1. Volume 114, Issue 4, Pages 724-736 (April 1998)
Interstitial cells of Cajal direct normal propulsive contractile activity in the mouse small intestine 
Tara Der–Silaphet, John Malysz, Sheila Hagel, A.Larry Arsenault, Jan D. Huizinga 
Gastroenterology 
Volume 114, Issue 4, Pages (April 1998)
DOI: /S (98)
Copyright © 1998 American Gastroenterological Association Terms and Conditions

2. Fig. 1
Peristalsis in a control +/+ mouse. On receiving barium contrast fluid, the small intestine displays focal luminal constrictions that propagate aborally at 47 waves per minute. The focal constrictions are caused by ring contractions of circular muscle. The figure shows 8 digitized frames from a video recording selected at 0.3-second intervals (left to right, top to bottom). One wave of contraction can be followed by the arrowheads. This contraction wave propagates at a velocity of 1.2 cm/s. Black arrow indicates position of the pyloric sphincter; white arrows indicate direction of propagation of a relaxed segment (bar = 1 cm). Note that several propagating waves of focal constriction can be identified at any point in time. White asterisk indicates position of stomach.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

3. Fig. 2
Movement of contents in a control +/+ mouse. Frame 0 indicates the start of a video recording of transit of barium contrast fluid through the proximal small intestine. Thirty seconds earlier, the mouse was given 0.5 mL of contrast fluid by gavage into the stomach (white asterisk) and placed in a restraining cage under the radiograph machine. The mouse had been accustomed to the cage (see Materials and Methods). Numbering of frames indicates the number of minutes elapsed after frame 0. Black arrow indicates position of the pyloric sphincter. Peristaltic activity started immediately (see Figure 1). White arrow indicates direction of content movement. At 2 minutes, 94 contraction waves had moved most of the contents out of the proximal 6 cm of the intestine. Dotted line indicates position of the empty proximal small intestine. At 3 minutes, the stomach continued to show normal peristaltic activity, but little contrast fluid can be seen in the proximal intestine. The column of contrast fluid moved steadily in an aboral direction and began to reach the cecum/colon area after 10 minutes (arrowhead). Note that the majority of contrast fluid remains in the distal small intestine; not much progression of contrast fluid into the colon can be seen at 20 minutes (bar = 1 cm).
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

4. Fig. 3
Electrical activities in a +/+ mouse are synchronized and propagate. Top left panel shows three simultaneous recordings of electrical activity from the first 6 cm of small intestine, measured in vitro with extracellular electrodes from a flat piece of tissue (top trace, most proximal). In this experiment, the distance between suction electrodes was 6 mm. Spontaneous slow wave activity with superimposed action potentials appeared synchronized, with an apparent propagation velocity of The frequency of slow waves was uniform at 44 cycles/min. Note that waxing and waning of the slow wave amplitudes can be seen in top tracing. Boxed area shows an enlarged view of electrical activity taken from the same recording (1 minute later at an increased chart speed) and shows apparent propagation of slow waves. The propagation velocity and frequency are similar to those of the contraction waves shown in Figure 1. In addition, the intrinsic frequencies were determined. Right panel shows representative intracellular recordings from 3 × 3–mm pieces of tissue taken at 0.5 and 6 cm distal to the pylorus. The proximal site (top trace) shows slow wave activity at 48 cycles/min; the distal site (bottom trace) shows slow wave activity at 35 cycles/min.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

5. Fig. 4
Slow waves are associated 1:1 with intraluminal pressure changes. Simultaneous recordings were performed on intact 6-cm tubes of small intestine, with long flexible extracellular electrodes and corresponding intraluminal pressure recorders placed directly beneath each electrode. (A) Slow wave activity with superimposed action potentials (top trace) always caused distinct transient increases in intraluminal pressure (bottom trace). (B) Simultaneous recordings of synchronized slow wave activity (top 3 traces) and the associated intraluminal pressure increases (bottom 3 traces). The frequency and propagation characteristics of slow waves with superimposed action potentials and intraluminal pressure increases were always identical.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

6. Fig. 4
Slow waves are associated 1:1 with intraluminal pressure changes. Simultaneous recordings were performed on intact 6-cm tubes of small intestine, with long flexible extracellular electrodes and corresponding intraluminal pressure recorders placed directly beneath each electrode. (A) Slow wave activity with superimposed action potentials (top trace) always caused distinct transient increases in intraluminal pressure (bottom trace). (B) Simultaneous recordings of synchronized slow wave activity (top 3 traces) and the associated intraluminal pressure increases (bottom 3 traces). The frequency and propagation characteristics of slow waves with superimposed action potentials and intraluminal pressure increases were always identical.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

7. Fig. 5
Relationship between intensity of action potential generation superimposed on slow waves, the force of a pressure wave, and outflow in control (+/+) mice. (A) Recording shows a typical example of intermittent occurrence of action potentials. The segment was distended by setting the intraluminal pressure at 4 cm H2O. Outflow (■) occurred only with sufficient generation of action potentials (top trace) and, consequently, sufficient amplitude of intraluminal pressure waves (bottom trace). (B) Average values from 7 different experiments are depicted in the graph. The maximum amplitude of the pressure waves observed with 3 or 4 action potentials was taken as 100% for each experiment.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

8. Fig. 6
Movement of contents in a W/Wv mouse. Frame 0 indicates the start of a video recording of transit of barium contrast fluid through the proximal small intestine. Thirty seconds earlier, the mouse was given 0.5 mL of contrast fluid by injection into the stomach (white asterisk) and placed in a restraining cage under the radiograph machine. The numbering of the frames indicates the number of minutes elapsed after frame 0. White arrow indicates the direction of content movement. Peristaltic contractions of the stomach and stomach emptying started immediately, as in controls (Figure 2). Vigorous contractile activity in the small intestine followed. The contractions appeared to occur randomly. Within the first minute, the proximal small intestine was relaxed, allowing for quick filling. Thereafter, contents moved back and forth over short distances because of apparently random contractile activity. Back-flow into the stomach occurred frequently. Note that the proximal small intestine still contains barium sulfate solution even at 20 minutes and that this same area is empty after only 3 minutes in control mice (see Figure 2). The proximal intestine remained filled with fluid up to at least 45 minutes, when the recording was stopped. Unlike controls, barium contrast fluid never reached the colon within 45 minutes. Black arrow indicates position of pyloric sphincter (bar = 1 cm).
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

9. Fig. 7
Back-flow into the stomach (white asterisk) in a W/Wv mouse. Four frames were digitized at time intervals of 0.3 seconds. The arrowhead indicates a stationary constriction, which lasted for several minutes. White arrows indicate the direction of flow (from left to right) of intraluminal contents. Contractions in the small intestine, proximal to the constriction (arrowheads) caused backflow into the stomach (bar = 1 cm).
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

10. Fig. 8
Action potentials in the W/Wv mouse small intestine appear largely independent. Left panel shows 3 simultaneous extracellular recordings of electrical activity from the first 6 cm of small intestine (top trace, most proximal), measured in vitro from a flat piece of tissue. The distance between the individual monopolar suction electrodes was 7.5 mm. Action potentials appeared to be independent at the 3 recording sites, and no consistent and regular propagation can be identified. Note, however, that for a short period, electrical activity appears to propagate in the bottom 2 traces (enlarged in boxed area). Also note that propagation is periodic and that propagation velocities are changing over time. Right panel shows intracellular recordings at 0.5 and 6 cm from the pylorus.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

11. Fig. 9
Apparent propagation of action potentials in a W/Wv mouse. The frequency of action potentials can be similar at different sites over 1 or 2 cm. Electrodes were placed 0.5 cm apart, and 1–2-minute sections of synchronized action potentials were observed. Note the variability in the direction of propagation of action potentials, indicating limited synchronization.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

12. Fig. 10
Individual action potentials are associated with transient intraluminal pressure increases in the W/Wv mouse. Simultaneous recordings were carried out on intact 6-cm tubes of small intestine, with 3 long flexible extracellular electrodes and 3 corresponding intraluminal pressure ports placed underneath each electrode. The distance between recording sites was 1 cm. Electrical activities (top 3 traces) appeared synchronized only at irregular intervals, and no consistent pattern of propagation of waves of intraluminal pressure (bottom 3 traces) could be identified. However, in an irregular manner, propagating waves of intraluminal pressure did occur and were related to propagating action potentials.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

13. Fig. 11
Reconstitution with bone marrow does not lead to appearance of ICC. (A) Narrow gaps can be observed (arrows) between the longitudinal muscle layer (LM) and the circular muscle layer (CM) in reconstituted mice, which show an abundance of mast cells in the mucosa (not shown) and even in the submucosa (Ma). The space between the muscle layers is normally occupied by cell bodies and/or processes of ICC, which are absent here. N, small nerve bundle of Auerbach's plexus (bar = 2 μm). (B) In a different section, a tertiary nerve bundle (N) is observed, which in control (+/+) mice invariably will have one of the ICC associated with it. Reconstitution did not lead to appearance of ICC in the Auerbach's plexus area (bar = 1 μm).
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

14. Fig. 11
Reconstitution with bone marrow does not lead to appearance of ICC. (A) Narrow gaps can be observed (arrows) between the longitudinal muscle layer (LM) and the circular muscle layer (CM) in reconstituted mice, which show an abundance of mast cells in the mucosa (not shown) and even in the submucosa (Ma). The space between the muscle layers is normally occupied by cell bodies and/or processes of ICC, which are absent here. N, small nerve bundle of Auerbach's plexus (bar = 2 μm). (B) In a different section, a tertiary nerve bundle (N) is observed, which in control (+/+) mice invariably will have one of the ICC associated with it. Reconstitution did not lead to appearance of ICC in the Auerbach's plexus area (bar = 1 μm).
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions

15. Fig. 12
Electrical activity in the reconstituted W/Wv mouse consisted of smooth muscle–type action potentials occurring in bursts, which was abolished by the addition of the L-type calcium channel blocker nifedipine. No slow wave activity was recorded.
Gastroenterology  , DOI: ( /S (98) )
Copyright © 1998 American Gastroenterological Association Terms and Conditions