Induction of cyclooxygenase-2 in the brain by cytokines.

The present study revealed that (1) a pyrogenic dose of IL-1 beta induced COX-2 mRNA in the brain vasculature and leptomeninges, and (2) the cells positive for COX-2 mRNA in the blood vessels were endothelial cells that possess receptors for IL-1. These results imply that circulating IL-1 beta acts on its receptor on the endothelial cells of the brain vasculature to induce COX-2 mRNA, which is possibly responsible for the elevated level of PGE2 seen during fever. In this sense, the endothelial cells in the brain vasculatures seem to play a role as an interface between the blood borne substance and the brain. The nature of the COX-2 mRNA-positive cells in the leptomeninges will be identified in our future study.