Structural Analysis of the Mab213-Immunoreactive ”Necklace Glomeruli” in the Rat Primary Olfactory System

The aim of the present study was to clarify detailed distribution of the Mab 213-immunoreactive (Mab 213-Ⅰ) olfactory receptor cells and glomeruli in the rat olfactory bulb, to elucidate the glomerular relationship with intensely acetylcholinesterase-reactive patchy repions, and to characterize the ultrastructural features of Mab 213- Ⅰ glomeruli. The great majority of Mab 213-Ⅰolfactory receptor cells were distributed over dorsal portions of the nasal epithelium at the caudal end of nasal cavity. Especially, such receptor cells were concentrated on the dorsal roof of epithelium adjacent to the nasal septum and near the caudal end of the turbinate 1. The mab 213-Ⅰ glomeruli were found to form a nesklace pattern surrounding the caudal end of the olfactory bulb, one of them being located in the ”modified glomerular complex” reported to be involved in rat suckling behavior. In addition, they were found to correspond to less eractive parts of intensely acetylcholinesterase reactive patchy regions which are next to the strongly reactive parts. The Mab 213-Ⅰ glomeruli were clarified to have dark nodules in toluidine-blue-stained sections and characterized by the olfactory nerves rich in large dense-cored vesicles in immuno-election microscopy. The present results strongly suggest that the Mab213-Ⅰ”necklace glomeruli” may be the same subset of previously reported Shinoda's ”neckrace glomeruli”.

olfactory bulb

olfactory receptor cells

dense-cored vesicles

acetylcholinesterase

suckling behavior