Journal of neuroscience research
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In this study, we examined whether a competitive AMPA receptor antagonist, NBQX, attenuates mechanical allodynia and hyperexcitability of spinal neurons in remote, caudal regions in persistent central neuropathic pain following spinal cord injury in rats. Spinal cord injury was produced by unilateral T13 transverse spinal hemisection, from dorsal to ventral, in male Sprague Dawley rats (200-250 g). Mechanical thresholds were measured behaviorally, and the excitability of wide-dynamic-range (WDR) dorsal horn neurons in the lumbar cord (L4-L5) was measured to assess central neuropathicpain. ⋯ The hyperexcitability of WDR neurons was attenuated by topical administration of NBQX (0.125, 0.25, 0.5, 1 mM), dose dependently (P < 0.05). Regression analysis indicated that at least three molecules of NBQX bond per receptor complex, and are needed to achieve inhibition of WDR hyperexcitability. In conclusion, our study demonstrates that the AMPA receptor plays an important role in behaviors related to the maintenance of central neuropathic pain below the level of spinal cord injury.