Sunday, 8:00 - 10:00 PM
Session 1: Keynote Speaker
- Christian Margot, PhD. (Firmenich SA, Switzerland)
"Nosing out structure/perception correlations of odors"
Monday, 9:00 AM - 12:30 PM
Session 2: Beyond cAMP vs. InsP3: Transduction Diversity in Olfaction
- Diego Restrepo (Univ. Colorado Health Sciences Center, Denver, CO)
- Vince Dionne (BU Marine Program, Boston University)
"Transduction Diversity in Olfaction"
- Shawn Lockery (Inst. Neurosci., Univ. Oregon)
"Physiology of Identified Sensory Neurons in C. Elegans"
- Juan Bacigalupo (Dept. Biol. Univ. Chile)
"Inhibitory Odorant-activated K+ Current in Toad Olfactory Neurons"
- Johannes Reisert (Physiological Laboratory, Cambridge Univ.)
"Sodium/calcium exchange and response termination in frog olfactory receptor cells"
- William C. Michel (Univ. Utah, Salt Lake City, UT)
- King-Wai Yau (Dept. Neurosci. Johns Hopkins Univ.) - Not confirmed yet
The study of transduction events and second messenger systems is one of the most active and productive areas of research in the chemical senses. Work in recent years in a number of different species has revealed a diversity of signaling pathways and provoked debate over the nature of their contributions to olfactory transduction. In this session, we bring together researchers who study different aspects of transduction and different species as model animals to address the following issues: 1. What are the signaling pathways that have been identified in different species, and is it likely that some remain to be discovered? 2. What is the range of different effects that odorants can have on membrane potential via different second messenger pathways? 3. What interactions may occur between pathways when more than one is present in a cell? And finally, 4. How might the answers to these questions differ for different species?
Monday, 5:00 - 6:00 PM
Monday, 7:00 - 9:00 PM
Session 3: Sweet Taste - Reconciling Genetics and Receptor Models
- Yuzo Ninomiya (Asahi Univ., Japan)
- Grant Dubois (Coca Cola Co., Atlanta, GA)
"Models for the coding of the sweet taste message in molecular structure: Review and critical assessment"
- Bachmanov (Monell Chem. Senses Center, Philadelphia, PA)
"Genes influencing sweetener responses in inbred strains of mice"
- Paul Breslin (Monell Chem. Senses Center., Philadelphia, PA)
- Bernd Lindemann (Saar Univ. Homberg, Germany)
- Teiichi Tanimura (Kyushu Univ., Japan)
An attractive notion is that each taste modality is coded by a single molecular receptor. However, data suggest that there are several different transduction mechanisms for a single taste quality such as "sweetness" in one species. Furthermore, these mechanisms vary significantly across species. Chemists who synthesize compounds and develop receptor models have proposed complex theoretical constructs for taste receptors (e.g. "the multi-point attachment" receptor of Nofre and Tinti). The impact of recent studies on the distribution of specified genes in inbred strains of mice with distinguishable neural and behavioral reactions to sweet stimuli on the conceptual "sweet receptor" will be explored.
Tuesday, 9:00 AM - 12:30 PM
Session 4: Bitter Taste: The Role of the Glossopharyngeal Nerve
- Susan Travers (Ohio State, Columbus, OH)
- Ding Ming (Pepsi Cola Co., Valhala, NY)
"Ligands of receptors that couple to gustducin"
- Vicktoria Danilova (Univ. Wisconsin, Madison, WI)
"Comparing glossopharyngeal and chorda tympani responses to different taste qualities"
- Alan Spector (Univ. Florida, Gainesville, FL)
"The effect of gustatory nerve transection on taste-guided behavior to quinine in rats"
- M. Scott Herness (Ohio State Univ., Columbus, OH)
- Charles F. Lamb (Black Hills State Univ., SD)
- Sidney Simon (Duke University, Chapel Hill, NC)
The neural processing of bitter stimuli has now been studied at several levels of analysis, but results from any one level are not simple and reconciling results from different levels of analysis is not straightforward. This session will present data on the initial ligand-receptor interaction, compare neurophysiological recordings from the glossopharyngeal and chorda tympani nerves, and relate these neurophysiological responses to the effects of cutting these nerves on quinine discrimination. One controversial issue is whether a special role for the glossopharyngeal in coding bitter stimuli has been demonstrated.
Tuesday, 5:00 - 6:00 PM
Tuesday, 7:00 - 9:00 PM
Session 5: Expression Systems in Olfaction - What Do We expect?
- Heinz Breer (University Stuttgart-Hohenheim, Stuttgart, Germany)
- Stuart Firestein (Columbia University, New York, NY)
"Viral mediated functional expression of odorant receptors in olfactory neurons"
- Hans Kiefer (University Stuttgart-Hohenheim, Stuttgart, Germany)
"Heterologous expression of olfactory receptors in pro- and eucaryotic cell lines"
- Doron Lancet (Weizmann Institute, Israel)
- Joseph G. Brand (Monell Chemical Senses Center, Philadelphia, PA)
The enormous capacity of chemical recognition in the olfactory system is probably based on a very large family of olfactory receptor types. These heptahelical transmembrane proteins initiate the chemoelectrical transduction of odorant signals via G protein-coupled cascades in olfactory sensory neurons. Different receptor types are supposed to recognize odorous compounds based on distinct chemical determinants (odotopes). A rigorous proof that the family of olfactory genes indeed encodes receptors for odorous molecules as well as an evaluation of their individual chemospecificity and functional properties can only be provided by functional expression of receptor-encoding complementary DNA demonstrating that the expressed polypeptides mediate specific reactions upon odorant stimulation. This requires both that the receptors are properly targeted to the plasma membrane, and that they couple efficiently with a second messenger cascade that produces a measurable response to ligand stimulation. Evidence will be presented for a viral mediated functional expression of receptors in olfactory neurons as well as a for heterologous expression of receptors in pro- and eucaryotic cell lines.
Wednesday, 9:00 AM - 12:30 PM
Session 6: The End or the Beginning - What is the Role of Maps?
- Kathleen Dorries (Tufts School of Medicine, Boston, MA)
- Peter Mombaerts (Rockefeller University)
- Rainer Friedrich (Max-Planck-Institut für Entwicklungsbiologie)
"Strategies of odorant coding by glomerular activity patterns"
- Mark Stopfer (California Institute of Technology)
"Temporal representation of odors by synchronous neural assemblies"
- Linda Buck (Dept. of Neurobiology, Harvard University Medical School)
- Burton Slotnick (Dept. Psychology, The American University)
- Detlev Schild (Physiologisches Institute, University of Göttingen)
One of the contributions molecular genetics have made to the study of olfaction has been demonstration of stereotyped patterns of olfactory bulb glomeruli characterized by the expression patterns of the presumed olfactory receptor genes. All or most receptor neurons expressing a particular gene appear to converge on one or two specific locations in the bulb, and those locations are invariant across individuals of a species. These findings, taken together with earlier physiological data, provide evidence that the functional organization of olfactory bulbs includes some sort of map, or maps, of receptor specificities across the glomerular layer. This is an important advance in our understanding of olfactory coding, yet receptor neurons and their projections constitute only the earliest level of processing. Maps of stimulus space are common in sensory systems, but in other modalities relationships between maps and stimulus dimensions, and the role of the maps in neural processing, are better understood. This session will address questions about the importance of olfactory maps in the coding of odor quality and intensity: What is the organizing principle of the maps; what "dimensions" are mapped? How are the maps related to "odor space"? What is the functional significance of this type of organization for processing odor information? What is the relationship between olfactory bulb maps and higher level processing?
Wednesday, 5:00 - 6:00 PM
Wednesday, 7:00 - 9:00 PM
Session 7: Transduction of Developmental Signals: Another Type of Chemical Sense
- Thomas Finger (Univ. Colorado Medical School, Denver, CO)
- Gail Burd (Univ. of Arizona, Tucson, AZ)
"Signals in the early development of the olfactory system"
- Thomas Reh (Univ. of Washington, Seattle, WA)
"Molecular signaling during eye development"
- Linda Barlow (Univ. Denver, Denver, CO)
- Albert Farbman (Northwestern Univ., Evanston, IL)
- Jim Schwob (SUNY, Syracuse, NY)
Specification and differentiation of sensory end organs require communication between the various component tissue elements. This session will examine the types of signals sent from one cell to another and the transduction mechanisms involved in reception of these signals.
Thursday, 9:00 AM - 12:30 PM
Session 8: Inhibitory Systems in Taste Processing: What is the Role in Coding?
- Barry Davis (Univ. Maryland School of Medicine, Baltimore, MD)
- Mark Whitehead (University of California, San Diego, CA)
"GABA, interneurons and inhibition in the gustatory NST"
- Gintautas Grabauskas (Univ.Michigan, Ann Arbor, MI)
"Inhibitory synaptic processing in the rostral NST"
- Linda Bartoshuk (Yale Univ. School of Medicine, New Haven, CT)
"The role of inhibition in human taste perception"
- David Smith (Univ. Maryland School of Medicine, Baltimore, MD)
- John Scott (Emory University, Atlanta, GA)
- Brad Formaker (Univ. Conn. Health Center, Farmington, CT)
GABA, a major inhibitory neurotransmitter, is found in many neurons of the taste CNS. In the brainstem nucleus of the solitary tract (NTS), these neurons are likely inhibitory interneurons. Suggested roles of CNS inhibition include 'control over an overabundance of inputs" from multiple peripheral taste nerves and 'opponent processing' of taste signals elicited by accepted or rejected stimuli. These and other potential roles for the inhibition will be discussed in the context of recent data on the structure and function of the inhibitory machinery in the NTS.
Thursday, 5:00 - 6:00 PM
Thursday, 7:00 - 9:30 PM
Session 9: Specialist vs. Generalist Systems in Vertebrates vs. Invertebrates
- Brian Smith (Ohio State University, Columbus, OH)
- Mike Meredith (Florida State University, Tallahassee, FL)
"Chemosensory Communication versus Chemosensory Association: How does the brain get the information it needs?"
- Hanna Mustaparta (University of Trondheim-AVH, Trondheim, Norway)
"Insect Olfaction: specialization to pheromones and plant volatiles"
- John Glendinning (Barnard College, New York, NY)
- Charles Wysocki (Monell Chemical Senses Center, Philadelphia, PA)
- Robyn Hudson (Mexico and Germany)
The term "specialist" was coined several decades ago to describe the narrowly tuned receptive fields of pheromone sensitive cells in moths and cockroaches. Almost immediately a distinction was made between that kind of coding versus the more broadly tuned cells that were thought to characterize the vertebrate coding scheme. Yet data from both vertebrates and invertebrates show that the term specialist cannot be equated to a pheromone processing system. So what conditions select for these different kinds of coding schemes? Can one be informative about the other, or are the two systems performing two fundamentally different tasks? This symposium will address these and other issues of chemosensory coding.