Hyperactivity and disruption of prepulse inhibition induced by NMDA infusion of the rat ventral hippocampus: Comparison of uni- and bilateral stimulation

Numerous studies have demonstrated that NMDA stimulation of the rat ventral hippocampus induces hyperactivity and disruption of prepulse inhibition (PPI) and some reports have provided insights into the different neural substrates of these two effects. Bilateral or unilateral NMDA stimulation have been applied in these studies, but have never been compared directly. Thus, results of these studies can be related to each other only with reservations. Therefore - given the substantial interest in the behavioral effects of hippocampal overactivity and the neural substrates underlying PPI with respect to schizophrenia - the present experiments compared hyperactivity and PPI disruption following uni- or bilateral NMDA stimulation of the ventral hippocampus. Both bilateral and unilateral infusion of NMDA (0.5 μg/0.5 μl/side) induced hyperactivity in the open field and disrupted PPI. The major difference noted between unilateral and bilateral infusions was that the effects of bilateral infusions were stronger than those of the unilateral infusions.