Distribution of neurotensin receptors in the primate hippocampal region: a quantitative autoradiographic study in the monkey and the postmortem human brain.

The distribution of [3H]neurotensin ([3H]NT) binding sites in the monkey and the postmortem human brain was studied by using quantitative in vitro receptor autoradiography. Biochemical experiments carried out on tissue sections of the monkey hippocampus showed that the binding of [3H]NT was saturable, reversible and of high specificity. The hippocampal [3H]NT binding was displaced by fragment NT 8-13 but not fragment NT 1-8 of the peptide. The anatomical analysis showed a highly heterogeneous distribution of [3H]NT binding sites within both the monkey and the human hippocampal region. In both species the highest density of [3H]NT binding sites was found in the presubiculum (rank order of binding density: layer 2 greater than 6 greater than 1 greater than 3, 4, 5 in both monkey and man) and the entorhinal area (monkey: layer 4 greater than 6 greater than 5 greater than 1 greater than 2 greater than 3; human: layer 1 = 2 greater than 5 greater than 3). The subiculum and Ammon's horn were relatively poor in [3H]NT binding sites in both species. In the area dentata the highest density of [3H]NT binding sites was found in the hilar region.