[Role of red nucleus in inhibiting nociceptive responses of rat spindle afferent].

Using extracellular recording techniques, the effect of excitation of red nucleus (RN) on C-responses of wide dynamic range (WDR) neurons and the roles of RN in the inhibitory effect of spindle afferent activated by succinycholine (SCH) on C-responses of WDR neurons were studied. Stimulation of RN caused a significant reduction of nociceptive responses of WDR neurons, which was significantly attenuated by intravenous cyproheptadine and contralateral lesion of RN. These results suggest that the inhibitory effect on nociceptive responses of WDR neurons caused by RN stimulation was partly mediated by 5-HT and RN plays an important role in analgesia induced by the muscle spindle afferent activity.