INTERACTION BETWEEN SUBSTANCE-P AND EXCITATORY AMINO-ACID RECEPTORS IN MODULATION OF NOCICEPTIVE RESPONSES OF CAT SPINAL DORSAL HORN NEURONS

Co-effects of microelectrophoretic application of 2-amino-5-phosphonov alerate (APV), ketamine, 6,7-dinitroqinoxaline-2,3-dione (DNQX), kynur enate (Kyn) and spantide on 34 spinal dorsal horn neurons were studied . Co-application of spantide and APV or DNQX produced a synergetic inh ibition of responses by tibial stimulation in 10/23 and 3/8 neurons, r espectively, and also in 3/8 neurons by administration of DL-sodium ho mocysteate. Spantide enhanced APV- or ketamine-induced inhibition of C responses of 8/19 neurons to sural stimulation, DNQX induced that of 2/4 neurons to gastrocnemius-soleous stimulation (GS), and Kyn induced that to both sural (8/19) and GS (2/4). The results suggest an intera ction of SP and NMDA, non-NMDA receptors in processing spinal nocicept ion.