Localization of neurotensin receptors in the forebrain of the common marmoset and the effects of treatment with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

The distribution of neurotensin binding sites was mapped in the brain of the common marmoset using [3H]neurotensin as the ligand. Autoradiographic techniques show that the density of receptors is particularly high in the substantia nigra, ventral tegmental area, olfactory tubercle and cerebral cortex and that the distribution of neurotensin receptors in the cerebral cortex and striatum is heterogenous. In the cerebral cortex neurotensin receptors are concentrated in layers I, II, III and V, whilst receptor density is generally less in all layers of middle temporal cortex. Striatal neurotensin receptors conformed to a striosomal distribution as defined by acetylcholinesterase staining with the highest density of binding sites in the matrix. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine selectively destroyed over 80% of the dopaminergic neurons of the marmoset substantia nigra and almost 60% of those in the adjacent ventral tegmental area. The subsequent loss of a large proportion of neurotensin receptors from marmoset substantia nigra and striatum suggests their presence on the dopaminergic nigrostriatal pathway.