THE INVOLVEMENT OF N-METHYL-D-ASPARTATE (NMDA) AND NON-NMDA RECEPTORSIN THE RESPONSIVENESS OF RAT SPINAL NEURONS WITH INPUT FROM THE CHRONICALLY INFLAMED ANKLE

Unilateral adjuvant inflammation was induced at the rat ankle 2 or 20 days before an evaluation of the contribution of N-methyl-D-aspartate (NMDA) and non-NMDA receptors to the processing of nociceptive informa tion by wide dynamic range neurons in the spinal cord. Microionophoret ic application of either the NMDA receptor antagonists ketamine and DL -2-amino-5-phosphonovalerate (AP5) or the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) reduced the responses to innocuous and noxious mechanical stimulation of the inflamed ankle. Th e pattern of these effects was comparable to that in rats with acute i nflammation suggesting that non-NMDA and NMDA receptors are similarly involved in acute, prolonged acute and chronic inflammation-evoked act ivity.