Ontogeny of [3H]neurotensin binding sites in the rat cerebral cortex: autoradiographic study.

The ontogeny of the neurotensin binding sites in the rat caudal cortex such as the retrosplenial cortex, the visual area containing area 17 and 18, the caudal somatosensory area and temporal area was examined by autoradiography. During the early postnatal period (from birth to day 10), very-high-density [3H]neurotensin binding sites were observed in the caudal cortical area, but the number of binding sites decreased markedly with age. On the other hand, the ventral tegmental area and substantia nigra pars compacta had a low density of binding sites at birth, but the density increased until about day 15 and remained even in the adult rat. These findings were confirmed by the biochemical binding analysis.