Effect of NMDA Receptors Antagonist AP5 on Peak-Interval Procedure in Rats

Abstract

The peak-interval (PI) procedure is a temporal discrimination task used with animals, significantly affected by the hippocampus and the striatum. We focused on N-methyl-D-aspartate (NMDA) receptors because they are found at high concentrations in the hippocampus, and investigated the effects of D, L-2-amino-5-phosphonopentanoic acid (AP5), an NMDA receptor antagonist, in the PI procedure. Rats were given acute administrations of AP5 into indusium griseum after PI training for 30 s. The result indicated that AP5 induced a rightward response distribution shift suggesting that AP5 produced an overestimation of the criterion time. This finding implies that NMDA receptors surrounding indusium griseum affect the PI procedure’s timing behavior, which indicates NMDA receptors’ role in time perception.