Mapping of neuropeptide Y-like immunoreactivity in the human forebrain

By means of immunohistochemistry the distribution of neuropeptide Y (NPY)-containing neurons and fibres was determined in the human forebrain on the basis of frontal paraffin sections from six individuals of different biological age. NPY was located in abundance in telencephalic cortical and subcortical structures like the striatum, the amygdaloid body and the substantia innominata. Variations in the distribution of immunoreactivity were observed and correlated with distinct subdivisions and structural elements of the basal forebrain region identified by Weigert or Nissl-stained neighbouring sections. The diencephalon was characterized by a relative paucity of labeled cells which were mostly confined to the area of the Nc. infundibularis and the median eminence while fibers were widely distributed in high density in most hypothalamic subnuclei except for the supraoptic nucleus. A periventricular zone of high fibre immunoreactivity was observed in the thalamus. NPY distribution in the developing brain was characterized by the finding of numerous labeled perikarya in the subcortical white matter and by far higher densities of labeled cells in the striatum as compared to the adult brain.