Synchrony between circular and longitudinal muscle contractions during peristalsis in normal subjects.
ABSTRACT The current understanding is that longitudinal muscle contraction begins before and outlasts circular muscle contraction during esophageal peristalsis in normal subjects. The goal of our study was to reassess the relationship between the contractility of two muscle layers using novel ways to look at the muscle contraction. We studied normal subjects using synchronized high-frequency ultrasound imaging and manometry. Swallow-induced peristalsis was recorded at 5 and 10 cm above the lower esophageal sphincter (LES). Ultrasound (US) images were analyzed for muscle cross-sectional area (CSA) and circularity index of the esophagus during various phases of esophageal contraction. A plot of the M mode US image, muscle CSA, and esophageal circularity index was developed to assess the temporal correlation between various parameters. The muscle CSA wave began before and lasted longer than the contraction pressure wave at both 5 and 10 cm above the LES. M mode US images revealed that the onset of muscle CSA wave was temporally aligned with the onset of lumen collapse. The peak muscle CSA occurred in close proximity with the peak pressure wave. The esophagus started to become more circular (decrease in circularity index) with the onset of the muscle CSA wave. The circularity index and muscle CSA returned to the baseline at approximately the same time. In conclusion, the onset of lumen collapse and return of circularity index of the esophagus are likely to be the true markers of the onset and end of circular muscle contraction. Circular and longitudinal muscle layers of the esophagus contract in a precise synchronous fashion during peristalsis in normal subjects.
- SourceAvailable from: Barry Philip Mcmahon[Show abstract] [Hide abstract]
ABSTRACT: The oesophagus serves to transport food and fluid from the pharynx to the stomach. Oesophageal function is usually evaluated by means of manometry which is a proxy of the force in the radial direction. However, force measurements in the axial direction will provide a better measure of oesophageal transport function. The aim of this study was to develop a probe based on electrical impedance measurements to quantify the axial force generated by oesophageal contractions, i.e. probe elongation was associated with the axial force. Calibration with weights up to 200 g was done. The dispersion, creep, temperature and bending dependence were studied at the bench. Subsequently, the probe was tested in vivo in a healthy human volunteer. The probe showed good reproducibility and the dispersion was <0.04. Some dependence on temperature, creep and bending was found. Interpolation of the calibration curves made it possible to compensate for temperature fluctuations. The maximum deviation was 6.1 +/- 3.7% at loads of 50 g. The influence of creep showed a maximum net creep of 6.1 g after 8 s. The swallowed bolus size correlated with the axial force measurements (P = 0.038) but not with manometric measurements. In conclusion, the new technique measures axial force in the oesophagus and may in the future provide valuable information about oesophageal function.Physiological Measurement 03/2008; 29(3):389-99. · 1.50 Impact Factor
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ABSTRACT: Muscularis propria of the esophagus is organized into circular and longitudinal muscle layers. Goal of this review is to summarize the role of longitudinal muscle in physiology and pathophysiology of esophageal sensory and motor function. Simultaneous manometry and ultrasound imaging that measure circular and longitudinal muscle contraction respectively reveal that during peristalsis 2 layers of the esophagus contract in perfect synchrony. On the other hand, during transient relaxation of the lower esophageal sphincter (LES), longitudinal muscle contracts independently of circular muscle. Recent studies provide novel insights, i.e., longitudinal muscle contraction of the esophagus induces LES relaxation and possibly descending relaxation of the esophagus. In achalasia esophagus and other motility disorders there is discoordination between the 2 muscle layers. Longitudinal muscle contraction patterns are different in the recently described three types of achalasia identified by high-resolution manometry. Robust contraction of the longitudinal muscle in type II achalasia causes pan-esophageal pressurization and is the mechanism of whatever little esophageal emptying that take place in the absence of peristalsis and impaired LES relaxation. It may be that preserved longitudinal muscle contraction is also the reason for superior outcome to medical/surgical therapy in type II achalasia esophagus. Prolonged contractions of longitudinal muscles of the esophagus is a possible mechanism of heartburn and "angina like" pain seen in esophageal motility disorders and possibly achalasia esophagus. Novel techniques to record longitudinal muscle contraction are on the horizon. Neuro-pharmacologic control of circular and longitudinal muscles is different, which provides an important opportunity for the development of novel pharmacological therapies to treat sensory and motor disorders of the esophagus.Journal of neurogastroenterology and motility 04/2013; 19(2):126-36.
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ABSTRACT: Current understanding is that swallow induces simultaneous inhibition of the entire esophagus followed by a sequential wave of contraction (peristalsis). We observed a pattern of luminal distension preceding contraction which suggested that inhibition may also traverses in a peristaltic fashion. Our aim is to determine the relationship between contraction and luminal distension during bolus transport. Eight subjects using two solid-state pressure and two ultrasound (US) transducers were studied. Synchronous pressure and US images were obtained with wet swallows and after edrophonium and atropine. Luminal cross-sectional area (CSA) at 2 cm and 12 cm above the lower esophageal sphincter (LES) were recorded. Relationship between pressure and CSA at each site, propagation velocity of peak pressure and peak distension waves were determined. Fluoroscopy coupled with manometry was also performed in five normal subjects. Esophageal distension precedes contraction wave at both-recorded sites. During distension, esophageal pressure remains constant while luminal CSA increases significantly. The onset and the peak of distension wave traverses in a peristaltic fashion between both sites. A tight coupling exists between the peak distension and peak contraction waves with similar velocities (3.7 cm s(-1) and 3.6 cm s(-1)) of propagation. The degree of distension is greater at 2 cm compared to 12 cm. Atropine and edrophonium reduced and increased the contraction pressure respectively, without affecting the distension wave. Fluoroscopic study confirmed that the wave of distension traverses the esophagus in a peristaltic fashion. Distension and contraction waves are tightly coupled to each other and both traverse in a peristaltic fashion.Neurogastroenterology and Motility 11/2010; 23(3):201-7, e110. · 2.94 Impact Factor