D2 receptors in the ventrolateral striatum are involved in feeding behavior in rats

To study the role of dopamine D1 and D2 receptors in the ventrolateral striatum in feeding behavior, a D1 receptor agonist (CY 208-243), a D1 receptor antagonist (SCH 23390), a D2 receptor agonist (quinpirole), and a D2 receptor antagonist [(-)-sulpiride] were perfused via a microdialysis probe into the ventrolateral striatum of rats fasted for 22 h. Then the rats were allowed to feed freely for 6 h. Sulpiride perfusion at a high concentration suppressed food and water intake significantly, whereas dopamine release and the levels of DOPAC and HVA were increased at all concentrations. In contrast, quinpirole perfusion at a high concentration increased food intake by 41%. Dopamine release and the levels of DOPAC and HVA were decreased at all concentrations. On the other hand, neither CY 208-243 nor SCH 23390 changed food intake or dopamine release, but both drugs decreased water intake. These results suggest that D2 receptors in the ventrolateral striatum have a more important role than D1 receptors in the feeding behavior of rats.