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document
Perceptual wind-up in the human oesophagus is enhanced by central sensitisation . BACKGROUND Oesophageal acid infusion induces enhanced pain hypersensitivity in non-acid exposed upper oesophagus ( secondary hyperalgesia ) in patients with non-cardiac chest pain , thus suggesting central sensitisation contributes to visceral pain hypersensitivity in functional gut disorders ( FGD ) . Perceptual wind-up ( increased pain perception to constant intensity sensory stimuli at frequencies > or=0.3 Hz ) is used as a proxy for central sensitisation to investigate pain syndromes where pain hypersensitivity is important ( for example , fibromyalgia ) . AIMS Wind-up in central sensitisation induced human visceral pain hypersensitivity has not been explored . We hypothesised that if wind-up is a proxy for central sensitisation induced human visceral pain hypersensitivity , then oesophageal wind-up should be enhanced by secondary hyperalgesia . METHODS In eight healthy volunteers ( seven males ; mean age 32 years ) , perception at pain threshold to a train of 20 electrical stimuli applied to the hand and upper oesophagus ( UO ) at either 0.1 Hz ( control ) or 2 Hz was determined before and one hour after a 30 minute lower oesophageal acid infusion . RESULTS Wind-up occurred only with the 2 Hz train in the UO and hand ( both p=0.01 ) . Following acid infusion , pain threshold decreased ( 17 ( 4 ) % ; p=0.01 ) in the UO , suggesting the presence of secondary hyperalgesia . Wind-up to the 2 Hz train increased in the UO ( wind-up ratio 1.4 ( 0.1 ) to 1.6 ( 0.1 ) ; p=0.03 ) but not in the hand ( wind-up ratio 1.3 ( 0.1 ) and 1.3 ( 0.1 ) ; p=0.3 ) CONCLUSION Enhanced wind-up after secondary oesophageal hyperalgesia suggests that visceral pain hypersensitivity induced by central sensitisation results from increased central neuronal excitability . Wind-up may offer new opportunities to investigate the contribution of central neuronal changes to symptoms in FGD .
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Intervention_Physical
electrical stimuli
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Intervention_Physical
2 Hz
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Intervention_Physical
2 Hz
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Intervention_Physical
2 Hz
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Outcome_Other
Perceptual wind-up
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Outcome_Other
Wind-up
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Outcome_Pain
pain threshold decreased
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Outcome_Other
Wind-up to the 2 Hz train
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Outcome_Physical
UO
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Participant_Condition
human oesophagus
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Participant_Sample-size
eight
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Participant_Condition
healthy
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Participant_Sample-size
seven
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Participant_Sex
males
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Participant_Age
mean age 32 years