2009 Abstracts - Association for Chemoreception Sciences

measures ANOVA demonstrated a significant interaction betweengroups and pre-/post-conditioning A1 detection thresholds; theExperimental group demonstrated a significant increase and theControl group a significant post-conditioning sensitivity decrease,relative to pre-conditioning. Re-testing of olfactory sensitivity toA1 two months post-conditioning indicated no differencebetween the two groups. Taken together, these data demonstratethat the olfactory system exhibits rapid plasticity with thefunctional benefit of a sharp and odorant specific increase inabsolute detection threshold.#P285 Poster session VI: Chemosensory developmentand Psychophysics IEffects of sub-threshold odorants on rapid olfactoryadaptation in human observersRyan R. Keith 1 , Swati Pradeep 1 , Erica M. Rodriguez 1 , KatherineE. Boylan 1 , Danielle A. Broome 1 , Neal R. Delvadia 1 , David W.Smith 1,21Dept. of Psychology, University of Florida Gainesville, FL,USA, 2 University of Florida Center for Smell and TasteGainesville, FL, USAIn previous presentations we have described use of a novelpsychophysical technique for estimating the onset time course ofperceptual odor adaptation in humans. The premise of thetechnique is that extended presentation of an odorant willproduce adaptation, decreasing the sensitivity of the receptor andincreasing thresholds for a brief, simultaneous target odorantpresented at various time-points after the adapting stimulus onset;where both the adapting odorant and the target odorant are thesame (i.e., self adapting). Those results suggested that perceptualodorant adaptation was measureable within 100-200 ms afterstimulus onset. In those initial studies, the adapting odorantconcentration for each subject was set to twice the baselinethreshold for the 600-ms target (i.e., the same level relative tothreshold). In this presentation, using the same stimulusparadigm, we report changes in perceptual adaptation collectedwith the adapting odorant set to different subthresholdconcentrations levels. To characterize the effect of adaptingodorant level we used a liquid-dilution olfactometer to estimatetwo-bottle discrimination thresholds for brief (600 ms)presentations of vanilla odor; 13 volunteers (ages 18-21) served assubjects. Adapting odorant concentration levels were then set to0.25, 0.5, 0.75 and 1 times threshold concentration for each subjectand threshold for the 600-ms target was measured as a function ofthe relative delay between the onset of the adapting stimulus andthe onset of the target. The results demonstrate that significantincreases in odorant sensitivity were evident even at subthresholdadapting odorant levels. The time course of this subthresholdadaptation was similar to that measured with suprathresholdadapting odorants.#P286 Poster session VI: Chemosensory developmentand Psychophysics IUpdate on Racial and Gender Differences in Odor PerceptionCharles J. Wysocki 1 , Danielle R. Reed 1 , Doron Lancet 2 , YehuditHasin 2 , Jennifer Louie 1 , Lisa Oriolo 1 , Fujiko Duke 11Monell Chemical Senses Center Philadelphia, PA, USA,2Weizmann Institute of Science Rehovot, IsraelFor the past four years we have been screening African-Americanand Caucasian men and women for sensitivity to a select group ofodorants, viz., 5-a-androst-16-en-3-one (androstenone; having aurinous or sandalwood odor), amyl acetate (banana- or pear-likeodor), Galaxolide (musky), isovaleric acid (sweaty), 3-methyl-2-hexenoic acid (3M2H; sweaty), pentadecalactone (musky), benzylsalicylate (balsamic), muscone (musky), Jeger’s Ketel (woody,amber), 2-nonenal (unpleasant, fatty), skatole (fecal) and geosmin(earthy), selected because some people have a specific anosmia tothe odorant. Psychophysical testing is performed in a singlesession and DNA is obtained for subsequent analysis. Phenotypicdifferences between the two racial groups and between men andwomen have been observed. Caucasians have a significantlygreater rate of specific anosmia to androstenone (7%) than doAfrican-Americans (0%). The opposite is true for benzylsalycilate (Caucasians, 22%; African-Americans, 35%).Disregarding race, men exhibit higher rates of specific anosmiasfor amyl acetate (3% vs 0%), Jeger’s Ketel (7% vs. 2%) andandrostenone (10% vs. 3%) than do women. Among individualswho can smell the odorants, Caucasians have higher olfactorydetection thresholds for 3M2H (0.0058 w/v), Galaxolide(0.0407% v/v) and isovaleric acid (0.0020% w/v) than doAfrican-Americans (respectively, 0.0024%; 0.0092%; and0.0006%). Data collection continues and the above is subjectto change.#P287 Poster session VI: Chemosensory developmentand Psychophysics ITaste cell specific over-expression of BDNF leads to multiplefold increase of expression levels of BDNF and increased sizeand number of taste budsIrina Nosrat 1 , Shailaja Kishan Rao 1 , Weikuan Gu 1 , RobertMargolskee 2 , Christopher Nosrat 11University of Tennessee Health Science Center Memphis, TN,USA, 2 Mount Sinai School Medicine New York, NY, USABrain-derived neurotrophic factor (BDNF) is the most potentneurotrophic factor in the taste system during development, and isalso expressed in taste cells of adult mice. We over-expressedBDNF using a promoter for alpha-gustducin to study the roles ofBDNF in the adult taste system. Gustducin is normally expressedin type II receptor cells that also express G-protein coupled tastereceptors. Taste buds were isolated using laser capturemicrodissection from circumvallate papillae of six weeks oldgustducin-BDNF taster mouse lines. RNA was isolated and realtime PCR analysis revealed a six-fold increase of BDNF in twotransgenic mouse lines. We also employed immunohistochemistryon taste papillae of gustducin-BDNF mice using Troma-1antibody which identifies taste buds. In addition, we analyzedtongue surface and papillae morphology using scanning electronmicroscopy. Circumvallate papillae are wider in gustducin-BDNFcompared to wild-type mice. Additionally, circumvallate tastebuds in high BDNF expressing transgenic mice are wider and116 | AChemS Abstracts 2009