Meeting Abstract
2.2 Monday, Jan. 4 Odorant-Induced Changes In Olfactory Receptor mRNA Expression In Sockeye Salmon (Oncorhynchus nerka) After Imprinting. DITTMAN, Andrew H.*; MAY, Darran; HAVEY, Michelle A.; Northwest Fisheries Science Center, NOAA Fisheries, Seattle, WA; School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA ; School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA andy.dittman@noaa.gov
Pacific salmon are well known for their extraordinary homing migrations from oceanic feeding grounds back to their river of origin to spawn. These migrations are governed by olfactory discrimination of homestream odors that juvenile salmon learn (imprint to) prior to their seaward migrations. Our previous studies have suggested that one component of imprinting may involve long-term sensitization of the peripheral olfactory system to specific odorants. In this current study, we examined the mechanism of peripheral sensitization during imprinting, by exposing juvenile sockeye salmon to L- arginine during several putative imprinting periods. Arginine is a potent salmon odorant for which a candidate olfactory receptor has been identified. We examined full life cycle changes in receptor expression in L-arginine-exposed vs. L-arginine-naïve fish using quantitative PCR. In parallel, we assessed imprinting success of these same exposure groups by behavioral assessments of odorant attraction using maturing adults in two-choice mazes. Fish exposed to L-arginine during appropriate developmental stages demonstrated long-term memory formation for this imprinting odorant (P≤ 0.05; two-sample t-tests). Treatment groups that successfully imprinted, as evidenced by adult behavior, also demonstrated increased expression (relative to arginine-naïve fish) of the putative arginine receptor mRNA in the olfactory epithelium during key life stages. Our results suggest that early odorant exposure may affect olfactory receptor expression levels throughout the life of a salmon. Funded by the Bonneville Power Administration and the NWFSC.
