Neuroanatomical site specific modulation of spontaneous motor activity by neurotensin.

Immunohistofluorescent neurotensin (NT) is found in the ventral tegmental area (VTA), and bilateral injection of NT into the VTA produces an increase in exploratory behaviors. The VTA also contains dopaminergic cell bodies with axonal projections to the nucleus accumbens. In this study it was shown that bilateral microinjection of NT (4.0 micrograms/side) into the nucleus accumbens blocked the behavioral hyperactivity produced by intra-VTA injection of NT (2.5 micrograms/side).