Sphincteric action of the diaphragm during a relaxed lower esophageal sphincter in humans

1989 ◽  
Vol 256 (1) ◽  
pp. G139-G144 ◽  
Author(s):  
R. K. Mittal ◽  
D. F. Rochester ◽  
R. W. McCallum
Keyword(s):  
Lower Esophageal Sphincter ◽  
Esophagogastric Junction ◽  
Voluntary Contraction ◽  
Pressure Increase ◽  
Healthy Human ◽  
Bipolar Electrodes ◽  
Human Volunteers ◽  
Esophageal Sphincter ◽  
Crural Diaphragm ◽  
Voluntary Contractions

We studied the effects of involuntary and voluntary contraction of the diaphragm on esophagogastric junction (EGJ) pressure during esophageal distension in healthy human volunteers. The EGJ pressure was monitored using a Dent sleeve device. Along with the pressure we concurrently monitored diaphragm electromyogram (EMG) using intra-esophageal bipolar electrodes that were placed on the nonpressure sensing surface of the sleeve device. Graded esophageal distensions were performed by graded inflations of a 2-cm-diameter balloon that was positioned 7 cm above the EGJ. The graded esophageal distensions caused a graded increase in the amplitude of lower esophageal sphincter (LES) relaxation (end-expiratory EGJ pressure). In a majority of the subjects, esophageal distension had no effect on spontaneous inspiratory EGJ pressure increase and diaphragm EMG. During sustained LES relaxation of greater than 70% induced by sustained esophageal distention, graded voluntary contractions of the diaphragm induced proportional increases in the EGJ pressure and diaphragm EMG. The EGJ pressure and diaphragm EMG were similar during diaphragmatic contraction both before and during esophageal distension. During a maximal and sustained diaphragm contraction, esophageal distension had no effect on the EGJ pressure. We conclude that there are two distinct sphincteric mechanisms at the EGJ, the LES and crural diaphragm, and they respond differently to distension of the distal esophagus.

Human lower esophageal sphincter pressure response to increased intra-abdominal pressure

1990 ◽  
Vol 258 (4) ◽  
pp. G624-G630 ◽  
Author(s):  
R. K. Mittal ◽  
M. Fisher ◽  
R. W. McCallum ◽  
D. F. Rochester ◽  
J. Dent ◽  
...  
Keyword(s):  
Lower Esophageal Sphincter ◽  
Esophagogastric Junction ◽  
Tonic Contraction ◽  
Pressure Response ◽  
Abdominal Pressure ◽  
Abdominal Compression ◽  
Gastric Pressure ◽  
Straight Leg Raising ◽  
Esophageal Sphincter ◽  
Crural Diaphragm

We studied the effects of increased intra-abdominal pressure on the lower esophageal sphincter (LES) pressure in 15 healthy subjects. The role of the diaphragm in the genesis of LES pressure during increased intra-abdominal pressure was determined by measuring diaphragm electromyogram (EMG). The latter was recorded using bipolar intraesophageal platinum electrodes that were placed on the nonpressure sensing surface of the sleeve device. We also measured the LES pressure response to increased intra-abdominal pressure during inhibition of the smooth muscles of the LES by intravenous atropine (12 micrograms/kg). Straight-leg raising and abdominal compression were used to increase intra-abdominal pressure. Our results show that the increase in LES pressure during straight-leg raising is greater than the increase in gastric pressure. During abdominal compression, the rate of LES pressure increase is faster than that of the gastric pressure, suggesting an active contraction at the esophagogastric junction. The increase in LES pressure during periods of increased intra-abdominal pressure is associated with a tonic contraction of the crural diaphragm as demonstrated by EMG recording. Atropine inhibited the resting LES pressure by 50-70% in each subject but had no effect either on the peak LES pressure attained during increased intra-abdominal pressure or tonic crural diaphragm EMG. We conclude that 1) there is an active contraction at the esophagogastric junction during periods of increased intra-abdominal pressure and 2) tonic contraction of the crural diaphragm is a mechanism for this LES pressure response.

scholarly journals Physiological and pathological roles of the accommodation response in lower esophageal sphincter relaxation during wet swallows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kazumasa Muta ◽  
Eikichi Ihara ◽  
Shohei Hamada ◽  
Hiroko Ikeda ◽  
Masafumi Wada ◽  
...  
Keyword(s):  
Clinical Practice ◽  
High Resolution ◽  
Observational Study ◽  
Lower Esophageal Sphincter ◽  
Relaxation Function ◽  
Esophagogastric Junction ◽  
Prospective Observational Study ◽  
Outflow Obstruction ◽  
High Resolution Manometry ◽  
Esophageal Sphincter

AbstractThe preparatory accommodation response of lower esophageal sphincter (LES) before swallowing is one of the mechanisms involved in LES relaxation during wet swallows, however, the physiological and/or pathological roles of LES accommodation remain to be determined in humans. To address this problem, we conducted a prospective observational study of 38 patients with normal high-resolution manometry (HRM) and 23 patients with idiopathic esophagogastric junction outflow obstruction (EGJOO) to assess dry and wet swallows. The LES accommodation measurement was proposed for practical use in evaluating the LES accommodation response. Although swallow-induced LES relaxation was observed in both dry and wet swallows, LES accommodation (6.4, 3.1–11.1 mmHg) was only observed in wet swallows. The extent of LES accommodation was impaired in idiopathic EGJOO (0.6, − 0.6–6 mmHg), and the LES accommodation measurement of patients with idiopathic EGJOO (36.8, 29.5–44.3 mmHg) was significantly higher in comparison to those with normal HRM (23.8, 18–28.6 mmHg). Successful LES relaxation in wet swallowing can be achieved by LES accommodation in combination with swallow-induced LES relaxation. Impaired LES accommodation is characteristic of idiopathic EGJOO. In addition to the IRP value, the LES accommodation measurement may be useful for evaluating the LES relaxation function in clinical practice.

Effect of hyperglycemia on triggering of transient lower esophageal sphincter relaxations

2004 ◽  
Vol 286 (5) ◽  
pp. G797-G803 ◽  
Author(s):  
Qing Zhang ◽  
Michael Horowitz ◽  
Rachael Rigda ◽  
Christopher Rayner ◽  
Andrew Worynski ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Lower Esophageal Sphincter ◽  
Blood Glucose Concentration ◽  
Gastric Wall ◽  
Gastric Distension ◽  
Healthy Human ◽  
Patients With Diabetes ◽  
Esophageal Sphincter ◽  
Volume Controlled ◽  
Pressure Controlled

Acute changes in blood glucose concentration have major effects on gastrointestinal motor function. Patients with diabetes mellitus have an increased prevalence of gastroesophageal reflux. Transient lower esophageal sphincter (LES) relaxation (TLESR) is the most common sphincter mechanism underlying reflux. The aim of this study was to investigate the effect of acute hyperglycemia on triggering TLESRs evoked by gastric distension in healthy volunteers. TLESRs were stimulated by pressure-controlled and volume-controlled (500 ml) gastric distension using an electronic barostat and performed on separate days. On each day, esophageal manometry was performed in the sitting position during gastric distension for 1 h under euglycemia (5 mM), and either marked hyperglycemia (15 mM) or physiological hyperglycemia (8 mM) in randomized order was maintained by a glucose clamp. Marked hyperglycemia doubled the rate of TLESRs in response to both pressure-controlled [5 (3–10.5, median or interquartile range) to 10 (9.5–14.5) per hour, P < 0.02] and volume-controlled [4 (2.5–7.5) to 10.5 (7–12.5) per hour, P < 0.02] gastric distension but had no effect on basal LES pressure. Physiological hyperglycemia had no effect on the triggering of TLESRs or basal LES pressure. In healthy human subjects, marked hyperglycemia increases the rate of TLESRs. Increase in the rate of TLESRs is independent of proximal gastric wall tension. Mechanisms underlying the effect remain to be determined. Hyperglycemia may be an important factor contributing to the increased esophageal acid exposure in patients with diabetes mellitus.

Diaphragmatic contribution to gastroesophageal competence and reflux in dogs

1992 ◽  
Vol 263 (4) ◽  
pp. G551-G557 ◽  
Author(s):  
C. J. Martin ◽  
W. J. Dodds ◽  
H. H. Liem ◽  
R. O. Dantas ◽  
R. D. layman ◽  
...  
Keyword(s):  
Gastroesophageal Reflux ◽  
Lower Esophageal Sphincter ◽  
Short Duration ◽  
Gastroesophageal Junction ◽  
Selective Inhibition ◽  
High Amplitude ◽  
Gastric Distension ◽  
Esophageal Body ◽  
Esophageal Sphincter ◽  
Crural Diaphragm

Events associated with gastroesophageal reflux have been determined by concurrent diaphragmatic and esophageal body electromyography, video radiography, and manometry in four conscious dogs. Three characteristic phenomena occurred in parallel immediately before and during gastroesophageal reflux: 1) transient lower esophageal sphincter relaxation, 2) profound (99.5%) and selective inhibition of crural diaphragmatic activity, and 3) a previously unrecognized dorsal movement of the gastroesophageal junction (mean 1.3 cm) demonstrated by implanted radiological markers. The patterns associated with spontaneous acid and gas reflux were indistinguishable from those induced by gastric distension. Costolumbar diaphragmatic activity was stable up until the instant of sphincter opening, when there was a single costolumbar contraction of short duration and high amplitude. Esophageal shortening did not occur before reflux. Reflux that occurred after atropine-induced inhibition of lower esophageal sphincter tone to < 2 mmHg was intermittent and coincided with selective crural inhibition. These studies demonstrated that selective crural inhibition is a prerequisite for gastroesophageal reflux and suggest that the crural diaphragm is an important factor for the maintenance of gastroesophageal competence.

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