LTP SPINAL A-BETA AND C-FIBER EVOKED-RESPONSES AFTER ELECTRICAL SCIATIC-NERVE STIMULATION

PLASTICITY in the central nervous system may play an important role in clinical pain. The present study shows that long-term potentiation (L TP) may be induced in single wide dynamic range (WDR) neurons in the d orsal horn after high-frequency stimulation of the sciatic nerve in in tact urethane anaesthetized rats. Extracellular recordings of firing r esponses after single pulse stimuli were made. The high-frequency cond itioning stimulus increased the A beta- and C-fibre-mediated firing re sponses to single pulse stimuli by 60 and 130%, respectively, for more than 6 h. This finding supports a role for WDR neurons in 'nociceptiv e memory' in the dorsal horn. The model presented here may be an impor tant tool for further investigations of mechanisms of plasticity withi n the dorsal horn.