DISTRIBUTION OF NEUROPEPTIDE-Y IN THE DEVELOPING HUMAN SPINAL-CORD

The distribution of neuropeptide Y at different levels of the spinal c ord of 23 human fetuses aged from 10-41 weeks of gestation was studied using immunocytochemical staining. Neuropeptide Y-immunoreactive neur ons were identified at all levels of the spinal cord examined as early as 10 weeks of gestation. These cells were localized in the superfici al layers (laminae I and II of Rexed) of the dorsal gray matter. As th e age of the fetuses increased, their cell number increased and the re gion containing positive neurons extended from the superficial to deep layers (laminae III and VI). Immunoreactive fibers started to appear in fetuses at 10 weeks of gestation. They were found not only in the g ray and white matters, but also in the pia mater lining the spinal cor d. As the fetuses aged, the neuropeptide Y-immunoreactive fibers becam e mostly concentrated in the intermediate zones of the thoracic and sa cral segments corresponding to the developing autonomic centers. Our r esults suggest that neuropeptide Y may play a role in the early develo pment of the autonomic system.