title: Effects of esophageal capsaicin instillation on acid induced excitation of secondary peristalsis in humans.
abstract: OBJECTIVE
  Esophageal instillation of capsaicin or hydrochloric acid enhances secondary peristalsis. Our aim was to investigate whether intra-esophageal capsaicin infusion can influence symptom perception and physiological alteration of secondary peristalsis subsequent to acid infusion.
  
  
  METHODS
  Secondary peristalsis was induced by mid-esophagus injections of air in 18 healthy subjects. Two different sessions including esophageal infusion of hydrochloric acid (0.1 N) following pretreatment with saline or capsaicin-containing red pepper sauce were randomly performed at least one week apart. Symptoms of heartburn and secondary peristalsis were determined and compared between each study session.
  
  
  RESULTS
  The intensity of heartburn symptom subsequent to acid infusion was significantly reduced after capsaicin infusion as compared with saline infusion (54 ± 3 vs 61 ± 3; P = 0.03). Capsaicin infusion significantly increased the threshold volume of secondary peristalsis to rapid air injections subsequent to esophageal acid infusion (8.0 ± 0.5 mL vs 4.4 ± 0.3 mL; P < 0.0001). The frequency of secondary peristalsis subsequent to acid infusion was significantly decreased after capsaicin infusion as compared to saline infusion (70% [60-82.5%] vs 80% [70-90%]; P = 0.03). Capsaicin infusion significantly decreased the pressure wave amplitude of secondary peristalsis subsequent to acid infusion during rapid air injections (90.6 ± 8.7 mmHg vs 111.1 ± 11.1 mmHg; P = 0.03).
  
  
  CONCLUSIONS
  Capsaicin appears to desensitize the esophagus to acid induced excitation of secondary peristalsis in humans, which is probably mediated by rapidly adapting mucosal mechanoreceptors. High capsaicin-containing diet might attenuate normal physiological response to abrupt acid reflux by inhibiting secondary peristalsis.
authors.affiliation: Department of Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and Tzu Chi University, Hualien, Taiwan.
authors.forename: Tso-Tsai
authors.initials: TT
authors.lastname: Liu
authors.affiliation: Department of Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and Tzu Chi University, Hualien, Taiwan.
authors.forename: Chih-Hsun
authors.initials: CH
authors.lastname: Yi
authors.affiliation: Department of Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and Tzu Chi University, Hualien, Taiwan.
authors.forename: Wei-Yi
authors.initials: WY
authors.lastname: Lei
authors.affiliation: Department of Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and Tzu Chi University, Hualien, Taiwan.
authors.forename: Jui-Sheng
authors.initials: JS
authors.lastname: Hung
authors.affiliation: Department of Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation and Tzu Chi University, Hualien, Taiwan.
authors.forename: Chien-Lin
authors.initials: CL
authors.lastname: Chen
authors.affiliation: Lynn Institute for Healthcare Research, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Orr
mesh_terms: D000328:Adult; D000388:Air; D002211:Capsaicin / Q000008:administration & dosage* / Q000494:pharmacology; D004947:Esophagus / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000178:diet therapy / Q000209:etiology; D006356:Heartburn / Q000139:chemically induced* / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage* / Q000009:adverse effects; D007322:Instillation, Drug; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D010528:Peristalsis / Q000187:drug effects* / Q000502:physiology*; D055815:Young Adult
chemical_list: D006851:Hydrochloric Acid; D002211:Capsaicin
keywords: acid; capsaicin; esophageal peristalsis; secondary peristalsis