Structure and Function of the Gastro-esophageal Junction

Aims of research project: To identify key features of the gastro-esophageal junction (structure and function) that protects the esophagus from gastro-esophageal reflux investigated by combined high resolution manometry and magnetic resonance imaging. Hypothesis: 1. Functional factors including GEJ function (e.g. sphincter pressure) and proximal gastric distension determine whether or not TLESR occurs; however 2. Structural factors including separation of GEJ anatomy, intra-gastric distribution of the meal and secretions determine whether TLESR is accompanied by no reflux event, gas reflux (belching) or reflux of ingested food and gastric secretion (\'true reflux\'). 3. Initial findings by descriptive studies in healthy volunteers (study #1) and patients with mild to moderate gastro-esophageal reflux disease (study #2) will be further interrogated by a randomized, double-blind control trial of baclofen in patients with GORD; a medication that inhibits reflux by effects on GOJ function (study #3) .