A comparative immunocytochemical study of development and regeneration of chemosensory neurons in the rat vomeronasal system.
Vomeronasal neurons undergo continuous neurogenesis during development and after neuronal injury. We used immunocytochemical methods to compare different stages of the vomeronasal organ development to those of regeneration following vomeronasal nerve transection. At E15 and at 6 to 10 days after injury, nestin-positive cells were observed throughout the sensory epithelium. We did not find nestin immunoreactivity to be localized to the boundary region of the epithelium. The early appearance and wide distribution of nestin-positive cells suggests that they represent chemosensory precursor cells that develop and migrate vertically in the epithelium. Vomeronasal receptor cells degenerated 6 to 8 days after nerve transection, but axon terminals in the accessory olfactory bulb (AOB) continued to show the presence of the chemosensory specific marker (OMP) for up to ten days, a significant finding observed in this study. It is likely that the distance from the site of nerve transection may contribute to differences in the time course of anterograde and retrograde axon degradation. OMP-positive neurons were observed in the normal adult epithelium and to a much lesser extent 10-60 days after recovery from nerve transection. Axons from regenerated receptor cells did not reach the AOB during this time period. This failure to reestablish connections with target cells in the AOB could explain why OMP-positive cells were rarely observed among the regenerated cells in the vomeronasal epithelium.
Division of Neurobiology and Anatomy, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Niigata 951-8510, Japan. winner@med.niigata-u.ac.jp
Masato
M
Matsuoka
Toshiya
T
Osada
Junko
J
Yoshida-Matsuoka
Atsushi
A
Ikai
Masumi
M
Ichikawa
Masao
M
Norita
Richard M
RM
Costanzo
D000375:Aging / Q000502:physiology; D000818:Animals; D002628:Chemoreceptor Cells / Q000502:physiology*; D003714:Denervation; D004622:Embryo, Mammalian / Q000502:physiology; D005314:Embryonic and Fetal Development; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000378:metabolism; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D009411:Nerve Endings / Q000196:embryology / Q000502:physiology; D009416:Nerve Regeneration / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D009830:Olfactory Bulb / Q000196:embryology / Q000502:physiology; D051842:Olfactory Marker Protein; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D019147:Vomeronasal Organ / Q000196:embryology* / Q000502:physiology
D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577486:Nes protein, rat; D064231:Nestin; D051842:Olfactory Marker Protein; C497599:Omp protein, rat