Effects of intrastriatal blockade of glutamatergic transmission on the acquisition of T-maze and radial maze tasks

Abstract

Prefrontal cortex and neostriatum constituting the prefrontal system are connected by glutamatergic neurones. The involvement of this corticostriatal projection in control of maze performance of rats was investigated. Glutamatergic transmission mediated by N-methyl-D-aspartate (NMDA) receptors was blocked by intrastriatal injections of dl-2-amino-5-phosphonovaleric acid (AP-5) (50 nmole in 0.5 Mgrl). In experiment 1, intrastriatal AP-5 was found to increase the number of errors during acquisition of a delayed alternation task in a T-maze. In experiment 2, the effect of intrastriatal AP-5 on acquisition of different 8 arm maze tasks was investigated. AP-5 did not affect the number of reentries on spontaneous and reinforced alternation; pre- and postdelay errors on delayed alternation were not altered. Therefore, intrastriatal NMDA receptor blockade impairs acquisition of a delayed alternation in a T-maze, while intrastriatal blockade of NMDA receptors does not affect acquisition of different 8 arm maze tasks.