Simultaneous reflex inhibition of lower esophageal sphincter and crural diaphragm in cats

1985 ◽  
Vol 249 (5) ◽  
pp. G586-G591 ◽  
Author(s):  
S. M. Altschuler ◽  
J. T. Boyle ◽  
T. E. Nixon ◽  
A. I. Pack ◽  
S. Cohen
Keyword(s):  
Lower Esophageal Sphincter ◽  
Gastroesophageal Junction ◽  
Pressure Profile ◽  
Gastric Fundus ◽  
Intraluminal Pressure ◽  
Neural Pathways ◽  
Balloon Distension ◽  
Esophageal Sphincter ◽  
Crural Diaphragm ◽  
High Pressure Zone

We have previously suggested that both the lower esophageal sphincter and diaphragm contribute to the high-pressure zone (HPZ) at the gastroesophageal junction. The purpose of this study in anesthetized cats was to compare changes in diaphragmatic electrical activity with changes in the intraluminal pressure profile in the HPZ following either balloon distension of the esophagus or swallowing evoked by pharyngeal stimulation. Intraluminal pressure was continuously recorded by a perfused manometric assembly anchored to the gastric fundus through an abdominal surgical approach. Integrated EMG was simultaneously measured in the costal and crural parts of the diaphragm. Our results indicate that simultaneous relaxation of the lower esophageal sphincter (LES) and crural diaphragm follows both swallowing and balloon distension of the esophagus; during swallowing both inhibitory reflexes depend on the initiation of esophageal peristalsis; crural relaxation abolishes respiratory-induced pressure oscillations in the HPZ during LES relaxation; ventilation is maintained during relaxation of the HPZ in part by continued contraction of the costal diaphragm; and different neural pathways control LES relaxation and crural relaxation. The data support the view that the crural diaphragm augments the intrinsic smooth muscle sphincter mechanism at the gastroesophageal junction and that crural relaxation may be an important factor in mouth-to-gastric transit.

Effect of lower esophageal sphincter tone and crural diaphragm contraction on distensibility of the gastroesophageal junction in humans

2004 ◽  
Vol 287 (4) ◽  
pp. G815-G821 ◽  
Author(s):  
Reza Shaker ◽  
Eytan Bardan ◽  
Chengming Gu ◽  
Benson T. Massey ◽  
Thomas Sanders ◽  
...  
Keyword(s):  
Lower Esophageal Sphincter ◽  
Gastroesophageal Junction ◽  
Elastic Tissue ◽  
Tissue Properties ◽  
Normal Breathing ◽  
Balloon Distension ◽  
Volume Increment ◽  
Esophageal Sphincter ◽  
Crural Diaphragm ◽  
Maximum Inspiration

Previous studies of distensibility of the gastroesophageal junction (GEJ) in humans have not tried to distinguish between the effects of muscle action and passive elastic tissue properties of the GEJ. We studied 15 healthy subjects (ages 23–67 yr, 11 men/4 women) by using a catheter with a highly complaint bag positioned manometrically at the GEJ. The bag was distended with air at a rate of 20 ml/min while intrabag pressure was recorded. Distensions were performed during normal breathing, with breath held at maximum inspiration (MI) to activate the diaphragmatic crura, and with midesophageal balloon distension (BD) to relax the lower esophageal sphincter. In 10 subjects, distensions were performed after atropine injection (12 μg/kg iv). Pressure-volume curves and incremental distensibility values were calculated and compared among the different conditions. Both MI and BD significantly altered the slopes of the pressure-volume curves, whereas no effect was seen with atropine. Maximum distensibility was seen at the volume increment of 5–10 ml and was reduced with larger volumes. Distensibility measurements for the various test conditions tended to converge at the largest volume increment, suggesting that distensibility at this degree of distension was more related to the passive elastic properties of the GEJ. On the basis of these findings, we conclude that there can be significant active muscular contributions to recordings of distensibility at the GEJ, variations that must be controlled for during different study conditions.

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.

Phasic contractions of the muscular components of human esophagus and gastroesophageal junction in vitro

1995 ◽  
Vol 73 (3) ◽  
pp. 356-363 ◽  
Author(s):  
Harold G. Preiksaitis ◽  
Nicholas E. Diamant
Keyword(s):  
Electrical Activity ◽  
Lower Esophageal Sphincter ◽  
Longitudinal Muscle ◽  
Gastroesophageal Junction ◽  
Gastric Fundus ◽  
Slow Waves ◽  
Phasic Activity ◽  
Esophageal Sphincter ◽  
Human Esophagus

This study was performed to assess the repetitive phasic mechanical and (or) electrical activity of the muscle from different regions of the human gastroesophageal junction (GEJ). Muscle strips from the circular and longitudinal layers of the gastric fundus and esophagus and of the clasp and sling components of the GEJ were obtained from surgical specimens and prepared for in vitro recording of contractile or electrical activity. Phasic contractions occurred in all regions except the longitudinal muscle of the gastric fundus and that overlying the sling. Robust phasic activity (2.6 ± 0.6 min−1) was most frequent (92% of specimens) in longitudinal muscle overlying the clasp, arising spontaneously in 67%. Stretch or carbachol stimulation increased the frequency of these contractions. Transmural electrical stimulation produced a transient cessation of phasic activity. Electrical recording showed slow waves with superimposed spiking coinciding with phasic contractions. These activities were unaltered by 1 μM atropine or 1 μM tetrodotoxin, but inhibited by 2 μM verapamil. In conclusion, several muscles of the human esophagus and GEJ manifest repetitive contractions in vitro, particularly the longitudinal muscle overlying the clasp muscle fibers. These oscillations are due to electrical slow waves, can potentially be modulated by intrinsic nerves, and may play a role in the intermittent phasic contractions of lower esophageal sphincter pressure in vivo.Key words: oscillators, myolgenic, cardia, pacemaker, lower esophageal sphincter.

scholarly journals Gastric and lower esophageal sphincter pressures during nausea: a study using visual motion-induced nausea and high-resolution manometry

2014 ◽  
Vol 306 (9) ◽  
pp. G741-G747 ◽  
Author(s):  
Nora Schaub ◽  
Kee Ng ◽  
Paul Kuo ◽  
Qasim Aziz ◽  
Daniel Sifrim
Keyword(s):  
High Resolution ◽  
Lower Esophageal Sphincter ◽  
Visual Motion ◽  
Gastroesophageal Junction ◽  
Gastric Fundus ◽  
Vagal Activity ◽  
High Resolution Manometry ◽  
Esophageal Sphincter ◽  
Configuration Changes ◽  
Motion Video

Nausea is the subjective unpleasant sensation that immediately precedes vomiting. Studies using barostats suggest that gastric fundus and lower esophageal sphincter (LES) relaxation precede vomiting. Unlike barostat, high-resolution manometry allows less invasive, detailed measurements of fundus pressure (FP) and axial movement of the gastroesophageal junction (GEJ). Nausea was induced in 12 healthy volunteers by a motion video and rated on a visual analog scale. FP was measured as the mean value of the five pressure channels that were clearly positioned below the LES. After intubation, a baseline (BL) recording of 15 min was obtained. This was followed by presentation of the motion video (at least 10 min, maximum 20 min) followed by 30 min recovery recording. Throughout the experiment we recorded autonomic nervous system (ANS) parameters [blood pressure, heart rate (HR), and cardiac vagal tone (CVT), which reflects efferent vagal activity]. Ten out of 12 subjects showed a drop in FP during peak nausea compared with BL (−4.0 ± 0.8 mmHg; P = 0.005), and 8/10 subjects showed a drop in LES pressure (−8.8 ± 2.5 mmHg; P = 0.04). Peak nausea preceded peak fundus and LES pressure drop. Nausea was associated with configuration changes at the GEJ such as LES shortening and esophageal lengthening. During nausea we observed a significantly increased HR and decreased CVT. In conclusion, nausea is associated with a drop in fundus and LES pressure, configuration changes at the GEJ as well as changes in the ANS activity such as an increased sympathetic tone (increased HR) and decreased parasympathetic tone (decreased CVT).

scholarly journals Functional morphology of the lower esophageal sphincter and crural diaphragm determined by three-dimensional high-resolution esophago-gastric junction pressure profile and CT imaging

2017 ◽  
Vol 313 (3) ◽  
pp. G212-G219 ◽  
Author(s):  
Ravinder K. Mittal ◽  
Ali Zifan ◽  
Dushyant Kumar ◽  
Melissa Ledgerwood-Lee ◽  
Erika Ruppert ◽  
...  
Keyword(s):  
Ct Scan ◽  
Lower Esophageal Sphincter ◽  
Functional Morphology ◽  
Three Dimensional ◽  
Pressure Profile ◽  
Esophageal Sphincter ◽  
Greater Curvature ◽  
Crural Diaphragm ◽  
Lesser Curvature

The smooth muscles of the lower esophageal sphincter (LES) and skeletal muscles of the crural diaphragm (CD) provide a closure/antireflux barrier mechanism at the esophago-gastric junction (EGJ). A number of questions in regard to the pressure profile of the LES and CD remain unclear, e.g., 1) Why is the LES pressure profile circumferentially asymmetric, 2) Is the crural diaphragm (CD) contraction also circumferentially asymmetric, and 3) Where is the LES and CD pressure profile located in the anatomy of the esophagus and stomach? The three-dimensional (3-D) high-resolution esophageal manometry (HRM) catheter can record a detailed profile of the EGJ pressure; however, it does not allow the determination of the circumferential orientation of individual pressure transducers in vivo. We used computed tomography (CT) scan imaging in combination with 3-D EGJ pressure recordings to determine the functional morphology of the LES and CD and its relationship to the EGJ anatomy. A 3-D-HRM catheter with 96 transducers (12 rings, 7.5 mm apart, located over 9-cm length of the catheter, with eight transducers in each ring, 45° apart (Medtronics), was used to record the EGJ pressure in 10 healthy subjects. A 0.5-mm diameter metal ball (BB) was taped to the catheter, adjacent to transducer 1 of the catheter. The EGJ was recorded under the following conditions: 1) end-expiration (LES pressure) before swallow, after swallow, and after edrophonium hydrochloride; and 2) peak inspiration (crural diaphragm contraction) for tidal inspiration and forced maximal inspiration. A CT scan was performed to localize the circumferential orientation of the BB. The CT scan imaging allowed the determination of the circumferential orientation of the LES and CD pressure profiles. The LES pressure under the three end-expiration conditions were different; however, the shape of the pressure profile was unique with the LES length longer toward the lesser curvature of the stomach as compared with the greater curvature. The pressure profile revealed circular and axial pressure asymmetry, with greatest pressure and shortest cranio-caudal length on the left (close to the angle of His). The CD contraction with tidal and forced inspiration increases pressure in the cranial half of the LES pressure profile, and it was placed horizontally across the recording. The CD, esophagus, and stomach were outlined in the CT scan images to construct a 3-D anatomy of the region; it revealed that the hiatus (CD) is placed obliquely across the esophagus; however, because of the bend of the esophagus to the left at the upper edge of the hiatus, the two were placed at right angle to each other, which resulted in a horizontal pressure profile of the CD on the LES. Our observations suggest a unique shape of the LES, CD, and the anatomical relationship between the two, which provides a possible explanation as to why the LES pressure shows circumferential and axial asymmetry. Our findings have implication for the length and circumferential orientation of myotomy incision required for the ablation of LES pressure in achalasia esophagus.NEW & NOTEWORTHY We used computed tomography scan imaging with three-dimensional esophago-gastric junction (EGJ) pressure recordings to determine functional morphology of the lower esophageal sphincter (LES) and crural diaphragm and its relationship to EGJ anatomy. The LES pressure profile was unique with the LES length longer and pressures lower toward the lesser curvature of the stomach, as compared with the greater curvature. Our findings have implications for the length and circumferential orientation of myotomy incision required for the ablation of LES pressure in the achalasia esophagus.

Responses of feline gastroesophageal junction to changes in abdominal pressure

1987 ◽  
Vol 253 (3) ◽  
pp. G315-G322 ◽  
Author(s):  
J. T. Boyle ◽  
S. M. Altschuler ◽  
T. E. Nixon ◽  
A. I. Pack ◽  
S. Cohen
Keyword(s):  
Gastroesophageal Junction ◽  
Gastric Distension ◽  
Abdominal Pressure ◽  
Electromyographic Activity ◽  
Abdominal Compression ◽  
Balloon Distension ◽  
Gastric Pressure ◽  
High Pressure Zone ◽  
Antireflux Barrier ◽  
Sustained Inhibition

The responses of the lower esophageal sphincter (LES), stomach, and diaphragm and their contribution to changes in the high-pressure zone (HPZ) at the gastroesophageal junction were determined during extrinsic abdominal compression or intragastric balloon distension in anesthetized cats. Abdominal compression consistently induced an increase in intraluminal end-expiratory LES and gastric pressure (P less than 0.01). Changes in LES pressure significantly exceeded the changes in gastric pressure (P less than 0.01). In contrast, the LES response during gastric distension was variable in the group of animals despite a consistent volume-dependent increase in gastric pressure. Mean LES pressure for the group was unchanged, although 33% of individual animals exhibited a decrease in LES pressure during gastric distension. Both abdominal stimuli induced sustained inhibition of crural (P less than 0.01), but not costal, diaphragmatic electromyographic activity. Vagotomy affected the LES but not the gastric or diaphragmatic responses to both stimuli. In the group of animals, the combined effect of the changes in the three measured variables on the HPZ resulted in maintenance of the antireflux barrier during abdominal compression but a significant decrease in the barrier during gastric distension.

Variability of lower esophageal sphincter pressure in the fasted unanesthetized opossum

1985 ◽  
Vol 248 (4) ◽  
pp. G398-G406
Author(s):  
R. H. Holloway ◽  
E. Blank ◽  
I. Takahashi ◽  
W. J. Dodds ◽  
W. J. Hogan ◽  
...  
Keyword(s):  
Phase I ◽  
Lower Esophageal Sphincter ◽  
Gastric Antrum ◽  
Phase Iii ◽  
In Vivo Studies ◽  
Intraluminal Pressure ◽  
Myoelectric Activity ◽  
Sphincter Pressure ◽  
Esophageal Sphincter ◽  
Cyclic Changes

The opossum has served as a useful animal model for in vivo studies of lower esophageal sphincter (LES) function. Previous investigations, however, have been confined to studies on anesthetized animals. In 10 opossums we investigated LES pressure during fasting cycles of the gastrointestinal migrating myoelectric complex (MMC) and examined the influences of anesthesia and feeding on LES pressure. Intraluminal pressure from the esophageal body, LES, and gastric antrum was recorded by a manometric assembly that incorporated a sleeve device. Myoelectric activity was recorded from the gastric antrum and duodenum via implanted electrodes. MMCs were readily recorded from all animals. MMC cycle length was 86 +/- 2.9 (SE) min. The LES exhibited cyclic changes in intraluminal pressure that occurred in synchrony with the gastric MMC cycle. During phase I of the gastric MMC cycle, LES pressure was essentially stable, although intermittent spontaneous oscillations at 3-4/min were sometimes noted. Forceful phasic LES contraction started during phase II of the gastric MMC, became maximal during phase III, and disappeared during phase I. The MMC-related phasic LES contraction occurred at a maximal rate of 1.4 +/- 0.05/min with amplitudes of 60-150 mmHg and were temporally associated with spike bursts and contractions in the gastric antrum. Pentobarbital sodium-induced anesthesia abolished MMC-related phasic LES activity and caused a transient rise in basal sphincter pressure. Phasic LES activity was also inhibited by atropine and feeding.(ABSTRACT TRUNCATED AT 250 WORDS)

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