XVI International Symposium on Olfaction and Taste - ecro

<strong>XVI</strong> <strong>International</strong> <strong>Symposium</strong> on Olfaction and Taste
Investigations focus, as far as possible, on monitoring the actual molecules involved in vivo or, at least, in physiological
systems as close as possible to the respective physiological conditions. To deal with the challenging issues of selectivity,
sensitivity and temporal resolution, novel techniques are developed and adapted for the specific analytical requirements. In
the course of such studies, it becomes increasingly clear that the human physiology not only senses and reacts to signals
obtained via volatiles / odorants, but also exerts quite pronounced (bio-) chemical modulations on such substances that in
turn result in new compounds that may further exert other potential physiological effects.
An overview of state-of-the-art analytics applied to monitor such substances in in vivo processes, together with discussion of
the respective (bio-) chemical principles will be provided in the presentation.
Poster session II Poster 190
Agonist profiling of the mouse formyl peptide receptors reveal a stereoselective tuning of mFprrs1
Bernd Bufe 1 , Timo I Schumann 1 , Hendrik Stempel 1 and Frank Zufall 1
1University of Saarland School of Medicine, Department of Physiology, Homburg, Germany
bernd.bufe@uks.eu
Recently several members of the mouse formyl peptide receptor (Fpr) family were discovered in the vomeronasal organ
(VNO), the key detector of pheromones and similar semiochemicals. The biological role of these Fpr receptors is yet not
clear. However, their homology to the human FPR-family that contributes to host immune defense suggests that Fpr-
receptors in the VNO may be involved in pathogen detection. A precise knowledge about their ligand profile provides
helpful insights towards unraveling their function. We tested all seven mouse Fpr-receptors in heterologous systems by
functional high-throughput calcium imaging with 29 compounds covering many prototypical ligand classes. We observed
broad tuning and an intriguing functional overlap between human FPRs, mFpr1 and mFpr2. 21 of the 29 compounds
activated either mFpr1 or mFpr2 that are expressed in mouse leucocytes, and most likely fulfill similar functions as their
human counterparts. In marked contrast Fpr-related receptors (Fpr-rs) expressed in the VNO are much more narrowly
tuned. Surprisingly, we observed that mFpr-rs1 is stereoselectively activated by a family of peptides containing D-amino
acids. These pharmacologic properties of mFpr-rs1 are consistent with its proposed role in pathogen detection because
similar peptides are known to exist in bacteria and fungi. To test the biological significance of these findings we
challenged acutely dissociated VNO neurons from OMP-GFP animals with a range of selected ligands in a novel high-
throughput calcium imaging assay. We observed several pharmacologically distinct subpopulations. Intriguingly, 2% of the
cells showed a stereoselective agonist profile that is similar to that of mFpr-rs1 in the heterologous system. Currently, we
are investigating the underlying molecular signal transduction and behavioral response to these compounds.
Supported by DFG-grants SFB894, INST 256/273-1 FUGG and Volkswagen Foundation.
Poster session II Poster #398
Pulsation induced taste enhancement: why continuous alternation makes sense
Kerstin M.M. Burseg1, 2 , Sara M. Camacho1 1, 2
, Johannes H.F. Bult
1 TI Food and Nutrition, Wageningen, The Netherlands
2 NIZO food research, Ede, The Netherlands
kerstin.burseg@nizo.nl
The successive alternation of high and low tastant concentrations (pulsatile stimulation) results in higher taste intensity
than stimulation with the same net but non-alternating tastant concentration (continuous stimulation) [1-3]. We conducted
several studies to elucidate the underlying mechanism of pulsation induced taste enhancement. We investigated the
effects of pulsation rate [3-4], pulse-interval contrast [5], taste quality and taste transduction mechanism [6] on the taste
intensity enhancement. In this contribution we summarize the key findings of those studies and propose a mechanism to
explain our findings. This mechanism is based on enhancement effects at preconscious stages of gustatory processing.
1. Meiselman, H.L. and B.P. Halpern, Enhancement of taste intensity through pulsatile stimulation. Physiol Behav,
1973. 11(5): p. 713-6.
2. Busch, J.L., et al., Temporal contrast of salt delivery in mouth increases salt perception. Chem Senses, 2009. 34(4): p.
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