SEARCH · PubMed Health

Results for “Myoelectric Complex, Migrating”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources

PubMed1995

Effect of electrical stimulation on gastric electrical activity, motility and emptying.

The aim was to measure the effect of gastric electrical stimulation on the frequency of canine antral pacesetter potentials (PPs), the strength of antral contractions, and the rate of gastric emptying while fasting, after feeding and with pentagastrin stimulation. Four conscious dogs with a stimulating electrode placed 10 cm proximal to the pylorus and recording electrodes and strain gauges placed 7, 5 and 3 cm proximal to the pylorus underwent myoelectric and strain gauge recordings while fasting, after feeding (250 ml 5% dextrose labelled with polyethylene glycol), and during pentagastrin infusion (0.5 micrograms kg-1 min-1) on four separate days. On each day, electrical stimulation was done using one of four stimulation frequencies (0, 6, 30 and 1200 stimuli per minute [s.p.m.]). Stimulation at 6 and 30 s.p.m. increased the fasting and fed PP frequency, whereas 1200 s.p.m. stimulation did not. Feeding decreased the maximum driven frequency, and pentagastrin increased it. Neither the motility index nor the gastric emptying rate were consistently changed by stimulation at any frequency. In conclusion, canine proximal antral stimulation at 6 and 30 s.p.m. sped PP frequency during fasting and after feeding, but stimulation over a wide range of frequencies had little effect on gastric contractions and emptying.

Animals↗

PubMed1995

Brain noradrenergic systems modulate the ceco-colonic myoelectric activity in rats.

The role of the brain noradrenergic systems in the control of the ceco-colonic myoelectric activity was investigated in rats following lesions with intracerebroventricular (icv) or intracisternal (ic) injection of 6-hydroxydopamine (6-OHDA). Controls received the vehicle alone. The ceco-colonic myoelectric activity was recorded 3 weeks later in conscious rats chronically fitted with electrodes. After icv injection of 6-OHDA, lesions of rostral and caudal (spinal) noradrenergic systems were observed whereas only spinal noradrenergic systems were lesioned after ic injection. This differential pattern of lesions was followed by a differential pattern of ceco-colonic myoelectric activity. In fasted animals, a significant increase of the long spike burst (LSB) frequency (nb min-1) was observed after icv injection of 6-OHDA whereas no modification was observed after ic injection of the neurotoxic. After a 6-g pelleted rat diet, a significant increase of the LSB frequency was also observed in the icv lesioned group when compared to controls. No modification of the ceco-colonic noradrenergic innervation was observed, thus confirming the central selectivity of these lesions. Lesions of central noradrenergic systems modify the LSB frequency in rats; the rostral noradrenergic systems seem to play the major role.

Animals↗

PubMed1996

High resolution electrical mapping in the gastrointestinal system: initial results.

High resolution electrical mapping in the gastrointestinal system entails recording from a large number of extracellular electrodes simultaneously. It allows the collection of signals from 240 individual sites which are then amplified, filtered, digitized, multiplexed and stored on tape. After recording, periods of interest can be analysed and the original sequence of activity reconstructed. This technology, originally developed to study normal rhythms and abnormal dysrhythmias in the heart, has been modified to allow recordings from the gastrointestinal tract. In this report, initial results are presented describing the origin and propagation of the slow wave in the isolated stomach and the isolated duodenum in the cat. These results show that in both organs it not uncommon to have more than one focus active during a single cycle. The conduction of slow waves from such a multiple pacemaker environment can become quite complex, and this may play a role in determining the contractile pattern in these organs.

Animals↗

PubMed2004

Effects of electroacupuncture on gastric myoelectrical activity in healthy humans.

The acupuncture point of the wrists (PC6) and the lower legs (ST36) are common points for the treatment of gastric symptoms. However, it remains unclear whether these two acupoints have different effects on gastric myoelectrical activity. We compared the effect of electroacupuncture (EAP) between PC6 and ST36 on gastric myoelectrical activity using surface electrogastrography (EGG). EAP (1 Hz, for 30 min) was applied at either ST36, or PC6, or both acupoints in eight healthy volunteers. EAP at both PC6 and ST36 did not change the percentage of normal slow waves and tachygastria. While EAP at either PC6 or ST36 did not change period dominant frequency (PDF), EAP at both PC6 and ST36 significantly decreased PDF to 78.1 +/- 8.4% of baselines. EAP at PC6 reduced period dominant power (PDP) to 47.2 +/- 5.3% of baselines, while EAP at ST36 increased PDP to 153.6 +/- 28.3% of baselines. EAP at shoulders (sham acupuncture) did not affect the gastric myoelectrical activity. EAP at either PC6 or ST36 shows an opposite effect on PDP, whereas EAP at both PC6 and ST36 has a synergistic effect on PDF. Understanding site-specific effects of acupuncture may contribute to the selection of appropriate acupoints for treating functional GI disorders.

Acupuncture Points↗

PubMed2004

Electrogastrographic biofeedback: a technique for enhancing normal gastric activity.

Biofeedback has been used effectively for approximately 40 years as a technique to help individuals learn to control muscle activity, brain waves, certain autonomic nervous system responses such as heart rate and blood pressure, and, more recently, constipation and fecal and urinary incontinence. In the present study, biofeedback of electrogastrographic (EGG) activity was used to determine the extent to which healthy subjects could increase normal 3 cpm gastric myoelectric activity. Thirteen experimental participants were provided with biofeedback of their EGG activity on a computer screen, and instructed to try to make their own EGG signal match a simulated 3 cpm signal that was also present on the screen. Subjects were told to relax using various forms of imagery, and to heighten their awareness of their stomach activity. Thirteen control participants did not receive any biofeedback but were otherwise given the same instructions. Both groups showed an increase in 3 cpm activity while relaxing. However, over four trials separated by 2-7 days, experimental participants showed an increased percentage of 3 cpm activity during biofeedback sessions, while control participants showed a decrease in 3 cpm activity during the corresponding sessions. In conclusion, we have demonstrated that healthy subjects can increase their normal gastric 3 cpm activity with the use of EGG biofeedback.

Adolescent↗

PubMed2004

Inhibitory effects of stress on postprandial gastric myoelectrical activity and vagal tone in healthy subjects.

The aim was to investigate gastric myoelectrical activity (GMA) and vagal activity in response to stress. The study was performed in 10 healthy subjects in three sessions (control, relaxation and stress). The control session was composed of 30-min recordings before and 30-min recordings after a test meal. The protocol of two other sessions was similar except that the fasting recording was extended to 60 min and the subjects were continuously watching a horror movie (stress) or guided meditation tape (relaxation) after the 30-min baseline. GMA was recorded using electrogastrography and heart rate variability (HRV) was derived from the electrocardiogram. Meal resulted in a postprandial increase in the dominant frequency (2.91 cpm vs 3.17 cpm, P < 0.007), dominant power (30.0 dB vs 32.5 dB, P < 0.05), and percentage of normal slow waves (79.8%vs 87.4%, P = 0.09). Similar responses were found in the relaxation session. Stress inhibited all these normal postprandial response and reduced the regularity of gastric slow waves (82.0%vs 66.0%, P < 0.01). In addition, spectral analysis of the HRV demonstrated an inhibition of postprandial vagal activity and an increase of postprandial sympathetic activity with stress. Stress has an inhibitory effect on postprandial GMA and this may involve both vagal and sympathetic pathway.

Adult↗

PubMed2004

Gastric distension alters frequency and regularity but not amplitude of the gastric slow wave.

Abstract The aim of this study was to assess effects of gastric distension on gastric slow waves using internal and cutaneous electrodes and the correlation between these two measurements. The study was performed in five dogs implanted with one pair of serosal electrodes and a gastric cannula. Gastric slow waves were recorded using both cutaneous and internal electrodes in several sessions with different volumes (150-600 mL) of gastric distension with a barostat balloon. Bethanechol was injected in one of sessions. The results revealed that (i) Gastric distension reduced slow wave frequency in a volume-dependent manner and induced bradyarrhythmia at a volume of 600 mL, but had no effects on the amplitude of gastric slow waves. (ii) The cutaneous electrogastrogram (EGG) was significantly correlated with the internal recording in slow wave frequency (r = 0.88, P < 0.001) and regularity (r = 0.44, P = 0.035). (iii) The EGG amplitude was not increased when the stomach was distended but increased after bethanechol. Gastric distension volume dependently reduces slow wave frequency and induces gastric dysrhythmia at a large volume. The frequency and rhythmicity of the slow wave measured from the EGG are significantly correlated with those recorded from the internal electrodes. Relative increase in EGG amplitude reflects contractility rather than the distension of the stomach.

Animals↗

PubMed2005

Effects of vasopressin and long pulse-low frequency gastric electrical stimulation on gastric emptying, gastric and intestinal myoelectrical activity and symptoms in dogs.

The aim of this study was to investigate the effect of vasopressin and long pulse-low frequency gastric electrical stimulation (GES) on gastric emptying, gastric and intestinal myoelectrical activity and symptoms in dogs. The study was performed in eight healthy female dogs implanted with four pairs of gastric serosal electrodes and two pairs of small bowel serosal electrodes, and a duodenal fistula for the assessment of gastric emptying. Each dog was studied in three sessions on three separate days in a randomized order with recordings of gastric and small bowel slow waves. Each study session consisted of 30-min baseline, 30-min stimulation and 30-min recovery period. In sessions 1 and 2, infusion of either saline or vasopressin (0.75 U kg(-1) in 30 mL saline instilled in 30 min) was given during the second 30-min period. The protocol of session 3 was the same as session 2 except long pulse-low frequency GES was performed during the second 30-min period. It was found that: (i) Vasopressin significantly delayed gastric emptying 30 and 45 min after meal and GES did not improve the vasopressin induced delayed gastric emptying; (ii) Vasopressin induced gastric dysrhythmias and GES significantly improved vasopressin induced gastric dysrhythmia; (iii) Vasopressin also induced intestinal slow wave abnormalities but GES had no effect on vasopressin induced small bowel dysrhythmia; (iv) Vasopressin induced symptoms and behaviours suggestive of nausea that were not improved by GES. We conclude that: (i) Vasopressin delays gastric emptying and induces gastric and small bowel dysrhythmias and symptoms in the fed state, and (ii) long pulse-low frequency GES normalizes vasopressin induced gastric dysrhythmia with no improvement in gastric emptying or symptoms.

Animals↗

PubMed2006

Efficacy and efficiency of gastric electrical stimulation with short pulses in the treatment of vasopressin-induced emetic responses in dogs.

The aim of this study was to determine the most effective and efficient anti-emetic parameters of short-pulse gastric electrical stimulation (GES) in dogs. Seven female beagle dogs implanted with four pairs of gastric electrodes were studied in eight randomized sessions (saline, vasopressin, and six GES sessions with different parameters). Each session consisted of four 20-min recordings of gastric slow waves and symptoms. In sessions 1 and 2, saline and vasopressin, respectively, were infused during the second 20-min period. The protocol of the other six sessions was the same as session 2 except that GES was continuously applied. It was found that: (1) vasopressin induced gastric dysrhythmia and emetic response (P < 0.01, anova); (2) short-pulse GES with a frequency of 14 or 40 Hz and pulse width of 0.1 or 0.3 ms, but not 0.6 ms was able to reduce symptoms induced by vasopressin; (3) short-pulse GES with a pulse width of 0.3 ms was the most effective in preventing vasopressin-induced symptoms; (4) none of the tested GES methods improved vasopressin-induced gastric dysrhythmia. We conclude that vasopressin induces gastric dysrhythmia and symptoms. Short-pulse GES with a pulse width of 0.3 ms and frequency of 14 Hz is most effective and efficient in preventing vasopressin-induced emetic responses in dogs.

Animals↗

PubMed2004

Gastroparesis following kidney/pancreas transplant.

This pilot study examined associations among patterns of gastric myoelectrical activity, symptoms of gastroparesis, years of diabetes, months of dialysis, and use of gastrointestinal medications in gastroparetic kidney-pancreas (KP) transplant recipients. Electrogastrography (EGG) and gastric symptom data were obtained from 42 transplant recipients before and after transplant (6, 12, and 24 months). Recipients were 38 +/- 7 yr of age, 88% Whites, and 60% male; 97% had hypertension. All had functioning grafts post-transplant (mean creatinine, 1.59 +/- 0.66 mg/dL, and serum glucose 91.97 +/- 24.92 mg/dL). Sixteen subjects had normal EGG (2.7-3.2 cycles per minute, cpm); two were tachygastric (>3.2 cpm) at all time points; one remained bradygastric (<2.7 cpm) throughout the study period. Following transplant, symptoms lessened and were associated with 6-month normalization of EGG (r = 0.41, p = 0.02). A small change in the percentage of patients with normal EGG was observed from baseline to 24 months (67% vs. 69% respectively); however, there was a shift from bradygastria (29% to 15% respectively) to tachygastria (5% to 15% respectively). Prescribed prokinetic and antisecretory medications use increased over the study period from 13 (31%) subjects at baseline to 32 (86%) at 6 months; 21 (78%) at 12 months; and 12 (92%) at 24 months. Although symptoms diminish following transplant, gastroparesis remains a significant problem for transplant patients. Normalization of EGG and shifts from bradygastria to tachygastria occur post-transplant. Our results suggest that serial EGGs and frequent assessment of symptoms can be used to follow gastroparesis in KP recipients.

Adult↗

PubMed1994

Colic motor complex of the cecum and proximal loop of the ascending colon observed in an experimental cow with large intestinal obstruction.

Myoelectric activity of the cecum and proximal loop of the ascending colon (PLAC) and the effect of xylazine on motility of this intestinal segment in an experimental cow with large intestinal obstruction are described and compared with the normal motility pattern. During obstruction, three major observations were made in the prestenotic area. (i) Mean spike duration, overall duration of spiking activity (expressed as percentage of total recording time), number of spikes propagated from the cecum towards the obstruction site, and velocity of propagated spikes were substantially increased. (ii) The spike frequency was in the physiologic range. (iii) A single injection of xylazine, administered intravenously at a dose of 0.05 mg/kg markedly reduced the mean spike duration, the overall spiking activity, and the number of propagated spike sequences, and abolished signs of abdominal discomfort. Our data indicate that obstruction of the bovine colon causes a similar pattern of prestenotic hypermotility (colic motor complex) as described for the small intestine of the horse. Xylazine may be a suitable drug to disrupt prestenotic hypermotility and alleviate abdominal discomfort during proximal colonic obstruction in cattle.

Animals↗

PubMed1998

Effect of cisapride on myoelectrical activity of the gastrointestinal tract in the conscious miniature pig.

In conscious miniature pigs with electrodes implanted in the wall of the antrum pylori, duodenum, jejunum, ileum and caecum, the influence of intravenous injection of cisapride, 0.5 and 1 mg/kg, on gastrointestinal myoelectrical activity, was examined. Cisapride, 1 mg/kg, induced a delayed and sustained increase in antral myoelectrical activity. The studied intestinal segments were rather insensitive to the stimulating effect of the benzamide, since only the jejunum and the caecum revealed an increase in myoelectrical activity with the higher dose studied.

Animals↗

PubMed1998

Effect of some gastrointestinal hormones on antral, small intestinal and caecal myoelectrical activity in the conscious miniature pig.

The effect of i.v. infusion of gastrin (CCK-4), cholecystokinin (CCK-8) and pancreatic polypeptide (PP), 20 and 200 ng/kg/min for 1 h, on gastrointestinal electrical activity and arterial pressure was studied in conscious miniature pigs. During infusion of CCK-8 a transient hypertension was observed. In the antrum, the 3 peptides provoked an increase in slow wave activity and a decrease in spike activity. In the intestine, CCK-8 induced an increase in ileal spiking activity, whereas infusion of PP resulted in an increased frequency of long spike bursts in the caecum.

Animals↗

PubMed1998

An improved electrogastrographic system in measuring myoelectrical parameters.

This study assessed the reliability of an improved electrogastrographic (EGG) system in recording stomach myoelectrical parameters and tried to establish the normal ranges of myoelectricity using this system. The analytical software of the current system mainly included an autoregressive modelling program to compute myoelectrical frequency and power. Forty healthy subjects were enrolled to receive myoelectrical measurement in two consecutively fasting and one postprandial 30 min sessions. The myoelectrical frequencies in both fasting and postprandial sessions were almost three cycles per min (c.p.m.) and showed little variation. The percentage of dominant frequencies (2.5-3.5 c.p.m.) in three sessions was approximately 80% while the computed myoelectrical powers in the first and second fasting sessions exhibited a significant correlation (r=0.84, P<0.001). Meal ingestion increased the myoelectrical powers by 6.8dB compared with the second fasting recording (P< 0.001). The mean variation in myoelectrical amplitude for the ratio of second: first fasting session was 110.3+/-88.8% (16-478%, median 88%). This new EGG system is, indeed, reliable for measuring myoelectrical frequency and power, whereas the interassay of recorded amplitudes appears markedly variable.

Adult↗

PubMed2004

Gastric electrical activity in patients with cholelithiasis undergoing laparoscopic cholecystectomy: a prospective controlled study.

BACKGROUND: The aim of the present study was to evaluate the effect of gallstone disease (GD) and laparoscopic cholecystectomy on gastric electrical activity of slow waves, which was recorded via transcutaneous electrogastrography (EGG). METHODS: Twenty-one consecutive patients (M/F: 12/9, 52.7 +/- 15 years old) with GD and no previous history of abdominal operations or known disease affecting gastrointestinal motility were studied. The EGG was performed for 30 min prior to and 90 min after a standard meal, during a 4-6 month period prior to and after laparoscopic cholecystectomy. The percentile proportion of the three spectra of gastric slow waves frequency was studied, defined as follows: bradygastria, 1-2.1 cycles per min (c.p.m.); normogastria, 2.2-3.9 c.p.m.; and tachygastria, 4-9 c.p.m. The findings were compared to those of nine healthy subjects (M/F: 5/4, 49.5 +/- 14.8 years old). RESULTS: No statistically significant difference was found in percentile distribution of bradygastria, normogastria and tachygastria, pre- or post-prandially, neither before or after laparoscopic cholecystectomy, nor between patients and controls. CONCLUSIONS: Patients with GD do not exhibit differences in gastric electrical activity of slow waves in comparison to normal subjects and laparoscopic cholecystectomy does not alter gastric electrical activity. These findings suggest that cholelithiasis does not seem to cause dyspeptic symptoms due to gastric dysrythmias.

Adult↗

PubMed2005

Electrogastrography: basic knowledge, recording, processing and its clinical applications.

The slow wave (SW) of the gastrointestinal (GI) tract mainly functions to trigger the onset of spike to elicit smooth muscle contraction, which provides the essential power of motility. Smooth muscle myogenic control activity or SW is believed to originate in the interstitial cells of Cajal (ICC). The electrical coupling promotes interaction between muscle cells, and ICC additionally contribute to SW rhythmicity. Stomach SW originates in the proximal body showing the continuous rhythmic change in the membrane potential and propagates normally to the distal antrum with a regular rhythm of approximately 3 c.p.m. A technique using electrodes positioned on the abdominal skin to pick up stomach rhythmic SW refers to electrogastrography (EGG). The stomach SW amplitude is very weak, while many visceral organs also produce rhythmic electricities, for example heartbeat, respiration, other organs of the GI tract and even body movements. Thus noise other than SW should be filtered out during the recording, while motion artifacts are visually examined and deleted. Finally, the best signal among all recordings is selected to compute EGG parameters based on spectral analysis. The latter is done not only to tranform frequency domain to time domain but also to provide information of time variability in frequency. Obtained EGG parameters include dominant frequency/power, % normal rhythm, % bradygastria, % tachygastria, instability coefficient and power ratio. Clinical experience in EGG has been markedly accumulated since its rapid evolution. In contrast, lack of standardized methodology in terms of electrode positions, recording periods, test meals, analytic software and normal reference values makes the significance of EGG recording controversial. Unlike imaging or manometrical studies, stomach motility disorders are not diagnosed based only on abnormal EGG parameters. Limitations of EGG recording, processing, computation, acceptable normal parameters, technique and reading should be known to conduct subjective assessments when EGG is used to resolve stomach dysfunction. Understanding basic SW physiology, recording methodology and indications may open EGG as a new domain to approach the stomach motor dysfunction.

Action Potentials↗

PubMed2005

Calcitonin gene-related peptide released by capsaicin suppresses myoelectrical activity of gastric smooth muscle.

BACKGROUND: It is widely accepted that the inhibition of gastric motor activity as well as the maintenance of gastric mucosal blood flow and mucous secretion are important for the homeostasis of the gastric mucosa. The present study was performed to ascertain whether or not capsaicin, which can protect the stomach from noxious stimuli, affects gastric motor activity. METHODS: Male Sprague-Dawley rats were anesthetized with urethane, and the stomach was cannulated by two catheters from esophageal and duodenal sides. A biopolar electrode was fixed to the serosal surface of the antrum and myoelectrical activity was recorded during the instillation of a small volume of solutions. RESULTS: The myoelectrical activity of rat gastric smooth muscle was increased at intragastric pressures of >2 cmH(2)O. Replacement of intragastric physiological saline with 1.6 mmol/L capsaicin solution significantly suppressed this myoelectrical activity by 50%. Intragastric capsaicin administration caused a significant release of substance P (SP) and calcitonin gene-related peptide (CGRP). The maximum released levels of CGRP in the gastric perfusates were 100-fold those of SP. The myoelectrical activity observed at an intragastric pressure of 2 cmH(2)O was avoided by continuous infusion of CGRP (0.1-3.0 nmol/kg per min) into the gastric artery in a dose-dependent manner, but not by that of SP (1.0 nmol/kg per min). Continuous CGRP-(8-37) infusion into the gastric artery completely blocked the reduction by intragastric capsaicin of myoelectrical activity. CONCLUSION: These results suggest that the suppression of the myoelectrical activity of gastric smooth muscle by capsaicin is attributable to the endogenous CGRP released.

Analysis of Variance↗

PubMed2005

Effects of enhanced viscosity on canine gastric and intestinal motility.

BACKGROUND AND AIM: The aim of this study was to investigate the effect of enhanced viscosity on gastric emptying and gastrointestinal motor and myoelectrical activities in dogs. METHOD: The study was performed in eight healthy female hound dogs chronically implanted with four pairs of gastric and two pairs of intestinal serosal electrodes and a duodenal fistula. Each dog was studied in three sessions and fed with three test meals with different viscosity. Gastric emptying was monitored for 2 h simultaneously with gastric and intestinal myoelectrical recordings. RESULTS: The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly delayed gastric emptying but had no effect on postprandial blood glucose levels in comparison with the meal containing no galactomannan. The liquid test meal containing either 0.78% or 1.21% of galactomannan significantly increased the frequency and strength of intestinal motility but had no effect on intestinal slow wave rhythms. The product with enhanced viscosity had no effect on gastric motor activity or gastric slow waves. CONCLUSION: It was concluded that enhanced viscosity delays gastric emptying, increases postprandial intestinal but not gastric motility, and has no effects on gastric or intestinal slow waves.

Animal Feed↗