Research reportEffects of ventral pallidal D1 dopamine receptor activation on memory consolidation in morris water maze test

- D1 dopamine receptor agonist SKF38393 was microinjected into the ventral pallidum.
- SKF38393 in lower doses enhances memory consolidation in spatial learning.
- SKF38393 in lower doses increases stability of the memory trace against extinction.
- D1 dopamine receptor antagonist SCH23390 pretreatment eliminates SKF38393 effects.

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 5.0 μg in 0.4 μl 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 (5.0 μg in 0.4 μl physiological saline) was administered 15 min prior to 1.0 μg agonist treatment. In another group of animals, the same dose of antagonist was applied by itself.The two lower doses (0.1 and 1.0 μg) 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.