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Expression of neuronal nitric oxide synthase/NADPH‐diaphorase during olfactory deafferentation and regeneration
Author(s) -
Weruaga E.,
Briñón J. G.,
Porteros A.,
Arévalo R.,
Aijón J.,
Alonso J. R.
Publication year - 2000
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2000.00003.x
Subject(s) - olfactory bulb , tyrosine hydroxylase , nitric oxide synthase , rostral migratory stream , olfactory system , neuroscience , chemistry , nitric oxide , microbiology and biotechnology , biology , olfactory mucosa , synapse , olfactory marker protein , central nervous system , endocrinology , dopamine , subventricular zone , progenitor cell , stem cell
Neuronal nitric oxide synthase (nNOS) expression can be regulated under natural or experimental conditions. This work aims at elucidating whether the expression of nNOS or its related NADPH‐diaphorase (ND) activity are modified by manipulation of the normal inputs to neurons. We used the olfactory bulbs from two mouse strains, BALB and CD1, because they show divergences in their synapse patterns, and these differences affect periglomerular cells, interneurons expressing tyrosine hydroxylase or nNOS/ND. The olfactory inputs to these neurons can be disrupted by inhalation of methyl bromide. The effect of this gas on olfactory axons, as well as the synaptic features in both mouse strains, were studied using electron microscopy. The changes in expression were analysed qualitatively and quantitatively at different times after lesion to nine topographical regions of the olfactory bulb. Methyl bromide inhalation induced a degeneration of olfactory axons in both strains, but had different effects on the expression of nNOS/ND and tyrosine hydroxylase. In BALB mice, where periglomerular cells do not receive direct inputs from olfactory axons, no changes were detected in tyrosine hydroxylase or in ND expression. In CD1 periglomerular cells, where olfactory axons establish direct synapses, a significant down‐regulation of both markers was observed. These changes were observed differentially across the olfactory bulb, being more pronounced in rostral regions and more acute for ND than for tyrosine hydroxylase. Our results indicate that the synaptic inputs influence the expression of ND activity related to nNOS and that the activation of the enzyme is more severely affected than its protein expression.