The class I metabotropic glutamate receptor antagonist, AIDA, improves short-term and impairs long-term memory in a spatial task for rats

Effects of the class I selective metabotropic glutamate receptor antagonist , 1-aminoindan-1,5-dicarboxylic acid (AIDA), on spatial procedural learning and episodic short-term memory of rats were investigated in an appetitivel y reinforced 3-choice delayed match-to-position task. First, an acute intra peritoneal injection of AIDA (2 mg/kg) was given 20 min before a single tra ining session of 20 trials using repeated reward position in one alcove out of three. AIDA caused facilitated short-term acquisition within such a ses sion compared to saline treated controls. Secondly, injections were given b efore each of ten sessions (48 h intervals) also using constant reward posi tion. The results showed AIDA induced inhibition of procedural between-sess ion acquisition. Finally, the use of reward positions in a non-repetitive b ut trial-specific version of the 3-choice test revealed a facilitating effe ct of AIDA on episodic short-term memory. (C) 1999 Elsevier Science Ltd. Al l rights reserved.