Immunohistochemical localization of nerve growth factor (NGF) and NGF-receptor in the hypothalamus of adult rats.

In the adult mammalian central nervous system (CNS) the nerve growth factor (NGF) has thus far been associated mainly with the metabolic support and pathophysiology of cholinergic basal forebrain (CBF) neurons. Recently, however, the presence of NGF and NGF mRNA has been demonstrated in the hypothalamus of adult mice. In addition there have been reports on the stimulation of the pituitary-adrenocortical axis by NGF. These and other findings suggest the involvement of NGF in hypothalamic functioning. The aim of the present study was to improve immunohistochemical methodologies for the investigation of NGF and NGF-receptor (NGF-r) in the hypothalamus of adult rats. Our results show NGF and NGF-r expression in various regions of the hypothalamus. Moreover, in some areas, distribution and morphology of immunoreactive neurons suggest neuronal colocalization of the two markers. To study the function of NGF in the hypothalamus, anti-NGF antibody was injected in the area of the paraventricular nucleus. We did not, however, find an effect of treatment on NGF-r immunoreactive neurons in this area.