NADPH DIAPHORASE-CONTAINING NONPYRAMIDAL CELLS IN THE RAT HIPPOCAMPUSEXHIBIT DIFFERENTIAL SENSITIVITY TO KAINIC ACID

Neurons containing nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase exhibit high resistance to several excitotoxins. In the ne ocortex and striatum, however, these neurons are sensitive to kainic a cid, Here we report that, 2 weeks after i.p. injection of kainic acid, the number of NADPH diaphorase neurons in the hilus and CA1 subfield was decreased, whereas the cell counts in the other hippocampal areas were to a great extent similar to those for the controls. We propose t hat the loss of NADPH diaphorase neurons in the hippocampus after syst emic injection of kainic acid is associated with the pathophysiologica l processes involved in the spreading of epileptic seizure activity ra ther than to the direct neurotoxic effect of the kainic acid per se.