2009 Abstracts - Association for Chemoreception Sciences

al 2008. Increases in glucose sensitivity were induced by treatmentwith glucose, Na-cyclamate and MSG, but not by water oracesulfame-K. Treatment with MSG, glucose or fructose increasedsensitivity to MSG, while water and acesulfame-K did not, andNa-cyclamate decreased MSG sensitivity. Treatment with IMPincreased MSG sensitivity, and that increase was reversed byadding Na-cyclamate to the IMP treatment solution. IMPtreatment had no effect on glucose sensitivity, and adding IMP toa Na-cyclamate treatment solution did not reverse the increasedglucose sensitivity produced by Na-cyclamate. The overall datasupport a peripheral mechanism and a role for T1R3 in theinduction. KMG is supported by NSF Graduate Fellowship.We thank Bio 040 students for assistance.#P308 Poster session VII: Chemosensory Psychophysics IIThe Effect of Amiloride on the Taste Quality of Salty SolutionsKathryn Luley, Anilet Tharp, James Bernhardt, Paul A. S. BreslinMonell Chemical Senses Center Philadelphia, PA, USASalt perception in humans may be partially mediated by theactivation of the epithelial sodium channel (ENaC), a selectiveion channel present in taste buds. Amiloride, an ENaC channelblocker, has been shown to affect salt taste perception in rodents;however its effect on human taste is not fully understood.While amiloride does not block salt taste in humans, it mayaffect the quality. In this study we investigated individualdifferences in amiloride sensitivity in humans, in particular theeffect of amiloride on the taste quality of salt. Subjects were askedto rate the intensity and quality of salt solutions tasted with andwithout amiloride. Our results suggest an effect of amiloride onsome humans and may help to futher elucidate the role of ENaCin human salt taste.#P309 Poster session VII: Chemosensory Psychophysics IISynchronicity Judgement of Gustation and OlfactionTatsu Kobayakawa, Hideki Toda, Naomi GotowAdvanced Industrial Science and Technology (AIST)Tsukuba, JapanSynchronicity of gustation and olfaction in food intake seriouslywill affect recognition of food perception. The synchronicity,however, is rarely investigated for integration process of gustationand olfaction. In this study, therefore, we focused on thesynchronicity perception between gustation and olfaction. Weused taste stimulator which was able to present pure gustationwithout tactile stimuli, and the timing of taste stimuli to tip ofparticipants’ tongues was measured in real time by three opticalsensors. We also used olfactometer equivalent Burghart’s OM4,with original developed real time stimulus monitoring usingultrasonic sensor. We used vision stimuli using LED in controlcondition. The distribution of synchronicity for “olfaction andvision”, and “gustation and vision” was almost equivalent as“vision and audition”. These results mean the perceptionprocesses for olfaction and gustation have equivalent temporalresolution compared to visual perception. The distribution ofsynchronicity for “olfaction and gustation” was quite differentfrom others. In other words, the synchronicity distribution ofolfaction and gustation was found to be much broader thanothers. This result might imply that the relation between olfactionand gustation is much closer than that between other sensations.#P310 Poster session VII: Chemosensory Psychophysics IIThe Effect of pH on Arginine Enhancement of Salty TasteNelsa Estrella, Paul A. S. BreslinMonell Chemical Senses Center Philadelphia, PA, USAWe have previously shown that L-arginine enhances saltytaste. The mechanism for this remains unclear. In this study, inorder to help elucidate the phenomenon further, we s determinedthe effects of pH on L-arginine’s enhancement of salty taste inhumans. Subjects were presented with mixtures of L-arginine andNaCl solutions of different pHs and asked to rate perceivedsaltiness using a general labeled magnitude scale. We replicatedour previous findings and showed that L-arginine does enhancesalty taste of salts. We further show that manipulations of pHaffect L-arginine’s ability to do so.#P311 Poster session VII: Chemosensory Psychophysics IISynergistic responses to L-glutamine and IMP in brief accesspreference testing in C57BL miceBenjamin K. Eschle, Meghan C. Eddy, J. Tyler Van Backer,Eugene R. DelayDepartment of Biology & Vermont Chemical Senses Group,University of Vermont Burlington, VT, USASynergy between 5’-inosine monophosphate (IMP) andL-glutamate is a defining characteristic of umami taste. Molecularexpression studies have shown that IMP may also interactsynergistically with other L-amino acids and, in some cases,IMP was necessary for cellular activation by the amino acid.These data suggest that IMP-induced synergy may extend to thetastes of other L-amino acids. Synergy is revealed when theresponse to a binary mixture is greater than the sum of theresponses to the components of the mixture. We examinedbehavioral synergy between glutamine and IMP in C57BL mice.Mice were studied in a non-deprived state in a brief accesspreference test paradigm. Lick rates were used to measurepreferences for a range of concentrations of both glutamine(10, 30, 100, and 200 mM) and IMP (0.3, 1, 3, and 10 mM) alone,as well as 16 binary combinations of the two. A predicted valuefor each of the binary mixtures was generated by summingthe lick rates for each the components presented along. Thesepredicted values are what would be expected in the absence of anysynergistic interaction. Actual lick rates to the mixtures werecompared to the predicted values to determine whether or notsynergy was present. Synergy was observed in mixtures withconcentrations of glutamine 30 mM and higher, and IMP 3 mMand higher. Testing will be continued with T1R3 KO mice toexamine what, if any, effect the absence of this receptor has onsynergistic interactions between L-glutamine and IMP.P O S T E R SAbstracts | 123