Neuropeptide tyrosine is expressed in ensheathing cells around the olfactory nerves in the rat olfactory bulb.
The olfactory bulbs of young and adult normal rats and of colchicine-treated rats and of some other species were analysed for the presence of neuropeptide Y and neuropeptide Y messenger RNA, using immunohistochemistry at the light- and electron-microscopic levels and with in situ hybridization. In the rat and mouse, but not in monkey and guinea-pig, neuropeptide Y-like immunoreactivity and neuropeptide Y messenger RNA were observed in ensheathing cells in the olfactory nerve layer of the olfactory bulb and within nerve bundles in the olfactory mucosa. Double staining experiments revealed that neuropeptide Y-like immunoreactivity was often present in a restricted compartment, mainly the Golgi apparatus, of S-100 protein-positive ensheathing cells. After colchicine treatment a different distribution of neuropeptide Y-like immunoreactivity and neuropeptide Y messenger RNA was observed. Thus, in the outer olfactory nerve layer both neuropeptide Y-like immunoreactivity and neuropeptide Y messenger RNA disappeared, whereas in the inner part messenger RNA levels remained high and neuropeptide Y-like immunoreactivity was observed in many granule-like structures distributed diffusely in the cytoplasm. The present findings suggest that neuropeptide Y may be involved in the control of regeneration, growth and/or guiding of the axons of the olfactory sensory neurons, the only mammalian neurons known to have a continuous renewal and growth during adult life.
Ubink
R
R
Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Halasz
N
N
Zhang
X
X
Dagerlind
A
A
Hökfelt
T
T
D000818:Animals; D003078:Colchicine / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006168:Guinea Pigs; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D009457:Neuroglia / Q000737:chemistry*; D009478:Neuropeptide Y / Q000096:biosynthesis*; D009830:Olfactory Bulb / Q000166:cytology*; D009831:Olfactory Mucosa / Q000166:cytology; D009832:Olfactory Nerve; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
D009478:Neuropeptide Y; D012333:RNA, Messenger; D003078:Colchicine