Name: Video: Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice
Uploaded: 2016-02-03T15:00:00.000+00:00
Duration: 7 min 41 s
Description: 13.9K Views. The University of Melbourne. This article describes a video imaging technique and high-resolution spatiotemporal mapping to identify changes in the neural regulation of colonic motility in adult mice. Subtle effects on gastrointestinal (GI) function can be detected using this approach in isolated tissue preparations to advance our understanding of GI disease.

JCB and ELH-Y were supported by the US Department of Defense CDMRP Autism Research Program (AR11034). NHMRC (1047674) to ELH-Y.The May Stewart Bursary-University of Melbourne trust funded scholarship to MS. We thank Ali Taher, F&#225;tima Ramalhosa and Gracia Seger for technical contributions.

Animal handling and cervical dislocation of animals prior to all experiments were performed strictly according to protocols approved by the Animal Experimentation Committee for the University of Melbourne (Ethics ID: 1212494.7)
1. Tissue Collection and Dissection
<ol>
	<li>Euthanize adult mice by cervical dislocation. If possible avoid anesthesia to prevent influences on gut function via receptors located on neuronal populations of interest.</li>
	<li>Record the animal&#39;s total body weight, pin the body (via the four paws, ventral side exposed to experimenter) firmly to a dissection board using hypodermic needles (Size: 20 G).</li>
	<li>Using dissecting forceps and scissors; make an incision through the epidermis overlaying the lower abdominal muscle layers. Continue to use the forceps and scissors to open the abdominal cavity along the midline of the abdomen to the sternum.</li>
	<li>To prevent the tissue dehydrating, pour physiological saline (Krebs solution: 118 NaCl, 4.6 KCl, 2.5 CaCl2, 1.2 MgSO4, 1 NaH2PO4, 25 NaHCO3, 11 D-glucose in mM - bubbled at RT with carbogen gas; 95% O2 and 5% CO2 for a minimum of 20 min) onto abdominal contents at regular intervals (i.e., every 30-60 sec) during the dissection process.</li>
	<li>To isolate the colon while attached to the cecum and rectum, hold the cecum (located adjacent to the proximal end of colon) gently using dissecting forceps approximately 4-5 cm above the body of the animal while trimming the mesentery using fine dissection scissors.</li>
	<li>Take care not to handle, stretch or cut the gastrointestinal tissue while removing the adjoining mesentery.</li>
	<li>Remove excess tissue (i.e., urinary bladder and testes). Using coarse dissecting scissors, make two vertical incisions (i.e.,&#160;approximately 0.5 cm from the midline) to cut the pelvic bone on each side of the colon.</li>
	<li>Use fine scissors to separate the rectum from adjoining pelvic tissue and trim surrounding muscle from the colon.</li>
	<li>Place the full-length colon (from cecum to rectum) into a beaker containing physiological saline (previously oxygenated with carbogen) and continue to oxygenate at RT. Remove the caecum and rectum using fine dissecting scissors and replace in beaker.</li>
	<li>Empty fecal pellets/intestinal content from colonic preparations by applying gentle positive pressure at the oral end using a 5 ml syringe attached to a 200 &#181;l pipette tip filled with physiological saline. In order to orientate the tissue in future, use an insect pin to mark the most proximal end of the colon, where striations in the mucosa are visible.
	<ol>
		<li>Modify the plastic pipette tip to fit the 5 ml syringe by removing approximately 1 cm of the widest/proximal end using a razor blade. To increase the flow rate, widen the distal/smaller end by cutting on an angle (approximately 45 &#176;C) using a razor blade.</li>
	</ol>
	</li>
	<li>Grip the colon tissue gently at its proximal end with dissecting forceps, insert the pipette tip into the lumen of the colon and flush physiological saline through the lumen.</li>
</ol>
2. Preparation of Colonic Tissue and Experimental Set Up for Video Imaging
<ol>
	<li>Flush physiological saline through all tubing attached to a two chambered organ bath set up (Figure 1 and Figure 3), using a syringe attached to a 200 &#181;l pipette tip. This step removes any debris within the tubing that could block the flow of solution. For tubing specifications refer to the materials table.</li>
	<li>Ensure that the chambers of the organ bath are continuously superfused with physiological saline bubbled with carbogen (95% O2 and 5% CO2, flow rate of 5 ml min-1). Using a temperature probe at regular intervals, ensure that the temperature of the bath is maintained between 33 &#176;C -37 &#176;C.</li>
	<li>Fill the inflow reservoir connected via a 3-way stopcock to the inlet tube with approximately 20-30 ml physiological saline using a 50 ml syringe.</li>
	<li>During the experiment, maintain the pressure in the inflow reservoir using arubber stopper with a glass tube (5 mm inside diameter) inserted through its center. Make sure that the upper opening of the inflow reservoir is securely sealed (with the inner glass tube remaining unsealed).</li>
	<li>Place the colon (length 5-7 cm) into the organ bath chamber, making sure that it is fully submerged in physiological saline.</li>
	<li>Cannulate each end of the colonic segment to the two submerged inlet/outlet tubes (inlet/outlet tubes of different diameter can be changed according to the size of the tissue lumen eg. postnatal tissue, adult mice and guinea pig) in the bath using standard cotton sewing thread. Attach the proximal end of the colon to the inlet tube and the distal end of the colon to the outlet tube (connected via a 3-way stopcock to a vertical outflow tube; 6 cm in height). Make sure that the tissue is not overstretched or too relaxed after cannulation to avoid interference with future measurements and analysis.</li>
	<li>Record the length of the colon by measuring the distance between the proximal and distal cannulations using a 15 cm ruler. This is important for interpreting changes in contraction length, propagation speed and contraction initiation points.</li>
	<li>Ensure a stable baseline luminal pressure (cm H2O) is established before beginning the experiment. Calculate luminal pressure by measuring the vertical distance from the tissue to the meniscus of physiological saline within the glass tube of inflow reservoir (oral) and the vertical outflow tube (anal).</li>
	<li>Maintain tissue preparations at a constant intraluminal pressure (e.g., 1-2 cm H2O) by ensuring that the inflow stopper seal pressure is kept constant and that no blockages are present in the set up.</li>
	<li>Leave the colon to equilibrate in physiological saline for 30 min before recording intestinal movements. Check for any blockages arising in the in- or outflow tubes and remove them by applying pressure through the inflow reservoir or by re-cannulating the oral and anal ends of the colon.</li>
</ol>
3. Image Capture and Experimental Protocol
<ol>
	<li>Record intestinal movements as video files using a video camera (30 frames/sec, 640 x 840 pixels) positioned 10-15 cm above the organ bath on a standard laboratory retort stand (Figure 1).</li>
	<li>Open Virtual Dub (video capture software) from the icon on the desktop. From the &#39;File&#39; tab, select &#39;capture AVI&#39; to view the camera image. On the &#39;Audio&#39; tab deselect &#39;enable audio capture&#39; to disable sound.
	<ol>
		<li>In the video tab select &#39;compression&#39; and &#39;DivX6.9.2. Codec&#39; to compress video files to minimize usage of storage space. This function will become available upon the installation of the compression software &#39;DivX&#39;.</li>
	</ol>
	</li>
	<li>Manually adjust the camera location so that the entire cannulated colon segment is visible (with cannulated regions immediately adjacent to the vertical edges of the video frame) via the video capture software window (see Figure 1). In order to improve image quality and minimize reflections, attach a paper/cardboard shield to the camera support to block extraneous light onto the organ bath. Optimize video quality by adjusting the brightness, contrast and exposure settings using the camera software interface.
	<ol>
		<li>Before recording, set a specific file name; in the &#39;File&#39; tab, select &#39;Set capture file&#39; and specify a unique name for the video.</li>
		<li>Begin capturing video by pressing &#39;Capture file&#39; from the &#39;Capture&#39; tool bar. To stop recording select the &#39;Stop capture&#39; button or the &#39;Esc&#39; key on the keyboard.</li>
	</ol>
	</li>
	<li>Replace the physiological saline contained within the inflow reservoir with fresh physiological saline every 30 min.
	<ol>
		<li>Record luminal pressure (see 2.9) and using a temperature probe, take note of the organ bath temperature. Repeat these steps throughout the experiment (i.e., every 30 min) to ensure that these variables are constant.</li>
	</ol>
	</li>
	<li>Record colonic activity in total for 3 hr (including drug application and washout duration). For data storage purposes, record data in 15 min video segments. A full experiment will typically be composed of 12 x 15 min video recordings.
	<ol>
		<li>Record activity for 1 hr under control conditions (physiological saline).</li>
		<li>Apply the drug (either superfused into the bath or administered into the lumen via the inflow reservoir) for 30 min to 1 hr. 
		Note: Different routes of administration can yield different effects23.</li>
		<li>Apply fresh physiological saline to the bath or lumen during a 1 hr washout period.</li>
	</ol>
	</li>
</ol>
4. Data Processing and Generation of Spatiotemporal Maps
<ol>
	<li>Process each video recording offline using in-house software written in MATLAB (R2012a, Version 7.4; available on request) in order to generate spatiotemporal maps illustrating colonic motility.
	<ol>
		<li>Open analysis software from the icon on the desktop.</li>
		<li>In the command window, enter &#34;Analyse2&#34; in order to open the analysis control panel.</li>
	</ol>
	</li>
	<li>Utilize the edge detection function to generate spatiotemporal maps by clicking &#34;Edge detection for .avi files&#34; in the control panel window. This function will enable the analysis software to read the recoded videos in Audio Video Interleaved (AVI) format.</li>
	<li>Carry out the following steps sequentially to generate spatiotemporal maps using an adaptive edge detection algorithm.
	<ol>
		<li>Open recorded video files by selecting the &#34;Add files&#34; tab, select &#39;Open video&#39; and select the location of the video files.</li>
		<li>From the video files listed within the analysis software, select the file of interest.</li>
		<li>Select a rectangular region of interest within the frame of the video, e.g., the entire length of the colon, from the point at which the colon is cannulated orally to the anal cannulation. Ensure that the proximal and distal cannulation points are adjacent to the vertical boundaries of the region of interest. Edge detection lines (red and green) will automatically appear superimposed on the real time image.</li>
		<li>Ensure that the edge detection threshold lines are immediately adjacent to the colon on both the upper and lower boundaries of the colon tissue (this can be optimized for each video by altering detection threshold values on the control panel). Ensure that the edge detection lines are continuous along the length of the colon image by adjusting the contrast and brightness using the control panel.</li>
		<li>Enter the full length of the colon (mm) into the width dialog box (as recorded in step 2.7). Then select &#34;Generate heat map&#34;.</li>
		<li>In the pop up window, select a location for the file to be saved and specify a file name for the spatiotemporal map.</li>
		<li>Select the &#39;.su2&#39; format and select &#39;Add to queue&#39;. 
		Note: .su2 format compresses data to a smaller file size and multiple video files can be added to the queue.</li>
		<li>Select &#39;Begin detection&#39; to generate spatiotemporal maps.</li>
	</ol>
	</li>
</ol>
5. Analysis of Spatiotemporal Maps
<ol>
	<li>Utilize spatiotemporal maps to estimate parameters such as frequency, propagation speed, length and duration of CMMCs, gut diameter and the point of initiation and direction of contractions.
	<ol>
		<li>To start analyzing spatiotemporal maps, type &#39;analyse2&#39; in the command window as described in the previous section. Instead of &#34;Edge detection&#34;, select the &#34;Heat map analysis&#34; button.</li>
		<li>Open spatiotemporal map files (.su2 files) by selecting the &#39;Add files&#39; tab and specifying the location of previously obtained .su2 files.</li>
		<li>Once the spatiotemporal map is visible on the screen, specify a color range on the control panel, ensuring that the minimum is set to 1. 
		Note that the maximum can range from 5-10 according to the contractility of the tissue.</li>
		<li>Select &#39;Lock color range&#39; to ensure all the maps from a single experiment are analyzed under the same conditions.</li>
		<li>Ensure that the time frame settings are constant for all spatiotemporal maps from a given experiment.</li>
	</ol>
	</li>
	<li>In order to determine CMMC frequency, manually count contractions that traverse more than 50% of the length of the colon. These contractions can be visualized as red/orange streaks (standard HSV color index) on the spatiotemporal map (see Figure 2 for an example). Other contractions that are shorter or do not propagate can also be identified and quantified.</li>
	<li>If desired, conduct further analysis at a higher resolution from these maps. For example, detailed properties including the speed and duration of each contraction can be examined.
	<ol>
		<li>In order to measure the speed and duration, select the &#34;Annotate contraction waves&#34; button on the heat map analysis control panel.</li>
		<li>Next, zoom in to each CMMC by clicking on the &#34;Zoom&#34; button and selecting the area of interest. Then select the &#34;Manually annotate&#34; button to annotate each contraction by using the mouse to draw a line from the most initial position to the end of each contraction. This method can be used to measure the apparent propagation speed and duration of dilations that appear to propagate (for e.g., see anal end of maps in Figure 2A, 2B). 
		Note: The data for speed and duration will appear under the results window. These values can be transferred to a spreadsheet of interest by selecting the &#34;Export data&#34; tab. Unwanted annotations can be removed by clicking on the &#34;Remove selected annotations&#34; button.</li>
	</ol>
	</li>
	<li>If desired, utilize the x and y coordinates of the spatiotemporal maps (time and position along the colon, respectively) to determine the position of initiation of small contractions or CMMCs.</li>
	<li>Similarly, in order to determine intervals between contractions, use the &#34;Annotate&#34; function to measure the duration between contractions. As previously, these results can be exported to a spreadsheet by selecting the &#34;Export data&#34; tab.</li>
	<li>In order to measure the resting gut width, select the &#34;Take cross section&#34; button on the Heat map analysis panel.
	<ol>
		<li>Select &#39;Add&#39; on the temporal cross sections panel. Double click at any location within the map to generate a horizontal line superimposed on the heat map. Gut diameter data will now be displayed in a new window.</li>
		<li>To measure gut diameter, place the cursor on a peak and adjacent trough to obtain average gut width for a specific experimental condition. Changes in gut diameter can be compared between experimental conditions.</li>
	</ol>
	</li>
</ol>

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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+autism-associated+point+mutation+in+the+neuroligin+cytoplasmic+tail+selectively+impairs+AMPA+receptor-mediated+synaptic+transmission+in+hippocampus.">An autism-associated point mutation in the neuroligin cytoplasmic tail selectively impairs AMPA receptor-mediated synaptic transmission in hippocampus.</a> EMBO J. 30, 2908-2919 (2011).</li><li>Zhang, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+of+neurexin+and+neuroligin+in+the+enteric+nervous+system+and+their+down-regulated+expression+levels+in+Hirschsprung+disease.">Expression of neurexin and neuroligin in the enteric nervous system and their down-regulated expression levels in Hirschsprung disease.</a> Mol Biol Rep. 40, 2969-2975 (2013).</li><li>Wang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+and+significance+of+neuroligins+in+myenteric+cells+of+Cajal+in+Hirschsprung's+disease.">Expression and significance of neuroligins in myenteric cells of Cajal in Hirschsprung's disease.</a> PloS One. 8, e67205 (2013).</li><li>Yang, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+down-regulation+of+neuroligin-2+and+the+correlative+clinical+significance+of+serum+GABA+over-expression+in+Hirschsprung's+disease.">The down-regulation of neuroligin-2 and the correlative clinical significance of serum GABA over-expression in Hirschsprung's disease.</a> Neurochem Res. 39, 1451-1457 (2014).</li><li>Roberts, R. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+first+intestinal+motility+patterns+in+fetal+mice+are+not+mediated+by+neurons+or+interstitial+cells+of+Cajal.">The first intestinal motility patterns in fetal mice are not mediated by neurons or interstitial cells of Cajal.</a> J Physiol. 588, 1153-1169 (2010).</li><li>Barnes, K. J., Spencer, N. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+colonic+migrating+motor+complexes+occur+in+mice+lacking+the+endothelin-3+gene?.">Can colonic migrating motor complexes occur in mice lacking the endothelin-3 gene?.</a> Clin Exp Pharmacol Physiol. 42, 485-495 (2015).</li><li>Chambers, J. D., Bornstein, J. C., Thomas, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiple+neural+oscillators+and+muscle+feedback+are+required+for+the+intestinal+fed+state+motor+program.">Multiple neural oscillators and muscle feedback are required for the intestinal fed state motor program.</a> PloS One. 6, e19597 (2011).</li><li>Heredia, D. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Important+role+of+mucosal+serotonin+in+colonic+propulsion+and+peristaltic+reflexes:+in+vitro+analyses+in+mice+lacking+tryptophan+hydroxylase+1.">Important role of mucosal serotonin in colonic propulsion and peristaltic reflexes: in vitro analyses in mice lacking tryptophan hydroxylase 1.</a> J Physiol. 591, 5939-5957 (2013).</li><li>Chambers, J. D., Bornstein, J. C., Thomas, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insights+into+mechanisms+of+intestinal+segmentation+in+guinea+pigs:+a+combined+computational+modeling+and+in+vitro+study.">Insights into mechanisms of intestinal segmentation in guinea pigs: a combined computational modeling and in vitro study.</a> Am J Physiol Gastrointest Liver Physiol. 295, G534-G541 (2008).</li><li>Huizinga, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+origin+of+segmentation+motor+activity+in+the+intestine.">The origin of segmentation motor activity in the intestine.</a> Nat Commun. 5, 3326 (2014).</li><li>Neild, T. O., Shen, K. Z., Surprenant, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vasodilatation+of+arterioles+by+acetylcholine+released+from+single+neurones+in+the+guinea-pig+submucosal+plexus.">Vasodilatation of arterioles by acetylcholine released from single neurones in the guinea-pig submucosal plexus.</a> J Physiol. 420, 247-265 (1990).</li></ol>

The authors have nothing to disclose

Using this video imaging technique, CMMC frequency was measured as an indication of colonic motility in wild type and NL3R451C mice, a mouse model of autism spectrum disorder17. Our results indicate a reduction in the number of CMMCs in mutant NL3R451C mice compared to wild type mice in the presence of the 5HT3/4 receptor antagonist Tropisetron suggesting that NL3R451C mice exhibit an increased sensitivity to Tropisetron. Accordingly, we propose that the neuroligin-3...

The enteric nervous system (ENS) is the intrinsic neuronal network of the gastrointestinal tract and modulates various functions such as digestion of intestinal content, absorption of nutrients and the secretion and reabsorption of fluid. Neurons of the ENS are located in the myenteric and submucosal plexuses. The myenteric plexus plays a major role in regulating gastrointestinal motility1 whereas the submucosal plexus is primarily involved in the control of secretion2,3. The myenteric plexus is situated between the longitudinal and circular muscle layers of the gastrointestinal wall. The contractile activity of the smooth muscle layers of the intestinal wall facilitates the primary functions of the gastrointestinal tract by mixing and propelling intestinal content along the length of the intestine3. Although the extrinsic nerve supply to the gastrointestinal tract from the CNS contributes to gastrointestinal function in vivo, the ENS is capable of regulating gastrointestinal function independently. This unique characteristic enables the functional investigation of enteric neuronal circuits and their contribution to gastrointestinal motility ex vivo.
Colonic migrating motor complexes (CMMCs) are spontaneous, neurogenic events that are the predominant motor pattern observed in isolated mouse colon in the absence of fecal pellets4-9. CMMCs are defined as rhythmic contractions that propagate along a horizontal distance that is at least half the total length of the colon (i.e.,&#160;from the cecum to the rectum)10. The relationship between CMMCs and the contractile patterns that propel fecal pellets is yet to be clearly established, however some pharmacological differences have been reported11. Nevertheless, the ability of the ENS to function independently of the CNS and the existence of neural-mediated motor patterns in the isolated colon provides an ideal assay system to examine disturbances in motility resulting from underlying ENS dysfunction. The spontaneity of gastrointestinal motor patterns allows functional changes in response to pharmacological stimuli to be evaluated.
The use of video imaging and spatiotemporal mapping was first developed to quantitatively examine small intestinal peristalsis in guinea pigs12. Here, an ex vivo technique is described that enables the study of mouse colonic motility patterns using video imaging and analysis of these recordings to construct high-resolution (~100 &#181;m, 33 msec) maps of colonic diameter as a function of position along the colon and of time (spatiotemporal maps). Using in-house edge detection software (Analyse2; available on request), data from full length colonic segments contracting in real time are processed to generate spatiotemporal maps for each experiment. In this step, video (AVI) files are summarized and converted to spatiotemporal maps using Analyse2. Spatiotemporal maps (Figure 2) depict contractility over time and enable the measurement of multiple parameters including propagation speed, magnitude, length and duration. Gut diameter is also recorded throughout the duration of the experiment as a measure of the overall contractility of the tissue segment. This method can be applied to identify differences in the point of initiation of contractile complexes which could indicate altered enteric neural connectivity.
A similar video imaging protocol designed to assess pellet propulsion in guinea pigs has been reported13 however here we outline the application of the video imaging approach for quantification of spontaneous colonic motility (i.e., in the absence of pellets). We also provide detailed information to assist in the dissection and preparation of gastrointestinal tissue for the video imaging approach. This protocol provides researchers with an accessible and easily replicated tool for analyzing enteric neural control of gastrointestinal function in animal models of disease including genetic mouse models.
The video imaging technique enables the analysis of colonic motility in response to various pharmacological agents. Drugs can be administered via the gut lumen or the organ bath external to the colonic preparation. Different regions of the mouse gastrointestinal tract exhibit specific motility patterns such as small intestinal segmentation and CMMCs in the colon.
This technique has been used to identify strain differences in small intestinal function; differential sensitivity to 5-HT3 and 5-HT4 antagonists were observed in the jejunum of Balb/c and C57/Bl6 mice due to the polymorphic nature of the tph2 gene expressed in the two strains6. The effect of 5-HT inhibition on motility remains controversial, as conflicting data has been reported on the importance of endogenous 5-HT on colonic peristalsis and CMMCs14,15. Alterations in motility pre- and postnatally during development7, and the effects of gene mutations on gastrointestinal motility in animal models of disease10 can also be examined by utilizing video imaging. Here we illustrate use of the method for a study of colonic motility in the NL3R451C mouse model of autism, which expresses a missense mutation in the Nlgn3 gene encoding the synaptic adhesion protein Neuroligin-316. This mutation was first identified in patients diagnosed with Autism spectrum disorder (ASD)17, which is strongly associated with GI dysfunction18-22. We investigated whether the NL3 R451C synaptic mutation affects neural outputs in the ENS using the video imaging technique. We present data characterizing CMMCs at baseline and in response to the serotonergic 5HT3/4 receptor antagonist tropisetron in the NL3R451C mouse model of autism.

<table><tbody><tr><td>&lt;strong&gt;Reagents&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>NaCl (MW: 58.44)</td><td>Sigma-Aldrich</td><td>S7653-250G</td><td></td></tr><tr><td>KCl (MW: 74.55)</td><td>Sigma-Aldrich</td><td>P9333-500G</td><td></td></tr><tr><td>NaH&lt;sub&gt;2&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;.2H&lt;sub&gt;2&lt;/sub&gt;O (MW: 156.01)</td><td>Chem Supply</td><td>471-500G</td><td></td></tr><tr><td>MgSO&lt;sub&gt;4&lt;/sub&gt;.7H&lt;sub&gt;2&lt;/sub&gt;0 (MW: 246.48)</td><td>Chem Supply</td><td>MA048</td><td></td></tr><tr><td>CaCl&lt;sub&gt;2&lt;/sub&gt;.2H&lt;sub&gt;2&lt;/sub&gt;O (MW: 147.02)</td><td>Chem Supply</td><td>CA033</td><td></td></tr><tr><td>D-Glucose anhydrous (MW: 180.16)</td><td>Chem Supply</td><td>GA018-500G</td><td></td></tr><tr><td>NaHCO&lt;sub&gt;3 &lt;/sub&gt;(MW: 84.01)</td><td>Chem Supply</td><td>GA018-500G</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Materials&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Two chambered organ bath&lt;br/&gt; Dimentions: 14 cm x 8 cm x 3 cm</td><td>Custom Made</td><td></td><td>Contact Laboratory Directly&amp;nbsp;</td></tr><tr><td>&amp;nbsp;732 MULTI -PURPOSE SEALANT CLEAR</td><td>Dow Corning Australia Pty Ltd</td><td>1890573</td><td></td></tr><tr><td>SYLGARD 184 SILICONE ELASTOMER KIT&amp;nbsp;</td><td>Dow Corning Australia Pty Ltd</td><td>1064291</td><td></td></tr><tr><td>STOPCOCK 3 WAY FEM-ML L/LOCK S</td><td>Terumo Medical Corporation</td><td>0912-2006</td><td></td></tr><tr><td>SYRINGES with Luer Lock Tips 50 ml, 20 ml, 10 ml</td><td>Terumo Medical Corporation</td><td>N/A</td><td></td></tr><tr><td>1.57 mm (ID) x 3.16 mm (OD) - Silastic Tubing</td><td>Masterflex</td><td>508-008</td><td></td></tr><tr><td>1.02 mm (ID) x 2.16 mm (OD) - Silastic Tubing</td><td>Masterflex</td><td>508-005</td><td></td></tr><tr><td>1.50 mm (ID) x 2.50 mm (OD) - Silastic Tubing</td><td>Masterflex</td><td>508-007</td><td></td></tr><tr><td>1.60 mm (ID) - Platinum cured silicone tubing&amp;nbsp;</td><td>Masterflex</td><td>96410 - 14</td><td></td></tr><tr><td>4.40 mm (ID) - Platinum cured silicone tubing&amp;nbsp;</td><td>Masterflex</td><td>96410 - 15&amp;nbsp;</td><td></td></tr><tr><td>3.10 mm (ID) - Platinum cured silicone tubing&amp;nbsp;</td><td>Masterflex</td><td>96410 -16</td><td></td></tr><tr><td>Graduated Laboratory Glass Bottles - 500 ml&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;</td><td>Thermofisher Scientific&amp;nbsp;</td><td>100-400</td><td></td></tr><tr><td>CHEMICAL RUBBER STOPPER 57 x 65 mm&amp;nbsp;</td><td></td><td></td><td></td></tr><tr><td>CHEMICAL RUBBER STOPPER 29 mm x 32 mm</td><td></td><td></td><td></td></tr><tr><td>Water heater&amp;nbsp; (thermo regulator)&amp;nbsp;</td><td>Ratek&amp;nbsp;</td><td>TH7000&amp;nbsp;</td><td></td></tr><tr><td>Logitech Webcam</td><td>Logitech</td><td></td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Software&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Virtual Dub - 1.9 11</td><td>virtualdub.org</td><td></td><td></td></tr><tr><td>MATLAB R2012a&amp;nbsp;</td><td>Graph Pad</td><td></td><td></td></tr><tr><td>Logitech Webcam Software</td><td>Logitech</td><td></td><td></td></tr></tbody></table>

video imaging and spatiotemporal maps to analyze gastrointestinal motility in mice

The enteric nervous system (ENS) plays an important role in regulating gastrointestinal (GI) motility and can function independently of the central nervous system. Changes in ENS function are a major cause of GI symptoms and disease and may contribute to GI symptoms reported in neuropsychiatric disorders including autism. It is well established that isolated colon segments generate spontaneous, rhythmic contractions known as Colonic Migrating Motor Complexes (CMMCs). A procedure to analyze the enteric neural regulation of CMMCs in ex vivo preparations of mouse colon is described. The colon is dissected from the animal and flushed to remove fecal content prior to being cannulated in an organ bath. Data is acquired via a video camera positioned above the organ bath and converted to high-resolution spatiotemporal maps via an in-house software package. Using this technique, baseline contractile patterns and pharmacological effects on ENS function in colon segments can be compared over 3-4 hr. In addition, propagation length and speed of CMMCs can be recorded as well as changes in gut diameter and contraction frequency. This technique is useful for characterizing gastrointestinal motility patterns in transgenic mouse models (and in other species including rat and guinea pig). In this way, pharmacologically induced changes in CMMCs are recorded in wild type mice and in the Neuroligin-3R451C mouse model of autism. Furthermore, this technique can be applied to other regions of the GI tract including the duodenum, jejunum and ileum and at different developmental ages in mice.

Up to 90% of patients with ASD experience an array of gastrointestinal disorders, including diarrhea and constipation18,24,25. However, the underlying causes of these gastrointestinal issues are unknown. Many mutations identified in patients with ASD are associated with synaptic proteins contributing to alterations and disturbances in synaptic transmission or function. One such mutation, in the gene coding for the cell adhesion molecule neuroligin-3 (NL3 R451C), was identified ...

Watch this Scientific Journal Video about Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice at JoVE.com

Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice

This article describes a video imaging technique and high-resolution spatiotemporal mapping to identify changes in the neural regulation of colonic motility in adult mice. Subtle effects on gastrointestinal (GI) function can be detected using this approach in isolated tissue preparations to advance our understanding of GI disease.

The enteric nervous system (ENS) plays an important role in regulating gastrointestinal (GI) motility and can function independently of the central ...

video-imaging-spatiotemporal-maps-to-analyze-gastrointestinal

Research

JoVE Journal

Neuroscience

13.9K Views.  The University of Melbourne. This article describes a video imaging technique and high-resolution spatiotemporal mapping to identify changes in the neural regulation of colonic motility in adult mice. Subtle effects on gastrointestinal (GI) function can be detected using this approach in isolated tissue preparations to advance our understanding of GI disease.

Video: Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an area of productive research with over 1,400 published animal studies in just the last 5 years. Numerous techniques have been developed for quantifying smooth muscle activity of the stomach, small intestine, and colon. In vitro and ex vivo techniques offer powerful tools for mechanistic studies of GI function, but outside the context of the integrated systems inherent to an intact organism. Typically, measuring in vivo smooth muscle contractions of the stomach has involved an anesthetized preparation coupled with the introduction of a surgically placed pressure sensor, a static pressure load such as a mildly inflated balloon or by distending the stomach with fluid under barostatically-controlled feedback. Yet many of these approaches present unique disadvantages regarding both the interpretation of results as well as applicability for in vivo use in conscious experimental animal models. The use of dual element strain gages that have been affixed to the serosal surface of the GI tract has offered numerous experimental advantages, which may continue to outweigh the disadvantages. Since these gages are not commercially available, this video presentation provides a detailed, step-by-step guide to the fabrication of the current design of these gages. The strain gage described in this protocol is a design for recording gastric motility in rats. This design has been modified for recording smooth muscle activity along the entire GI tract and requires only subtle variation in the overall fabrication. Representative data from the entire GI tract are included as well as discussion of analysis methods, data interpretation and presentation.

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

The in vivo measurement of smooth muscle contractions along the gastrointestinal tract of laboratory animals remains a powerful, though underutilized, technique. Flexible, dual element strain gages are not commercially available and require fabrication. This protocol describes the construction of reliable, inexpensive strain gages for acute or chronic implantation in rodents.

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an ...

Bioengineering

Real-time Imaging of Myeloid Cells Dynamics in ApcMin/+ Intestinal Tumors by Spinning Disk Confocal Microscopy

Myeloid cells are the most abundant immune cells within tumors and have been shown to promote tumor progression. Modern intravital imaging techniques enable the observation of live cellular behavior inside the organ but can be challenging in some types of cancer due to organ and tumor accessibility such as intestine. Direct observation of intestinal tumors has not been previously reported. A surgical procedure described here allows direct observation of myeloid cell dynamics within the intestinal tumors in live mice by using transgenic fluorescent reporter mice and injectable tracers or antibodies. For this purpose, a four-color, multi-region, micro-lensed spinning disk confocal microscope that allows long-term continuous imaging with rapid image acquisition has been used. ApcMin/+ mice that develop multiple adenomas in the small intestine are crossed with c-fms-EGFP mice to visualize myeloid cells and with ACTB-ECFP mice to visualize intestinal epithelial cells of the crypts. Procedures for labeling different tumor components, such as blood vessels and neutrophils, and the procedure for positioning the tumor for imaging through the serosal surface are also described. Time-lapse movies compiled from several hours of imaging allow the analysis of myeloid cell behavior in situ in the intestinal microenvironment.

Real-time Imaging of Myeloid Cells Dynamics in ApcMin/+ Intestinal Tumors by Spinning Disk Confocal Microscopy

By using transgenic reporter mice and injectable fluorescent labels, long-term intravital spinning disk confocal microscopy enables direct visualization of myeloid cell behavior into intestinal adenoma in the ApcMin/+ colorectal cancer model.

Myeloid cells are the most abundant immune cells within tumors and have been shown to promote tumor progression. Modern intravital imaging techniques ...

Immunology and Infection

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions preclinically. However, valid assessment of pathological alterations often requires histological analysis, and when performed ex vivo, necessitates death of the animal. Therefore in conventional experimental settings, intra-individual follow-up examinations are rarely possible. Thus, development of murine endoscopy in live mice enables investigators for the first time to both directly visualize the gastrointestinal mucosa and also repeat the procedure to monitor for alterations. Numerous applications for in vivo murine endoscopy exist, including studying intestinal inflammation or wound healing, obtaining mucosal biopsies repeatedly, and to locally administer diagnostic or therapeutic agents using miniature injection catheters. Most recently, molecular imaging has extended diagnostic imaging modalities allowing specific detection of distinct target molecules using specific photoprobes. In conclusion, murine endoscopy has emerged as a novel cutting-edge technology for diagnostic experimental in vivo imaging and may significantly impact on preclinical research in various fields.

Murine Endoscopy for In Vivo Multimodal Imaging of Carcinogenesis and Assessment of Intestinal Wound Healing and Inflammation

Small animal imaging techniques allow serial diagnostic examinations and therapeutic interventions in vivo. Recently, the scope of applications has significantly widened and currently includes assessment of colonic tumor development, wound healing and monitoring of inflammation. This protocol illustrates these diverse potential applications of murine endoscopy.

Mouse models are widely used to study pathogenesis of human diseases and to evaluate diagnostic procedures as well as therapeutic interventions ...

Medicine

Imaging Neutrophils and Monocytes in Mesenteric Veins by Intravital Microscopy on Anaesthetized Mice in Real Time

Efficient immune response is dependent on rapid mobilization of blood leukocytes to the site of infection or injury. Investigating leukocyte migration in vivo is crucial for understanding the molecular basis of leukocyte transendothelial migration and interaction with vascular endothelium. One powerful approach involves intravital microscopy on transgenic mice expressing fluorescent proteins in cells of interest.
Here we present a protocol for imaging monocytes and neutrophils in the CX3CR1gfp/wt mouse i.v. injected with orange dye-labeled neutrophils with an inverted confocal microscope. Time-lapse movies gathered from 30 min&#160;to several hours of imaging allow the analysis of leukocyte behavior in mesenteric veins under both steady state and inflammatory conditions. We also describe the steps to locally induce blood vessel inflammation with TLR2/TLR1 agonist Pam3SK4 and monitor the subsequent recruitment of neutrophils and monocytes.
The presented technique can also be used to monitor other populations of leukocytes and investigate molecules implicated in leukocyte recruitment or trafficking using other stimuli or transgenic mice.

We detail a protocol to monitor the behavior of neutrophils and monocytes in mesenteric veins under steady state and inflammatory conditions using intravital confocal microscopy on anaesthetized mice.

Efficient immune response is dependent on rapid mobilization of blood leukocytes to the site of infection or injury. Investigating leukocyte migration in ...

Non-invasive Assessment of the Efficacy of New Therapeutics for Intestinal Pathologies Using Serial Endoscopic Imaging of Live Mice

Animal models of inflammatory bowel disease (IBD) and colorectal cancer (CRC) have provided significant insight into the cell intrinsic and extrinsic mechanisms that contribute to the onset and progression of intestinal diseases. The identification of new molecules that promote these pathologies has led to a flurry of activity focused on the development of potential new therapies to inhibit their function. As a result, various pre-clinical mouse models with an intact immune system and stromal microenvironment are now heavily used. Here we describe three experimental protocols to test the efficacy of new therapeutics in pre-clinical models of (1) acute mucosal damage, (2) chronic colitis and/or colitis-associated colon cancer, and (3) sporadic colorectal cancer. We also outline procedures for serial endoscopic examination that can be used to document the therapeutic response of an individual tumor and to monitor the health of individual mice. These protocols provide complementary experimental platforms to test the effectiveness of therapeutic compounds shown to be well tolerated by mice.

We describe methods for longitudinal monitoring of the efficacy of therapeutics for the treatment of colonic pathologies in mice using a rigid endoscope. This protocol can be readily used for the characterization of the therapeutic response of an individual tumor in live mice and also for monitoring potential disease relapse.

Animal models of inflammatory bowel disease (IBD) and colorectal cancer (CRC) have provided significant insight into the cell intrinsic and extrinsic ...

Gastrointestinal Motility Monitor (GIMM)

The Gastrointestinal Motility Monitor (GIMM; Catamount Research and Development; St. Albans, VT) is an in vitro system that monitors propulsive motility in isolated segments of guinea pig distal colon. The complete system consists of a computer, video camera, illuminated organ bath, peristaltic and heated water bath circulating pumps, and custom GIMM software to record and analyze data. Compared with traditional methods of monitoring colonic peristalsis, the GIMM system allows for continuous, quantitative evaluation of motility. The guinea pig distal colon is bathed in warmed, oxygenated Krebs solution, and fecal pellets inserted in the oral end are propelled along the segment of colon at a rate of about 2 mm/sec. Movies of the fecal pellet proceeding along the segment are captured, and the GIMM software can be used track the progress of the fecal pellet. Rates of propulsive motility can be obtained for the entire segment or for any particular region of interest. In addition to analysis of bolus-induced motility patterns, spatiotemporal maps can be constructed from captured video segments to assess spontaneous motor activity patterns. Applications of this system include pharmacological evaluation of the effects of receptor agonists and antagonists on propulsive motility, as well as assessment of changes that result from pathophysiological conditions, such as inflammation or stress. The guinea pig distal colon propulsive motility assay, using the GIMM system, is straightforward and simple to learn, and it provides a reliable and reproducible method of assessing propulsive motility.

Gastrointestinal Motility Monitor GIMM

Evaluation of colonic motility in the guinea pig distal colon with the Gastrointestinal Motility Monitor (GIMM) is a straightforward and simple to learn approach to quantitatively evaluate propulsive motility in the gastrointestinal tract.

The Gastrointestinal Motility Monitor (GIMM; Catamount Research and Development; St. Albans, VT) is an in vitro system that monitors propulsive motility ...

Biology

Visualization of the Interstitial Cells of Cajal (ICC) Network in Mice

The interstitial cells of Cajal (ICC) are mesenchymal derived "pacemaker cells" of the gastrointestinal (GI) tract that generate spontaneous slow waves required for peristalsis and mediate neuronal input from the enteric nervous system1. Different subtypes of ICC form distinct networks in the muscularis of the GI tract 2,3. Loss or injury to these networks is associated with a number of motility disorders4. ICC cells express the KIT receptor tyrosine kinase on the plasma membrane and KIT immunostaining has been used for the past 15 years to label the ICC network5,6. Importantly, normal KIT activity is required for ICC development5,6. Neoplastic transformation of ICC cells results in gastrointestinal stromal tumor (GIST), that frequently harbor gain-of-function KIT mutations7,8. We recently showed that ETV1 is a lineage-specific survival factor expressed in the ICC/GIST lineage and is a master transcriptional regulator required for both normal ICC network formation and for of GIST tumorigenesis9. We further demonstrate that it cooperates with activating KIT mutations in tumorigenesis. Here, we describe methods for visualization of ICC networks in mice, largely based on previously published protocols10,11. More recently, the chloride channel anoctamin 1 (ANO1) has also been characterized as a specific membrane marker of ICC11,12. Because of their plasma membrane localization, immunofluorescence of both proteins can be used to visualize the ICC networks. Here, we describe visualization of the ICC networks by fixed-frozen cyrosections and whole mount preparations.

Visualization of the Interstitial Cells of Cajal ICC Network in Mice

The interstitial cells of Cajal (ICC) are the pacemaker cells of the gastrointestinal (GI) tract. They form complex networks between smooth muscle cells and post-ganglionic neuronal fibers to regulate GI contractility. Here, we present immunofluorescence methods cross-sectional and whole-mount visualization of murine ICC networks.

The interstitial cells of Cajal (ICC) are mesenchymal derived "pacemaker cells" of the gastrointestinal (GI) tract that generate spontaneous slow waves ...

Intravital Imaging of Intraepithelial Lymphocytes in Murine Small Intestine

Intraepithelial lymphocytes expressing &#947;&#948; T cell receptor (&#947;&#948; IEL) play a key role in immune surveillance of the intestinal epithelium. Due in part to the lack of a definitive ligand for the &#947;&#948; T cell receptor, our understanding of the regulation of &#947;&#948; IEL activation and their function in vivo remains limited. This necessitates the development of alternative strategies to interrogate signaling pathways involved in regulating &#947;&#948; IEL function and the responsiveness of these cells to the local microenvironment. Although &#947;&#948; IELs are widely understood to limit pathogen translocation, the use of intravital imaging has been critical to understanding the spatiotemporal dynamics of IEL/epithelial interactions at steady-state and in response to invasive pathogens. Herein, we present a protocol for visualizing IEL migratory behavior in the small intestinal mucosa of a GFP &#947;&#948; T cell reporter mouse using inverted spinning disk confocal laser microscopy. Although the maximum imaging depth of this approach is limited relative to the use of two-photon laser-scanning microscopy, spinning disk confocal laser microscopy provides the advantage of high speed image acquisition with reduced photobleaching and photodamage. Using 4D image analysis software, T cell surveillance behavior and their interactions with neighboring cells can be analyzed following experimental manipulation to provide additional insight into IEL activation and function within the intestinal mucosa.

We describe a method to visualize GFP-labeled &#947;&#948; IELs using intravital imaging of murine small intestine by inverted spinning disk confocal microscopy. This technique enables the tracking of live cells within the mucosa for up to 4 h and can be used to investigate a variety of intestinal immune-epithelial interactions. &#160;

Intraepithelial lymphocytes expressing &#947;&#948; T cell receptor (&#947;&#948; IEL) play a key role in immune surveillance of the intestinal ...

Spatiotemporal Mapping of Motility in Ex Vivo Preparations of the Intestines

Multiple approaches have been used to record and evaluate gastrointestinal motility including: recording changes in muscle tension, intraluminal pressure, and membrane potential. All of these approaches depend on measurement of activity at one or multiple locations along the gut simultaneously which are then interpreted to provide a sense of overall motility patterns. Recently, the development of video recording and spatiotemporal mapping (STmap) techniques have made it possible to observe and analyze complex patterns in ex vivo whole segments of colon and intestine. Once recorded and digitized, video records can be converted to STmaps in which the luminal diameter is converted to grayscale or color [called diameter maps (Dmaps)]. STmaps can provide data on motility direction (i.e., stationary, peristaltic, antiperistaltic), velocity, duration, frequency and strength of contractile motility patterns. Advantages of this approach include: analysis of interaction or simultaneous development of different motility patterns in different regions of the same segment, visualization of motility pattern changes over time, and analysis of how activity in one region influences activity in another region. Video recordings can be replayed with different timescales and analysis parameters so that separate STmaps and motility patterns can be analyzed in more detail. This protocol specifically details the effects of intraluminal fluid distension and intraluminal stimuli that affect motility generation. The use of luminal receptor agonists and antagonists provides mechanistic information on how specific patterns are initiated and how one pattern can be converted into another pattern. The technique is limited by the ability to only measure motility that causes changes in luminal diameter, without providing data on intraluminal pressure changes or muscle tension, and by the generation of artifacts based upon experimental setup; although, analysis methods can account for these issues. When compared to previous techniques the video recording and STmap approach provides a more comprehensive understanding of gastrointestinal motility.

Spatiotemporal Mapping of Motility in Ex Vivo Preparations of the Intestines

Recently available video recording and spatiotemporal mapping (STmap) techniques make it possible to visualize and quantify both propagating and mixing patterns of intestinal motility. The goal of this protocol is to explain the generation and analysis of STmaps using the GastroIntestinal Motility Monitoring (GIMM) system.

Multiple approaches have been used to record and evaluate gastrointestinal motility including: recording changes in muscle tension, intraluminal pressure, ...

Studying Murine Small Bowel Mechanosensing of Luminal Particulates

Gastrointestinal (GI) motility is critical for normal digestion and absorption. In the small bowel, which absorbs nutrients, motility optimizes digestion and absorption. For this reason, some of the motility patterns in the small bowel include segmentation for mixing of luminal contents and peristalsis for their propulsion. Physical properties of luminal contents modulate the patterns of small bowel motility. The mechanical stimulation of GI mechanosensory circuits by transiting luminal contents and underlying gut motility initiate and modulate complex GI motor patterns. Yet, the mechanosensory mechanisms that drive this process remain poorly understood. This is primarily due to a lack of tools to dissect how the small bowel handles materials of different physical properties. To study how the small bowel handles particulates of varying sizes, we have modified an established in vivo method to determine small bowel transit. We gavage live mice with fluorescent liquid or tiny fluorescent beads. After 30 minutes, we dissect out the bowels to image the distribution of fluorescent contents across the entirety of the GI tract. In addition to high-resolution measurements of the geometric center, we use variable size binning and spectral analysis to determine how different materials affect small bowel transit. We have explored how a recently discovered "gut touch" mechanism affects small bowel motility using this approach.

To study how the small bowel handles particulates of varying sizes, we have modified an established in vivo method to determine small bowel transit.

Gastrointestinal (GI) motility is critical for normal digestion and absorption. In the small bowel, which absorbs nutrients, motility optimizes digestion ...

Video Imaging and Spatiotemporal Maps to Analyze Gastrointestinal Motility in Mice

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