title: Postprandial cardiac vagal tone and transient lower esophageal sphincter relaxation (TLESR).
abstract: BACKGROUND
  Transient lower esophageal sphincter relaxation (TLESR) is a vagally mediated reflex that occurs most frequently after a meal. Cardiac vagal tone (CVT) decreases after a meal, and correlates with changes in gastric electrical activity. Furthermore, decreased CVT has been reported in patients with gastro-esophageal reflux disease. We therefore aimed to characterize the association between postprandial changes in CVT and the occurrence of TLESR and reflux.
  
  
  METHODS
  Ten healthy volunteers underwent simultaneous autonomic nervous system, gastric myoelectric activity, lower esophageal-sphincter pressure, and reflux monitoring for 30 min in the fasting state, followed by a standard meal, and a further 4 h postprandially. Results are in mean ± SEM.
  
  
  RESULTS
  The number of TLESRs (P < 0.0001) and reflux episodes (P < 0.0001) increased after the meal, while CVT decreased (P < 0.01). Cardiac sensitivity to baroreceptor reflex (CSB) showed similar time course changes to CVT (P = 0.06). During the first postprandial hour there was a strong correlation between the number of TLESRs and reflux episodes with CVT (R(2)  = 0.51 and R(2)  = 0.50, respectively; P < 0.05). There was also an increase in the dominant power and power ratio on electrogastrography (P < 0.05) after the meal.
  
  
  CONCLUSIONS
  In healthy volunteers, the increase in the number of TLESRs and reflux episodes after a meal occurred mostly at a time of reduced CVT. Further studies should explore whether modulation of CVT can modify frequency of TLESRs and also this relationship should be further explored in patients with reflux disease.
authors.affiliation: Centre for Digestive Diseases, Blizard Institute and Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Kuo
authors.forename: I
authors.initials: I
authors.lastname: Bravi
authors.forename: U
authors.initials: U
authors.lastname: Marreddy
authors.forename: Q
authors.initials: Q
authors.lastname: Aziz
authors.forename: D
authors.initials: D
authors.lastname: Sifrim
mesh_terms: D000328:Adult; D017097:Electric Impedance; D049630:Esophageal Sphincter, Lower / Q000502:physiology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006321:Heart / Q000294:innervation / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry; D009126:Muscle Relaxation / Q000502:physiology*; D009129:Muscle Tonus / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology; D019518:Postprandial Period / Q000502:physiology*; D014630:Vagus Nerve
keywords: LES; autonomic nerve; reflux; vagal tone