Involvement of hippocampal metabotropic glutamate receptors in radial maze performance.

We investigated the role of hippocampal metabotropic glutamate receptors in spatial learning and memory, using an eight-arm radial maze task. (S)-4-Carboxyphenylglycine, a group I metabotropic glutamate receptor antagonist, or trans-(+/-)-1-amino-(1S,3R)-cyclopentanedicarboxylic acid, a broad-spectrum metabotropic glutamate receptor agonist, was administered into the dorsal hippocampus after rats had acquired the task. Both of these agents significantly impaired radial maze performance, suggesting a functional importance of hippocampal metabotropic glutamate receptors in spatial working memory.