Transient expression of low affinity NGF receptor in human developing somatosensory pathways

A monoclonal antibody recognizing the low affinity receptor for nerve growth factor (p75(NGFR)) has been used to determine and compare the immunohistochemical expression of p75(NGFR) in foetal (8 to 25 weeks of gestation) and adult human spinal cord. This comparison was carried out with the aim to get a better insight on neurotrophin functions during spinal cord development. In developing spinal cords an intense p75(NGFR) fiber immunoreactivity was observed in the dorsal root, the dorsal and dorsolateral funiculi, and in restricted regions of the dorsal horn. A plexus of p75(NGFR) immunostaining was found in the ventral hem. In adult spinal cord, strong fiber immunoreactivity was localized in the dorsal root, in the superficial layers of the dorsal horn (lamina I and II) but not in dorsal and dorsolateral funiculi. Immunoreactive neurons were detected in the ventral horn (lamina IX). The transient, selective pattern of p75(NGFR) in the dorsal and dorsolateral funiculi may indicate an involvement of neurotrophins in the modulation of tactile and kinaesthetic information during foetal life.