Lipopolysaccharlde inhibits long term potentiation in the rat dentate gyrus by activating caspase-1

Abstract

Lipopolysaccharide, a component of the cell wall of Gram-negative bacteria, may be responsible for at least some of the pathophysiological sequelae of bacterial infections, probably by inducing an increase in interleukin-1β (IL-1β) concentration. We report that intraperitoneal injection of lipopolysaccharide increased hippocampal caspase-1 activity and IL-1β concentration; these changes were associated with increased activity of the stress-activated kinase c-Jun NH2-terminal kinase, decreased glutamate release, and impaired long term potentiation. The degenerative changes in hippocampus and entorhinal cortical neurones were consistent with apoptosis because translocation of cytochrome c and poly(ADP-ribose) polymerase cleavage were increased. Inhibition of caspase-1 blocked these changes, suggesting that IL-1β mediated the lipopolysaccharide-induced changes.