Medullary raphé lesions do not reduce descending inhibition of dorsal horn neurones of the cat.

In anaesthetized cats spinal cold block was used to examine the effects of medullary raphé lesions on the responses of dorsal horn neurones to impulses in unmyelinated primary afferents. Lesions failed to affect these responses, casting doubt on the importance of this region and its serotonergic spinal projections to the control of nociceptive transmission at the spinal level.