Journal
BEHAVIOURAL BRAIN RESEARCH
Volume 142, Issue 1-2, Pages 41-52Publisher
ELSEVIER
DOI: 10.1016/S0166-4328(02)00371-6
Keywords
consolidation; memory; passive avoidance; PD168,077; L745,870; SCH23390; eticlopride; U99194A; SKF38393; quinelorane; 7-OH-DPAT; dopamine D4 receptors; C57BL/6J mice
Categories
Ask authors/readers for more resources
The still unknown contribution of the D4 receptors to memory consolidation was studied examining the memory effects of the dopamine D4 agonist PD168,077, the putative dopamine D4 antagonist L745,870, their mutual combination, and the combination of the D4 agonist with representative compounds acting as agonist or antagonist on the D1, D2 and the D3 receptors. Memory consolidation was assessed in C57BL/6J mice using the one-trial step-through inhibitory avoidance task, the compounds being injected immediately after training (foot-shock) and performance measured 24h later. PD168,077 (0.5-10mg/kg) dose-dependently improved memory performance and L745,870 (0.05-5mg/kg) at doses lower than 1 mg/kg increased and at doses higher than I mg/kg impaired memory performance. PD168,077 did not affect the paradoxical promnesic effect of low doses (0.1-0.5mg/g) of L745,870, but antagonised the memory-impairing effect induced by 5 mg/kgL745,870. The D1 antagonist SCH23390 (0.025-0.05 mg/kg) and the D2 antagonist eticlopride (0.01-0.05 mg/kg) antagonised the promnesic effects of PD168,077, which attenuated the decreasing effect on memory consolidation of both D1 and D2 antagonists. Accordingly, the D1 agonist SKF38393 (5-20 mg/kg) and the D2 agonist quinelorane (0.1-1 mg/kg) both synergistically magnified the memory-improving effects of the D4 agonist. The dopamine D3 antagonist U99194A (2.5-10mg/kg) did not affect the promnesic effects induced by the D4 agonist, which nevertheless abolished the U99194A-induced promnesic effects. Additionally, the amnesic effects produced by the D3 agonist 7-OH-DPAT (0.01-1 mug/kg) was attenuated by PD168,077. These results suggest a potential role of dopamine D4 receptors in memory consolidation, which would be similar to that of the D I and D2 receptors and probably opposite to that of the D3 receptors. (C) 2002 Elsevier Science B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available