Gastric Slow Waves Research Articles

Serosal and cutaneous recordings of gastric myoelectrical activity in patients with gastroparesis

The aims of this study were to 1) investigate gastric myoelectrical activity in patients with gastroparesis, 2) validate the cutaneous electrogastrogram (EGG) in tracking the frequency change of the gastric slow wave, and 3) investigate the effect of electrical stimulation on gastric myoelectrical activity. Gastric myoelectrical activity was recorded in 12 patients with documented gastroparesis using serosal electrodes for > 200 min in each subject. All recordings were made at least 4 days after surgery. Each session consisted of a 30-min recording in the fasting state and a 30-min recording after a test meal. The test meal (liquid or mixed) was selected according to patient's tolerance. Electrical stimulation was performed in three subjects via the serosal electrodes at a frequency of 3 cycles/min. Gastric myoelectrical activity was recorded using serosal electrodes in each session. The serosal recording showed slow waves of 2.5 to 4.0 cycles/min in all 12 subjects. Absence of spikes was noted in 11 of the 12 subjects. The simultaneous serosal and cutaneous recording of gastric myoelectrical activity showed that the frequency of the EGG was exactly the same as that of the serosal recording. Liquid meals resulted in a significant decrease in slow-wave frequency (Student's t test, P = 0.006), and the EGG accurately reflected this change. Electrical stimulation had no effect on the frequency of the gastric slow wave and did not induce spikes.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of fat preload on gastric myoelectrical activity in normal humans

AbstractThe aim of this study was to investigate the effect of fat preload on gastric myoelectrical activity in normal humans. The study was performed in 10 normal subjects (five males, five females) fasted for 6h or more. Gastric myoelectrical activity was recorded using surface abdominal electrodes. In the study session the subjects ingested a 40‐g liquid fat meal (2 oz of lipomul) after a 30‐min baseline recording. A test meal (225 kcal beef stew) was then consumed 15 min after drinking the lipomul, and the recording was continued for 2 h after the test meal. The control session performed on a separate day followed the same procedure except that the lipomul was replaced by 2 oz of water. The order of the study and control sessions was randomized. The cutaneous recording of gastric myoelectrical activity (electrogastrogram or EGG) was digitized and subjected to computerized quantitative data analysis. The peak power and the corresponding frequency of the EGG during every 15‐min time interval were computed using spectral analysis. Student's t‐test was applied to determine the effect of fat preload on the surface recording of gastric myoelectrical activity. It was found that: (1) the power of the 15‐min EGG at the dominant frequency immediately after fat preload was significantly lower than that of the baseline EGG (P = 0.01); (2) the postprandial power increase of the EGG at the dominant frequency was significantly lower with fat preload than with placebo preload (P = 0.002); (3) the dominant frequency of the EGG was not affected by fat preload. It was concluded that fat preload significantly decreases the power of the EGG but does not affect the frequency of the gastric slow wave.

Spectral analysis of episodic rhythmic variations in the cutaneous electrogastrogram.

Electrical activity of the stomach can be measured using surface electrodes. The cutaneous recording of gastric electrical activity is called the electrogastrogram (EGG). Gastric electrical dysrhythmic events associated with abnormal conditions of the stomach may be detected from the EGG. An adaptive spectral analysis method which is based on autoregressive moving average modeling has previously been developed. The aim of this paper is to demonstrate the ability of the previous method in detecting gastric dysrhythmic events from the EGG. A series of bench tests stimulating typical problems with the analysis of nonstationary electric potentials was conducted. The application of the adaptive spectral analysis method to dysrhythmic events and rhythmic variations of the gastric slow wave is presented in this paper. The adaptive spectral analysis approach provides several advantages: narrow frequency peaks permitting more precise frequency identification, determination of changes in frequency components at any time point, and enhanced interpretation of cutaneous EGG recordings.

Human gastric myoelectric activity and gastric emptying following gastric surgery and with pacing

Postoperative gastric myoelectric activity, gastric emptying, and clinical course were correlated in 17 patients at high risk of developing gastroparesis after gastric surgery. In addition, an attempt was made to pace the stomach with an electrical stimulus and determine the effect of pacing on early post-operative gastric emptying. Gastric dysrhythmias (bradygastria, slow wave frequency <2 cycles/min; tachygastria, slow wave frequency >4 cycles/min) persisted beyond the first postoperative day in 6 patients (35%). Delayed gastric emptying was identified by a radionuclide meal in 15 patients (88%), but symptoms of gastroparesis developed in only 6 of 15 (40%). Patients with postoperative gastroparesis had more frequent dysrhythmias than asymptomatic patients (67% vs. 18%), but these differences were not significant, although we cannot exclude a type II statistical error. Gastric rhythm was entrained in 10 of 16 patients (63%). Pacing increased the gastric slow wave frequency (3.1 vs. 4.1 cycles/ min; P < 0.01) but did not improve gastric emptying (gastric retention at 60 minutes, 86% ± 6% for control and 90% ± 2% for paced). In conclusion, gastric dysrhythmias do not appear to play a major role in the development of postsurgical gastroparesis. Although gastric rhythm could be entrained in the majority of patients, pacing did not improve gastric emptying overall.

Hyperglycemia but not hyperinsulinemia induces gastric slow wave dysrhythmias with suppression of gastric motility in the fed state

Hyperglycemia but not hyperinsulinemia induces gastric slow wave dysrhythmias with suppression of gastric motility in the fed state

Gastric slow wave abnormalities in patients with gastroparesis.

The aim of this study was to determine whether cutaneous electrogastrograms (EGGs) could be used to differentiate gastroparetic patients from asymptomatic healthy controls. Pre- and postprandial cutaneous EGGs were obtained from 24 asymptomatic healthy volunteers and 27 patients with gastroparesis documented by a delayed gastric emptying of a solid test meal. A definition of slow wave abnormality was introduced. For the fasted condition, all 24 controls showed highly regular, predominant peaks in the 2-4 cycles/min (cpm) range, in contrast to the patient group in which 11 subjects showed an absence of normal slow wave activity (p less than 0.001). For the postprandial condition, again, all 24 controls showed slow wave normality consisting of increased amplitude and regularity of the 2-4 cpm frequency component. This was in sharp contrast to the patient group in which 13 subjects showed abnormalities (p less than 0.0001). Approximately 75% of the patients had an abnormal pre- or postprandial EGG: four patients had abnormal EGGs both during fasting and after eating, seven patients had abnormal EGGs during fasting but normal EGGs after eating, and nine patients had normal EGGs during fasting but abnormal EGGs after eating. We conclude that the cutaneous EGG may be used to differentiate gastroparetic patients from asymptomatic normals.

Distributions of interstitial cells of Cajal in stomach and colon of cat, dog, ferret, opossum, rat, guinea pig and rabbit

Electrical slow waves vary in prominence from one location to another in stomach and colon. If interstitial cells of Cajal are involved in generation of the slow waves, they might be more abundant in regions where slow waves are prominent than in regions where slow waves are small or absent. We calculated the density of distribution of interstitial cells of Cajal in colon and stomach of cat, dog, ferret, guinea pig, opossum, rabbit, and rat, using the zinc iodide-osmic acid reaction for light microscopy. The cells in the stomach were concentrated in the myenteric plexus and in the circular muscle layer. Along the greater curvature, cells were relatively sparse in the fundus, more frequent in the corpus and densest in the antrum. Along the lesser curvature, they were denser distally than proximally in all species except guinea pig. In the colon most cells lay with an axonal network at the circular muscle-submucosal interface. The axons were sparse in the cecum but uniformly conspicuous from the ileocolonic junction to the internal anal sphincter. The density of the interstitial cells of Cajal in cat, dog, opossum, and rabbit rose from a relatively low level in the cecum to a maximum in the mid-colon, declining toward the rectum. In guinea pig, rat, and ferret, the levels throughout the most proximal colon were high. Since gastric slow waves are absent from the fundus, diminutive in the body, and prominent in the antrum, the density of interstitial cells of Cajal in the stomach roughly parallels the prominence of slow waves. Colonic slow waves are most prominent in the right colon and mid-colon, and so the density distribution of interstitial cells of Cajal in the colon also roughly parallels the prominence of slow waves.

Response of the electric activity in the human stomach to water and a solid meal

The gastric electric activity paces the contractions of the stomach and can be measured noninvasively using surface electrodes placed on the abdomen. In this paper, response of the gastric electric activity to water and a solid meal was investigated using surface electrodes. Applying an improved recording technique, power spectral analysis and statistical analysis methods, the gastric electric activity in preprandial, postwater and postprandial states was measured and analysed from ten healthy volunteers. To more convincingly show the effect of water and the solid meal on the gastric slow wave and gastric motility, simultaneous recordings of the cutaneous EGG and manometric activities in the stomach were performed in three gastroparetic patients. It was found that water does not induce contractions of the stomach, but the gastric slow wave amplitude increases (p less than 0.05) and frequency decreases (p less than 0.05). The solid meal results in an increase in both the amplitude (p less than 0.01) and the frequency (p less than 0.02) of the gastric slow wave. It appears that the postprandial EGG amplitude increases because of a combination of stomach contractions and gastric distension bringing the stomach closer to the recording electrodes. The slow wave frequency, however, correlates well with stomach contractions.

Inhibition of electrical slow waves and Ca2+ currents of gastric and colonic smooth muscle by phosphatase inhibitors.

The effects of calyculin A, a phosphatase inhibitor isolated from the marine sponge Discodermia calyx, on the electrical activity of colonic and gastric muscles were studied. Calyculin A reduced the amplitude and duration of slow waves, primarily by inhibiting the plateau component. Okadaic acid, another phosphatase inhibitor, also reduced the amplitude and duration of gastric slow waves. The mechanism of action of calyculin A was investigated by studying its effects on inward currents of isolated gastric and colonic myocytes. Calyculin A reduced the amplitude of the peak and the sustained components of the inward current. Okadaic acid had similar effects. These data suggest that phosphorylation of Ca2+ channels of gastrointestinal smooth muscles may inhibit Ca2+ currents. This mechanism may provide an important means of regulating the currents responsible for excitation-contraction coupling in these muscles.

Electrogastrography: measuremnt, analysis and prospective applications

Electrogastrography (EGG), the cutaneous recording of the myoelectrical activity of the stomach using surface electrodes, is attractive due to its noninvasiveness and its correlation with gastric motility. Since the first measurement of the EGG, a great deal of research effort has been expended on investigating its relationship with specific activities of the stomach in question. In this review, we discuss how to measure the EGG, what information is available in the EGG, how to extract useful information from the EGG and the prospective applications of the EGG. After a brief historic evolution of the EGG, we first discuss the measurement of the EGG, the importance of localisation of the stomach and the characteristics of the EGG. The most commonly used EGG data-analysis methods, both power spectral analysis and waveform analysis, are then outlined. Some of prospective applications of the EGG in clinical diagnosis and medical research are described, mainly concerning the correlation between EGG amplitude and gastric motility and that between EGG rhythmic variations and motility disorders. Specifically, we present studies on pre- and postprandial EGGs, observation of the propagation direction of the gastric slow wave and gastric electrical dysrhythmias and their correlation with gastric motility.

Gastrointestinal Electrical Activity in the Prairie Dog During Fasting, Feeding, and After High‐Cholesterol Diet

This study describes the electromyographic characteristics of the gastrointestinal tract of prairie dogs, and examines the effects of a 1.2% cholesterol diet on intestinal myoelectrical activity. Twelve prairie dogs were implanted with eight bipolar electrodes in the stomach and small bowel. Recordings were obtained during fasting (n = 12), gastric instillation of food (n = 7), and chronic cholesterol feeding for 3 weeks (n = 7). Gastric slow waves had a frequency per minute of 4.9 ± 1. Intestinal slow waves had a frequency per minute of 19.1 ± 2 in the duodenum, and of 16.8 ± 1 in the ileum. The migrating myoelectric complex (MMC) was identified, with an interval between two consecutive phases I of 145 ± 33 minutes. The delivery of diets of equal weight into the stomach interrupted fasting activity for approximately 3 hours. This was followed by a duodenal phase III and return of the fasted pattern. The interval between the first two postprandial phases I of the MMC not only was shorter than in the fasted state, but also was shorter after cholesterol diet than after regular diet (89 ± 33 min versus 116 ± 24 min, p ≤ 0.05). Chronic feeding of cholesterol diet did not affect the length of the MMC. In conclusion, the gastrointestinal tract of prairie dogs exhibits slow waves, spike bursts, and an MMC that is interrupted by feeding. High‐cholesterol diet does not induce significant changes in the pattern of electrical activity.

Organization of electrical activity in the canine pyloric canal.

1. The electrical activity of the canine gastroduodenal junction was investigated using cross-sectional muscle preparations and intracellular recording techniques. 2. Spontaneous electrical slow waves were recorded from antral and pyloric cells but not from duodenal cells adjacent to the pyloric region. Slow waves were generated in the antrum and propagated to the pyloric region via the circular layer. Pyloric slow waves consisted of an upstroke phase, a plateau phase and oscillations superimposed upon the plateau, whereas antral slow waves had smooth plateau potentials. 3. Within the pylorus slow waves decayed in amplitude with distance from the myenteric border of the circular muscle; the majority of pyloric circular cells were normally electrically quiescent. 4. The longitudinal muscle in the pylorus was electrically coupled and paced by the circular muscle. In longitudinal cells slow waves were usually of long duration with multiple spikes superimposed upon the plateau phase. 5. Nifedipine (10(-8) to 10(-5) M) decreased slow waves amplitude and duration. Tetraethylammonium ions (TEA; 10 mM) increased the duration of slow waves, caused spiking activity during the plateau phase and also elicited spiking in the quiescent regions. 6. The results suggest that gastric slow waves pace the myenteric portion of the circular muscle layer and the longitudinal layer of the pylorus, but do not traverse the gastroduodenal junction, nor pace the majority of cells within the circular muscle of the pylorus. Other excitatory mechanisms are necessary to activate these regions and to co-ordinate their motility with gastric motility.

Effect of dopamine on electrical activity of isolated stomach muscle in cats.

The effect of dopamine on electrical activity (gastric slow wave) of the stomach was studied in isolated stomach muscle strips of 145 cats. The gastric slow wave was recorded by four monopolar electrodes (Ag-AgCl) in Krebs-Ringer solution (pH 7.4, temperature 36 +/- 0.5 degrees C) bubbled with 5% CO2 in O2. Dopamine induced concentration-dependent alterations in frequency and propagation of slow waves. Development of irregular propagation was significantly suppressed by domperidone pretreatment. The variation of dopamine-induced slow-wave frequency was significantly inhibited by domperidone and phentolamine but not by propranolol, hexamethonium, and tetrodotoxin. The study indicates that a dopamine receptor exists in the stomach and plays a role in the genesis of gastric electrical abnormality.

Are relaxation oscillators an appropriate model of gastrointestinal electrical activity?

Mathematical models based on relaxation oscillators have heavily influenced the terminology and experimental designs of investigations in gastrointestinal motility for nearly two decades. Relaxation oscillator equations have been used to stimulate the electrical activities of the esophagus, stomach, small intestine, colon, and rectosigmoid region. It has been suggested that many attributes of gastrointestinal electrical activity cannot be adequately explained by classic "core-conductor" or "cable" models of excitation and conduction. This article critically reviews the relaxation oscillator model and provides an explanation for each of the putative inadequacies of core-conductor theory. Furthermore, we question whether relaxation oscillator equations are able to simulate the waveforms of gastrointestinal slow waves, alterations in waveform in response to drugs or electrical stimulation, patterns of slow-wave activity when stimulated at physiological frequencies, prolonged periods of constant resting membrane potential between gastric slow waves and electrotonic spread into inactive regions. We conclude that the relaxation oscillator equations do not fully describe gastrointestinal electrical activity; excitation and propagation can be modeled by a theory that provides for morphological features, ionic conductances, and other elements included in the cable equations.

The action of histamine on the isolated stomach muscle of the cat.

The effect of histamine on contractile and electric activity was studied in the isolated stomach muscle strips of 138 cats. Histamine dose-dependently produced tonic and phasic contractions of the muscle preparations from the fundus and the corpus but only phasic contraction of the antral muscle preparations. The frequency of gastric slow waves (SWs) was also increased dose-dependently by histamine. The responses of muscle contractions and gastric SW frequency to histamine were completely blocked by pretreatment with pyrilamine (10(-6) M) and were significantly inhibited by atropine (10(-5) M) but not by cimetidine (10(-5) M), hexamethonium (10(-5) M), phentolamine (10(-5) M), or propranolol (10(-5) M). The inhibition by pyrilamine was competitive. Although atropine inhibited the effect of histamine significantly, it could not completely block the effect of histamine even at a high concentration (3 x 10(-5) M). It is concluded that histamine may participate in the regulation of gastric motility in the cat by acting on the H1 receptor to cause the release of acetylcholine and also other contractile substance(s).

Etude de l'activité électrique gastroduodénale,in situ, au cours de I'anesthésie et du réveil. Etude chez le rat porteur d'électrodes chroniques

The effect of anaesthesia (sodium pentobarbital, two various doses) was studied in the rat with chronic gastric and duodenal electrodes. Gastric and duodenal electrical activity was recorded in pre- and peranesthesia period. All rhythmic slow and fast components are slowed in the same condition of time when an important decrease of central temperature is observed (external controlled temperature 22 degrees C). Gastric slow wave (650 microV, frequency normal level 5.6 c/min) decreases about 40% in 180 min. The waking arise after 5h30, 1h30 before the complete recuperation of the previous rhythm. For half dose conditions, gastric slow wave frequency decreases about 30% in 30 min; waking up occurs in 90 min. Gastric emptying complex observed previously. Is only observed during 20-30 min of the initial period of the anaesthesia at 50 mg/kg, and throughout the anaesthesia at 25 mg/kg.

Effect of prostaglandin E 2 on the electrical activity of cat isolated stomach muscle

Prostaglandins (PGs) are believed to be present in the gastrointestinal tract and to increase the tone of longitudinal muscle layer. However the influence of PGs on the gastric slow wave (SW) is not clarified yet. We therefore investigated the effect of prostaglandin E 2 (PGE 2) on the electrical and the mechanical activities of feline isolated stomach muscle strips (7 × 1.5 cm), using five capillary electrodes (Ag-AgCl) and an isometric force transducer connected to the antral edge. One hundred and ninety-six strips, obtained from the corpus and antrum of 196 anaesthetized cats, were studied in a muscle chamber filled with Krebs solution (pH 7.4, temperature 36°C) bubbled with 5 % CO 2 in O 2. Exogenous PGE 2 concentration-dependently increased the gastric SW frequency without affecting the spike and mechanical activities. Indomethacin decreased the SW frequency. These responses to PGE 2 or indomethacin were not blocked by phentolamine, propranolol, hexamethonium, atropine or tetrodotoxin. It is therefore suggested that PGE 2 facilitates the development of the gastric SW by an action on the muscle that does not involve cholinergic or adrenergic mechanism.

Coordinated motor activity of the human gastroduodenal region.

Using real-time ultrasonic imaging, and a test meal of 500 ml of dilute orange juice, we have studied the temporal relationships among contractions of the terminal antrum, pylorus, and proximal duodenum of 22 normal subjects. A total of 259 cyclical periods of motor activity were observed. Individual mean gastroduodenal cycle times ranged from 17.9 to 29.6 seconds (2.0-3.3 cycles/min). Terminal antral contractions (TACs) were observed in 98% of cycles and pyloric closure invariably occurred at the midpoint of these contractions. The pylorus then opened as the terminal antrum relaxed and remained open until the next TAC. Only 67% of TACs were associated with contractions of the proximal duodenum (DC), but 94% of these occurred about 1 sec (range 1 sec before to 2 sec after) after pyloric closure. Only 6% of DCs were ectopic, in that their occurrence was apparently uncoordinated with the TACs. Our observations demonstrate that after ingestion of a test meal, the human terminal antrum, pylorus, and proximal duodenum usually contract in a sequential coordinated manner, presumably under the control of the gastric slow wave. No evidence of independent pyloric closure was obtained.

Premature control potentials in the dog stomach and in the gastric computer model.

ARTICLESPremature control potentials in the dog stomach and in the gastric computer modelSK Sarna, EE Daniel, and YJ KingmaSK Sarna, EE Daniel, and YJ KingmaPublished Online:01 Jun 1972https://doi.org/10.1152/ajplegacy.1972.222.6.1518MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByAdvanced spatiotemporal mapping methods give new insights into the coordination of contractile activity in the stomach of the ratR. G. Lentle, G. W. Reynolds, C. M. Hulls, and J. P. Chambers13 December 2016 | American Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 311, No. 6Origin, propagation and regional characteristics of porcine gastric slow wave activity determined by high-resolution mapping6 July 2010 | Neurogastroenterology & Motility, Vol. 22, No. 10Origin and propagation of human gastric slow-wave activity defined by high-resolution mappingGregory O'Grady, Peng Du, Leo K. Cheng, John U. Egbuji, Wim J. E. P. Lammers, John A. Windsor, and Andrew J. Pullan1 September 2010 | American Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 299, No. 3High-resolution entrainment mapping of gastric pacing: a new analytical toolGregory O'Grady, Peng Du, Wim J. E. P. Lammers, John U. Egbuji, Pulasthi Mithraratne, Jiande D. Z. Chen, Leo K. Cheng, John A. Windsor, and Andrew J. Pullan1 February 2010 | American Journal of Physiology-Gastrointestinal and Liver Physiology, Vol. 298, No. 2A Tissue Framework for Simulating the Effects of Gastric Electrical Stimulation and In Vivo ValidationIEEE Transactions on Biomedical Engineering, Vol. 56, No. 12Magnetogastrographic detection of gastric electrical response activity in humans15 February 2006 | Physics in Medicine and Biology, Vol. 51, No. 5Multiscale modelling of human gastric electric activity: can the electrogastrogram detect functional electrical uncoupling?3 March 2006 | Experimental Physiology, Vol. 91, No. 2Fifty-eight years in science – a commentaryCanadian Journal of Physiology and Pharmacology, Vol. 83, No. 8-9An anatomical model of the gastric system for producing bioelectric and biomagnetic fields23 July 2004 | Physiological Measurement, Vol. 25, No. 4Modelling gastrointestinal bioelectric activityProgress in Biophysics and Molecular Biology, Vol. 85, No. 2-3A Simple Nonlinear Model of Electrical Activity in the IntestineJournal of Theoretical Biology, Vol. 204, No. 1Interstitial cells of Cajal: are they major players in control of gastrointestinal motility?28 June 2008 | Neurogastroenterology & Motility, Vol. 4, No. 1In vivo myoelectric activity: methods, analysis, and interpretation1 January 2011Effect of prostaglandin E2 on the electrical activity of cat isolated stomach muscleProstaglandins, Vol. 30, No. 1Glucagon-evoked gastric dysrhythmias in humans shown by an improved electrogastrographic techniqueGastroenterology, Vol. 88, No. 6Postoperative gastrointestinal electrical and mechanical activities in a patient with idiopathic intestinal pseudoobstructionGastroenterology, Vol. 74, No. 1The stability of entrainment conditions forRLC coupled van der pol oscillators used as a model for intestinal electrical rhythmsBulletin of Mathematical Biology, Vol. 39, No. 3Gastroenterology, Vol. 71, No. 4Gastrointestinal Electrical Activity: TerminologyGastroenterology, Vol. 68, No. 6Symposium on colonic function. Electrophysiology of the colon.Gut, Vol. 16, No. 4Myoelectric Control of the ColonGastroenterology, Vol. 68, No. 3Vagal Control of Gastric Electrical Control Activity and MotilityGastroenterology, Vol. 68, No. 2Models of Smooth Muscle Electrical ActivityElectrical activity of gastrointestinal smooth muscle.Gut, Vol. 15, No. 8Migrating Spike Bursts and Electrical Slow Waves in the Cat Colon: Effect of SectioningGastroenterology, Vol. 66, No. 2 More from this issue > Volume 222Issue 6June 1972Pages 1518-1523 Copyright & PermissionsCopyright © 1972 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1972.222.6.1518PubMed5030211History Published online 1 June 1972 Published in print 1 June 1972 Metrics

Patterns of canine gastric electrical activity.

Patterns of canine gastric electrical activity.