Anxiolytic-like Effects and Increase in Locomotor Activity Induced by Infusions of NMDA into the Ventral Hippocampus in Rat: Interaction with GABAergic System

Introduction: in this study, we investigated the role of n-methyl-d-aspartate (nmda) receptors in the ventral hippocampus (vh) and their possible interactions with gabaa system on anxiety-like behaviors.methods: we used an elevated-plus maze test (epm) to assess anxiety-like behaviors and locomotor activity in male wistar rats.results: the results showed that intra-vh infusions of different doses of nmda (0.25 and 0.5 μg/rat) increased locomotor activity, and also induced anxiolytic-like behaviors, as revealed by a tendency to increase percentage of open arm time (%oat), and a significant increase in percentage of open arm entries (%oae). the results also showed that intra-vh infusions of muscimol (0.5 and 1 μg/rat) or bicuculline (0.5 and 1 μg/rat) did not significantly affect anxiety-like behaviors, but bicuculline at dose of 1 μg/rat increased locomotor activity. intra-vh co-infusions of muscimol (0.5 μg/rat) along with low doses of nmda (0.0625 and 0.125 μg/rat) showed a tendency to increase %oat, %oae and locomotor activity; however, no interaction was observed between the drugs. interestingly, intra-vh co-infusions of bicuculline (0.5 μg/rat) along with effective doses of nmda (0.25 and 0.5 μg/rat) decreased %oat, %oae and locomotor activity, and a significant interaction between two drugs was observed.discussion: it can be concluded that gabaergic system may mediate the anxiolytic-like effects and increase in locomotor activity induced by nmda in the vh.