2009 Abstracts - Association for Chemoreception Sciences

#P150 Poster session III: Cortical chemosensory processing/Receptor genomics and molecular biologyIdentifying TRPA1 agonists by monitoring intracellularcalcium levels in HEK cellsPaige M. Roe, Erik C. Johnson, Wayne L. SilverWake Forest University Winston-Salem, NC, USANasal trigeminal chemoreceptors appear to be stimulated byvirtually all volatile compounds if presented in highconcentrations. Trigeminal nerve endings contain several differenttypes of receptors; however, the specific receptors stimulated bymany trigeminal stimuli are unknown. Transient receptor proteins(TRPs) are non-specific cation channels, associated withtrigeminal nerve fibers, which display an affinity for calcium.TRPA1, found in a subset of neurons in the trigeminal ganglion,has at least 90 different known agonists and was considered alikely target of known trigeminal stimuli that work through anunidentified mechanism. The goal of this experiment was todetermine if certain known trigeminal stimuli activate TRPA1.Both naive HEK and hTRPA1-HEK cells were allowed to growin a 96-well plate for a minimum of 24 hours. Intracellular calciumlevels were measured by a plate reader using the Ca 2+ -sensitivefluorescent dye FLUO-3AM. Baseline fluorescence of each wellwas measured. A potential TRPA1 agonist was then added andfluorescence was measured again. The relative change influorescence elicited by the test stimuli from wells containinghTRPA1-HEK cells was compared to the relative fluorescentchange elicited from wells containing naive HEK cells. In all,11 stimuli were tested in various concentrations ranging from0.1 mM to 100 mM. Based on preliminary data analysis, allylisothiocyanate, alpha-terpineol, acetic acid, benzaldehyde,cinnamaldehyde, eugenol, and d-limonene stimulated TRPA1.It is presently unclear whether amyl acetate, cyclohexanone,nicotine or toluene did or did not stimulate TRPA1. This methodidentifies TRPA1 agonists and future studies examiningbehavioral responses will assess whether trigeminal irritationdue to these stimuli is solely mediated by TRPA1.#P151 Poster session III: Cortical chemosensory processing/Receptor genomics and molecular biologyIn Vitro Nematocidal Activity of TRPA1 ActiveCompounds from Perilla FrutescensAngela Bassoli 1 , Gigliola Borgonovo 1 , Sara Caimi 1 , GabriellaMorini 2 , Francesco D’ErricoSeveral food plants used in traditional cooking contain interestingbioactive compounds. We are particularly interested inchemestetic compounds, both for their use in gastronomy and fortheir medical and agronomical applications. Perilla frutescensBritton (Labiatae) is a native plant of eastern Asia, where it ispopular as culinary and medicinal herb named keaennip in Koreaand shiso in Japan. One of the major components of Perillaessential oil is perillaketone PK. We discovered that this moleculeis a potent activator of TRPA1 in in vitro assays on rat clonedreceptors [2]. TRP ion channels are important cellular sensorsactivated by several stimuli and involved in many aspects ofchemical sensing [3,4]. In particular TRPA1 is involved innociception and has an established role in sensing mechanisms ininsects and invertebrates. This finding suggests that PK could beresponsible of specific nematocidal activity of Perilla extracts.We isolated pure PK from the leaves and evaluated its nematocidalactivity against second-stage larvae of cystic nematode Heteroderadaverti, showing that it is characterized by a remarkablenematocidal activity. [1] Handbook of herbs and spices vol. 3,Peter K.V. Ed., CRC Press, Boca Raton Boston New YorkWashington, DC 2006; [2] Bassoli A.; Borgonovo G.; Caimi S.;Scaglioni L.; Morini G.; Schiano Moriello A.; Di Marzo V.; DePetrocellis L., J. Bioorganic & Med. Chem., 2009, (DOI10.1016/j.bmc.2008.12.057); [3] Clapham D.E., Nature, 2003, 426,517-524; [4] TRP ion channels in sensory trasduction and cellularsignaling cascades, Liedtke, W.B.; Heller, S. Eds., Taylor andFrancis, 2007.#P152 Poster session III: Cortical chemosensory processing/Receptor genomics and molecular biologyOlfactory rivalry: Competing olfactory processing betweenthe two nostrils and in the cortexWen Zhou, Denise ChenRice University Houston, TX, USAWhen two different images are presented to the two eyes, weperceive alternations between seeing one image and seeing theother. Termed binocular rivalry, this visual phenomenon wasrecognized over a century ago, and its neural mechanism has beenconsiderably studied. Here we report the discovery of alternatingolfactory percepts when two different odorants are presented tothe two nostrils. We show that both cortical and peripheral(olfactory receptor) adaptations are involved in this process. Ourdiscovery extends the perceptual rivalry to olfaction, and opensup entirely new avenues to explore the workings of the olfactorysystem and olfactory awareness.#P153 Poster session III: Cortical chemosensory processing/Receptor genomics and molecular biologyIs there a difference in odor processing in response toleft vs. right-sided odor stimulation?Anna M. Kleemann 1 , Jessica Albrecht 1, 2 , Veronika Schöpf 3 ,Rainer Kopietz 1 , Katrin Haegler 1 , Rebekka Zernecke 1 ,Marco Paolini 1 , Imke Eichhorn 1 , Jennifer Linn 1 , HartmutBrückmann 1 , Martin Wiesmann 1,41Department of Neuroradiology, Ludwig-Maximilians-Universityof Munich Munich, Germany, 2 Monell Chemical Senses CenterPhiladelphia, PA, USA, 3 MR Centre of Excellence, MedicalUniversity Vienna Vienna, Austria, 4 Department of Radiology andNeuroradiology, Helios Kliniken Schwerin Schwerin, GermanyObjectives: The results of a previous localization studydemonstrated, that humans need trigeminal perception to localizeodors. Based on these findings a functional magnetic resonanceimaging (fMRI) experiment was carried out to assess whetherthere are differences in odor processing in response to left versusright-sided odorant stimulation. Methods: We used two odors:8ppm H 2 S (hydrogen sulphide), which is known to be a pureodorant in this concentration, and 17.5% isoamyl acetate (IAA)as an olfactory-trigeminal stimulus. We tested 22 healthy subjectswith H 2 S and 24 subjects with IAA. Functional images wereacquired using a 3T MR scanner. The odorant stimulation wasperformed using an olfactometer. The experiment was carried outbased on an event-related design paradigm and the stimulus lengthwas 500 ms. After every stimulus the participants were asked to74 | AChemS Abstracts 2009