Neurochemical research
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Neurochemical research · Aug 2009
Activation of NMDA receptor is associated with up-regulation of COX-2 expression in the spinal dorsal horn during nociceptive inputs in rats.
Cyclooxygenases-2 (COX-2) in the spinal dorsal horn is up-regulated and plays an important role in pain and hyperalgesia induced by nociceptive stimulation. The mechanisms involved in the up-regulation of spinal COX-2 during nociceptive stimulation are yet not well understood. Because the important role of NMDA and its receptor in transmission of nociceptive information in the spinal cord, activation of the spinal NMDA receptor might contribute to the up-regulation of spinal COX-2 expression. ⋯ Whereas, intrathecal injection of NMDA significantly up-regulated the expression of COX-2 in the spinal dorsal horn in a time course corresponding to that of nociceptive behavioral responses elicited by the intrathecal NMDA administration. In addition, the up-regulation of the COX-2 expression induced by the intrathecal NMDA was dose-dependent and blocked by prior administration of MK-801. These findings proved that activation of NMDA receptor is associated with the up-regulation of COX-2 expression in the spinal dorsal horn during nociceptive stimulation in rats.