R. Ubink et al., NEUROPEPTIDE TYROSINE IS EXPRESSED IN ENSHEATHING CELLS AROUND THE OLFACTORY NERVES IN THE RAT OLFACTORY-BULB, Neuroscience, 60(3), 1994, pp. 709-726
The olfactory bulbs of young and adult normal rats and of colchicine-t
reated rats and of some other species were analysed for the presence o
f neuropeptide Y and neuropeptide Y messenger RNA, using immunohistoch
emistry 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 RN
A were observed in ensheathing cells in the olfactory nerve layer of t
he olfactory bulb and within nerve bundles in the olfactory mucosa. Do
uble staining experiments revealed that neuropeptide Y-like immunoreac
tivity was often present in a restricted compartment, mainly the Golgi
apparatus, of S-100 protein-positive ensheathing cells. After colchic
ine treatment a different distribution of neuropeptide Y-like immunore
activity and neuropeptide Y messenger RNA was observed. Thus, in the o
uter olfactory nerve layer both neuropeptide Y-like immunoreactivity a
nd neuropeptide Y messenger RNA disappeared, whereas in the inner part
messenger RNA levels remained high and neuropeptide Y-like immunoreac
tivity was observed in many granule-like structures distributed diffus
ely 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 neu
rons known to have a continuous renewal and growth during adult life.