2024-03-29T09:19:51Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/433062022-11-17T02:08:08Zhdl_2115_20049hdl_2115_141Morphometry of olfactory lamellae and olfactory receptor neurons during the life history of chum salmon (Oncorynchus keta)Kudo, HideakiShinto, MasakazuSakurai, YasunoriKaeriyama, Masahidesalmonolfactory receptor neuronolfactory lamelladevelopmentmigration487It is generally accepted that anadromous Pacific salmon (genus Oncorhynchus) imprint to odorants in their natal streams during their seaward migration, and use olfaction to identify these during their homeward migration. Despite the importance of the olfactory organ during olfactory imprinting, the development of this structure is not well understood in Pacific salmon. Olfactory cues from the environment are relayed to the brain by the olfactory receptor neurons (ORNs) in the olfactory organ. Thus, we analyzed morphometric changes in olfactory lamellae of the peripheral olfactory organ and in the quantity of olfactory receptor neurons (ORNs) during life history from alevin to mature in chum salmon (O. keta). The number of lamellae increased markedly during early development, reached 18 lamellae per unilateral peripheral olfactory organ in young salmon with a 200 mm in body size, and maintained this lamellar complement after young period. The number of ORNs per olfactory organ was about 180,000 and 14.2 million cells in fry and mature salmon, respectively. The relationship between the body size (fork length) and number of ORNs therefore revealed an allometric association. Our results represent the first quantitative analysis of the number of ORNs in Pacific salmon, and suggest that the number of ORNs is synchronized with the fork length throughout its life history.Oxford University PressJournal Articleapplication/pdfhttp://hdl.handle.net/2115/43306https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/43306/1/Kudo_CS_HUSCAP.pdf0379-864X1464-3553AA00142441Chemical Senses3476176242009-07-08enginfo:pmid/19587025info:doi/10.1093/chemse/bjp042This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Chemical Senses following peer review. The definitive publisher-authenticated version in Chemical Senses 2009 34(7):617-624 is available online at: http://chemse.oxfordjournals.org/cgi/content/short/34/7/617.author