Management of chronic constipation with refractory symptoms can be challenging. Although new drugs and behavioral treatments have improved outcome, when they fail, there is little guidance on what to do next. At this juncture, typically most doctors may refer for surgical intervention although total colectomy is associated with morbidity including complications such as recurrent bacterial overgrowth. Recently, colonic manometry with sensory/tone/compliance assessment with a barostat study has been shown to be useful. Technical challenges aside, adequate preparation, and appropriate equipment and knowledge of colonic physiology are keys for a successful procedure. The test itself appears to be safe with little complications. Currently, colonic manometry is usually performed with a 6-8 solid state or water-perfused sensor probe, although high-resolution fiber-optic colonic manometry with better spatiotemporal resolutions may become available in the near future. For a test that has evolved over 3 decades, normal physiology and abnormal findings for common phenotypes of chronic constipation, especially slow transit constipation, have been well characterized only recently largely through the advent of prolonged 24-hour ambulatory colonic manometry studies. Even though the test has been largely restricted to specialized laboratories at the moment, emerging new technologies and indications may facilitate its wider use in the near future.
Colectomy ; Colon* ; Constipation* ; Manometry* ; Phenotype ; Physiology

Contraction of smooth muscle cells is triggered by an increase in cytosolic Ca(2+) upon agonist stimulation. Ca(2+) influx across the plasma membrane constitutes a major component of the agonist-induced response in smooth muscle cells. Traditionally, voltage-operated Ca(2+) channel (VOCC) is considered as the channel mediating the Ca(2+) entry. However, this view has been challenged by recent discoveries, which demonstrated that other types of ion channels, such as store-operated and/or receptor-operated Ca(2+) channels (SOCC and/or ROCC), also participate in Ca(2+) response induced by agonists in smooth muscle cells. SOCC is defined as the channel activated in response to the depletion of the internal Ca(2+) stores, an event secondary to G protein coupled receptor or receptor tyrosine kinase stimulation. The Ca(2+) flow mediated by SOCC is termed as capacitative Ca(2+) entry (CCE). Previous study from other group has demonstrated that VOCC played a predominant role in ACh-induced contraction of distal colon smooth muscle in guinea pig. However, whether SOCC participates in the agonist-induced contractile response in this particular tissue is unknown. The present study was performed to investigate the role of CCE in ACh-induced mechanical activity of distal colon smooth muscle in rats. The contractile function of the smooth muscle was assessed by measuring isometric force of isolated rat distal colon rings. We showed that both high extracellular K(+) (40 mmol/L) and ACh (5 mumol/L) evoked striking contraction of the smooth muscle. The contractile responses were almost abolished by removal of extracellular Ca(2+) with ethylene glycol-bis(2-aminoethylether)-N,N,N',N' tetraacetic acid (EGTA), suggesting a critical contribution of extracellular source of Ca(2+) to the contraction. Verapamil (5 mumol/L), an L-type VOCC blocker, significantly attenuated, but didn't completely eliminate the high K(+)- and ACh-induced contraction (74% and 41% for high K(+) and ACh, respectively), indicating that additional channels might be involved in the contractile mechanism. Furthermore, ACh only induced transient contractions in the absence of extracellular Ca(2+). Readmission of Ca(2+) into the extracellular compartment resulted in a significant and sustained increase in the tension of the smooth muscle. This response was not affected by verapamil (5 mumol/L) and Cd(2+) (5 mumol/L), both of which efficiently block VOCC at the doses. However, La(3+), a known inhibitor of SOCC, significantly suppressed the Ca(2+) readdition-induced contraction in a dose-dependent manner. On the basis of these results, we conclude that contraction of smooth muscle in the distal colon is regulated by multiple Ca(2+) channels. In addition to VOCC-mediated Ca(2+) influx, SOCC-mediated CCE participates in agonist-induced contractile response of distal colon smooth muscle in rats.
Acetylcholine ; physiology ; Animals ; Calcium ; metabolism ; Calcium Channels ; physiology ; Colon ; physiology ; Female ; Male ; Muscle Contraction ; physiology ; Muscle, Smooth ; physiology ; Myocytes, Smooth Muscle ; physiology ; Rats ; Rats, Sprague-Dawley ; Verapamil ; pharmacology

Animals ; Colon ; physiology ; Female ; Indoles ; pharmacology ; Male ; Myoelectric Complex, Migrating ; Rats ; Rats, Wistar ; Viscera ; physiology

To investigate the biomechanical behavior of human intestines. The tensile test human intestine was performed with the electronic tension machine in this paper. The results indicate that the exponential relationship for the stress-strain of the human intestine was obtained, and the exponential coefficient a of each segment of the intestine is almost the same although the constant C is different. It also shows that the relative rate of stretch length of each segment intestines is different in longitudinal and circumferential directions. And the incremental elastic modulus of colon is less than those of small intestine. It is considered that the colon can be more easily deformed. The experimental results provide the theoretic basis for research on intestinal endoscopic microrobot.
Biomechanical Phenomena ; Colon, Transverse ; physiology ; Elasticity ; Humans ; In Vitro Techniques ; Intestine, Small ; physiology ; Stress, Mechanical ; Tensile Strength

In recent years, colonic manometry has been gradually introduced into clinical practice. It helps clinicians to gain a better understanding of the physiology and pathophysiology of colonic contractile activity in healthy adults and patients with colonic dysfunction. More and more patterns of colonic motility are being discovered with the help of colonic manometry. However, the clinical significance of these findings still needs to be further investigated. This review enhances our understanding of colonic motility and the current state of development and application of colonic manometry, as well as the limitations, future directions and potential of the technique in assessing the impact of treatment on colonic motility patterns, by analyzing and summarizing the literature related to colonic manometry.
Humans ; Adult ; Gastrointestinal Motility/physiology* ; Colon/physiology* ; Colonic Diseases ; Manometry/methods* ; Clinical Relevance ; Constipation

BACKGROUND/AIMS: Although bisacodyl is a widely administered laxative, its underlying mechanism of action remains generally unknown. This study focuses on investigating the effects of bisacodyl on the human colon muscle contraction, and elucidating its mechanism of action. METHODS: Sigmoid colon muscle strips (20 longitudinal and 18 circular muscles) were obtained from 20 subjects who underwent colectomy for colon cancer. Isometric force measurements were calculated in response to electrical field stimulation (EFS, 0.3 milliseconds in trains of 10 Hz for 20 seconds, 150 V). Peak and nadir (tone) during and after EFS, were measured in a controlled state, and after sequential addition of bisacodyl (1 μM), atropine (1 μM), N-nitro-L-arginine (L-NNA, 100 μM), MRS2500 (1 μM), and tetrodotoxin (TTX, 1 μM) to the organ bath. RESULTS: Transient phasic contractions were observed during EFS, and after cessation of EFS. In the longitudinal muscles, nadir during EFS, and tone after EFS, significantly increased after addition of bisacodyl, and persisted after sequential addition of atropine, L-NNA, MRS2500, and TTX, indicating a direct action of bisacodyl on the smooth muscle. In the second experiment, pretreatment of TTX abolished EFS-induced phasic contractions. Although no phasic contraction was produced after perfusion of bisacodyl, tone was increased, thereby supporting evidence of a direct mechanism of action of bisacodyl on the colon smooth muscle. CONCLUSIONS: Bisacodyl increases the tone of longitudinal muscle in the human sigmoid colon through a direct action on the smooth muscle. Further study is warranted to investigate the neural mechanism of action of bisacodyl.
Atropine ; Baths ; Bisacodyl ; Colectomy ; Colon ; Colon, Sigmoid ; Colonic Neoplasms ; Humans ; In Vitro Techniques ; Muscle Contraction ; Muscle, Smooth ; Muscles ; Perfusion ; Physiology ; Tetrodotoxin

Using the method of detrended fluctuation analysis (DFA) and power spectral analysis (PSA), the paper deals with the characteristics of long-range correlations of colonic pressure activities and their surrogate data of healthy subjects. The DFA is a period representation of such correlations, whereas the PSA is a frequency representation. The analysis of the two methods consistently shows that there are long memories in colonic pressure activities and there exist long-range correlations, whereas there are no such long memories and long-range correlations in the surrogate data, whose sequential orders are randomly shuffled. The results to some extent indicate that human colonic pressure activities with normal motilities do have long memories, but these memories may be weaker or may even be destroyed with dysmotilities.
Adult ; Colon ; physiology ; Data Interpretation, Statistical ; Female ; Humans ; Male ; Middle Aged ; Pressure ; Signal Processing, Computer-Assisted

OBJECTIVETo study possible mechanisms of Shangjuxu (ST37) and the large intestine.

METHODSTotally 40 SD rats were selected. The distension of end colon was used as injured afferent stimulus. Activities of locus coeruleus (LC) neurons were recorded by extracellular microelectrode technique. Shangjuxu (ST37) and Hegu (L14) were needled to observe general features of discharge reactions, distention of colon induced discharge reactions of LC, and its effects on distention of colon induced discharge reactions of LC.

RESULTSDistention of colon could induce incrased discharge of LC neurons by 127.33% ± 45.48%. But needling at Shangjuxu (ST37) and Hegu (L14) could inhibit this injured response by 38.24% ± 7.69% and 21.29% ± 13.16% respectively (all P < 0.01).

CONCLUSIONSNeedling at Shangjuxu (ST37) and afferent signals of colon distension converged and interacted with each other. Needling at Shangjuxu (ST37) could significantly inhibit colon distension induced discharge of LC neurons, which might be one of mechanisms for Shangjuxu (ST37) and the large intestine relationship.

Acupuncture Therapy ; Animals ; Colon ; Intestine, Large ; Locus Coeruleus ; physiology ; Neurons ; Rats ; Rats, Sprague-Dawley

Successful assessing intestinal lumen content with ultrasound signals might lay a strong basis for the development of the artificial anal sphincter. In the present study, we utilized a modified MLU02-212 ultrasonic gas bubble detector to test the distal part of proximal colon in each rabbit, for the group of twenty healthy New Zealand rabbits. Voltage signals of solid, liquid, gas and empty content of the lumen were collected and compared. The results indicated that there were significant differences among the voltage signals in the 4 conditions (P = 0.000), respectively. Multiple comparison showed significant differences existed in any pair of the four conditions (P = 0.000). Three signal non-overlapping regions existed in these 4 conditions. Thus it seemed that ultrasound could be utilized to distinguish various contents inside the intestinal lumen and could act as "artificial sensory nerve".
Anal Canal ; innervation ; physiology ; Animals ; Artificial Organs ; Colon ; diagnostic imaging ; Enteric Nervous System ; physiology ; Fecal Incontinence ; surgery ; Female ; Gastrointestinal Contents ; Gastrointestinal Motility ; physiology ; Male ; Rabbits ; Sensory Receptor Cells ; physiology ; Ultrasonography

OBJECTIVETo evaluate the roles of enteric nervous system neurotransmitters, nitric oxide (NO), substance P (SP) and vasoactive intestinal polypeptide (VIP), and interstitial cells of Cajal (ICC) in the colon in slow transit constipation in rats.

METHODSThirty-two healthy Wistar rats were randomly assigned to control and constipated groups. In the constipated group, the rats were daily administered with diphenoxylate (8 mg/kg) to develop slow transit constipation, while the control rats were fed with water. The number and the weight of fecal granule and the body weight of rats were recorded every 5 days for 90 days. Transit functions of intestinal movement were examined by an activated charcoal suspension pushing test one week after stopping the administration of diphenoxylate. The levels of NO and SP in the colonic mucosa were measured by nitrate reductase methods and ELISA respectively. The distribution of VIP and ICC positive cells confirmed with symbolic c-kit+ cells in the colonic wall were observed by immunohistochemical methods.

RESULTSThe daily number of fecal granule in the constipated group was significantly less than that in the control group (P<0.01). The mean weight of each fecal granule in the constipated group was significantly higher than that in the control group (P<0.01). The discharge time of the first granule of black faeces in the constipated group (430.2+/- 132.1 min) was significantly longer than that in the control group (337.2+/- 74.7 min; P<0.05). There were no significant differences in NO and SP levels and the density of VIP positive cells in the distal colonic segment between the two groups. The number of c-kit+ cells in the distal colonic wall in the constipated group was significantly reduced compared with that in the control group (P<0.05).

CONCLUSIONSThe reduction of ICC number in the distal colon may be contributed to the pathogenesis of slow transit constipation in rats.

Animals ; Body Weight ; Coiled Bodies ; Colon ; cytology ; innervation ; Constipation ; etiology ; Male ; Neurotransmitter Agents ; physiology ; Nitric Oxide ; analysis ; physiology ; Proto-Oncogene Proteins c-kit ; analysis ; Rats ; Rats, Wistar ; Substance P ; analysis ; physiology ; Vasoactive Intestinal Peptide ; analysis ; physiology