title: Acid infusion does not affect intraesophageal balloon distention-induced sensory and pain thresholds.
abstract: OBJECTIVE
  We sought to evaluate the potential interaction between acid-sensitive chemoreceptors and pressure-sensitive mechanoreceptors.
  
  
  METHODS
  Twenty-one normal control subjects underwent esophageal balloon distention with a commercially produced combined-manometry, acid-infusion, balloon-distention catheter. The intraesophageal balloon was localized 10 cm above the lower esophageal sphincter. With a mechanical pump, sensory and pain thresholds were determined by using sequentially increasing balloon volumes (range 0-23 cc, increment 1 cc). A 15-min acid infusion (0.1 N HCl at 6-8 cc/min) or a 0.9 N saline infusion was then applied just proximal to the distending balloon, followed by a second determination of sensory and pain thresholds. The results of the trials before and after acid and placebo were compared.
  
  
  RESULTS
  All subjects tolerated the procedure. The initial mean volume-to-sensory threshold was 9.1 ml (range 5-16), decreasing to 6.2 (range 4-11) after acid infusion (p < 0.005). The sensory threshold also decreased from 9.8 ml (range 6-16) to 6.8 ml (range 4-14) after saline infusion (p = 0.06). The mean volume-to-pain threshold was 16.0 (range 14-21) before and 15.2 (range 11-23) after acid infusion and 15.8 (range 12-20) before and 14.0 (range 10-20) after saline infusion (NS).
  
  
  CONCLUSIONS
  We conclude that infused acid has no effect on pain threshold and has a nonspecific effect on sensory threshold induced by esophageal balloon distention.
authors.affiliation: Department of Medicine, Mayo Clinic Jacksonville, Florida 32224, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: DeVault
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002404:Catheterization / Q000295:instrumentation*; D002628:Chemoreceptor Cells / Q000503:physiopathology*; D004943:Esophagogastric Junction / Q000503:physiopathology; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage; D008297:Male; D008365:Manometry / Q000295:instrumentation; D008465:Mechanoreceptors / Q000503:physiopathology*; D008875:Middle Aged; D017288:Pain Threshold / Q000502:physiology*; D010919:Placebos; D012684:Sensory Thresholds / Q000502:physiology*; D012965:Sodium Chloride / Q000008:administration & dosage
chemical_list: D010919:Placebos; D012965:Sodium Chloride; D006851:Hydrochloric Acid