Expression of the low affinity neurotrophin receptor, p75(NGFR), in the rat forebrain, following unilateral bulbectomy

It has been hypothesized that the main olfactory bulb, with its relatively rich source of neurotrophins, may provide trophic support for neurons that project to the bulb. We monitored expression of the common, low affinity re ceptor for neurotrophins, p75(NGFR), in, the olfactory bulb and basal foreb rain of unilaterally bulbectomized and sham-treated rats, 1-16 weeks post-s urgery, using the monoclonal antibody MAb192. An induction of p75(NGFR)-imm unoreactivity was observed in both the glomerular and olfactory nerve layer s of the right, contralateral main olfactory bulb of lesioned animals. The naturally occurring regeneration taking place in the olfactory neuroepithel ium is known to be altered by olfactory bulbectomy, with subsequent changes in the sensory input to the remaining bulb. These changes in expression of p75(NGFR) in the olfactory bulb support the hypothesis we have developed i n previous papers, that changes in the extent of the peripheral input from the olfactory neuroepithelium to the main olfactory bulb regulate p75(NGFR) expression in both the glomerular and the olfactory nerve layers. Expressi on of p75(NGFR) in, the basal forebrain of bulbectomized animals was found to be no different than sham-treated controls and does not support the hypo thesis that the olfactory bulb provides trophic support to this region of t he central nervous system. (C) 1998 ISDN. Published by Elsevier Science Ltd .