The olfactory system is faced with the task of extracting biologically and socially relevant signals from the diversity of chemicals occurring in the environment. To accomplish this task, vertebrates, including humans, possess several morphological types of receptor neurons, the most obvious being the microvillous and ciliated types. The proposed studies test the hypothesis that anatomically different olfactory receptor neurons respond to different classes of odorants, express different odorant receptor molecules and connect to different sites in the olfactory bulb. This proposition will be studied in catfishes and goldfishes because these are the only vertebrates for which both feeding- related odorants and sex-signaling pheromones are chemically well- defined. Thus correlative physiological, anatomical and molecular methodologies can be used to test the hypothesis rigorously and directly. We already have shown that anatomically different receptor neurons project to specific target sites within the olfactory bulb and that different sites in the olfactory bulb respond preferentially to different classes of odorants. The first group of experiments will utilize electrophysiological and anatomical methods to test whether specific bulbar areas respond preferentially to one of the known classes of natural odorants: amino acids, nucleotides, bile salts or sex pheromones; and whether any of these areas are targeted uniquely by microvillous or ciliated receptor cells. The second group of experiments will examine which molecular features of the odorant molecules are key to the specificity of the bulbar responses. The final group of experiments will use combined retrograde tracing and in situ hybridization to test whether the anatomically and physiologically different types of receptor neurons express different olfactory receptor molecules. Use of multiple methodologies permits a systems level analysis of the olfactory representation of biologically-important chemical stimuli from the level of molecular receptor to neuronal assemblages. These studies will determine whether, in vertebrates, specific types of olfactory receptor neurons and receptor molecules mediate specific odorant-driven behaviors such as feeding, courting behavior or even subconscious sexual hormonal responses to specific odor signals.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC003792-04
Application #
6516189
Study Section
Special Emphasis Panel (ZRG1-IFCN-4 (01))
Program Officer
Davis, Barry
Project Start
1999-04-01
Project End
2004-03-31
Budget Start
2002-04-01
Budget End
2003-03-31
Support Year
4
Fiscal Year
2002
Total Cost
$329,574
Indirect Cost
Name
Louisiana State University A&M Col Baton Rouge
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
075050765
City
Baton Rouge
State
LA
Country
United States
Zip Code
70803
Nikonov, Alexander A; Caprio, John (2007) Responses of olfactory forebrain units to amino acids in the channel catfish. J Neurophysiol 97:2490-8
Rolen, S H; Caprio, J (2007) Processing of bile salt odor information by single olfactory bulb neurons in the channel catfish. J Neurophysiol 97:4058-68
Hansen, Anne; Rolen, Shane H; Anderson, Karl et al. (2005) Olfactory receptor neurons in fish: structural, molecular and functional correlates. Chem Senses 30 Suppl 1:i311
Hansen, Anne; Zielinski, Barbara S (2005) Diversity in the olfactory epithelium of bony fishes: development, lamellar arrangement, sensory neuron cell types and transduction components. J Neurocytol 34:183-208
Nikonov, Alexander A; Caprio, John (2005) Processing of odor information in the olfactory bulb and cerebral lobes. Chem Senses 30 Suppl 1:i317-8
Sorensen, Peter W; Sato, Koji (2005) Second messenger systems mediating sex pheromone and amino acid sensitivity in goldfish olfactory receptor neurons. Chem Senses 30 Suppl 1:i315-6
Nikonov, Alexander A; Caprio, John (2004) Odorant specificity of single olfactory bulb neurons to amino acids in the channel catfish. J Neurophysiol 92:123-34
Hansen, Anne; Rolen, Shane H; Anderson, Karl et al. (2003) Correlation between olfactory receptor cell type and function in the channel catfish. J Neurosci 23:9328-39
Rolen, S H; Sorensen, P W; Mattson, D et al. (2003) Polyamines as olfactory stimuli in the goldfish Carassius auratus. J Exp Biol 206:1683-96
Nikonov, Alexander A; Parker, James M; Caprio, John (2002) Odorant-induced olfactory receptor neural oscillations and their modulation of olfactory bulbar responses in the channel catfish. J Neurosci 22:2352-62

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