Effects of Metoclopramide on Esophageal Motor Activity and Esophagogastric Junction Compliance in Healthy Volunteers

BACKGROUND/AIMS: Prokinetic drugs such as metoclopramide are frequently used as second-line therapy for patients with gastroesophageal reflux disease. However, their beneficial effects remain unclear. Esophageal motor activities and compliance of the esophagogastric junction (EGJ) are important for prevention of gastroesophageal reflux. Although metoclopramide has been reported to increase lower esophageal sphincter (LES) pressure, its effects on EGJ compliance have not been evaluated. In the present study, we investigated the effects of metoclopramide on esophageal motor activities and EGJ compliance. METHODS: Nine healthy male volunteers without abdominal symptoms were enrolled. Peristaltic esophageal contractions and LES pressure were examined using high-resolution esophageal manometry, while EGJ compliance was evaluated with an endoluminal functional lumen-imaging probe. After obtaining baseline values for esophageal motor activities and EGJ compliance, metoclopramide (10 mg) was intravenously administered, then all measurements were repeated at 15 minutes after administration in each subject. RESULTS: Following administration of metoclopramide, mean resting LES pressure was significantly increased as compared with the baseline (13.7 +/- 9.2 vs 26.7 +/- 8.8 mmHg, P < 0.05). In addition, metoclopramide significantly augmented peristaltic contractions, especially in the distal esophageal segment (P < 0.05). On the other hand, distensibility index did not change after administration (4.5 +/- 0.5 vs 4.1 +/- 0.5 mm2/mmHg), suggesting no significant effect of metoclopramide on EGJ compliance. CONCLUSIONS: Metoclopramide augmented esophageal contractions without changing EGJ compliance in healthy adults.

Generation of Gastroesophageal Reflux Disease Symptoms During Esophageal Acid Infusion With Concomitant Esophageal pH Monitoring in Healthy Adults

BACKGROUND/AIMS: The sensitivity of the upper and lower esophageal mucosa to acid is considered to differ. We investigated the relationship between pH changes in different sites of the esophagus and generation of gastroesophageal reflux symptoms during an acid infusion test. METHODS: An acid infusion catheter was placed at 5 or 15 cm above the lower esophageal sphincter (LES) in 18 healthy volunteers, while a 2-channel pH sensor catheter was also placed in each with the sensors set at 5 and 15 cm above the LES. Solutions containing water and hydrochloric acid at different concentrations were infused through the infusion catheter. RESULTS: Acid infusion in the upper esophagus caused a pH drop in both upper and lower esophageal sites, whereas that in the lower esophagus resulted in a significant pH drop only in the lower without a corresponding pH decline in the upper esophagus. Stronger heartburn, chest pain, and chest oppression symptoms were noted when acid was infused in the upper as compared to the lower esophagus, while increased intra-esophageal acidity strengthened each symptom. Regurgitations caused by upper and lower esophageal acid infusions were similar, and not worsened by a larger drop in intra-esophageal pH. Chest pain was caused only by lowered intra-esophageal pH, while heartburn, chest oppression, and regurgitation were induced by a less acidic solution. CONCLUSIONS: Higher intra-esophageal acidity caused stronger heartburn, chest pain, and chest oppression symptoms. However, regurgitation was not significantly influenced by intra-esophageal acidity. The upper esophagus showed higher acid sensitivity than the lower esophagus.

Observations of Acid Reflux and Motor Function in Distal Esophagus Using Simultaneous Measurements of Intra-esophageal pH and Pressure in 8 Directions With Novel Sensor Catheter: A Feasibility Study

BACKGROUND/AIMS: Esophagogastric junctional lesions, such as mucosal breaks with Los Angeles grade A or B reflux esophagitis, lacerations in Mallory Weiss syndrome, and short segment Barrett's esophagus, are mainly found in the right anterior wall of the distal esophagus. Asymmetrical lower esophageal sphincter pressure and resting radial asymmetrical acid reflux may be causes of this asymmetrical distribution of reflux esophagitis and short segment Barrett's esophagus. We developed a novel pH and pressure catheter to investigate the asymmetrical distributions of pH and intra-esophageal pressure in the distal esophagus. METHODS: One healthy male volunteer was enrolled in this study. Acid reflux and motor function in distal esophagus was investigated using simultaneous measurements of intra-esophageal pH and pressure in 8 directions with novel sensor catheter. RESULTS: Thirty-six acid and weak acid reflux events were observed, of which 22 were circumferential refluxes with pH drops in all channels and 14 were partial refluxes with pH drops in some channels. Increase in transient circumferential intraesophageal pressure was observed just after 72.7% of the circumferential reflux and 42.9% of the partial reflux events. CONCLUSIONS: Using a novel sensor catheter, 2 different types of acid reflux events were identified in the present study.

Influence of Full-body Water Immersion on Esophageal Motor Function and Intragastric Pressure

BACKGROUND/AIMS: In Japan, it is customary to take a daily bath during which the body is immersed in water to the neck. During full-body immersion, hydrostatic pressure is thought to compress the chest and abdomen, which might influence esophageal motor function and intra-gastric pressure. However, whether water immersion has a significant influence on esophageal motor function or intragastric pressure has not been shown. The aim of this study was to clarify the influence of full-body water immersion on esophageal motor function and intragastric pressure. METHODS: Nine healthy male volunteers (mean age 40.1 +/- 2.8 years) were enrolled in this study. Esophageal motor function and intragastric pressure were investigated using a high-resolution 36-channel manometry device. RESULTS: All subjects completed the study protocol. Intragastric pressure increased significantly from 4.2 +/- 1.1 to 20.6 +/- 1.4 mmHg with full-body water immersion, while the lower esophageal high pressure zone (LEHPZ) value also increased from 20.5 +/- 2.2 to 40.4 +/- 3.6 mmHg, with the latter being observed regardless of dietary condition. In addition, peak esophageal peristaltic pressure was higher when immersed as compared to standing out of water. CONCLUSIONS: Esophageal motor function and intragastric pressure were altered by full-body water immersion. Furthermore, the pressure gradient between LEHPZ and intragastric pressures was maintained at a high level, and esophageal peristaltic pressure was elevated with immersion.