Propagation velocities and frequencies of contractions along canine small intestine

Abstract

This study was performed to clarify in detail the behavior of the propagation velocities and frequencies of contractions along the canine small intestine. In conscious dogs, duodenal, jejunal, and ileal contractions were recorded by multiple, closely spaced strain gauges and analyzed by a computerized method. During both the interdigestive and postprandial states, the propagation velocity increased from the duodenal bulb to the distal duodenum and declined aborally within the jejunum, reaching rather constant values in the ileum. The decrease was steepest in the proximal part of the jejunum. In contrast to the propagation velocities, the contraction frequencies were almost constant in the upper small intestine. In the ileum, the contraction frequencies were markedly lower than in the upper small intestine, indicating that the aboral decrease in frequency occurred in the distal parts of the jejunum. We conclude that both the propagation velocities and the frequencies of contractions decline aborally in a nonlinear fashion. However, the nonlinear patterns of the frequency and the propagation velocity gradients are different.

Quantitative analysis of peristaltic and segmental motion in vivo in the rat small intestine using dynamic MRI

“…The frequency and period of these peristaltic waves correlates well with the frequency of the short length propagating slow wave activity of the interstitial cells of Cajal. A number of studies have pointed out that the maximum frequency of the peristaltic motility is determined by the frequency of electrical spikes generated by interstitial cells of Cajal and have reported the maximum frequency in the jejunum regions of different animal models, such as dogs (17 cycles/min) (41) and pigs (15 cycles/min) (42) It should also be noted that the in vivo experiments carried out by Ferens et al (11) have described propagating contractions occurring in clusters at very low frequencies of 2.28 ± 0.04 min −1 . These very low frequencies were not detected from the MRI data in the current study and are probably masked by low‐frequency modulations in the data; caused by, for example, uncorrected respiration effects and inaccuracies in the segmentation.…”

Evaluation of computerized analysis of the propagation of human duodenojejunal contractions

“…Is it possible to derive useful information relating to propagation using transducers which are not positioned with the optimum spacings described by Seigle et a1.? 16 The model of propagation used illustrates the problem; showing that for a spacing of 150 mm, with contractions propagating at a rate of 15 mm sec-', all are correctly identified with a time lag of 10 sec between sites; however, there are also additional events detected as propagated which are seen as multiples of the slow wave periodicity on either side of the main peak. Clearly the magnitude of these sub-peaks will reduce the overall specificity of the technique if a recognition window is used which encompasses them.…”

Introduction. Motility of small intestine: a case for pattern recognition

“…In digestive motility, the distances between the registration points in the gut have to be so short that a contraction at the next aboral registration point occurs before the start of the following contraction at the oral registration point. To achieve these requirements, the distance between the registration points has to be adapted to the frequency and propagation velocity of the contraction waves in the bowel segment studied [6]. In the proximal small intestine, the duration of a contraction is maximally 5 s, and the propagation velocity of a single contraction is about 2 cm s-'.…”