Motility of the small intestine: a look ahead

1985 ◽  
Vol 248 (5) ◽  
pp. G495-G500 ◽  
Author(s):  
J. R. Mathias ◽  
C. A. Sninsky
Keyword(s):  
Small Intestine ◽  
Action Potential ◽  
Muscle Layer ◽  
Control Mechanisms ◽  
Muscularis Mucosa ◽  
Longitudinal Muscle Layer ◽  
Look Ahead ◽  
Health And Disease ◽  
And Function ◽  
Contraction And Relaxation

Motility of the gastrointestinal tract has become an important discipline of gastroenterology. In this paper we review important observations made during the early development of this discipline, note the current level of knowledge, and look ahead to some of the questions we believe will be addressed in the near future. Is the slow wave the action potential equivalent of the longitudinal muscle layer? How does the migrating action potential complex interrelate with the migrating myoelectric complex--are they two separate complexes under different control mechanisms? How do the myenteric plexus neurons relate to these complexes? Does the muscularis mucosa control the contraction and relaxation of the villous tips? Is there a finite area in the small intestine that can function as the pacemaker? How important are substances within the lumen in controlling motility? Finally, we emphasize the importance of structure and function of the plexus neurons in motility studies. We also stress the importance of collaboration and a multidisciplinary approach for future understanding of the mechanisms of the small intestine in health and disease.

Separation of enkephalin-degrading enzymes from longitudinal muscle layer of bovine small intestine

1985 ◽  
Vol 34 (17) ◽  
pp. 3179-3183 ◽  
Author(s):  
Tadahiko Hazato ◽  
Mariko Shimamura ◽  
Ryoichi Kase ◽  
Mikio Iijima ◽  
Takashi Katayama
Keyword(s):  
Small Intestine ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Longitudinal Muscle Layer ◽  
Degrading Enzymes ◽  
Bovine Small Intestine

Responses of muscles of cat small intestine to autonomic nerve stimulation

1963 ◽  
Vol 204 (2) ◽  
pp. 352-358 ◽  
Author(s):  
Gordon L. Van Harn
Keyword(s):  
Small Intestine ◽  
Muscle Contraction ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Intraluminal Pressure ◽  
Sympathetic Nerve Stimulation ◽  
Longitudinal Muscle Layer

The externally recorded slow waves from the cat small intestine originate in the longitudinal muscle layer. In vitro the slow waves are recorded from all layers of the intestine if the segment is not immersed in a saline bath. When the longitudinal layer is removed from one region, the magnitude of the slow-wave potential in the other intestinal layers decreases as the distance from the intact longitudinal muscle layer is increased. An active intestine, in vivo, responds to sympathetic nerve stimulation by a hyperpolarization, cessation of spikes, and inhibition of muscle contraction. During inactivity of the intestine, either vagus or sympathetic nerve stimulation results in a depolarization, initiation of spikes, and muscle contraction. The nature of the response is influenced by the frequency of nerve stimulation and by the level of activity of the intestinal muscle, which is altered by intraluminal pressure changes. The effect of drugs on the response of the intestine to vagal and sympathetic nerve stimulation is such as to indicate that both inhibitory and excitatory nerve fibers are present in each of the autonomic nerves. The duration of the latent period of the response is long and highly variable, and a response requires 50–100 nerve volleys.

Proteolytic Inactivation of Substance P and Neurokinin A in the Longitudinal Muscle Layer of Guinea Pig Small Intestine

2006 ◽  
Vol 47 (3) ◽  
pp. 856-864 ◽  
Author(s):  
R. Nau ◽  
G. Schäfer ◽  
C. F. Deacon ◽  
T. Cole ◽  
D. V. Agoston ◽  
...  
Keyword(s):  
Small Intestine ◽  
Substance P ◽  
Guinea Pig ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Neurokinin A ◽  
Longitudinal Muscle Layer

scholarly journals MORPHOLOGICAL CHANGES IN THE MUSCLE LAYERS OF SMALL INTESTINE IN THE SHORT BOWEL SYNDROME IN EXPERIMENT

2019 ◽  
Vol 23 (4) ◽  
pp. 176-180
Author(s):  
R. R. Khasanov ◽  
D. Svoboda ◽  
M. Kohl ◽  
Aytbai А. Gumerov ◽  
V. S. Vagapova ◽  
...  
Keyword(s):  
Small Intestine ◽  
Short Bowel Syndrome ◽  
Morphological Changes ◽  
Intestinal Adaptation ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Control Group ◽  
Longitudinal Muscle Layer ◽  
Short Bowel ◽  
Intestinal Functions

Introduction. Patients with the short bowel syndrome often have intestinal dilatation which impairs intestinal functions. Changes in the muscle intestinal layers, which cause this condition, are not studied well yet. Purpose. To study the role of small intestine muscle layers in the intestinal adaptation and dilatation in the short bowel syndrome. Materials and methods. 22 rats were taken into the experimental trial; short bowel syndrome was modelled in 12 of them; 10 other rats which had only laparotomy were in the control group. The diameter and thickness of muscle layers in the small intestine and ileum were studied. Results. In the short bowel syndrome, one can observe a significant dilatation of the small intestine and ileum. Thickness of longitudinal and circular layers of the small intestine was significantly larger in rats with the short bowel syndrome in comparison to the control group. In the ileum, only the circular muscle layer was hypertrophied; there was no difference in the thickness of longitudinal muscle layer in rats with the short bowel syndrome and in rats from the control group. Conclusion. In rats with the short bowel syndrome, morphological changes occur not only in the mucous layer, but also in muscle layers of the small intestine what is manifested by the intestinal dilatation and hypertrophy of muscle layers. These changes are results of intestinal adaptation and are pathophysiological for the short bowel syndrome.

scholarly journals The effect of pectin on the structure and function of the rat small intestine

1979 ◽  
Vol 42 (3) ◽  
pp. 357-365 ◽  
Author(s):  
R. C. Brown ◽  
J. Kelleher ◽  
M. S. Losowsky
Keyword(s):  
Small Intestine ◽  
Small Bowel ◽  
Specific Activity ◽  
Basal Diet ◽  
Muscle Layer ◽  
Glucose Absorption ◽  
Structure And Function ◽  
Rat Small Intestine ◽  
And Function

1. The effect of pectin on the structure and function of the rat small intestine was compared with that of a standard pellet diet and of a fibre-free basal diet.2. The length and wet weight of the small bowel was significantly greater inpect in-fed rats than in either pellet- or basal-diet-fed rats.3. Histological measurements of longitudinal sections from the small bowel showed a significantly greater crypt depth and muscle layer thickness in the mid-jejunum and ileum of the pectin fed rats. Villous height showed less variation.4. The specific activity of alkaline phosphatase (EC 3.1.3.1)and leucyl-P-naphthylamidase (EC 3.4.11.1) in mucosal scrapings was significantly lower in the upper jejunum of pectin-fed rats compared with either of the other dietary groups. The differences were not so marked in mid-jejunum or ileum.5. Glucose absorption measured in vivo from jejunal and ileal loops was similar in all three dietary groups.6. With two minor exceptions there were no significant differences in any of these measurements between the pellet- and basal-diet-fed rats.7. These findings could be explained by increased epithelial cell turnover caused by pectin. The possible mechanisms of this are discussed.8. The effect of pectin on the human small bowel requires study before it can be widely prescribed in man.

Transmission of electrical activity through the gastroduodenal junction

1965 ◽  
Vol 208 (3) ◽  
pp. 531-536 ◽  
Author(s):  
Alex Bortoff ◽  
Noah Weg
Keyword(s):  
Small Intestine ◽  
Electrical Activity ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Pyloric Antrum ◽  
Longitudinal Muscle Layer ◽  
Proximal Duodenum ◽  
Electrical And Mechanical Activities ◽  
Electrode Technique

The electrical and mechanical activities of the gastroduodenal junction were studied in isolated cat preparations, using the pressure-electrode technique. The spontaneous electrical activity of the pyloric antrum consists of periodic depolarizations, the configuration of which is somewhat more complex than that of comparable potentials recorded from the longitudinal muscle layer of the small intestine. Like their intestinal counterparts these antral slow waves may be associated with spike potentials which are thought to initiate contractions. The electrical activity at the gastroduodenal junction consists of a combination of antral and duodenal slow waves, sometimes accompanied by spike potentials. In the proximal duodenum, antral slow waves are represented by periodic depolarizations which may be associated with spike potentials followed by contractions. Because of the extension of the antral slow waves into the proximal duodenum, contractions initiated in the antrum may also extend into the proximal duodenum. It is concluded that the gastroduodenal junction is a transition zone, coordinating the electrical and corresponding mechanical activities of the antrum and proximal duodenum.

scholarly journals Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease

2016 ◽  
Vol 311 (3) ◽  
pp. G431-G443 ◽  
Author(s):  
Ravinder K. Mittal
Keyword(s):  
Longitudinal Muscle ◽  
Muscularis Propria ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Motor Disorders ◽  
Longitudinal Muscle Layer ◽  
Peristaltic Reflex ◽  
Strong Contraction ◽  
Health And Disease ◽  
Entire Gastrointestinal Tract

Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed contract and relax together in almost perfect synchrony during ascending contraction and descending relaxation of the peristaltic reflex, respectively. Studies in patients with various types of esophageal motor disorders reveal temporal disassociation between the circular and longitudinal muscle layers. We suggest that the discoordination between the two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain. Certain pathologies may selectively target one and not the other muscle layer, e.g., in eosinophilic esophagitis there is a selective dysfunction of the longitudinal muscle layer. In achalasia esophagus, swallows are accompanied by the strong contraction of the longitudinal muscle without circular muscle contraction. The possibility that the discoordination between two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain are discussed. The purpose of this review is to summarize the regulation and dysregulation of peristalsis by the coordinated and discoordinated function of circular and longitudinal muscle layers in health and diseased states.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

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