title: Mucosal acid exposure sensitizes a subset of normal subjects to intra-oesophageal balloon distension.
abstract: OBJECTIVE
  To assess the effect of acid infusion on the response of normal subjects to progressive intra-oesophageal balloon distension (IOBD).
  
  
  METHODS
  Twenty-one volunteers underwent slow IOBD. Subjects were asked to indicate the first perception of sensation (S1) and the onset of pain (S2), balloon volumes being recorded at both points. A 15-min infusion of 0.1 M HCl (8 ml/min) was then instilled proximal to the balloon. Subjects were designated as acid-sensitive if they reported chest pain or heartburn during the acid infusion. Thereafter S1 and S2 were assessed again in the same manner.
  
  
  RESULTS
  Nine subjects were acid-sensitive, 12 were acid-insensitive. The subgroup of 12 acid-insensitive subjects had an increase of pain threshold after acid infusion (P < 0.05), whereas the nine acid-sensitive subjects showed a decrease of pain threshold after acid infusion (P < 0.05). No change of the threshold for sensation occurred in either of these groups after acid infusion.
  
  
  CONCLUSIONS
  Individuals showing mucosal acid sensitivity have a lower threshold for mechanoreceptor stimulation after acid exposure.
authors.affiliation: Department of Medicine, Graduate Hospital, Philadelphia, PA 19146, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Peghini
authors.forename: B T
authors.initials: BT
authors.lastname: Johnston
authors.forename: L P
authors.initials: LP
authors.lastname: Leite
authors.forename: D O
authors.initials: DO
authors.lastname: Castell
mesh_terms: D000328:Adult; D002404:Catheterization; D002637:Chest Pain / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D004947:Esophagus / Q000502:physiology*; D005260:Female; D006801:Humans; D006851:Hydrochloric Acid / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D012016:Reference Values; D015203:Reproducibility of Results; D012684:Sensory Thresholds
chemical_list: D006851:Hydrochloric Acid