[Study of the function of nerve growth factor in the olfactory tract of the mouse]

The aim of this study was to examine the function of nerve growth factor (BGF) in the olfactory tract of mice. Using the mice which had received unilateral olfactory bulbectomy and in which antibodies to NGF had been continuously infused with into the contralateral olfactory blub, three kinds of analysis were performed: histological analysis of the olfactory epithelium by HE staining, immunohistochemical analysis of the olfactory epithelium using polyclonal antibodies to trk which forms the NGF receptor, and olfactory-mediated behavioral analysis with cycloheximide. These animals had been sacrificed at day 1, 3, 7, 14, 21 or 28. Several findings were obtained as a result of the above analysis. Degeneration of the olfactory epithelium and trk expression by the olfactory cells were observed on day 7, and the olfactory epithelium was incompletely regenerated on day 28. However, trk expression by the olfactory cell was still recognized and the olfactory function was not restored by day 28. These examinations suggest that NGF produced in the olfactory bulb was transported retrogradely to olfactory cells through the olfactory nerves, and was associated with sustaining the existence of those cells and with regenerating the olfactory tract after injury.