EXPRESSION OF INDUCIBLE CYCLOOXYGENASE MESSENGER-RNA IN THE MOUSE-BRAIN AFTER SYSTEMIC ADMINISTRATION OF BACTERIAL LIPOPOLYSACCHARIDE

Cyclooxygenase (COX) is an enzyme involved in the biosynthesis of pros taglandins and is one of the principle targets of non-steroidal anti-i nflammatory drugs. Two isoforms of this enzyme are known to exist in t he brain; one of these (type 1 COX or COX1) is constitutively expresse d, whereas the other form of the enzyme, which is inducible, has been called type 2 COX (COX2). We have used systemic administration of bact erial lipopolysaccharide (LPS) as a model of the acute phase response to study the expression of COX2 in the murine CNS. We observed COX2 ex pression in neurons of several regions of the normal murine telencepha lon. Robust expression of COX2 mRNA was induced in perivascular cells between 45 min and 6 h after LPS injection. The role of prostaglandins produced by these perivascular cells in the cerebral components of th e acute phase response remains to be elucidated.