Pain-signalling systems in the dorsal and ventral spinal cord

The effect of transcutaneous electrical nerve stimulation in the treatment of lichen simplex: a prospective study

“…Various clinical studies have showed the efficacy and relative safety of transcutaneous electrical nerve stimulation (TENS), but its mechanism of action has not been firmly established 5–7 . TENS is known to have an effect in pain control, probably by producing feedback inhibitory impulses on afferent fibre terminals 8 . No definitive pathway for itching has been shown, 9 but it is thought that TENS may work in a similar way to the effect on pain 10 …”

“…[5][6][7] TENS is known to have an effect in pain control, probably by producing feedback inhibitory impulses on afferent fibre terminals. 8 No definitive pathway for itching has been shown, 9 but it is thought that TENS may work in a similar way to the effect on pain. 10 We report our experience of using TENS treatment to relieve pruritus in a group of patients with LS for whom the use of other treatments had proved insufficient.…”

Effects of salt-loading hypertension on nociception in rats

“…Although both early and late phase have nociceptive effect and travel through the same pathways (ie, Aδ and C fibers), the early phase is thought to act by direct chemical stimulation of nociceptors,27 while late phase response acts through inflammation 22. The results may reflect reduced activity in chemical sensitivity of afferents, Aδ and C fibers that mediate the second phase response 21.…”

Effect of morphine‐induced cortical excitation on spinal sensory transmission

“…In the rat, the VLF includes two main somatosensory pathways originating from cells lying in the marginal zone and in deeper parts of the dorsal horn, the spinothal- amic tract, and the spinoreticular tract [Dennis and Melzack, 1977;Willis et al, 1979;Dubner and Bennett, 19831, These systems are largely concerned with nociceptive afferent information, but also include output axons of wide-dynamic-range cells transmitting inocuous information in addition to pain [Dubner and Bennett, 19831. There exist several reports indicating that dorsal horn neurons can be controlled by pathways descending from the brain stem [Oliveras et al, 1974;Fields et al, 1977;Willis, 19821. In addition, convincing evidence indicates that these descending systems play a major role in opiate-induced analgesia [Fields and Anderson, 1979;Willis, 1982;Gebhart et al, 19841.…”