Lumbar dorsal root potentials elicited by stimulation of nucleus locus coeruleus.

Lumbar dorsal root potentials (DRP) were elicited by nucleus locus coeruleus (LC) stimulation in the cat. Inhibition, by LC stimulation, of dorsal horn cells responding to noxious inputs corresponded in time with the DRPs evoked by LC stimulation. Comparing cutaneous stimulation-evoked DRPs with LC stimulation-evoked DRPs and their respective effects on dorsal horn single-unit activity suggested a shared segmental underlying mechanism and the possible involvement of the coeruleospinal system with that of a diffuse noxious inhibitory suprasegmental loop.