Functional activity in the lateral habenular and dorsal raphe nuclei following administration of several dopamine receptor antagonists.

2-[14C]deoxyglucose autoradiography was used to show regional functional activity in the rat brain following administration of the dopamine antagonists, cis-flupenthixol, metoclopramide, and pimozide. Elevation of functional activity was observed in the lateral habenula (LHb) following administration of all antagonists. The dorsal raphe nucleus (DR) exhibited decreased functional activity following cis-flupenthixol, which exerts effects at both the D1 and D2 receptors, but not following pimozide or metoclopramide, which primarily act at the D2 receptor. These results converge with previous reports suggesting that the functional status of the LHb is regulated by dopaminergic systems, and that LHb efferents may exert a major influence upon DR neurons. These data further suggest that an influence of the LHb upon DR neurons may be affected via the D1 receptor.