2009 Abstracts - Association for Chemoreception Sciences

utyl, hexyl, and octyl benzene). We employed dynamicolfactometry, natural odor sampling (sniffing), a three-alternativeforced-choice procedure against carbon-filtered air blanks, and alarge, tightly controlled, vapor stimulus source quantified via gaschromatography. Concentration-detection, i.e., psychometric,functions, from which odor detection thresholds (ODTs) can bedetermined, constituted the outcome of interest. Among ketones,ODTs decreased from acetone to 2-heptanone, remainingconstant for 2-nonanone. Among alkylbenzenes, ODTs decreasedfrom toluene to butyl benzene, then increased for hexyl andfurther for octyl benzene. These ODT trends resembled thosefound in the literature but the absolute ODTs were consistentlyamong the lowest previously reported. Interindividual variabilityof ODTs amounted to about one order of magnitude. Theoutcome provides additional support to the key role played inodor potency by physicochemical parameters governing thetransfer of the odorant from the vapor phase (where it enters thenose) through the various biophases (from the nasal mucus to theolfactory receptor environment), but it also indicates that, at somepoint, molecular dimensions begin to put a limit, and even reverse,the gain in olfactory potency observed with increasing carbonchain length. Supported by grant number R01 DC002741 formthe NIDCD, NIH.#P282 Poster session VI: Chemosensory developmentand Psychophysics ICigarette Smoking and the Olfactory Detection of CyanideJeneca J. Dovey, David E. HornungSt. Lawrence University Canton, NY, USASome organic chemists of a bygone era claimed smoking waslinked to an increased sensitivity to cyanide and so they justifiedsmoking because cyanide exposure was a profession hazard.The purpose of this study was to text this claim. Smokers andnonsmokers between the ages of 18 and 22 were ask to rate theintensity of a series of odors using the Green Scale (ChemicalSenses 21:323-334, 1996). Olfactory threshold measurements werealso determined for four odorants. Included in the odorants usedfor the intensity ratings were almond oil, ground-up peach pitsand trans-2-hexenal. Almond was included because it has acyanide-like smell, peach pits because they contain cyanidecompounds and trans-2-hexenal because it closely resembles themolecular structure of cyanide. Two of the odors used for thethreshold measurements were almond oil and trans-2-hexenal.Confirming what has been reported in many other studies, on theaverage, smokers gave lower intensity ratings and had higherthresholds compared to nonsmokers. However the intensityratings for trans-2-hexenal were not as reduced when compared tothe ratings for the other odorants and its threshold was notreduced by smoking. As a possible explanation for thisobservation, perhaps the cyanide like compounds found in somecigarettes are facilitating olfactory detection for this compoundand this facilitation offsets the overall decrease in olfactory abilitythat often accompanies smoking. In conclusion, although theremay be some validity in the claims of the organic chemists, theseresults suggest they would have been even better at detectingcyanide if they had not smoked at all.#P283 Poster session VI: Chemosensory developmentand Psychophysics IRetronasal olfaction influences swallowingMyriam Ebnoether 1 , Antje Welge-Luessen 1 , MarkusWolfensberger 1 , Thomas Hummel 21Dept. of Otorhinolaryngology, University Hospital Basel,Switzerland, 2 Smell & Taste Clinic, University of Dresden MedicalSchool Dresden, GermanyObjectives: Identical ortho- and retronasal stimuli are processeddifferently. Since retronasal odorant perception is stronglyassociated with food intake and flavour, an influence of retronasalstimulation on swallowing can be assumed. It was the aim of ourstudy to evaluate the impact of retronasal olfaction onswallowing. Subjects and Methods: Fifty normosmic andnormogeusic subjects (23 male, 24 female, mean age: 24 .2 years,range: 18-42) took part in the study. Olfactory stimuli (vanillin,40 % vol/vol) were presented randomized ortho- and retronasally(8 stimuli each) using a computer-controlled olfactometer.Simultaneously a sweet taste (glucose) was continuously deliveredthrough a taste dispenser which was kept within the mouth.Ultrasound examination of the mouth floor was continuouslyrecorded on a videotape to monitor swallowing activity. Thevideotapes were evaluated by one of the authors´ blindedconcerning place of stimulation (ortho- vs. retro). Results: Afterretronasal stimulation swallowing not only occurred faster(7.49 vs. 9.42s; p