Regional metabolic alterations induced by systemic administration of kainic acid were investigated in rat brains. The histochemical study revealed that an acidic pH shift preceded an ATP decrease in the limbic structures. In the hippocampal Ammon's horn, it was noted that a selective decrease of ATP occurred in the dendritic subfield, such as the stratum radiatum and/or the stratum oriens. It was suggested that this selective ATP decrease in the dendrite is directly related to kainate neurotoxicity.