Viscero-somatic reflexes in referred pain areas evoked by capsaicin stimulation of the human gut

• Published in: European journal of pain 2008-07, Vol.12 (5), p.544-551
• Main Authors: Arendt-Nielsen, Lars, Schipper, Klaus-Peter, Dimcevski, Georg, Sumikura, Hiroyuki, Krarup, Anne Lund, Giamberardino, Maria Adele, Drewes, Asbjørn Mohr
• Format: Article
• Language: English
• Subjects: Administration, Topical; Adult; Afferent Pathways - physiopathology; Aged; Anesthesia & Perioperative Care; Blood Flow Velocity - drug effects; Blood Flow Velocity - physiology; Body Temperature Regulation - drug effects; Body Temperature Regulation - physiology; Capsaicin; Capsaicin - pharmacology; Capsaicin - toxicity; Colon - blood supply; Colon - drug effects; Colon - innervation; Experimental; Female; Gut; Human; Humans; Ileum - blood supply; Ileum - drug effects; Ileum - innervation; Intestinal Mucosa - blood supply; Intestinal Mucosa - drug effects; Intestinal Mucosa - innervation; Laser doppler flowmetry; Male; Microcirculation - drug effects; Middle Aged; Models, Neurological; Nociceptors - drug effects; Nociceptors - physiology; Pain; Pain Medicine; Pain, Referred - physiopathology; Reflex - drug effects; Single-Blind Method; Skin - innervation; Sympathetic Nervous System - physiopathology; Thermography; Vaso-motor reflexes; Vasodilation - drug effects
• ISSN: 1090-3801; 1532-2149
• DOI: 10.1016/j.ejpain.2007.08.010

Abstract The interaction between visceral pain and the sympathetic nervous system is only sparsely investigated in quantitative human studies. Referred visceral pain can be evoked experimentally by application of substances such as capsaicin (the pungent substance of chilli pepper) to the gut. The aim of the present study was to induce referred visceral pain from the small and large intestine in 32 volunteers via the stomal opening in patients with ileo- or colostomy and quantify the viscero-somatic reflex responses in these referred pain areas by thermography and laser doppler flowmetry. Capsaicin evoked pain and referred pain areas in all subjects. In the referred pain area, the temperature increased by approximately 0.6 °C ( P < 0.001) and the blood flow by approximately 35 AU ( P < 0.001). Saline was used in a control experiment, and no temperature and blood flow changes were found. The present quantitative human study of viscero-somatic reflexes showed dramatic sympathetic responses in the referred pain areas after experimentally induced gut pain.