title: A unique longitudinal muscle contraction pattern associated with transient lower esophageal sphincter relaxation.
abstract: OBJECTIVE
  Contraction of the longitudinal muscle of the esophagus may play a role in the relaxation and opening of the lower esophageal sphincter (LES). The goal of our study was to determine the pattern and precise temporal correlation between local longitudinal muscle contraction (LMC) of the esophagus during peristalsis and transient LES relaxation (TLESR).
  
  
  METHODS
  Esophageal pressures and high-frequency intraluminal ultrasound imaging of the esophagus were recorded in 24 healthy subjects during swallow-induced peristalsis and spontaneous TLESR. Intraluminal multiple impedance recordings were obtained to determine the relationship between "common cavity pressure" and gastroesophageal reflux (GER).
  
  
  RESULTS
  During swallow-induced peristalsis, there is simultaneous contraction of circular and longitudinal muscles of the esophagus. On the other hand, TLESR is associated with a distinct pattern of LMC in the esophagus that has the following characteristics: (1) it is restricted to the distal esophagus; (2) it begins before the onset of TLESR and spreads in a retrograde manner; (3) it is generally stronger than the swallow-induced contraction; and (4) it is sustained during the entire duration of TLESR. The increase in esophageal pressure during TLESR is temporally correlated with the contraction of the LM of the distal esophagus, rather than with the impedance recorded GER.
  
  
  CONCLUSIONS
  We propose that the LMC of the distal esophagus may play an important role in the relaxation of LES and induction of GER.
authors.affiliation: Division of Gastroenterology, San Diego VA Health Care System and University of California, San Diego, California.
authors.forename: Arash
authors.initials: A
authors.lastname: Babaei
authors.forename: Valmik
authors.initials: V
authors.lastname: Bhargava
authors.forename: Hariprasad
authors.initials: H
authors.lastname: Korsapati
authors.forename: Wei Hao
authors.initials: WH
authors.lastname: Zheng
authors.forename: Ravinder K
authors.initials: RK
authors.lastname: Mittal
mesh_terms: D000328:Adult; D003679:Deglutition / Q000502:physiology; D017097:Electric Impedance; D019160:Endosonography; D049630:Esophageal Sphincter, Lower / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009126:Muscle Relaxation / Q000502:physiology*; D010528:Peristalsis / Q000502:physiology; D011312:Pressure; D012016:Reference Values