Pain wind-up is the increase in
pain
Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...
intensity over time when a given stimulus is delivered repeatedly above a critical rate. It is caused by repeated stimulation of
group C peripheral nerve fibers, leading to progressively increasing electrical response in the corresponding spinal cord (
posterior horn) neurons due to priming of the
NMDA
''N''-methyl--aspartic acid, or ''N''-methyl--aspartate (NMDA), is an amino acid derivative that acts as a specific agonist at the NMDA receptor mimicking the action of glutamate, the neurotransmitter which normally acts at that receptor. Unl ...
receptor based response.
[{{cite book, author1=Feng Xu, author2=Tianjian Lu, title=Introduction to Skin Biothermomechanics and Thermal Pain, url=https://books.google.com/books?id=fMggKzt8ofoC&pg=PA347, accessdate=25 April 2012, date=29 May 2011, publisher=Springer, isbn=978-3-642-13201-8, page=347][Pitcher and Henry (2000). ''Eur. J. Neurosci.'', 12:2006–2020.] It describes an exponentially progressive increase in firing of
WDR neurons with repeated stimulation.
References
Pain