UP-REGULATION OF CYCLOOXYGENASE-2 MESSENGER-RNA IN THE RAT SPINAL-CORD FOLLOWING PERIPHERAL INFLAMMATION

Prostaglandins (PG) have been described as mediators in spinal nocicep tive processing after peripheral inflammation. Enzymes essential for P G biosynthesis, cyclooxygenase isozymes COX-1 and COX-2, have not yet been investigated in the spinal cord, In two studies on rats with adju vant-induced peripheral inflammation levels of mRNA expression of both COX isoforms were analyzed in the lumbar section of the spinal cord u sing reverse transcription-polymerase chain reaction (RT-PCR) techniqu e. We could show that mRNA of both COX isoforms is expressed constitut ively in the spinal cord with COX-2 as the predominant isoform, Six ho urs after induction of peripheral inflammation, levels of COX-2 mRNA e xpression were raised significantly in respect to untreated control ra ts and returned to baseline within 3 days after induction of inflammat ion, COX-2 might therefore be regarded as the COX isozyme responsible for spinal PG release in nociceptive processing under a peripheral inf lammatory stimulus.