Experiments were performed on rats with bilateral photothrombosis of vessels in the prefrontal cortex. Intranasal administration of antibodies to glutamate (1 h after ischemia of the brain cortex) improved retention of conditioned passive avoidance response, which was elicited before ischemic damage. The content of antibodies to glutamate in the serum of rats increased significantly on day 8 after bilateral photochemical thrombosis of vessels in the prefrontal cortex compared to that in the control.