THE EFFECTS OF LOCAL INHIBITION OF N-METHYL-D-ASPARTATE AND AMPA KAINATE RECEPTORS IN THE ACCESSORY OLFACTORY-BULB ON THE FORMATION OF AN OLFACTORY MEMORY IN MICE/

Female mice form a memory to the pheromones of the mating male, during a critical period after mating. Previous experiments have shown that this memory is located in the accessory olfactory bulb and most likely involves changes at the mitral/granule cell reciprocal synapse. Memor y formation can be prevented by local infusions of a non-selective ion otropic glutamate receptor antagonist. However, selective antagonism o f N-methyl-D-aspartate receptors during the critical period did not di srupt the memory. The present study shows that memory formation is not prevented by local infusions of the AMPA/kainate receptor antagonist 6,7-dinitroquinoxaline-2,3-dione. Thus, it appears that the formation of a memory to the mating male can occur via both N-methyl-D-aspartate receptor-dependent and independent mechanisms. Far from preventing me mory formation, local infusions of 6,7-dinitroquinoxaline-2,3-dione re sulted in the formation of a non-selective ''memory'' to unfamiliar ma le pheromones. In addition, local infusions of 6,7-dinitroquinoxaline- 2,3-dione during pheromonal exposure alone resulted in memory formatio n without mating having occurred. These results suggest that activity via N-methyl-D-aspartate receptors might be more effective in promotin g the synaptic changes underlying memory formation, than activity via AMPA/kainate receptors.