Effects of ventral pallidal D1 dopamine receptor activation on memory consolidation in morris water maze test.

In the present experiments, in adult male Wistar rats, the effect of microinjection of the D1 dopamine receptor agonist SKF38393 into the ventral pallidum on memory consolidation, as well as on resistance of the resulting memory trace against extinction were investigated in Morris water maze test. SKF38393 was applied in three doses (0.1, 1.0 or 5.0μg in 0.4μl physiological saline, respectively). To clarify whether the effect of the agonist was specific, in a separate group of animals, the D1 dopamine receptor antagonist SCH23390 (5.0μg in 0.4μl physiological saline) was administered 15min prior to 1.0μg agonist treatment. In another group of animals, the same dose of antagonist was applied by itself. The two lower doses (0.1 and 1.0μg) of the agonist accelerated memory consolidation relative to controls and increased the stability of the consolidated memory trace against extinction. Antagonist pretreatment eliminated the effects of the agonist, thus confirming that the effect was selectively specific to D1 dopamine receptors. Our findings indicate that the ventral pallidal D1 dopamine receptors are intimately involved in the control of the consolidation processes of spatial memory.