Neurotrophin expression in the adult olfactory epithelium.
Published reports of neurotrophin expression in the olfactory system are incomplete because of missing data and conflicting results. Previous studies used a variety of fixation procedures and antibodies on different species and different ages. The aim of the present study was to examine expression of neurotrophins and their receptors using optimized methodologies: five methods of fixation, multiple antibodies, a variety of immunochemical protocols, and RT-PCR. We show here that (i) transcripts for all neurotrophins and their receptors are found in the adult olfactory epithelium; (ii) all neurotrophins are expressed in the supporting cells and the neuronal layers of the undisturbed adult olfactory epithelium while NT4 is found additionally in the horizontal basal cells; (iii) neurotrophin immunoreactivity required a fixative that included parabenzoquinone (not used in previous studies of olfactory tissue); (iv) TrkB and TrkC are restricted to the globose basal cell and neuron layers while TrkA is found in the horizontal basal cells and in the supporting cells where it co-localizes with the low affinity receptor for NGF (p75NTR). These findings confirm that neurotrophins are produced within the olfactory epithelium, suggesting autocrine and paracrine regulation of olfactory neurogenesis.
Feron
F
F
Eskitis Institute for Cell and Molecular Therapies, Griffith University, Nathan, QLD 4111, Australia. francois.feron@univmed.fr
Bianco
J
J
Ferguson
I
I
Mackay-Sim
A
A
D000818:Animals; D015870:Gene Expression / Q000502:physiology*; D008297:Male; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D009831:Olfactory Mucosa / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009414:Nerve Growth Factors