title: Ultrastructural and histochemical properties of the olfactory system in the japanese jungle crow, Corvus macrorhynchos.
abstract: Although it has been commonly believed that birds are more dependent on the vision and audition than the olfaction, recent studies indicate that the olfaction of birds is related to the reproductive, homing, and predatory behaviors. In an attempt to reveal the dependence on the olfactory system in crows, we examined the olfactory system of the Japanese jungle crow (Corvus macrorhynchos) by histological, ultrastructural, and lectin histochemical methods. The olfactory epithelium (OE) of the crow occupied remarkably a small area of the nasal cavity (NC) and had the histological and ultrastructural features like other birds. The olfactory bulb (OB) of the crow was remarkably small and did not possess the olfactory ventricle. The left and right halves of the OB were fused in many cases. In the lectin histochemistry, soybean agglutinin (SBA) and Vicia villosa agglutinin (VVA) stained a small number of the receptor cells (RCs) in the OE and the olfactory nerve layer (ONL) and glomerular layer (GL) on the dorsocaudal region of the OB. Phaseolus vulgaris agglutinin-E (PHA-E) stained several RCs in the OE and the ONL and GL on the ventral region of the OB. These results suggest that 1) the crow has less-developed olfactory system than other birds, and 2) the dedicated olfactory receptor cells project their axons to the specific regions of the OB in the crow.
authors.affiliation: Laboratory of Veterinary Anatomy, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kondoh
authors.forename: Mai
authors.initials: M
authors.lastname: Nashimoto
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Kanayama
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Nakamuta
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Taniguchi
mesh_terms: D000818:Animals; D046368:Crows / Q000033:anatomy & histology*; D007150:Immunohistochemistry / Q000662:veterinary; D007564:Japan; D008297:Male; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D009830:Olfactory Bulb / Q000033:anatomy & histology* / Q000378:metabolism; D009831:Olfactory Mucosa / Q000033:anatomy & histology* / Q000294:innervation / Q000648:ultrastructure; D009832:Olfactory Nerve / Q000648:ultrastructure; D018034:Olfactory Receptor Neurons / Q000378:metabolism; D010835:Phytohemagglutinins / Q000378:metabolism; D037121:Plant Lectins / Q000378:metabolism; D030262:Soybean Proteins / Q000378:metabolism
chemical_list: D010835:Phytohemagglutinins; D037121:Plant Lectins; D030262:Soybean Proteins; C042242:Vicia lectins; C028824:soybean lectin