[Effects of lateral habenular stimulation on nociceptive response of neurons in rat spinal dorsal horn].

Ipsilateral stimulation of the LHb produced a significant attenuation of nociceptive response of wide dynamic range (WDR) neurons in the rat spinal dorsal horn. The inhibitory effect produced by LHb stimulation was partially blocked by systemic cyproheptadine and phentolamine but not naloxone. No significant change was observed in the activity of WDR neurons after ipsilateral electrolytical lesions of the LHb. These results suggest that the LHb participates in the supraspinal descending control on nociceptive response of WDR neurons in the spinal dorsal horn. However, tonic inhibitory mechanism seems not to be involved.