Characterization and autoradiographic distribution of neurotensin binding sites in the human brain

The characteristics and topographical distribution of monoiodo¹²⁵I-Tyr₃-neurotensin (NT) binding sites in normal human brain tissue were studied on brain sections and by quantitative autoradiography. Sections at the level of the substantia nigra show a dissociation constant and maximal binding capacity of4.8 ± 0.8nM and 70 ± 7fmol/mg protein, respectively. High density of¹²⁵I-NT binding sites were mainly found in dopaminergic (DA)-rich areas such as the substantia nigra, the ventral tegmental area, the striatum and the nucleus accumbens, further supporting an interaction between NT and DA neurons in human brain.