Aims

To support the free and open dissemination of research findings and information on alcoholism and alcohol-related problems. To encourage open access to peer-reviewed articles free for all to view.

For full versions of posted research articles readers are encouraged to email requests for "electronic reprints" (text file, PDF files, FAX copies) to the corresponding or lead author, who is highlighted in the posting.

___________________________________________

Monday, September 29, 2008

Modulation of ethanol state-dependent learning by dorsal hippocampal NMDA receptors in mice
Alcohol Article in Press 9 September 2008


The possible role of N-methyl-d-aspartate (NMDA) receptors of dorsal hippocampus on ethanol state-dependent learning was studied in adult male mice (Pasteur Institute, Iran).

As a model of memory, a single-trial step-down passive avoidance task was used. All animals were bilaterally implanted with cannulae into the CA1 regions of dorsal hippocampi.

Results show that intraperitoneal (i.p.) administration of ethanol (0.5 and 1 g/kg) 30 min before training impaired memory performance in animals when tested 24 h later. Pretest administration of the same doses of ethanol-induced state-dependent retrieval of the memory acquired under pretraining ethanol (1 g/kg, i.p.) influence. Pretest intra-CA1 microinjection of NMDA (0.001, 0.01, and 0.1 μg/mouse) by itself had no effect on memory retrieval and ethanol-induced amnesia.

However, pretest intra-CA1 administration of the same doses of NMDA with an ineffective dose of ethanol (0.25 g/kg, i.p.) significantly restored the retrieval and potentiated ethanol state-dependent learning.

On the other hand, pretest administration of a competitive NMDA receptor antagonist d-AP5 (d-(−)-2-Amino-5-phosphonopentanoic acid) (0.01, 0.1, and 1 μg/mouse, intra-CA1) or a noncompetitive NMDA receptor antagonist MK-801 maleate [(5S, 10R)-(+)-5-Methyl-10, 11-dihydro-5H-dibenzo [a, d] cyclohepten-5, 10-imine maleate] (0.25, 0.5, and 1 g/mouse, intra-CA1) 5 min before the administration of ethanol (1 g/kg, i.p.) significantly inhibited ethanol state-dependent learning.

Intra-CA1 pretest administration of d-AP5 (0.01, 0.1, and 1 μg/mouse) or MK-801 maleate [5S, 10R)-(+)-5-Methyl-10, 11-dihydro-5H-dibenzo [a, d] cyclohepten-5, 10-imine maleate] (0.25, 0.5, and 1 μg/mouse) alone did not affect memory retention.

It may be concluded that dorsal hippocampal NMDA receptors are involved in mediating ethanol state-dependent learning.

Read Full Abstract

Request Reprint E-Mail: rezayof@khayam.ut.ac.ir
___________________________________________________________________