Distribution of cyclooxygenase-3 [COX-3] in rat nervous system

ABSTRACT

Cyclooxygenase-3 [Cox-3] is a recently identified cyclooxygenase which is inhibited by paracetamol related drugs rather than traditional non-steroidal anti-inflammatory. In this study the distribution of Cox-3 has been studied in the rat nervous system both in the central and peripheral nervous system. Ten adult male Wistar rats weighing 300-400 g were killed by decapitation under brief anesthesia. Nervous system; brains, spinal cords, spinal ganglia and spinal nerves were removed and processed for immunohistochemisty using an antibody raised against Cox-3. Cox-3 was widely distributed in the rat nervous system. The expression appeared mainly neuronal. In the central nervous system, Cox-3 was localized in neurons in the brain and spinal cord. In the brain Cox-3 was highly expressed in cerebral cortex, hippocampus and cerebellum. In the peripheral nervous system Cox-3 was localized in neurons in the spinal ganglia and in the spinal nerves. Cox-3 was widely distributed in the nervous system. Thus, this isoform could be contributing to the generation of the physiological levels of prostaglandins normally for needed for homeostatic regulation in the nervous system. Localisation of Cox-3 in areas associated with nociception and pain such as brain, spinal cord and spinal ganglia support the hypothesis that Cox-3 may be the central target of paracetamol and other related centrally acting analgesics/antipyretics