Synchrony between circular and longitudinal muscle contractions during peristalsis in normal subjects

Division of Gastroenterology, University of California, and San Diego Veterans Affairs Medical Center, San Diego, CA 92161, USA.
AJP Gastrointestinal and Liver Physiology (Impact Factor: 3.8). 04/2006; 290(3):G431-8. DOI: 10.1152/ajpgi.00237.2005
Source: PubMed


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.

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Available from: Valmik Bhargava, Dec 11, 2015
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    • "Esophageal pressure (due to circular muscle contraction) in the contracted segment is distributed in the form of a bell shaped curve, with peak pressure in the middle. Simultaneous US imaging and manometry shows that longitudinal muscle also contracts in a fashion identical to the circular muscle, i.e., the 2 contract synchronously, peak of 2 muscle contraction occur within 1 second of each other.10 Secondary peristalsis or esophageal propulsive force induced by distension of a balloon in the esophagus also induces contraction and relaxation of the 2 muscle layers synchronously, above and below the site of distension respectively.11 "
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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.
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    • "We observed similar physiological responses and pharmacological sensitivity of esophageal muscles from longitudinal and from circular layers of the EB. This similarity supports the notion advanced by Mittal et al. (2006) that both muscle layers of esophagus contract in a coordinated fashion during peristalsis. "
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