title: Upper sphincter function during transient lower oesophageal sphincter relaxation (tLOSR); it is mainly about microburps.
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.
authors.affiliation: Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA. j-pandolfino@northwestern.edu
authors.forename: J E
authors.initials: JE
authors.lastname: Pandolfino
authors.forename: S K
authors.initials: SK
authors.lastname: Ghosh
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: A
authors.initials: A
authors.lastname: Han
authors.forename: P J
authors.initials: PJ
authors.lastname: Kahrilas
mesh_terms: D000328:Adult; D004884:Eructation / Q000503:physiopathology*; D049630:Esophageal Sphincter, Lower / Q000502:physiology*; D049631:Esophageal Sphincter, Upper / Q000502:physiology*; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009126:Muscle Relaxation / Q000502:physiology