Wind-up and neuroplasticity: is there a correlation to clinical pain?

It is neurophysiologically and neurobiologically verified that the central nociceptive system can undergo changes and become hyperexcitable. Hyperexcitability involves wind-up (exaggerated responses) of dorsal horn neurones which in humans can be studied (temporal summation) by electrophysiological and psychophysical reactions to repeated nociceptive stimuli. Temporal summation occurs if repeated stimuli evoke increasing pain reactions. Human experimental models are adequate to investigate basic aspects and pharmacological modulation of summation and to bridge the gap between basic and clinical sciences facilitating the transfer of knowledge from basic science into the clinic. Human experimental investigations have confirmed animal studies that show that central summation is a potent mechanism in both normal and pathophysiological (hyperexcitable) conditions. Central summation should be considered as a target for the development of new centrally acting analgesics, for designing management regimens to treat intractable pain, and as a possible way of inhibiting surgically-induced afferent barrage from reaching brain centres (subconscious pain) during anaesthesia.