EFFECTS OF NMDA ANTAGONISTS ON SEIZURE THRESHOLDS INDUCED BY INTRAHIPPOCAMPAL MICRODIALYSIS OF PICROTOXIN IN FREELY MOVING RATS

The role of N-methyl-D-aspartate (NMDA) receptors on individual variat ions in animal seizure threshold induced by picrotoxin microperfusion in the hippocampus of freely moving rats was analyzed by testing the e ffects of NMDA receptor antagonists 2-amino 5-phosphonovalerate (AP-5) and dizocilpine (MK-801) on individual seizure thresholds. rme found a correlation between the increased threshold levels induced by AP-5 a nd control seizure levels of each individual animal. However, no corre lation was found with the increased threshold level induced by MK-801. These data suggest that the individual variations in seizure threshol d in different animals reflect dynamic processes of NMDA mediated acti vity and emphasizes the value of whole-animal models to analyze NMDA r eceptor functions.