Open field behaviour in rats: role of metabotropic glutamate receptors.

Previous studies have shown that spatial memory retention is affected by the metabotropic glutamate receptor (mGluR) influencing agents (R,S)-alpha-methyl-4-carboxyphenylglycine (MCPG) and trans-azetidine-2,4-dicarboxylic acid (tADA). In the present investigation we examined whether the mGluR antagonist MCPG (20 mM and 200 mM/5 microliters, respectively) and the agonist tADA (20 mM/5 microliters) have other behavioural effects using the open field test on two successive days. Only minor effects of MCPG (decrease of crossings during the 1st min on day 1) and tADA (increase of rearings on both days) were found. These results suggest that memory influencing doses of MCPG and tADA have no or only little behavioural effects in the open field situation.