Evoked Human Oesophageal Hyperalgesia: A Potential Tool for Analgesic Evaluation?

Authors

  • Anne Estrup Olesen,

    1. Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Aalborg, Denmark
    2. Center for Sensory-Motor Interactions, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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  • Camilla Staahl,

    1. Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Aalborg, Denmark
    2. Center for Sensory-Motor Interactions, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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  • Christina Brock,

    1. Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Aalborg, Denmark
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  • Lars Arendt-Nielsen,

    1. Center for Sensory-Motor Interactions, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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  • Asbjørn Mohr Drewes

    1. Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Aalborg, Denmark
    2. Center for Sensory-Motor Interactions, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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Author for correspondence: Asbjørn Mohr Drewes, Mech-Sense, Department of Gastroenterology, Aalborg Hospital, Hobrovej 18-22, 9000, Aalborg, Denmark (fax +45 99326507, e-mail drewes@smi.auc.dk).

Abstract

Abstract:  Hypersensitivity is a common finding in visceral disorders. Therefore, in the development and testing of analgesics for the treatment of visceral pain, it is important to establish an experimental pain model of visceral hypersensitivity. Such a model will mimic the clinical situation to a higher degree than pain models where the receptors and peripheral afferents are briefly activated as with, for example, electrical, thermal, and mechanical stimulations. In this study, a model to evoke experimental hyperalgesia of the oesophagus with a combination of acid and capsaicin was introduced. The study was a randomised, double-blind, cross-over study. Fifteen healthy volunteers were included. Sensory assessments to mechanical, heat, and electrical stimulations were done in the distal oesophagus, before and after perfusion with a 200 ml solution of acid+capsaicin (180 ml HCL 0.1 M and 2 mg capsaicin in 20 ml solvent) or saline. Oesophageal pain assessment and referred pain areas were evaluated. There were reproducible pain assessments between repetitions within the same day and between days (all P > 0.05). Acid+capsaicin perfusion induced 56% reduction of the pain threshold to heat (P = 0.04), 19% reduction of the pain threshold to electrical stimuli (P < 0.001), 78% increase of the referred pain areas to mechanical stimulation (P < 0.001) and 52% increase of the referred pain areas to electrical stimulus (P = 0.045). All volunteers were sensitised to one or more modalities by acid+capsaicin. The model was able to evoke consistent hyperalgesia and may be useful in future pharmacological studies.

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