Cyclic Motor Activity Research Articles

Electrocolonography: Non-Invasive Detection of Colonic Cyclic Motor Activity From Multielectrode Body Surface Recordings.

This work validates a novel non-invasive method to identify periods of cyclic motor activity in the colon using multichannel skin-surface electrical recordings on the lower abdominal region, termed electrocolonography (EColG). EColG recordings were made from 21 human subjects during a 3 hr meal-response study. A signal processing pipeline based on Continuous Wavelet Transform time-frequency analysis was used to quantify the spectral power in the colonic frequency band ( ≈ 2-6 cycles per minute; cpm) during the fasted and fed states. EColG identified a substantial 7.4 ± 3.5× maximum transient increase in motor activity in the fed state versus the fasted state, as well as a 38.3 ± 16.7% sustained spectral power increase in the colonic frequency band. The dominant frequency was 3.61 ± 0.49cpm, with activity localized primarily in the infraumbilical region near the (recto-)sigmoid colon segments. The colonic meal-responses identified with EColG were closely concordant with rectosigmoid motor activity previously characterized by intracolonic high-resolution manometry. This study is the first to demonstrate that body surface electrical recordings can properly identify rhythmic colonic activity stimulated by food intake. The new EColG technique is inexpensive, portable, and presents the opportunity for reliably measuring colonic motility by noninvasive means. We anticipate that EColG could be applied to monitor the progression of post-operative ileus, and more precisely diagnose abnormal colonic motor patterns in patients suffering from common functional disorders, such as irritable bowel syndrome.

Pacemaker network properties determine intestinal motor pattern behaviour.

Pacemaker network properties determine intestinal motor pattern behaviour.

Hyperactive cyclic motor activity in the distal colon after colonic surgery as defined by high-resolution colonic manometry.

Recovery after colonic surgery is invariably delayed by disturbed gut motility. It is commonly assumed that colonic motility becomes quiescent after surgery, but this hypothesis has not been evaluated rigorously. This study quantified colonic motility through the early postoperative period using high-resolution colonic manometry. Fibre-optic colonic manometry was performed continuously before, during and after surgery in the left colon and rectum of patients undergoing right hemicolectomy, and in healthy controls. Motor events were characterized by pattern, frequency, direction, velocity, amplitude and distance propagated. Eight patients undergoing hemicolectomy and nine healthy controls were included in the study. Colonic motility became markedly hyperactive in all operated patients, consistently dominated by cyclic motor patterns. Onset of cyclic motor patterns began to a minor extent before operation, occurring with increasing intensity nearer the time of surgery; the mean(s.d.) active duration was 12(7) per cent over 3 h before operation and 43(17) per cent within 1 h before surgery (P = 0.024); in fasted controls it was 2(4) per cent (P < 0·001). After surgery, cyclic motor patterns increased markedly in extent and intensity, becoming nearly continuous (active duration 94(13) per cent; P < 0·001), with peak frequency 2-4 cycles per min in the sigmoid colon. This postoperative cyclic pattern was substantially more prominent than in non-operative controls, including in the fed state (active duration 27(20) per cent; P < 0·001), and also showed higher antegrade velocity (P < 0·001). Distal gut motility becomes markedly hyperactive with colonic surgery, dominated by cyclic motor patterns. This hyperactivity likely represents a novel pathophysiological aspect of the surgical stress response. Hyperactive motility may contribute to gut dysfunction after surgery, potentially offering a new therapeutic target to enhance recovery.

New insights into neurogenic cyclic motor activity in the isolated guinea-pig colon.

The contents of the guinea pig distal colon consist of multiple pellets that move anally in a coordinated manner. This row of pellets results in continued distention of the colon. In this study, we have investigated quantitatively the features of the neurally dependent colonic motor patterns that are evoked by constant distension of the full length of guinea-pig colon. Constant distension was applied to the excised guinea-pig by high-resolution manometry catheters or by a series of hooks. Constant distension elicited regular Cyclic Motor Complexes (CMCs) that originated at multiple different sites along the colon and propagated in an oral or anal direction extending distances of 18.3±10.3cm. CMCs were blocked by tetrodotoxin (TTX; 0.6μmolL-1 ), hexamethonium (100μmolL-1 ) or hyoscine (1μmolL-1 ). Application of TTX in a localized compartment or cutting the gut circumferentially disrupted the spatialcontinuity of CMCs. Localized smooth muscle contraction was not required for CMC propagation. Shortening the length of the preparations or disruption of circumferential pathways reduced the integrity and continuity of CMCs. CMCs are a distinctive neurally dependent cyclic motor pattern, that emerge with distension over long lengths of the distal colon. They do not require changes in muscle tension or contractility to entrain the neural activity underlying CMC propagation. CMCs are likely to play an important role interacting with the neuromechanical processes that time the propulsion of multiple natural pellets and may be particularly relevant in conditionsof impaction or obstruction, where long segments of colon are simultaneously distended.

Detailed Characteristics of the Migrating Motor Complex in Man and Animals

During the interdigestive state occurring in monogastric species, the stomach and small intestine are almost empty. The meal consumed during the foregoing period undergoes the digestive and transport processes. Notwithstanding, the relatively small amounts of indigestible food remnants, cellular debris, bacteria and possibly the small portions of ingested liquids and solid foods may remain in the gastrointestinal lumen. The secretion of the digestive juices is not inhibited completely during the fasting state and the presence of the digestive juices in the gastrointestinal lumen appears to be one of the main reasons to maintain the transport of the luminal content during this period. There is no need to retain an uninterrupted mixing of gastrointestinal flow of digesta as it occurs during the postprandial period. Thus, the character of motor activity present in nonfed humans and monogastric animals adapts to the actual conditions and the interdigestive motility exhibits the cyclical character. Therefore, it was defined as cyclic motor activity and these cycles are regarded as the migrating motor complexes (MMCs). The MMC comprises four phases exhibiting the exponential intensity of contractions: phase I was defined as the weakest or with no contractions; during usually the longest phase II, divided sometimes into phase IIa and IIb, the increased frequency and amplitude of contractions are noticed; in the course of phase III, the strongest contractions occur at the maximal frequency; during phase IV, not always observed, the irregular submaximal contractions, similar to those during phase II can be recorded. There are quite precise criteria for MMC identification and it is possible to distinguish normal and abnormal MMCs. This fasting pattern occurring in most mammals and birds, is organized during the fetal life and in some species, like ruminants and other herbivores, is not abolished by feeding. The manometric technique still appears to be the gold standard method in man and promising in animals at least for the gastric and small-intestinal MMC registration to allow more detailed analysis of the interdigestive motility than the other minimally invasive methods used for clinical purposes.

Functional Gallbladder and Sphincter of Oddi Disorders

The functional disorder of the gallbladder (GB) is a motility disorder caused initially either by metabolic abnormalities or by a primary motility alteration. The functional disorders of the sphincter of Oddi (SO) encompass motor abnormalities of either the biliary or the pancreatic SO. Dysfunction of the GB and/or biliary SO produce similar patterns of pain. The pain caused by a dysfunction of the pancreatic SO can be similar to that of acute pancreatitis. The symptom-based diagnostic criteria of motility dysfunction of the GB and biliary SO are episodes of moderate to severe steady pain located in the epigastrium and right upper abdominal quadrant that last at least 30 minutes. GB motility disorder is suspected after gallstones and other structural abnormalities have been excluded. This diagnosis should then be confirmed by a decreased GB ejection fraction induced by cholecystokinin at cholescintigraphy and after disappearance of the recurrent biliary pain after cholecystectomy. Symptoms of biliary SO dysfunction may be accompanied by features of transient biliary obstruction, and those of pancreatic SO dysfunction are associated with elevation of pancreatic enzymes and even pancreatitis. Biliary-type SO dysfunction is more frequently recognized in postcholecystectomy patients. SO manometry is valuable to select patients with sphincter dysfunction; however, because of the high incidence of complications, these patients should be referred to an expert unit for such assessment. Thus invasive tests should be performed only in the presence of compelling clinical evidence and after noninvasive testing has yielded negative findings. The committee recommends that division of the biliary or pancreatic sphincters only be considered when the patient has severe symptoms, meets the required criteria, and other diagnoses are excluded.

Relationship between intraduodenal 5-hydroxytryptamine release and interdigestive contractions in dogs.

5-hydroxytryptamine (5-HT) is released into the intestinal lumen during the fasting state. However, the relationship between the intraduodenal 5-HT and the interdigestive cyclic motor activity in conscious dogs is unclear. To correlate intraduodenal 5-HT concentrations with the interdigestive gastroduodenal migrating motor complex (MMC). 6 dogs were implanted with 2 force transducers for recording gastroduodenal contractions and 2 catheters for measuring duodenal volume by a non-absorbable marker perfusion technique. Intraduodenal 5-HT concentrations were determined by high performance liquid chromatography at 5-min intervals. During fasting, gastroduodenal motor activity cycled as the MMC; luminal 5-HT concentrations and total outputs varied cyclically in temporal association with the MMC. Mean 5-HT concentrations peaked during phase II (P<0.05 vs. phase I and III), and 5-HT outputs during phases II or III were greater than during phase I (P<0.05). Exogenous motilin (0.3 microg/kg-hr, IV) stimulated 5-HT release into the duodenal lumen with peak values (P<0.05) during motilin-induced phase II and III. Gastroduodenal motor activity was not altered, however, during exogenous intraduodenal administration of 5-HT (300 ng/mL-min). 5-HT is released cyclically into the duodenal lumen in close temporal association with the MMC, but its physiologic significance in regulation of gastroduodenal motility is unknown.

Fetal cyclic motor activity in diabetic pregnancies: sensitivity to maternal blood glucose.

Spontaneous fetal movement in the last third of human gestation is dominated by irregular oscillations on a scale of minutes (cyclic motility, CM). The core properties of these oscillations are stable during the third trimester of gestation in normal fetuses, but disrupted by poorly controlled maternal diabetes. Here we investigated whether fetal CM is linked to short-term instabilities in maternal glucose metabolism. The fetuses of 40 mothers with type I (n = 28) or gestational (n = 12) diabetes were studied one to six times between 27 and 40 postmenstrual weeks of gestation. Fetal movement and maternal blood glucose concentration were measured during two separate periods of fetal activity in each session. Fetal CM was quantified with spectral analysis. Early in the third trimester, changes in the rate of oscillation in fetal CM between the two periods of activity were inversely related to changes in maternal blood glucose levels. Fetal CM was unrelated to concurrent maternal blood glucose levels at any point in the third trimester. The pattern of results suggests that disruption of the temporal organization of spontaneous fetal motor activity in pregnancies complicated by maternal diabetes represents an acute response to fluctuations in the metabolic environment rather than an alteration of CM development.

Preserved extrinsic neural connection between gallbladder and residual stomach is essential to prevent dysmotility of gallbladder after distal gastrectomy.

Many reports have been made on gallbladder dysfunction after gastric surgery. We reported that the gallbladder contractions were abolished after antrectomy. Our hypothesis is that preservation of the neural connection along gastric vessels maintains normal gallbladder function during fasting after antrectomy. Six dogs underwent antrectomy with preservation of the extrinsic nerves and six other dogs underwent conventional antrectomy with dissection of the extrinsic nerves and vessels. Laparotomy alone was performed on another six control dogs. Motor activities of the gallbladder and upper gastrointestinal tract were recorded by strain gauges in conscious dogs. Motilin and CCK-OP were used for pharmacological interventions. In conventional antrectomy, the amplitudes of the cyclic motor activity of the gallbladder and the stomach during fasting were significantly reduced, while this activity was maintained in dogs when extrinsic nerves were preserved. The coordination of the motor activity among the gallbladder, stomach and the duodenum was not impaired in the dogs when extrinsic nerves were preserved. The contractions of the gallbladder induced by exogenous motilin were reduced significantly in conventional antrectomy. Therefore, the preserved neural connection along the gastric vessels maintains normal gallbladder function in the fasting state even after distal gastrectomy.

Role of extrinsic innervation in release of motilin and patterns of upper gut canine motility

The need for extrinsic neural input to the upper gut in regulation/control of cyclic interdigestive motility and release of motilin remains a topic of controversy. Our aim was to determine whether extrinsic denervation of the upper gut disrupts cyclic release of motilin in relation to the migrating motor complex. Ten dogs underwent transection of all extrinsic innervation and enteric neural input to the stomach, small intestine, colon, pancreas, and liver while enteric neural continuity within this multivisceral complex was maintained. A cyclic pattern of motility occurred during fasting in all dogs in the small bowel (period = 100 ± 3 min, mean ± standard error of the mean) and in 8 of 10 dogs in the stomach (period = 98 ± 4 min). Gastric cycles were temporally coordinated with small bowel cycles. Plasma motilin concentrations cycled temporally with the motility pattern with the greatest concentrations occurring during gastroduodenal phase III—like activity. Exogenous motilin induced a burst of gastric contractions and a premature migrating motor complex in all dogs. Oral meals disrupted cyclic motility and cyclic changes in plasma motilin. Extrinsic innervation to the upper gut is not necessary for cyclic motor activity, for coordinated cyclic release of motilin, or to initiate a premature migrating motor complex—like response to motilin. Central nervous system input (afferent, efferent) is not necessary for cyclic interdigestive activity or cyclic release of motilin.

Cyclic motor activity of the gallbladder maintained in a pylorus-preserving gastrectomy in dogs.

The gallbladder has cyclic motor activity (CMA), which is impaired after a conventional gastrectomy. We conducted experiments to determine whether or not a pylorus-preserving gastrectomy (PPG) could maintain gallbladder CMA. Six strain gauge force transducers were implanted into the gastrointestinal tract and gallbladder of six dogs, respectively. The motor activity of the gastrointestinal tract and gallbladder was recorded as a control. PPG was then carried out. The phasic contractions of the gallbladder, which were correlated with the antral contractions in the control state, were synchronized with contractions of the pylorus after PPG. Intravenous administration of CCK-OP (40 ng/kg) induced phasic contractions of the gallbladder at 4.6 +/- 0.2 c/min in 3 of the 6 days with gastric contractions. After PPG, the gallbladder had phasic contractions (4.5 +/- 0.2 c/m), which were synchronized with the contractions of the pylorus in all dogs regardless of the contractions in the remnant stomach. These findings suggest that gallbladder CMa has a closer relationship with the CMA of the pylorus than with the remnant stomach after PPG. Thus, a preservation of the pylorus at the time of gastric surgery will help in maintaining gallbladder function and coordination with the remnant stomach.

Cocaine alters cyclic motor activity in the fetal rat

Individual rat fetuses were exposed to cocaine by injection into the cisterna magna on E20 or E21 of gestation. On E20, cocaine elevated motor activity throughout the 20-min session, with activity increasing to double SAL-injected levels by the end of the session. On E21, overall activity also was elevated after cocaine, increasing four- to fivefold in the first 5 min of the session, and decreasing to twice the levels of SAL controls thereafter. Movement time series were subjected to spectral analysis to characterize cyclic motor organization. Cyclicity was evident in 67% of control and 97% of cocaine-injected fetuses. Cocaine increased the number of peaks in the movement spectrum and resulted in greater spectral density at the primary frequency of cyclic movement. Prenatal exposure to cocaine may alter patterns of cyclicity in the fetus, with consequences for the normal development of attention and behavioral state in the neonate.

Nitric oxide regulates migrating motor complex cycling and its postprandial disruption.

We investigated the role of nitric oxide (NO) in the regulation of migrating motor complex (MMC) cycling during the fasting state and its postprandial disruption. Intravenous infusion of N omega-nitro-L-arginine methyl ester (L-NAME) first produced a premature MMC and then disrupted MMC cycling for the rest of the day. The cycle length of the MMCs was significantly shorter than the control on the 2nd, 3rd, and 4th day after L-NAME infusion. The gastric cyclic motor activity (CMA) did not usually exhibit a premature cycle on the day of L-NAME infusion but was disrupted by L-NAME infusion; the duration of CMA disruption in the stomach was significantly longer than that of MMC disruption in the small intestine. Infusion of N omega-nitro-L-arginine (L-NNA) exhibited similar effects. The intravenous infusion of L-NAME also significantly shortened the duration of MMC disruption by a meal. L-Arginine alone had no significant effect on gastrointestinal motor activity during the fasting or the fed state, but when infused with L-NAME, it blocked the effects of NO synthase inhibition. Angiotensin II increased the mean arterial pressure to a level similar to that produced by L-NAME but had no significant effect on the fasting or the fed pattern of gastrointestinal motor activity. We conclude that NO containing nonadrenergic noncholinergic (NANC) neurons play a significant role in regulating MMC and CMA cycling during the fasting state and their disruption by a meal. However, NO may not be the only NANC neurotransmitter to inhibit contractions in the gut; phase I activity in the small intestine persisted during NO synthase inhibition by L-NAME or L-NNA.

Oscillation and Complexity in Early Infant Behavior

Cyclic fluctuation is a ubiquitous property of spontaneous motor activity in the human fetus and neonate. Oscillation occurs on the scale of minutes, and irregularity is one of its most characteristic properties. To determine whether cyclic motor activity (CM) persists beyond the neonatal period (1 month after birth), and beyond what has been called the period of the fetus ex utero (2-3 months after birth), 30 infants were studied at monthly intervals from 1 to 4 months after birth during active sleep and awake. Spectral analysis was used to quantify the rate, strength, and irregularity of CM. To examine the characteristic irregularity of awake CM more closely, a nonlinear forecasting technique, developed to study chaotic dynamic in other fields, was used to estimate the predictability of spontaneous movement in a state space reconstructed from the time series. The rate and irregularity of CM during active sleep and awake, and its strength during active sleep, did not change across the first 4 postnatal months. However, there was a pronounced drop in the strength of awake CM from 2 months onward and a concurrent increase in the broad-band power of fluctuations faster than 2 cycles/min. The predictability of awake CM also dropped abruptly between 1 and 2 months, especially for prediction intervals less than 20 sec. The changes at 2 months reflect the introduction of a source of variation with a shorter time constant than fetal-neonatal CM, and which is specific to awake periods. The source of these effects may be moment-to-moment interactions between CM and attention.

Possible organization pattern of interaction between the generators of cyclic motor activity and inputs from supraspinal and afferent systems

Possible organization patterns of scratching and locomotor generators that allow interpretation of experimentally demonstrated reorganizations in temporal parameters of these generator activities after electrical stimulation of descending and peripheral afferent systems were analyzed with application of mathematical simulation of neuronal generator systems. The results obtained led to the conclusion that patterns of such reorganizations influenced by signals from suprasegmental and/or peripheral systems may be determined by only two factors: 1) the structure of synaptic connections between interneuronal functional groups underlying these generator associations, and 2) the structure of connections between these groups of interneurons and fibers from suprasegmental and peripheral afferent sources. The existence of inhibitory-excitatory actions from descending and afferent systems upon the neurons of locomotor or scratching generator half-centers is a sufficient condition to ensure phasic changes in the sensitivity of these generators to supraspinal and afferent signals. The locomotor generator, unlike the scratching generator, is apparently characterized by a more complex organization of connections between functional neuronal groupings and descending fibers.

Antral control of gallbladder cyclic motor activity in the fasting state

The hypothesis that gastric antrum controls the phasic contractions of gallbladder cyclic motor activity in the fasting state was tested. Gallbladder, gastric, and small bowel motor and myoelectric activity was recorded by strain gauge transducers and bipolar electrodes. Gallbladder pressure was measured manometrically by a surgically implanted intraluminal catheter. After control recordings for 4 to 6 weeks, antrectomy and gastroduodenostomy were performed. Six weeks later, bilateral truncal vagotomy was performed in each dog. Recordings were made after each surgical procedure. In the control state, the gallbladder exhibited cyclic motor activity consisting of phasic contractions at a frequency of 0.75 ± 0.02/min superimposed on an increase in baseline pressure. Antrectomy and gastroduodenostomy completely abolished the phasic contractions of gallbladder cyclic motor activity and significantly decreased the incidence of the cyclic increase in baseline pressure. Subsequent vagotomy had no additional effect on gallbladder cyclic motor activity. In intact dogs, the gallbladder filled from 0% to 80% and emptied from 80% to 100% of the duodenal migrating motor complex cycle, which was considered to begin at the start of phase I activity. Antrectomy significantly altered this pattern; after antrectomy, the gallbladder filled from 0% to 10% and from 90% to 100% and emptied during the remainder of the duodenal migrating motor complex cycle. Subsequent vagotomy had no additional effect on periodic gallbladder filling and emptying. It is concluded that major changes occur in gallbladder cyclic motor activity and its periodic filling and emptying pattern in the fasting state after antrectomy and vagotomy. It is hypothesized that in the absence of cyclic phasic contractions after antrectomy, periodic stirring and agitation of gallbladder bile and its mixing with fresh hepatic bile may not occur in the fasting state. The absence of this phenomenon may lead to supersaturation of bile near the mucosal surface and increase the propensity for precipitation of salts and formation of gallstones.

The migrating myoelectric complex of the small intestine.

Gastric and small intestinal myoelectric and motor activity is divided into two main patterns, fed and fasted. During fasting, the predominant pattern of activity is the migrating myoelectric complex (MMC), a cyclically occurring pattern of electric and mechanical activity that is initiated in the stomach and duodenum almost simultaneously and, from there, propagates the length of the small intestine. Cyclic motor activity also occurs in the lower esophageal sphincter, the gallbladder, and the sphincter of Oddi with a duration that is related to the MMC in the small intestine. Of the possible mechanisms for initiation of the MMC in the small intestine (extrinsic neural control, intrinsic neural control, and hormonal control), intrinsic neural control via a series of coupled is the most likely. The keep this sentence in! hormone motilin also plays a role in the initiation of MMCs. After a meal, in man the MMC is disrupted and replaced by irregular contractions. The physiologic role of the MMC is to clear the stomach and small intestine of residual food, secretions, and desquamated cells and propel them to the colon. Disruption of the MMC cycle is associated with bacterial overgrowth in some patients, an observation that supports the proposed cleansing function of the MMC cycle.

Bilateral truncal vagotomy abolishes gallbladder cyclic motor activity

Bilateral truncal vagotomy abolishes gallbladder cyclic motor activity

Investigations of the migrating motor complex in domestic turkeys

The motor correlate of the migrating myoelectric complex (MMC) was characterized in domestic turkeys, and feeding state, age, sex, and time of day were examined as possible factors influencing the motor activity observed. Strain gauge transducers, and in a few birds Ag-AgCl bipolar electrodes, were implanted on the caudoventral thin muscle of the muscular stomach, the duodenum, ileum, cecum, and colon. Contractility was recorded for 8-10 h per bird on alternating days for 2-3 wk, except in birds involved in four 24-h recording sessions during a 2-wk period. Intense motor activity characteristic of phase III of the MMC occurred only in the ileum; other phases could not be identified. The duration, propagation velocity, and percent of cyclic motor patterns propagating from one site to another were similar to those reported in other galliform species. The occurrence of cyclic motor activity appeared to be related to food consumption; the number of motor patterns occurring during an intense feeding session was less than the number observed 1.5-2 h after feeding. In addition, more motor patterns were recorded in fasted poults during the light period than in the dark; however, the reverse was observed in juveniles fed ad libitum. Cyclic motor activity recorded in fasted 18-wk-old birds was of longer duration than that in fasted 8-wk-old birds. No statistically significant differences were noted in the cyclic motor patterns of male vs. female poults.

The neural control of cyclic motor activity in the fetal rat ( Rattus norvegicus)

The spontaneous behavior of rat fetuses (in a saline bath with fetal-placental-uterine connections intact) was observed directly for 30 minutes on Day 20 of gestation. Rearleg and nonrearleg movements from fetuses with a mid-thoracic spinal cord transection or sham operation were analyzed for cyclic organization. Oscillations in rearleg activity occurred at the same frequency in fetuses with spinal cord transections (0.74 cycle/min) and sham-operated fetuses (0.72 cycle/min). However, oscillations in nonrearleg activity were much slower in the fetuses with spinal cord transections (0.30 vs. 0.77 cycle/min). Other characteristics of the cyclic patterns in motor activity were unaffected. The findings demonstrate 1) the caudal half of the spinal cord can generate cyclic output in the absence of descending input from the brain, 2) there is no single timing center, and 3) rostral sources are slower.