Dopaminergic modulation of hippocampus-dependent learning: Blockade of hippocampal D1-class receptors during learning impairs 1-trial place memory at a 30-min retention delay

作者：Pezze Marie^*; Bast Tobias

来源：Neuropharmacology, 2012, 63(4): 710-718.

DOI：10.1016/j.neuropharm.2012.05.036

• Hippocampus
• Dopamine
• Spatial learning
• Watermaze
• Early LTP
• Rat

Consistent with the requirement of D1-class dopamine receptors for the induction of late (%26gt;3 h) hippocampal long-term potentiation (LIP), hippocampus-dependent 1-trial memory at long retention delays (%26gt;6 h) requires hippocampal D1-class receptors during learning. Hippocampal D1-class receptors also modulate the induction and magnitude of early LTP (%26lt;1-3 h). However, a corresponding modulation of the formation of hippocampus-dependent early (%26lt;1 h) memory remains to be revealed. We addressed this conceptually important issue, using a novel modification of the watermaze delayed-matching-to-place (DMP) test with an improved measure of hippocampus-dependent 1-trial place memory. On the DMP test, rats learn the novel location of a hidden escape platform on trial 1 of every day, so that 1-trial place memory can be measured on trial 2. Our new task modification includes the measurement of search preference for the correct location on trial 2 - a very sensitive index of hippocampus-dependent place memory. We examined the effects of hippocampal D1-class receptor blockade or stimulation during learning on memory at a 30-min retention delay. Bilateral hippocampal infusion of the D1-class receptor antagonist SCH23390 (1 or 5 mu g/1 mu l/side) before trial 1 dose-dependently impaired such early memory: rats infused with the higher dose showed reduced search preference for the correct location and took longer paths to reach this location. Infusion of the D1-class partial agonist SKF38393 (1 or 5 mu g/1 mu l/side) did not affect measures of 1-trial place memory. Our data reveal a behavioural correlate of the dopaminergic modulation of early LIP, thereby supporting the close correspondence between hippocampal LTP and hippocampus-dependent learning.

• 出版日期2012-9