Odors coming to the nose of vertebrates are trapped in a film of olfactory mucus, which provides a microenvironment for the initial interactions between odorant molecules and the olfactory receptor cell surfaces. This mucus is important in determining the solubility and diffusibility of the stimuli, and can change the response of olfactory receptor neurons to odorants. The mucus is secreted by accessory glands rather than the receptors themselves and its composition is variable; it is a perireceptor modulator of olfactory function. Neural mechanisms that regulate the secretion and composition of the mucus may in turn be influenced by odorant stimuli. To fully understand olfactory receptor function, these properties and mechanisms must be known. This project will experimentally manipulate the olfactory mucosa, and use immunohistochemistry and pharmacology to explore the relations between odorants and secretions. Identification of the innervating pathways to the mucosa will be combined with characterization of the neurotransmitters involved in regulation of secretion. Odorants and pharmacological agents will be tested for their ability to stimulate neuromodulator release and activate secretion. Functional carbohydrate compounds will be identified in the secretory products, and proteins within the secretory cells will also be identified to compare with those found in other mucus-secreting systems. This project involves a unique approach to the important topic of modulation of sensory input, and results will be important to how we think about olfactory systems, and modulation of other sensory receptors in general.
