Upper sphincter function during transient lower oesophageal sphincter relaxation (tLOSR); it is mainly about microburps

Neurogastroenterol Motil. 2007 Mar;19(3):203-10. doi: 10.1111/j.1365-2982.2006.00882.x.

Abstract

Transient lower oesophageal sphincter relaxations (tLOSRs) are both a dominant mechanism of reflux and an element of the belch reflex. This study aimed to analyse the interplay between reflux and upper oesophageal sphincter (UOS) activity during meal-induced tLOSRs. Fifteen normal subjects were studied with a solid-state high-resolution manometry assembly positioned to record from the hypopharynx to the stomach and a catheter pH electrode 5 cm above the LOS. Subjects ate a 1000-calorie high-fat meal and were monitored for 120 min in a sitting posture. The relationship among tLOSRs, common cavities, pressure changes within the oesophagus and UOS contractile activity were analysed. A total of 218 tLOSRs occurred among the 15 subjects. The majority (79%) were coupled with UOS relaxation and 84% (145/173) of these occurred in association with a common cavity. Upper oesophageal sphincter relaxation was usually preceded by a pressure change in the oesophagus; however, some relaxations (16%) occurred without a discernable increase in pressure or before the pressure increase began. Acid reflux did not appear to play a role in determining UOS response to tLOSRs. The majority of post-prandial tLOSRs were associated with brief periods of UOS relaxation, likely permissive of gas venting (microburps). Intraoesophageal pressure changes likely modulate this UOS response; however, an anticipatory characteristic was evident in some subjects. Whether or not GORD patients with extra-oesophageal symptoms exhibit an exaggeration of the UOS relaxation response during reflux is yet to be determined.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Eructation / physiopathology*
  • Esophageal Sphincter, Lower / physiology*
  • Esophageal Sphincter, Upper / physiology*
  • Gastroesophageal Reflux / physiopathology*
  • Humans
  • Male
  • Manometry
  • Middle Aged
  • Muscle Relaxation / physiology