Levels of CCK immunoreactivity and dopamine in the nucleus accumbens after 6-hydroxydopamine lesions of the ventral tegmental area and the nucleus accumbens.

The effects of 6-hydroxydopamine (6-OHDA) injected into either the ventral tegmental area (VTA) or the nucleus accumbens on dopamine and its metabolite DOPAC and CCK-immunoreactivity in the nucleus accumbens were studied. Measurements were made 1, 3 and 6 weeks after the lesion in both the anterior and posterior part of the nucleus accumbens. 6-OHDA applied in the VTA reduced the level of DA and DOPAC, but did not affect the CCK content in the nucleus accumbens. 6-OHDA lesions in the anterior part of the nucleus accumbens produced depletion of DA and DOPAC from one week after the injection, and decreased the CCK content 6 weeks after the injection. The results suggest that in the nucleus accumbens DA and CCK are localized, at least for the major part, in different nerve terminals.