Cometto-muñiz, William S. CainAbstract: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 ter-penes). 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, VOC
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Human chemosensory perception of methyl isothiocyanate: Chemesthesis and odor.
Regulatory toxicology and pharmacology : RTP, 2010Co-Authors: William S. Cain, Michael Dourson, Melissa Kohrman-vincent, Bruce C. AllenAbstract:Abstract An unpublished laboratory study by Russell and Rush (1996) showed that human subjects sense the presence of methyl isothiocyanate (MITC) via the eyes at concentrations as low as hundreds of ppb in air, with dependence upon duration of exposure. The longer the stimulation, the lower the concentrations sensed. Application of benchmark concentration (BMC10) modeling indicated a best estimate of 330 ppb by the end of 4 h. With a confidence limit (BMCL) applied, the level dropped to 220 ppb, when employing a probit model. Receptors known as TRPA1 ion channels present in trigeminal and associated peripheral afferent nerves have shown particular sensitivity to isothiocyanates. Sensitivity to these electrophiles, which occur naturally in plants (e.g., capers and mustard greens), most likely derives from a mechanism of reversible covalent bonding. Such sensing can provide warning of potential damage rather than actual damage itself. Based upon its reputation as a lachrymator, Russell and Rush assumed that the eyes would sense MITC, before the upper airways, so gathered no data from the airways, except for odor. Field results from spills and results of acute exposures to animals covered in Dourson et al. (2010) add pertinent information on the matter.
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Odor and Chemesthesis from exposures to glutaraldehyde vapor
International Archives of Occupational and Environmental Health, 2007Co-Authors: William S. Cain, Roland Schmidt, Alfredo A JalowayskiAbstract:Objectives Assessment of olfactory and chemesthetic sensitivity (feel, sensory irritation) to vapor of glutaraldehyde in young adult females. For chemesthetic sensitivity, assessment included the variable of duration, with focus on whether concentrations initially too low to evoke feel in the eye or upper airway might do so in exposures up to 15 min. Methods Experiment 1 probed sensitivity with forced-choice testing of detection over ranges of concentrations appropriate to three endpoints: odor, feel in the eye, and feel in the nose. A subject participated in hours of testing per endpoint to yield enough data to erect a psychometric (concentration-response) function. Exposure in Experiment 1 entailed use of a vapor-delivery system that stimulated sites of interest separately. Exposure in Experiment 2 occurred in the ambient environment of a chamber, with the sites stimulated simultaneously. In that case, subjects rated confidence by the minute that they felt the presence of vapor in the eyes, nose, and throat during exposures of 15 minutes to 35, 50, 75, and 100 ppb, a blank, and an odor control of mild heptane. Results In Experiment 1, the typical subject achieved 50% detection (threshold) of odor at 0.3 ppb. The typical subject achieved 50% detection of feel in the eye and nose at 390 and 470 ppb, respectively. Psychometric functions for feel showed much sharper dependence on concentration than those for odor. In Experiment 2, confidence in detection of feel migrated progressively away from no—with certainty toward the zone of uncertainty, with bigger change when the exposures contained any glutaraldehyde. The ratings of confidence failed, however, to show distinguish among these concentrations. Conclusions Glutaraldehyde has much higher odor potency than previously thought. Its green-apple odor should signal presence of the vapor at levels more than a 100-fold below any that might evoke sensory irritation in brief exposures. Exposures that start decidedly below irritating (100 ppb and below) seem unlikely to turn irritating over time. Although the effects from these concentrations differentiated themselves from those of air and an odor control, they exhibited none of the concentration dependence seen for sensations of feel. They seemed likely driven by the penetrating odor of glutaraldehyde.
Michael H. Abraham - One of the best experts on this subject based on the ideXlab platform.
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2007b) A quantitative structure-activity analysis on the relative sensitivity of the olfactory and the nasal trigeminal chemosensory systems
2016Co-Authors: Michael H. Abraham, Enrique J. Cometto-muñiz, William S. CainAbstract: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 ter-penes). 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, VOC
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Nasal Chemosensory Irritation in Humans
Toxicology of the Nose and Upper Airways, 2016Co-Authors: J. Enrique Cometto-mun˜iz, William S. Cain, Michael H. Abraham, Ricardo Sa´nchez-moreno, Javier Gil-lostesAbstract:Author(s): Cometto-Muniz, J. Enrique; Cain, William S.; Abraham, Michael H.; Sanchez-Moreno, Ricardo; Gil-Lostes, Javier | Abstract: Nasal chemosensory irritation (i.e., Chemesthesis) in humans results form stimulation of the trigeminal nerve. Almost all chemical vapors that produce odor can evoke nasal Chemesthesis at higher concentrations, although there is a cut-off point along homologous series beyond which larger homologs fail to be detected by Chemesthesis. The failure seems to rest on some aspect of molecular structure or dimensions rather than on a low vapor concentration. In turn, almost all irritants can also elicit an odor with the arguable exception of carbon dioxide (CO2). To separate the trigeminal from the olfactory response of the nose, investigators have tested subjects lacking olfaction (i.e., anosmics) and have measured nasal lateralization thresholds, i.e., the ability to localize whether a vapor entered the right or the left nostril when air enters the contralateral nostril. Such ability rests on trigeminal, not olfactory input. Detection of nasal Chemesthesis from chemical mixtures reveals additive effects among constituents, particularly at low levels of detectability (but still above chance detection). As a rule, increases in time of exposure decrease chemesthetic thresholds (i.e., enhances sensitivity) and produce higher ratings of irritation intensity. Nasal Chemesthesis can produce alterations in respiration, including a reflex, transitory apnea, and reductions in the duration and volume of nasal inhalations. Relative consistency has been found for irritation thresholds among two of three anatomical structures subsumed within “sensory irritation” – i.e., the nose and eye. Thus for predictive toxicology and risk assessment purposes, an argument can be made that measurements using one system can often be extrapolated to the other.
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A Quantitative Structure–Activity Analysis on the Relative Sensitivity of the Olfactory and the Nasal Trigeminal Chemosensory Systems
2015Co-Authors: Michael H. Abraham, Enrique J. Cometto-muñiz, William S. CainAbstract: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 ter-penes). 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, VOC
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olfactory detectability of homologous n alkylbenzenes as reflected by concentration detection functions in humans
Neuroscience, 2009Co-Authors: J E Comettomuniz, Michael H. AbrahamAbstract:Abstract As part of our systematic exploration of chemical determinants for the olfactory potency of vapors towards humans, we measured concentration-detection functions for the odor of the homologous n- alkylbenzenes toluene, ethylbenzene, butylbenzene, hexylbenzene, and octylbenzene. A vapor delivery device based on dynamic olfactometry and calibrated by gas chromatography, served to test groups of 16 to 17 participants. Subjects were young adults from both genders, normosmics, and nonsmokers. Odor functions were tightly modeled by a sigmoid (logistic) function, both at the group and the individual level. Odor detection thresholds (ODTs), defined as the concentration producing a detectability halfway between chance and perfect detection, decreased with alkyl chain length from toluene (79 ppb) to butylbenzene (2.5 ppb), and then increased form butyl to octylbenzene (89 ppb). The “U”-shaped trend of ODTs as a function of alkyl chain length indicated a loss of odor potency beyond a certain molecular size, a phenomenon recently described for chemosensory irritation (Chemesthesis) and that will need consideration in structure–activity models of chemosensory potency. Interindividual ODTs' variability for any single odorant amounted to one order of magnitude, in agreement with recent studies of other homologous series but quite smaller than commonly depicted.
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A cut-off in ocular Chemesthesis from vapors of homologous alkylbenzenes and 2-ketones as revealed by concentration-detection functions.
Toxicology and applied pharmacology, 2008Co-Authors: J. Enrique Cometto-muñiz, Michael H. AbrahamAbstract:Studies of homologous series of environmental vapors have shown that their chemesthetic (i.e., sensory irritation) potency increases with carbon chain length (that is, their detection thresholds decrease) until they reach a homolog that fails to be detected, even at vapor saturation. All ensuing homologs cannot be detected either. In this investigation, we measured concentration-detection (i.e., psychometric) functions for ocular Chemesthesis from homologous alkylbenzenes (pentyl, hexyl, and heptyl benzene) and 2-ketones (undecanone, dodecanone, and tridecanone). Using a three-alternative forced-choice procedure against air blanks, we tested a total of 18 to 24 subjects, about half of them females, average age 31 years, ranging from 18 to 56 years. Stimuli were generated and presented by a computer-controlled, vapor delivery device whose output was quantified by gas chromatography. Exposure time was 6 s and delivery flow 2.5 L/min. Within the context of present and previous findings, the outcome indicated that the functions for heptylbenzene and 2-tridecanone reached a plateau where further increases in concentration did not enhance detection. We conclude that: a) a cut-off point in ocular chemesthetic detection is reached along homologous alkylbenzenes and 2-ketones at the level of heptylbenzene and 2-tridecanone, respectively, and b) the observed effect rests on the homologs exceeding a critical molecular size (or dimension) rather than on them failing to achieve a high enough vapor concentration.
Barry G. Green - One of the best experts on this subject based on the ideXlab platform.
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Surveying Chemosensory Dysfunction in COVID-19.
Chemical senses, 2020Co-Authors: Barry G. GreenAbstract:Soon after the outbreak of COVID-19, reports that smell and taste are disrupted by the illness drew the attention of chemosensory scientists and clinicians throughout the world. While other upper respiratory viruses are known to produce such disruptions, their occurrence with the deadly and highly infectious SARS-CoV-2 virus raised new questions about the nature of the deficits, their cause, and whether they might serve as indicators of the onset of the disease. Published in the July and August 2020 issues of Chemical Senses are 2 innovative, large-scale survey studies that were quickly devised and launched by separate multinational groups to address these questions in olfaction, taste, and Chemesthesis. The surveys, which took different approaches and had somewhat different goals, add significant new data on the incidence and severity of smell loss in COVID-19, and the potential for olfactory dysfunction to serve as an indicator of the spread and severity of the disease. Less definitive evidence of the frequency, characteristics, and magnitude of disruptions in taste and Chemesthesis point to the need for future survey studies that combine and refine the strengths of the present ones, as well as clinical studies designed to selectively measure deficits in all 3 chemosensory systems.
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Chemesthesis and the chemical senses as components of a chemofensor complex
Chemical Senses, 2012Co-Authors: Barry G. GreenAbstract:An important function of the chemical senses is to warn against dangerous biological and chemical agents in the environment. The discovery in recent years of “taste” receptor cells outside the oral cavity that appear to have protective functions has raised new questions about the nature and scope of the chemical senses in general and of Chemesthesis in particular. The present paper briefly reviews these findings within the context of what is currently known about the body's chemically sensitive protective mechanisms, including nonsensory processes that help to expel or neutralize threatening agents once they have been encountered. It is proposed that this array of defense mechanisms constitutes a “chemofensor complex” in which Chemesthesis is the most ubiquitous, functionally diverse, and interactive chemosensory component.
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Chemesthesis and the Chemical Senses as Components of a “Chemofensor Complex”
Chemical senses, 2011Co-Authors: Barry G. GreenAbstract:An important function of the chemical senses is to warn against dangerous biological and chemical agents in the environment. The discovery in recent years of “taste” receptor cells outside the oral cavity that appear to have protective functions has raised new questions about the nature and scope of the chemical senses in general and of Chemesthesis in particular. The present paper briefly reviews these findings within the context of what is currently known about the body's chemically sensitive protective mechanisms, including nonsensory processes that help to expel or neutralize threatening agents once they have been encountered. It is proposed that this array of defense mechanisms constitutes a “chemofensor complex” in which Chemesthesis is the most ubiquitous, functionally diverse, and interactive chemosensory component.
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Chemesthesis and taste: Evidence of independent processing of sensation intensity
Physiology & Behavior, 2005Co-Authors: Barry G. Green, Marty Alvarez-reeves, Pravin George, Carol AkiravAbstract:The ability to perceive taste from temperature alone (“thermal taste”) was recently shown to predict higher perceptual responsiveness to gustatory and olfactory stimuli. This relationship was hypothesized to be due in part to individual differences in CNS processes involved in flavor perception. Here we report three experiments that tested whether subjects who differ in responsiveness to thermal taste and/or chemical taste also differ in responsiveness to oral Chemesthesis. In experiment 1, subjects identified as ‘thermal tasters’ (TTs) or ‘thermal non-tasters’ (TnTs) used the general Labeled Magnitude Scale to rate the intensity of sensations produced on the tongue tip by capsaicin, menthol, sucrose, NaCl, citric acid, and QSO4. TTs rated all four taste stimuli higher than did TnTs, whereas sensations of burning/stinging/pricking and temperature from capsaicin and menthol did not differ significantly between groups. In experiment 2, testing with capsaicin on both the front and back of the tongue confirmed there was no difference in ratings of burning/stinging/pricking when subjects were grouped according to the ability to perceive thermal taste. In experiment 3, subjects were classified as high- or low-tasters according to their ratings of sucrose sweetness rather than thermal taste. No group difference was found for perception of capsaicin even when presented in mixture with sucrose or NaCl. The results are discussed in the context of previous evidence of an association between Chemesthesis and sensitivity to the bitter tastant PROP, and in terms of the various peripheral and central neural processes that may underlie intensity perception in taste and Chemesthesis.
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Capsaicin as a probe of the relationship between bitter taste and Chemesthesis.
Physiology & behavior, 2003Co-Authors: Barry G. Green, John E HayesAbstract:Previous studies have indicated that capsaicin, traditionally considered to be a pure chemesthetic stimulus, can evoke a bitter taste and might also cross-desensitize the tastes of some bitter and sour tastants. The purpose of the present study was to investigate further the scope and nature of capsaicin's effects on bitter taste. In Experiment 1, subjects rated the taste and burning/stinging of QSO4 (0.32 and 1.0 mM), saccharin (1.0 and 3.2 mM), urea (3.2 and 10 M), MgCl2, (0.18 and 0.56 M), PROP (0.32 mM), and sucrose (0.32 and 1.0 M) applied to the tongue tip with cotton swabs before and after 10 applications of 300 microM capsaicin. Capsaicin initially evoked a weak bitterness in some subjects that quickly diminished over repeated exposures. Following capsaicin treatment, the bitterness of QSO4, urea, MgCl2, and PROP was reduced, as was the burning sensation produced by MgCl2 and urea. In Experiment 2, we tested 29 subjects in the circumvallate (CV) region of the tongue using the same general procedure. Capsaicin induced a weak but persistent bitterness in a subset of subjects but failed to desensitize its own bitterness or that of any other tastant. Overall, the results confirm that capsaicin can both stimulate and desensitize bitter taste, but in amounts that vary for different bitter stimuli and between the front and back of the tongue. Possible reasons for these regional and stimulus-dependent differences are discussed.
J. Enrique Cometto-muñiz - One of the best experts on this subject based on the ideXlab platform.
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A cut-off in ocular Chemesthesis from vapors of homologous alkylbenzenes and 2-ketones as revealed by concentration-detection functions.
Toxicology and applied pharmacology, 2008Co-Authors: J. Enrique Cometto-muñiz, Michael H. AbrahamAbstract:Studies of homologous series of environmental vapors have shown that their chemesthetic (i.e., sensory irritation) potency increases with carbon chain length (that is, their detection thresholds decrease) until they reach a homolog that fails to be detected, even at vapor saturation. All ensuing homologs cannot be detected either. In this investigation, we measured concentration-detection (i.e., psychometric) functions for ocular Chemesthesis from homologous alkylbenzenes (pentyl, hexyl, and heptyl benzene) and 2-ketones (undecanone, dodecanone, and tridecanone). Using a three-alternative forced-choice procedure against air blanks, we tested a total of 18 to 24 subjects, about half of them females, average age 31 years, ranging from 18 to 56 years. Stimuli were generated and presented by a computer-controlled, vapor delivery device whose output was quantified by gas chromatography. Exposure time was 6 s and delivery flow 2.5 L/min. Within the context of present and previous findings, the outcome indicated that the functions for heptylbenzene and 2-tridecanone reached a plateau where further increases in concentration did not enhance detection. We conclude that: a) a cut-off point in ocular chemesthetic detection is reached along homologous alkylbenzenes and 2-ketones at the level of heptylbenzene and 2-tridecanone, respectively, and b) the observed effect rests on the homologs exceeding a critical molecular size (or dimension) rather than on them failing to achieve a high enough vapor concentration.
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A Quantitative Structure–Activity Analysis on the Relative Sensitivity of the Olfactory and the Nasal Trigeminal Chemosensory Systems
Chemical senses, 2007Co-Authors: Michael H. Abraham, J. Enrique Cometto-muñiz, Ricardo Sánchez-moreno, William S. CainAbstract: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.
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Chemesthesis from volatile organic compounds: Psychophysical and neural responses.
Physiology & behavior, 2006Co-Authors: William S. Cain, Roland Schmidt, J. Enrique Cometto-muñiz, Paul M. Wise, Nam-soo Lee, Byung-hoon Ahn, Michael H. AbrahamAbstract:In Experiment 1, subjects sought to localize the nostril stimulated, left or right, in tests with nine esters (acetates, propionates, and butyrates) at concentrations meant to trigger Chemesthesis (pungency, irritation). The task produced psychometric functions for chemesthetic detection unconfounded by olfactory sensations. The functions indicated a sharp transition from no detection to perfect detection, rather uniform across the esters, which themselves varied in potency by two log units. The correlation between the thresholds for the eight materials that yielded thresholds and predictions from a published linear free energy relationship (LFER) equaled 0.99. In Experiment 2, amplitude of the negative mucosal potential (NMP) was recorded from the septum. The resulting functions also increased with concentration sharply. Against a criterion amplitude of the NMP, thresholds measured in the first experiment (and predictions from the LFER) correlated 0.99. The NMP seems to offer an adequate objective measure of sensory irritation. The LFER, although effective predictively, could stand to have a parameter to anticipate that molecules beyond a certain size fail to trigger irritation. In the present case, a cut-off of chemesthetic potency occurred between butyl butyrate and hexyl butyrate for the group of subjects, with some variation of the boundary among individuals.
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Determinants for nasal trigeminal detection of volatile organic compounds.
Chemical senses, 2005Co-Authors: J. Enrique Cometto-muñiz, William S. Cain, Michael H. AbrahamAbstract:We explored the influence of methodological and chemical parameters on the detection of nasal Chemesthesis (i.e., trigeminal stimulation) evoked by volatile organic compounds (VOCs). To avoid odor biases, Chemesthesis was probed via nasal pungency detection in anosmics and via nasal localization (i.e., lateralization) in normosmics, in both cases using forced-choice procedures. In the experiments with anosmics, 12 neat VOCs were selected based on previous reports of lack of chemesthetic response. Although none of the VOCs reached 100% detection, detectability and confidence of detection were higher when using a glass vessel system adapted with nosepieces to fit the nostrils tightly than when using wide-mouth glass jars. Half the stimuli were detected well above chance and half were not. When the latter were tested again after being heated to 37 degrees C, that is, body temperature (from room temperature, 23 degrees C), to increase their vapor concentration, only one, octane, significantly increased its detectability. Chemesthesis gauged with normosmics mirrored that with anosmics. Gas chromatography measurements showed that, even at 23 degrees C, the saturated vapor concentrations of the undetected stimuli, except vanillin, were well above the respective calculated nasal pungency threshold (NPT) from an equation that, in the past, had accurately described and predicted NPTs. We conclude that, except for octane and perhaps vanillin, the failure of the other four VOCs to precipitate nasal Chemesthesis rests on a chemical-structural limitation, for example, the molecules lack a key property to fit a receptor pocket, rather than on a concentration limitation, for example, the vapor concentration is too low to reach a threshold value.
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Chemosensory additivity in trigeminal chemoreception as reflected by detection of mixtures
Experimental Brain Research, 2004Co-Authors: J. Enrique Cometto-muñiz, William S. Cain, Michael H. AbrahamAbstract:A series of experiments probed into the degree of chemosensory detection additivity exhibited by mixtures of ethyl propanoate and heptanoate in terms of their trigeminal detectability via nasal pungency (i.e., irritation) and eye irritation. Nasal pungency was tested in subjects lacking a functional sense of smell (i.e., anosmics) to avoid olfactory biases. First, we built concentration-detection functions for each chemical and sensory endpoint. Second, we used the data from the functions to prepare mixtures of the two compounds in complementary proportions, and suitable single-chemical standards, all of which should be equally detectable under a rule of complete additivity, i.e., independence of detection. Third, we compared the experimentally obtained detectability with that expected under such rule. The outcome revealed that, at a low detectability level (but still above chance), the mixtures showed complete additivity for both trigeminal endpoints. At a high detectability level (but below perfect detection), the mixtures showed complete additivity for nasal pungency but less than complete additivity for eye irritation. In the context of previous studies, the results consolidate a picture of higher degree of detection additivity at perithreshold levels in trigeminal than in olfactory chemoreception. The outcome presents another line of evidence suggesting broader chemical tuning in Chemesthesis compared to olfaction.
Paul M. Wise - One of the best experts on this subject based on the ideXlab platform.
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The Effect of Temperature and Menthol on Carbonation Bite
Chemical senses, 2014Co-Authors: Paul M. Wise, Bruce P. BryantAbstract:Temperature and Chemesthesis interact, but this interaction has not been fully examined for most irritants. The current experiments focus on oral pungency from carbonation. Previous work showed that cooling carbon dioxide (CO2) solutions to below tongue temperature enhanced rated bite. However, to the best of our knowledge, the effects of warming to above tongue temperature have not been examined. In Experiment 1, subjects sampled CO2 solutions at 4 nominal concentrations (0.0, 2.0, 2.8, and 4.0 v/v) × 5 temperatures (18.3, 24.5, 29.9, 34.5, and 39.6 (o)C). Subjects dipped their tongue tips into samples and rated bite. As in previous work, subjects rated cool solutions (25.0 (o)C and lower) as more intense. Warming solutions above tongue temperature (39.6 (o)C) did not affect ratings. Experiment 2 examined warmer temperatures (18.3, 33.9, 39.0, 44.9, and 48.2 oC). Bite was enhanced only at 48.2 oC, and a follow-up experiment suggested that enhancement was probably due to confusion between carbonation bite and mild heat pain. Experiment 3 examined the effect of menthol cooling by pretreating the tongue with menthol. Unlike physical cooling, menthol cooling had little or no effect on rated bite. The results are discussed in the context of candidate transduction mechanisms for carbonation sensation.
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The Effect of Temperature and Menthol on Carbonation Bite
2014Co-Authors: Paul M. Wise, Bruce BryantAbstract:Temperature and Chemesthesis interact, but this interaction has not been fully examined for most irritants. The current experiments focus on oral pungency from carbonation. Previous work showed that cooling carbon dioxide (CO2) solutions to below tongue temperature enhanced rated bite. However, to the best of our knowledge, the effects of warming to above tongue temperature have not been examined. In Experiment 1, subjects sampled CO2 solutions at 4 nominal concentrations (0.0, 2.0, 2.8, and 4.0 v/v) × 5 temperatures (18.3, 24.5, 29.9, 34.5, and 39.6 oC). Subjects dipped their tongue tips into samples and rated bite. As in previous work, subjects rated cool solutions (25.0 oC and lower) as more intense. Warming solutions above tongue temperature (39.6 oC) did not affect ratings. Experiment 2 examined warmer temperatures (18.3, 33.9, 39.0, 44.9, and 48.2 ºC). Bite was enhanced only at 48.2 ºC, and a follow-up experiment suggested that enhancement was probably due to confusion between carbonation bite and mild heat pain. Experiment 3 examined the effect of menthol cooling by pretreating the tongue with menthol. Unlike physical cooling, menthol cooling had little or no effect on rated bite. The results are discussed in the context of candidate transduction mechanisms for carbonation sensation. Key words: acid, Chemesthesis, pungency, sensory irritatio
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Stimulus selection for intranasal sensory isolation: eugenol is an irritant.
Chemical senses, 2012Co-Authors: Paul M. Wise, Charles J. Wysocki, Johan N. LundströmAbstract:Both the olfactory and the trigeminal systems are able to respond to intranasal presentations of chemical vapor. Accordingly, when the nose detects a volatile chemical, it is often unclear whether we smell it, feel it, or both. The distinction may often be unimportant in our everyday perception of fragrances or aromas, but it can matter in experiments that purport to isolate olfactory processes or study the interaction between olfaction and Chemesthesis. Researchers turn to a small pool of compounds that are believed to be “pure olfactory” stimuli with little or no trigeminal impact. The current report reexamines one such commonly used compound, namely eugenol, a flavor and fragrance ingredient that has anesthetic properties under some conditions. Using a standard method involving many trials during an experimental session (Experiment 1), subjects were unable to reliably lateralize eugenol, consistent with claims that this compound is detected primarily through olfaction. However, with more limited exposure (Experiments 2 and 3), subjects were able to lateralize eugenol. We speculate that anesthetic properties of eugenol could blunt its trigeminal impact in some paradigms. Regardless, the current experiments suggest that eugenol can in fact stimulate the trigeminal nerve but in a complex concentration–dependent manner. Implications and strategies for selection of model odorants are discussed.
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Dynamics of Nasal Chemesthesis
Annals of the New York Academy of Sciences, 2009Co-Authors: Paul M. Wise, Kai Zhao, Charles J. WysockiAbstract:Dynamics, or how stimulation occurs over time, influences the somatosensory impact of volatile chemicals. Within an experimental session, sensation waxes with steady presentation over seconds to minutes, may reach a plateau, and then may fade. Long-term occupational exposure can desensitize the trigeminal system. Short- and long-term dynamics might be mediated by different mechanisms. For brief intranasal exposures (i.e., up to about 10 seconds), studies have systematically manipulated both time (duration of exposure) and concentration to maintain a fixed perceived intensity or a fixed level of detection. A simple mass integration model describes the trade-off between concentration and time quite well: a fixed-ratio increase in duration compensates for a fixed-ratio decrease in concentration. However, for most compounds, more than a two-fold increase in duration are required to compensate for cutting concentration in half. For example, for ethanol, an increase in duration of about six-fold are required. For such compounds that display highly imperfect integration, a fixed number of molecules might have a much greater sensory impact when presented over 0.2 seconds than over 0.5 seconds. Nasal Chemesthesis may be temporally sluggish compared to olfaction, but fine-grained dynamics still matter. Time-intensity ratings of nasal irritation from dynamic stimuli also support this conclusion. Although integration is generally imperfect, compounds vary widely in how far they fall short of perfect time-concentration trading. Current studies use a structure-activity approach to determine how molecular parameters correlate with how well a compound integrates over time.
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4 – TASTE, SMELL AND Chemesthesis IN PRODUCT EXPERIENCE
Product Experience, 2008Co-Authors: Armand V. Cardello, Paul M. WiseAbstract:Publisher Summary The oldest human senses are those that respond to chemicals in the environment. In humans, the senses of taste, smell, and Chemesthesis have become secondary to those of vision and audition, but they still play a pre-eminent role in how humans experience a wide range of everyday objects, including all foods and beverages, as well as many important products in the perfume, healthcare, and personal product markets. In spite of the importance of the chemical senses to human experience, they have not received the scientific attention that the higher senses have received. However, exciting discoveries during the past decade have produced greater interest in the chemical senses. This chapter explores taste, smell, and Chemesthesis in product experience. It examines the role of three sensory systems that signal the presence of chemicals in the environment and that influence one’s product experiences. Taste(gustation) is the sensory system that detects chemicals dissolved in the liquids one drinks and the foods he or she eats. Smell (olfaction) detects airborne chemicals emitted by natural, living, and synthetic products. Chemesthesis detects chemical irritants via the same skin-sense nerves that give sensitivity to touch, temperature, and pain. These three sensory systems have different specialties but work together to contribute to our overall experience of the products one uses. This chapter outlines the anatomical, physiological, and biochemical mechanisms that underlie chemosensory experience. It discusses the fundamental sensory and perceptual phenomena that operate when products are experienced through these senses. Furthermore, it examines how chemosensory product experiences are quantified for practical applications in industry and the roles of nonsensory information, beliefs, expectations, and product context in experience, concluding with a discussion of how age, gender, social, and cultural variables can influence chemosensory product experience.