Neurotensin neurons in the ventral tegmental area project to the medial nucleus accumbens.

A high density of neurotensin-containing neuronal perikarya are found in the ventral tegmental area, and some of these neurons also contain dopamine. In this study, we used retrograde transport of horseradish peroxidase (HRP) coupled with immunohistochemical staining for neurotensin to determine whether ventral tegmental neurotensin neurons project to known dopamine terminal areas of the limbic forebrain. It was found that HRP injection into the medial nucleus accumbens and diagonal band of Broca resulted in neurons in the ventral and medial ventral tegmental area containing both HRP granules and neurotensin immunoreactivity.