Expression of nerve growth factor receptor immunoreactivity in the rat choroid plexus

The presence and localization of nerve growth factor receptors (NGFr) in the choroid plexus of the adult rat has been investigated immunohistochemically using an anti-rat NGFr monoclonal antibody (192-IgG). A moderate to strong immunoreaction was observed in the epithelial cells of the choroid plexus, whereas the choroidal blood vessels and connective tissue remained unlabelled. Moreover, no sex-differences were encountered in the NGFr immunoreaction intensity and Bouin fixative was more effective than 10% formaldehyde evidenciating the NGFr immunostain. Occasionally, ependymal cells displaying NGFr immunoreactivity were observed. Present data demonstrate that the choroid plexus of the rat contain NGFr, probably low-affinity NGFr, and suggest an involvement of NGF in the regulation of cerebrospinal fluid secretion, but the importance of these findings, if any, must be investigated in future studies.