SPLTRAK Abstract Submission
Olfactory Activity Selectively Regulates the Neurogenesis of a Subset of Olfactory Sensory Neurons
Stephen W. Santoro, Carl J. van der Linden, Kelci R. Germann, Pooja Gupta, Ashraful I. Bhuiya
Neuroscience Program and Dept. of Zoology and Physiology, University of Wyoming, Laramie, WY, United States

Olfactory sensory neurons (OSNs) are one of a small number of neuron types that turn over throughout life in mammals. OSN turnover is thought to function primarily to replace OSNs that are damaged as a result of exposure to environmental insults. Newborn OSNs are thought to stochastically express just one odorant receptor (OR) allele from among hundreds present within a typical mammalian genome. Using gene expression analysis of the mouse olfactory epithelium (OE) in combination with RNA fluorescent in situ hybridization (RNA-FISH), we found that olfactory deprivation on one side of the OE via unilateral naris occlusion causes significant differences in the number of OSNs that express particular ORs on the two sides of the OE. We hypothesized that these differences might be due in part to selective changes in the neurogenesis rates of OSNs that express these ORs. To test this hypothesis, we developed a method involving EdU detection combined with RNA-FISH to quantify the neurogenesis rates of OSNs that express specific ORs. Using this method, we found that olfactory activity deprivation causes selective and significant decreases in the neurogenesis rates of OSNs that express a particular subset of ORs, while not affecting intermingled OSNs that express other ORs. Moreover, we found that OSN subtypes that exhibit activity-dependent neurogenesis are not more active than those whose neurogenesis is activity-independent, indicating that high levels of olfactory activity are not sufficient to cause particular OSN subtypes to exhibit activity-dependent neurogenesis. These findings reveal a previously unknown type of plasticity within the olfactory system that may have fundamental implications for how the system develops and changes based on experience.