Expression of NGF receptor in the developing and adult primate central nervous system

Monoclonal antibodies against human NGF receptor have been used for immunocytochemical localization of NGF receptors in the CNS of macaques and baboons at various stages of development. In the adult, neurons in most brain regions are devoid of detectable NGF receptors. However, abundant NGF receptor immunoreactivity is present on a population of neurons in basal forebrain, which, on the basis of appearance and pattern of distribution, probably correspond, at least in part, to magnocellular cholinergic neurons of this region. NGF receptors were also associated with the vasculature in most brain regions. NGF receptor immunoreactivity is present on Mueller glia of neural retina. In macaque fetuses, approximately 1 month prenatally, retinal Mueller glia possess lower levels of receptor, while higher levels of receptor are present in the retinal nerve fiber layer. In fetal cerebellum, abundant receptor immunoreactivity is present on Purkinje cells, granule cells of the premigratory zone of the external granule layer, and neurons of the deep nuclei. Immunoreactivity decreases with subsequent development and is absent in the adult. In cerebellum, levels of NGF receptor assayed by affinity crosslinking to radioiodinated NGF, and levels of NGF receptor mRNA assayed by Northern blot analysis decrease dramatically during the last month of fetal life.