It is widely accepted that interleukin-1beta (IL-1beta), a cytokine produced not only by cells of the immune system but also by cells of the central nervous system, modulates hippocampal function. Here we investigate the effect of a seizure-induced increase in hippocampal IL-1beta concentration on neurotransmitter release. We report that oral administration of glycerol evoked seizure activity in BALB/c mice. Associated with these convulsions was an induction of IL-1beta gene expression and a significant increase in cytokine protein in the hippocampus. Release of glutamate in synaptosomes prepared from hippocampi of these animals was reduced compared to control. These results are consistent with previous data suggesting a modulatory effect of IL-1beta on glutamate release in hippocampus.