Anxiolytic-like action of intra-hippocampally administered NMDA antagonists in rats.

The effects of intra-hippocampally administered NMDA receptor antagonists MK-801, and AP-7 on rat behavior in the Vogel's and open field tests of anxiety were examined. MK-801 and AP-7 given locally stimulated at the same time rat exploratory and motor activities, in the open field. In the Vogel's test, both compounds attenuated the suppressive effect of shock on drinking, in a dose-range not affecting rat motility. It is concluded that hippocampal NMDA innervation may play a role in the control of motor activity. Furthermore, the Vogel's test data indicate more selective involvement of hippocampal NMDA innervation in processing of fear-related signals.