List of Abstracts of the Seventeenth Annual Meeting of the European Chemoreception Research Organisation

2006 Chemical Senses  
We have explored how mammals detect odorants and pheromones and how the brain translates those chemicals into diverse perceptions and instinctive behaviors. We found that odorants are detected in the nasal olfactory epithelium (OE) by ;1000 different odorant receptors (ORs), whereas pheromones are detected in the vomeronasal organ (VNO) by two smaller receptor families. Our studies showed that ORs are used combinatorially to encode odor identities. Exploring the patterning of OR inputs, we
more » ... that each sensory neuron in the OE expresses a single type of OR and that neurons with the same OR are scattered in one zone but synapse in a stereotyped fashion in OR-specific glomeruli in the olfactory bulb. At the next level, the olfactory cortex, we discovered another stereotyped map of OR inputs but here signals from different ORs are targeted to partially overlapping clusters of neurons and single neurons receive combinatorial OR inputs. By comparing responses to binary odorant mixtures versus their components, we found evidence that the cortical neurons act as coincidence detectors whose activation requires combinatorial OR inputs, thus providing an initial step in the reconstruction of an odor image from its deconstructed features. To explore how pheromones alter reproductive physiology and behavior, we made mice expressing a transneuronal tracer in gonadotropin releasing hormone (GNRH) neurons. These studies revealed that GNRH neurons receive pheromone signals from the OE as well as the VNO. We recently discovered a second class of chemosensory receptors in the OE, called TAARs, that recognizes at least one pheromone and may also be involved in the detection of other social cues by the OE. Pheromones are species-specific chemosignals. A hallmark of pheromonal communication is the ability of the chemosignal to modify endocrine state in conspecifics. While clear in many species, whether humans communicate with pheromones remains highly controversial. Here we found that merely a few sniffs of androstadienone, a molecule present in the saliva, semen, and sweat of men, significantly increased the sexual arousal, physiological reactivity, and critically, levels of the hormone cortisol in women. That a single molecule emitted by men is capable of stereotypically modifying mood, physiological arousal, and endocrine state in women qualifies this molecule as a human pheromone. Some bitter and sweet tastants were previously found to activate the inhibitory pathway of adenylyl cyclase (AC) in frog melanophores via melatonin and alpha-2-adrenergic receptors (Zubare-Samuelov et al. 2003. Am J Physiol 285:C1255-C1262). Since previous and present results suggest that such receptors are present in taste-bud cells, their responses to stimulation by some tastants were investigated in taste tissue. A 10-s stimulation of isolated intact circumvallate (CV) taste-bud sheets (TBS) by the bitter naringin and the sweetener saccharin reduced the isoproterenol-stimulated cAMP formation, whereas the bitter cyclo(Leu-Trp) peptide had no effect. The melatonin receptor antagonist, luzindole, or the alpha-2-adrenergic receptor antagonist, yohimbine, almost abolished the naringin-reduced cAMP but had no effect on the saccharinreduced cAMP. On the other hand, the presence of alpha-1adrenergic receptor antagonist, prazosin, almost abolished the saccharin-induced reduction of cAMP. As in the 10-s stimulation paradigm, subsecond stimulation by naringin of isolated broken foliate and CV taste papillae homogenate (BCH) reduced cAMP levels, and this effect was abolished in the presence of either luzindole or yohimbine. However, cAMP level was elevated following subsecond stimulation of BCH by either cyclo(Leu-Trp) or saccharin. It is concluded that naringin stimulates the inhibitory pathway of AC via melatonin and alpha-2-adrenergic receptors in taste tissue during both subsecond and 10-s stimulation paradigm. Saccharin stimulates the inhibitory pathway of AC via alpha-1-adrenergic receptors but it does so only in TBS during the 10-s stimulation paradigm. Avenanthramides are a class of natural polyphenolic compounds isolated from oat and other plants. They have antioxidant properties and have been positively correlated to the fresh taste of such cereal. However, it is not reported whether such property is to be intended as cooling effect or as not rancid and, in any case, the sensory properties of the singular avenanthramides are unknown. We developed new structure-activity relationships (SAR) considering the chemical and physical properties of 75 known cooling compounds owing to different chemical classes (menthol and derivatives, icilin, cyclic alpha-ketoenamines, etc.) and a group E2 ECRO Abstracts In this paper, we estimate the information capacity of a synthetically generated population of olfactory receptor neurons (ORN) expressing the same olfactory receptor protein (ORP). This study is aimed ECRO Abstracts E3 Wounds are injuries to body tissues caused by disease processes or events such as burns, punctures, chronic leg or decubitus ulcers, and results of surgery. Wounds become infected when microorganisms from the environment or from the patient's body enter the open wound and multiply. The symptoms related to an infection include abnormal flushing of the skin, heat, pain, and tenderness and abnormal odours, such as fruity odours that often indicate the presence of Staphylococcus or foul odours due to presence of gram-negative bacteria. Standard techniques for microbiological detection are surface swabbing and wound biopsy culture. Surface swabbing is the most used technique mainly because it is quite inexpensive and is not invasive but can give only a representation of the surface infected and is time consuming. Biopsies are invasive and are inconvenient. We are developing a fast reliable method for detection of microbial infection by monitoring the headspace from the infected wounds. In this paper we present preliminary results obtained by analysing the headspace volatiles emitted from Streptococcus aureus, Pseudomonas aeruginosa, and Bacterium fragilis in order to identify volatile markers of infection. The results obtained from this GC-MS study will allow us to build a noninvasive mobile system for noninvasive wound monitoring using an array of gas and odour sensors to be used for point of care monitoring of patients. Objectives: Free microvascular flaps are commonly used to reconstruct intraoral defects after tumour resection. Even though functional results are usually good, little is known about taste function in these patients. Methods: In 15 (age: 45-70 years) patients (postoperative range: 1-4.5 years) and 15 age-matched controls, taste function and subjective impairment were evaluated. Psychophysical threshold testing was done using taste strips. Moreover, olfactory function was psychophysically evaluated using the Sniffin' Sticks test battery. Nine out of 15 patients had additional radiotherapy postoperatively. Results: In contrast to normogeusic controls, in 11 patients taste was significantly reduced. One patient was hypogeusic, 10 ageusic, and only in 4 patients taste testing revealed normogeusia. Subjective impairment was low. Olfactory function-in contrast-was only slightly reduced. Conclusions: There is a high incidence of taste disorders in patients after E6 ECRO Abstracts Chemosensory function has poorly been investigated in chronic renal failure patients. The effect of haemodialysis on the chemosensory functions remains largely unknown. Several authors showed poorer olfactory performances in chronic renal failure patients compared to controls. Recent works on chronic renal failure patients tested by the Sniffin' Sticks test battery evidenced a gap between the olfactory threshold performances and their ability to identificate and discriminate odors. Thus, poorer olfactory performance in these patients results rather from a central (identification) than from a peripherical (threshold) impairment. We have studied the effect of haemodialysis on both olfactory identification and threshold. Methods: Eighteen patients with chronic renal failure were included in the study. Olfactory tests were done 1 h before and after haemodialysis. Olfactory testing was done with the SniffinÕ Sticks test battery, a well-established and validated olfactory test device. Thresholds were evaluated with an n-butanol and acetic acid step dilution test. Data were compared to published normative data. Results: Overall olfactory performance was slightly poorer compared to a normal population before haemodialysis. Olfactory identification and acetic acid threshold were impaired before haemodialysis. After dialysis, identification (P = 0.0043) and acetic acid threshold (P = 0.0034) improved significantly, while n-butanol threshold did not change (P = 0.34). Conclusion: This confirms previous studies on poorer olfactory overall performances in chronic renal failure patients. The improvement of olfactory identification performance after haemodialysis brought some further arguments for a central cause of olfactory impairment in chronic renal failure patients. Current knowledge on the anatomic and functional organization of the learning and memory support a hippocampal role on contextdependent learning phenomena. The study of this specific hippocampal function may benefit from a developmental approach, ECRO Abstracts E11 Sperm chemotaxis is a general guidance mechanism of spermatozoa to eggs throughout the animal kingdom. Since the G protein subunit a-gustducin is accepted as a marker of chemosensitive cells, attempts were made to explore whether a-gustducin is also expressed in spermatozoa of different mammalian species. RT-PCR experiments performed with specific primers revealed PCR products which sequences were fully consistent with the reported a-gustducin sequences. To identify the testicular developing cell type in which a-gustducin is expressed, immunohistochemical experiments were performed with an anti-a-gustducin-specific antibody. The most intense immunoreactivity was visible in differentiating spermatids ECRO Abstracts E17 Little is known about working memory for odors. Dade et al. compared working memory for odors and faces in a two-back samedifferent task and found similar levels of performance. Because the E48 ECRO Abstracts Endoscopy of the olfactory mucosa is important for clinical examination of patients with hyposmia and/or anosmia. However, ECRO Abstracts E75 The sorghum chafer, Pachnoda interrupta (Coleoptera: Scarabidae), is a major pest on sorghum that is an important Ethiopian staple crop. Our objective is to improve a locally developed "lure and kill" trapping method by replacing the current bait (fruit) with E80 ECRO Abstracts
doi:10.1093/chemse/bjl029 fatcat:bhjdee37fjbqtgolwpshbpes5y