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Show 38 Jacob Saunders college of health Extracellular adenosine triphosphate (ATP) is shown to have an inhibitory effect on olfactory sensitivity at a cellular level (1). Extracellular ATP binds to P2X and P2Y purinergic receptors that increase the calcium ion (Ca2+) concentration within olfactory sensory neurons (OSNs) and disrupts the Ca2+ homeostasis of the cells. Odorant-induced Ca2+ responses in OSNs are reduced in the presence of ATP. Theoretically, this should result in a decreased ability to smell. To determine the effect of extracellular ATP on odor detec-tion in vivo, a series of olfactory behavioral tests were conducted. A buried food test was conducted on the adult mouse with intranasal infusions of saline control or saline with ATP. Latency was measured for the mouse to find the buried food. Results from this test showed higher latencies after an ATP infusion. Next, an olfactory differentiation test was conducted with a food odor-milk, social odor-mouse urine, and aversive odor-fox urine at varying dilutions. Mice were tested on latency to arrive at odors and time spent investigating the odors. This test was developed and proven effective in determining olfactory sensitivity in various transgenic mice such as PACAP and Pde6 knockout mice. Results show that ATP infusions re-duced sensitivity to milk and water. However, the results from the social and aversive odors were scattered. Further tests will be done to determine a dose response and duration of the intranasal ATP. Additionally, infusions of ATP receptor antagonists could show increased olfactory sensitivity. ATP and the accompa-nying antagonist may be viable olfactory modifiers in various settings and could have many potential applications. 1. Hegg,C.C., Greenwood,D., Huang,W., Han,P., and Lucero,M.T. (2003). Activation of purinergic receptor subtypes modulates odor sensitivity. J. Neurosci. 23, 8291-8301. DOES EXTRACELLULAR ATP REDUCE OLFACTORY SENSITIVITY? Jacob Saunders (Mary Lucero) Department of Physiology University of Utah UNDERGRADUATE RESEARCH ABSTRACTS Mary Lucero |
