Cyclooxygenase-2: Molecular biology, pharmacology, and neurobiology

In the nervous system, prostanoids are well recognized as mediators in a variety of processes, including fever generation, modulation of the stress response, sleep/wake cycle, control of cerebral blood flow, and hyperalgesia. Two isoforms of cyclooxygenase (COX), the enzyme that catalyzes the conversion of arachidonic acid to prostanoids, are now recognized: a constitutively expressed COX-1 and a highly regulated COX-2. New molecular and pharmacologic tools have provided a better understanding of the roles of COX-generated prostanoids in the nervous system. Other studies reveal that COX may represent an important target for new therapeutic approaches to neurologic disorders. This review summarizes our current understanding of cyclooxygenase expression and prostanoid actions in the nervous system, with special reference to COX-2 and studies demonstrating its expression in different cell types responding to a variety of stimuli. A brief review of the molecular biology, pharmacology, and primary actions of COX-2 outside of the nervous system provides a context for understanding potential neurobiological roles for COX-2 and prostanoid production. Information about the role of COX in human neurological disorders, including cerebrovascular disease, Alzheimer's disease, and hyperalgesia, is covered in the last section.