Efecto de la práctica mental kinestésica en la fuerza y actividad mioeléctrica del bíceps braquial, luego de un periodo de inmovilización de codo en adultos-jóvenes sanos / Effects of kinesthetic mental practice in strength and myoelectric activity of the brachialis biceps due to an elbow immobilization period in healthy young adults

RESUMEN: El objetivo de este estudio fue determinar el efecto de la práctica mental kinestésica (PMK) en la fuerza y actividad eléctrica muscular (AEM) del bíceps braquial, luego de un periodo de inmovilización del codo en un grupo de personas adultos jóvenes sanos. Un total de 14 personas (18,64 ± 0,92 años de edad) participaron voluntariamente del estudio, a las cuales se les evaluó la fuerza muscular de prensión y la AEM del bíceps braquial utilizando un dinamómetro de mano y un equipo de electromiografía, respectivamente, antes y después de un periodo de inmovilización del brazo no dominante, y se asignaron aleatoriamente a uno de dos grupos: grupo control (GC) o experimental (GE). El GE realizó PMK: tres series de 15 repeticiones con un minuto de descanso entre series, tres veces al día durante los seis días de inmovilización, mientras que el GC no realizó PKM durante su inmovilización. Al aplicar una prueba de ANOVA de dos vías, no se encontraron diferencias significativas en la fuerza ni en la AEM. Sin embargo, la fuerza del GC disminuyó en 23,75%, mientras que la del GE aumentó en 33,19%. Los resultados sugieren que un periodo de inmovilización del codo de seis días no fue suficiente para que la fuerza ni la AEM disminuyan significativamente, lo que supone que la PMK realizada no es necesaria en periodos menores a seis días.

ABSTRACT: The aim of this study was to determine the effect of kinesthetic mental practice (KMP) on the strength and muscular electrical activity (MEA) of the brachial biceps, after a period of immobilization of the elbow in a group of healthy young adults. A total of 14 volunteer participants (18.64 ± 0.92 years of age) were part in the study. The muscle strength and the AEM of the brachial biceps were assessed using a hand dynamometer and an electromyography equipment, respectively, before and after a period of immobilization of the non-dominant arm. After the pretest, they were randomly assigned to one of two groups: control group (GC) or experimental group (GE). The GE performed 3 sets of 15 repetitions with one-minute rest between sets, three times a day of PMK during the 6 days of immobilization, while the GC did not perform PKM during its immobilization. A 2-way ANOVA test (group x measurement) indicated non-significant differences in strength or AEM. However, the strength of the GC decreased by 23.75%, while increased by 33.19% in the GE. The results suggest that a period of immobilization of the elbow of 6 days was not enough for the strength or the AEM to decrease significantly, which means that the PMK is not necessary in periods of immobilization of less than 6 days.

Análise do exercício agachamento com e sem o uso de physioball e banda elástica em diferentes intensidades / Analysis of the squat exercise with and without physioball and elastic band in different intensities

RESUMO O objetivo do presente estudo foi analisar a atividade mioelétrica (EMG), o tempo sob tensão (TST) e a projeção dos joelhos no exercício agachamento sem o uso de implementos (SI) e com o uso de physioball (PH) e banda elástica (BE) em diferentes intensidades de esforço. Dez homens realizaram o exercício nos três protocolos com a intensidade de 50 e 100% de 10 RM. A distância entre joelhos no protocolo controle (51,25cm) foi menor quando comparada com o SI 50% (84,38cm; p < 0,001), com o SI 100% (88,80cm; p < 0,001) e com BE 100% (67,41cm; p = 0,014). A distância entre os joelhos também foi menor para os protocolos PH 100% (53,10cm; p < 0,001) e BE 100% (67,41cm; p < 0,001) comparada ao SI 100% (88,80cm). O Vasto Medial Oblíquo (VMO) apresentou maior ativação nos protocolos SI 50% (p = 0,035) e PH 50% (p = 0,028) quando comparados ao protocolo BE 50%. A realização do agachamento com cargas submáximas parece aumentar e diminuir a ativação do VMO quando realizado com PH e BE, respectivamente.

ABSTRACT The objective of the present study was to analyze the myoelectric activity (EMG), the time under tension (TST) and the knee projection in the squat exercise without the use of implements (SI) and with the use of physioball (PH) and elastic band (EB) at different intensities of effort. Ten men performed the exercise in the three protocols with the intensity of 50 and 100% of 10 RM. The distance between knees in the control protocol (51.25 cm) was lower when compared to SI 50% (84.38 cm, p <0.001), with SI 100% (88.80 cm, p <0.001) and with EB 100% (67.41cm, p = 0.014). The distance between the knees was also lower for the protocols PH 100% (53.10cm, p <0.001) and EB 100% (67.41, p <0.001) compared to the SI 100% (88.80 cm) protocols. The Vasto Medial Oblique (VMO) presented greater activation in the SI 50% protocols (p = 0.035) and PH 50% (p = 0.028) when compared to the EB 50% protocol. The accomplishment of squatting with submaximal loads seems to increase and decrease the activation of VMO when performed with physioball and BE, respectively.

Colonic Dysmotility in Murine Partial Colonic Obstruction Due to Functional Changes in Interstitial Cells

BACKGROUND/AIMS: Interstitial cells play important roles in gastrointestinal (GI) neuro-smooth muscle transmission. The underlying mechanisms of colonic dysmotility have not been well illustrated. We established a partial colon obstruction (PCO) mouse model to investigate the changes of interstitial cells and the correlation with colonic motility. METHODS: Western blot technique was employed to observe the protein expressions of Kit, platelet-derived growth factor receptor-α (Pdgfra), Ca²⁺-activated Cl⁻ (Ano1) channels, and small conductance Ca²⁺- activated K⁺ (SK) channels. Colonic migrating motor complexes (CMMCs) and isometric force measurements were employed in control mice and PCO mice. RESULTS: PCO mice showed distended abdomen and feces excretion was significantly reduced. Anatomically, the colon above the obstructive silicone ring was obviously dilated. Kit and Ano1 proteins in the colonic smooth muscle layer of the PCO colons were significantly decreased, while the expression of Pdgfra and SK3 proteins were significantly increased. The effects of a nitric oxide synthase inhibitor (L-NAME) and an Ano1 channel inhibitor (NPPB) on CMMC and colonic spontaneous contractions were decreased in the proximal and distal colons of PCO mice. The SK agonist, CyPPA and antagonist, apamin in PCO mice showed more effect to the CMMCs and colonic smooth muscle contractions. CONCLUSIONS: Colonic transit disorder may be due to the downregulation of the Kit and Ano1 channels and the upregulation of SK3 channels in platelet-derived growth factor receptor-α positive (PDGFRα⁺) cells. The imbalance between interstitial cells of Cajal-Ano1 and PDGFRα-SK3 distribution might be a potential reason for the colonic dysmotility.

High-resolution Mapping of Hyperglycemia-induced Gastric Slow Wave Dysrhythmias

BACKGROUND/AIMS: It is now recognised that gastric dysrhythmias are best characterised by their spatial propagation pattern. Hyperglycemia is an important cause of gastric slow wave dysrhythmia, however, the spatiotemporal patterns of dysrhythmias in this context have not been investigated. This study aims to investigate the relationship between hyperglycemia and the patterns of dysrhythmias by employing high-resolution (multi-electrode) mapping simultaneously at the anterior and posterior gastric serosa. METHODS: High-resolution mapping (8 × 16 electrodes per serosal) was performed in 4 anesthetized hounds. Baseline recordings (21 ± 8 minutes) were followed by intravenous injection of glucagon (0.5 mg per dose) and further recordings (59 ± 15 minutes). Blood glucose levels were monitored manually using a glucose sensing kit at regular 5-minute intervals. Slow wave activation maps, amplitudes, velocity, anisotropic ratio, and frequency were calculated. Differences were compared between baseline and post glucagon injection. RESULTS: Baseline slow waves propagated symmetrically and antegrade. The blood glucose levels were increased by an average of 112% compared to the baseline by the end of the recordings. All subjects demonstrated elevated incidence of slow wave dysrhythmias following injection compared to the baseline (48 ± 23% vs 6 ± 4%, P < 0.05). Dysrhythmias arose simultaneously or independently on anterior and posterior serosa. Spatial dysrhythmias occurred before and persisted after the onset and disappearance of temporal dysrhythmias. CONCLUSIONS: Infusion of glucagon induced gastric slow wave dysrhythmias, which occurred across a heterogeneous range of patterns and frequencies. The spatial dysrhythmias of gastric slow waves were shown to be more prevalent and persisted over a longer period of time compared to the temporal dysrhythmias.

Colonic Transit Disorder Mediated by Downregulation of Interstitial Cells of Cajal/Anoctamin-1 in Dextran Sodium Sulfate-induced Colitis Mice

BACKGROUND/AIMS: Interstitial cells of Cajal (ICC) and their special calcium-activated chloride channel, anoctamin-1 (ANO1) play pivotal roles in regulating colonic transit. This study is designed to investigate the role of ICC and the ANO1 channel in colonic transit disorder in dextran sodium sulfate (DSS)-treated colitis mice. METHODS: Colonic transit experiment, colonic migrating motor complexes (CMMCs), smooth muscle spontaneous contractile experiments, intracellular electrical recordings, western blotting analysis, and quantitative polymerase chain reaction were applied in this study. RESULTS: The mRNA and protein expressions of c-KIT and ANO1 channels were significantly decreased in the colons of DSS-colitis mice. The colonic artificial fecal-pellet transit experiment in vitro was significantly delayed in DSS-colitis mice. The CMMCs and smooth muscle spontaneous contractions were significantly decreased by 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), an ANO1 channel blocker, and NG-Nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of nitric oxide synthase activity, in DSS-colitis mice compared with that of control mice. Intracellular electrical recordings showed that the amplitude of NPPB-induced hyperpolarization was more positive in DSS-colitis mice. The electric field stimulation-elicited nitric-dependent slow inhibitory junctional potentials were also more positive in DSS-colitis mice than those of control mice. CONCLUSION: The results suggest that colonic transit disorder is mediated via downregulation of the nitric oxide/ICC/ANO1 signalling pathway in DSS-colitis mice.

Propagation Characteristics of Fasting Duodeno-Jejunal Contractions in Healthy Controls Measured by Clustered Closely-spaced Manometric Sensors

BACKGROUND/AIMS: High-resolution methods have advanced esophageal and anorectal manometry interpretation but are incompletely established for intestinal manometry. We characterized normal fasting duodeno-jejunal manometry parameters not measurable by standard techniques using clustered closely-spaced recordings. METHODS: Ten fasting recordings were performed in 8 healthy controls using catheters with 3–4 gastrointestinal manometry clusters with 1–2 cm channel spacing. Migrating motor complex phase III characteristics were quantified. Spatial-temporal contour plots measured propagation direction and velocity of individual contractions. Coupling was defined by pressure peak continuity within clusters. RESULTS: Twenty-three phase III complexes (11 antral, 12 intestinal origin) with 157 (95% CI, 104–211) minute periodicities, 6.99 (6.25–7.74) minute durations, 10.92 (10.68–11.16) cycle/minute frequencies, 73.6 (67.7–79.5) mmHg maximal amplitudes, and 4.20 (3.18–5.22) cm/minute propagation velocities were recorded. Coupling of individual contractions was 39.1% (32.1–46.1); 63.0% (54.4–71.6) of contractions were antegrade and 32.8% (24.1–41.5) were retrograde. Individual phase III contractions propagated > 35 fold faster (2.48 cm/sec; 95% CI, 2.25–2.71) than complexes themselves. Phase III complexes beyond the proximal jejunum were longer in duration (P = 0.025) and had poorer contractile coupling (P = 0.025) than proximal complexes. Coupling was greater with 1 cm channel spacing vs 2 cm (P < 0.001). CONCLUSIONS: Intestinal manometry using clustered closely-spaced pressure ports characterizes novel antegrade and retrograde propagation and coupling properties which degrade in more distal jejunal segments. Coupling is greater with more closely-spaced recordings. Applying similar methods to dysmotility syndromes will define the relevance of these methods.

Cutaneous Patches to Monitor Myoelectric Activity of the Gastrointestinal Tract in Postoperative Pediatric Patients / 대한소아소화기영양학회지

PURPOSE: Limited means exist to assess gastrointestinal activity in pediatric patients postoperatively. Recently, myoelectric gastrointestinal activity recorded by cutaneous patches has been shown in adult patients to be predictive of clinical return of gastrointestinal function postoperatively. The aim of this case series is to demonstrate the feasibility of this system in pediatric patients and to correlate myoelectric signals with return of bowel function clinically. METHODS: Pediatric patients undergoing abdominal surgery were recruited to have wireless patches placed on the abdomen within two hours postoperatively. Myoelectric data were transmitted wirelessly to a mobile device with a user-interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters and nominally assigned them to specific gastrointestinal organs based on their frequencies. RESULTS: Three patients (ages 5 months, 4 year, 16 year) were recruited for this study. Multiple patches were placed on the older subjects, while the youngest had a single patch due to space limitations. Rhythmic signals of the stomach, small intestine, and colon could be identified in all three subjects. Patients showed gradual increase in myoelectric intestinal and colonic activity leading up to the first recorded bowel movement. CONCLUSION: Measuring myoelectric intestinal activity continuously using a wireless patch system is feasible in a wide age range of pediatric patients. The increase in activity over time correlated well with the patients' return of bowel function. More studies are planned to determine if this technology can predict return of bowel function or differentiate between physiologic ileus and pathologic conditions.

Factors Influencing Gastric Microbiota

Researches on microbiota in the stomach have entered a revolutionary period in recent years due to the advanced technology that can detect culture-independent gastric microfloras. In spite of its harsh environment, stomach plays a role as an ecosystem for some microbiota. Their composition and number of colony forming units are influenced by several innate defense mechanisms such as low gastric pH, gastric mucus layer, migrating motor complex and some external factors such as gastric acid lowering medications and diet patterns. Here, we review the literatures concerning factors that influence the gastric microbiota.We believe this will be helpful for understanding the role of microbiota in the stomach.

Lipase Supplementation before a High-Fat Meal Reduces Perceptions of Fullness in Healthy Subjects

BACKGROUND/AIMS: Postprandial symptoms of fullness and abdominal discomfort are common after fatty meals. Gastric lipases hydrolyze 10% to 20% of dietary triglycerides during the stomach trituration period of digestion. The aim of this study was to evaluate the effects of acid-resistant lipase on upper gastrointestinal symptoms, including fullness and bloating, as well as on gastric myoelectrical activity after healthy subjects ingested a high-fat, liquid meal. METHODS: This study utilized a double-blind, placebo-controlled, crossover design with 16 healthy volunteers who ingested either a capsule containing 280 mg of acid-resistant lipase or a placebo immediately before a fatty meal (355 calories, 55% fat). Participants rated their stomach fullness, bloating, and nausea before and at timed intervals for 60 minutes after the meal. Electrogastrograms were obtained to assess the gastric myoelectrical activity. RESULTS: Stomach fullness, bloating, and nausea increased significantly 10 minutes after ingestion of the fatty meal (p<0.01), whereas normal gastric myoelectrical activity decreased and tachygastria increased (p<0.05). With lipase, reports of stomach fullness were significantly lower compared with placebo (p<0.05), but no effect on gastric myoelectrical activity or other upper gastrointestinal symptoms was observed. CONCLUSIONS: The high-fat meal induced transient fullness, bloating, nausea, and tachygastria in healthy individuals, consistent with post-prandial distress syndrome. Acid-resistant lipase supplementation significantly decreased stomach fullness.

Electrophysiological and Mechanical Characteristics in Human Ileal Motility: Recordings of Slow Waves Conductions and Contractions, In vitro

Little human tissue data are available for slow waves and migrating motor complexes, which are the main components of small bowel motility. We investigated the electrophysiological and mechanical characteristics of human ileal motility, in vitro. Ileum was obtained from patients undergoing bowel resection. Electrophysiological microelectrode recordings for membrane potential changes and mechanical tension recordings for contraction from smooth muscle strips and ileal segments were performed. Drugs affecting the enteric nervous system were applied to measure the changes in activity. Slow waves were detected with a frequency of 9~10/min. There were no cross-sectional differences in resting membrane potential (RMP), amplitude or frequency between outer and inner circular muscle (CM), suggesting that electrical activities could be effectively transmitted from outer to inner CM. The presence of the interstitial cell of Cajal (ICC) at the linia septa was verified by immunohistochemistry. Contractions of strips and segments occurred at a frequency of 3~4/min and 1~2/min, respectively. The frequency, amplitude and area under the curve were similar between CM and LM. In segments, contractions of CM were associated with LM, but propagation varied with antegrade and retrograde directions. Atropine, NW-oxide-L-arginine, and sodium nitroprusside exhibited different effects on RMP and contractions. There were no cross-sectional differences with regard to the characteristics of slow waves in CM. The frequency of contractions in smooth muscle strips and ileal segments was lower than slow waves. The directions of propagation were diverse, indicating both mixing and transport functions of the ileum.

Effects of acupuncture at "Tianshu" (ST 25) on electro-activity and mechanical motility of migrating motor complex during jejunal digestion period in rats with detached jejunum / 中国针灸

<p><b>OBJECTIVE</b>To observe the effects of acupuncture at "Tianshu" (ST 25) on electro-activity and mechanical motility at different phases of migrating motor complex (MMC) during jejunal digestion period in rats with detached jejunum, so as to explore the effect and mechanism of acupuncture on regulating intestinal movement.</p><p><b>METHODS</b>Sixteen adult SD rats were selected. Electrodes were implanted in the serous membrane of intestinal smooth muscl.e and high-sensitivity sensors of strain gauge were sutured on serosal surface, and then the rat was anesthetized and its jejunum was detached. Electro-acriviry and mechanical motility of jejunal smooth muscle were recorded simultaneously. Acupuncture was applied at "Tianshu" (ST 25) at MMC I , MMCII and MMC III, respectively, to observe its influence on electro-activity and mechanical motility.</p><p><b>RESULTS</b>At phase of MMC I, there was no obvious change of the fast wave before and after the acupuncture, while the frequency and amplitude of slow wave and mechanical motility were both significantly decreased compared with baseline (P < 0.01). At MMCII-Ill, the frequency and amplitude of fast wave, slow wave and motility were all significantly decreased compared with baseline (P < 0.01). Acupuncture at "Tianshu" (ST 25) had prohibited effects on electro-activity and mechanical motility of jejunal smooth muscle in rats with detached jejunum.</p><p><b>CONCLUSION</b>Acupuncture at "Tianshu" (ST 25) has obvious prohibited effects on electro-acrivity and mechanical motility at MMC I , MMC II and MMC III time phases in rats with detached jejunum. The possible mechanism is that acupuncture at "Tianshu" (ST 25) could prohibit jejunum movement through reflex path of skin-sympathetic.</p>

The Effects of Eupatilin (Stillen(R)) on Motility of Human Lower Gastrointestinal Tracts

Gastrointestinal motility consists of phasic slow-wave contractions and the migrating motor complex (MMC). Eupatilin (Stillen(R)) has been widely used to treat gastritis and peptic ulcers, and various cytokines and neuropeptides are thought to be involved, which can affect gastrointestinal motility. We performed a study to identify the effects of eupatilin on lower gastrointestinal motility with electromechanical recordings of smooth muscles in the human ileum and colon. Ileum and colon samples were obtained from patients undergoing bowel resection. The tissues were immediately stored in oxygenated Krebs-Ringer's bicarbonate solution, and conventional microelectrode recordings from muscle cells and tension recordings from muscle strips and ileal or colonic segments were performed. Eupatilin was perfused into the tissue chamber, and changes in membrane potentials and contractions were measured. Hyperpolarization of resting membrane potential (RMP) was observed after administration of eupatilin. The amplitude, AUC, and frequency of tension recordings from circular and longitudinal smooth muscle strips and bowel segments of the ileum and colon were significantly decreased after admission of eupatilin. Eupatilin elicited dose-dependent decreases during segmental tension recordings. In conclusion, eupatilin (Stillen(R)) showed inhibitory effects on the human ileum and colon. We propose that this drug may be useful for treating diseases that increase bowel motility, but further studies are necessary.

Colonic Migrating Motor Complexes, High Amplitude Propagating Contractions, Neural Reflexes and the Importance of Neuronal and Mucosal Serotonin

The colonic migrating motor complex (CMMC) is a critical neurally mediated rhythmic propulsive contraction observed in the large intestine of many mammals. It seems to be equivalent to the high amplitude propagating contractions (HAPCs) in humans. This review focuses on the probable neural mechanisms involved in producing the CMMC or HAPC, their likely dependence on mucosal and neuronal serotonin and pacemaker insterstitial cells of Cajal networks and how intrinsic neural reflexes affect them. Discussed is the possibility that myenteric 5-hydroxytryptamine (5-HT) neurons are not only involved in tonic inhibition of the colon, but are also involved in generating the CMMC and modulation of the entire enteric nervous system, including coupling motility to secretion and blood flow. Mucosal 5-HT appears to be important for the initiation and effective propagation of CMMCs, although this mechanism is a longstanding controversy since the 1950s, which we will address. We argue that the slow apparent propagation of the CMMC/HAPC down the colon is unlikely to result from a slowly conducting wave front of neural activity, but more likely because of an interaction between ascending excitatory and descending (serotonergic) inhibitory neural pathways interacting both within the myenteric plexus and at the level of the muscle. That is, CMMC/HAPC propagation appears to be similar to esophageal peristalsis. The suppression of inhibitory (neuronal nitric oxide synthase) motor neurons and mucosal 5-HT release by an upregulation of prostaglandins has important implications in a number of gastrointestinal disorders, especially slow transit constipation.

transient receptor potential vanilloid receptor 1, TRPV1 [VR1] inhibits peristalsis in the mouse jejunum

The transient receptor potential vanilloid receptor 1, TRPV1 [previously termed the capsaicin or vanilloid receptor 1 [VR1]] is a nonselective cation channel that has been cloned and is expressed predominantly in sensory neurons. TRPV1 is activated by protons as well as capsaicin. Despite extensive research, the physiological function of TRPV1 in the gastrointestinal tract and other tissues remains elusive. We have examined the effect of the selective TRPV1-receptor ligand, capsaicin, on intestinal peristalsis by studying migrating motor complexes [MMCs]. We performed experiments on Knockout mice [KO] in which the TRPV1 gene was disrupted using standard gene targeting techniques and their wildtype [WT] littermates. Jejunal contractile activity was recorded from in vitro segments of the jejunum, 4 - 5cm in length. When distended to 2 - 3 cm with H2O, the segments generated regular MMCs that were recorded as changes in intraluminal pressure. Capsaicin [1 - 100 nM] caused a dose-dependent inhibition of motility manifested as an increase in the interval between motor complexes [MCs] in the WT animal only, a response abolished by pre-treatment with TRPV1 antagonist capsazepine [Capz], ruthenium red [RR], and L-NAME. At higher doses of capsaicin [1 - 100 microM], periodic MCs were replaced by tonic increases in pressure upon which were superimposed continuous phasic contractions. This stimulation occurred in both KO and WT mice and was unaffected by pre-treatment with Capz, RR, and L-NAME. These data demonstrate the potential role of TRPV1 receptors in organized peristalsis in the mouse jejunum. These findings also suggest that inhibition of contractions in mouse jejunum by TRPV1-receptor activation does involve a nitric oxide synthetase [NOS] pathway

Study on the removal method of electrogastrogram baseline wander based on wavelet transformation / 生物医学工程学杂志

This paper presents a removal method of electrogastrogram (EGG) baseline wander based on wavelet transformation. The basic idea of this method is using the low-frequency signal which is obtained through multi-scale decomposition of EGG signals to approximate the baseline wander of EGG, so the component of baseline wander is filtered out from the sampling EGG signals. The method was applied successfully to process the experimental data of dog EGG in our laboratory. The experimental data and analysis of results showed that this method could filter out the baseline wander of EGG, and this method would not affect the gastric spike and slow wave bandwidth signals, which could be shown from the characteristics of bandwidth filter of wavelet transformation.

Mechanism of Interdigestive Migrating Motor Complex

Migrating motor complex (MMC) is well characterized by the appearance of gastrointestinal contractions in the interdigestive state. This review article discussed the mechanism of gastrointestinal MMC. Luminal administration of 5-hydroxytryptamine (5-HT) initiates duodenal phase II followed by gastrointestinal phase III with a concomitant increase of plasma motilin release in conscious dogs. Duodenal 5-HT concentration is increased during gastric phase II and phase III. Intravenous infusion of motilin increases luminal 5-HT content and induces gastrointestinal phase III. 5-HT4 antagonists significantly inhibits both of gastric and intestinal phase III, while 5-HT3 antagonists inhibited only gastric phase III. These suggest that gastrointestinal MMC cycle is mediated via the interaction between motilin and 5-HT by the positive feedback mechanism. Gastric MMC is regulated via vagus, 5-HT3/4 receptors and motilin, while intestinal MMC is regulated via intrinsic primary afferent neurons and 5-HT4 receptors. Stress is highly associated with the pathogenesis of functional dyspepsia. Acoustic stress attenuates gastric phase III without affecting intestinal phase III in conscious dogs, via reduced vagal activity and increased sympathetic activity. It has been shown that subset of functional dyspepsia patients show reduced vagal activity and impaired gastric phase III. The physiological importance of gastric MMC is a mechanical and chemical cleansing of the empty stomach in preparation for the next meal. The impaired gastric MMC may aggravate dyspeptic symptoms following a food ingestion. Thus, maintaining gastric MMC in the interdigestive state is an important factor to prevent the postprandial dyspeptic symptoms.

Effect of ghrelin on duodenal migrating myoelectric complex in rats with chronic renal failure / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of ghrelin on duodenal migrating myoelectric complex (MMC) in rats with chronic renal failure (CRF).</p><p><b>METHODS</b>Thirty healthy male SD rats were randomly assigned into sham-operated group (n=6) and CRF group (n=24), and the latter group was divided into 4 subgroups according to ghrelin doses administered with or without pretreatment with the receptor antagonist D-Lys(3)-GHRP-6. After a 18-h fasting, the rats with or without pretreatment with D-Lys(3)-GHRP-6 were given subcutaneous injections of ghrelin at different doses to observe the changes in duodenal MMC recorded using a multi lead physiological recording system.</p><p><b>RESULTS</b>Ghrelin significantly increased the MMC cycle duration and dose-dependently enhanced the frequency, amplitude and percentage of phase III MMC cycle. This effect was inhibited by the pretreatment with ghrelin receptor antagonist D-Lys(3)-GHRP-6.</p><p><b>CONCLUSION</b>Ghrelin can promote gastrointestinal motilities of rats with CRF, and the receptor of ghrelin can regulate the activity of MMC.</p>

Migrating motor complex changes after side-to-side ileal bypass in mouse ileum ex-vivo: mechanism underlying the blind loop syndrome? / 대한외과학회지

PURPOSE: This study was intended to investigate the migrating motor complex (MMC) changes after ileal bypass in ex-vivo mouse models. METHODS: Partial (side-to-side) and total bypass (occlusion of proximal part of bypassed loop) were performed on ileums of female Institute of Cancer Research mice. After 2 and 4 weeks, the bypassed segments were harvested and MMCs were recorded at 4 different sites ex-vivo. Amplitude, duration, interval, direction of propagation, and the area under the curve (AUC) of MMCs were measured and compared to those of the controls. RESULTS: In control mice (n = 7), most MMCs propagated aborally (91.1%). After 2 weeks of partial bypass (n = 4), there was a significant decrease in both amplitude and AUC, and orally-propagating MMCs increased significantly (45%, P = 0.002). Bidirectional MMCs (originating in the bypassed loop and propagating in both directions) were also observed (10%). The amplitude of the MMCs remained decreased at 4 weeks after partial bypass (n = 4), and neither the AUC nor the direction of propagation showed significant changes compared to 2 weeks. Similarly, in the total bypass model, both the amplitude and AUC of the MMCs decreased significantly compared to controls. In contrast to partial bypass, 95% of the MMCs within the bypassed loop propagated aborally after 2 weeks (n = 6), which was similar to the control state. After 4 weeks (n = 5), however, MMCs either lost their temporal relationship or completely disappeared. CONCLUSION: The changes in propagation direction of the MMCs in the partially bypassed loop may contribute to stagnation of bowel contents and the development of blind loop syndrome.

The changes of interdigestive migrating motor complex in rats with acute liver failure / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To observe the changes and characteristics of interdigestive migrating motor complex (MMC) in rat models of acute liver failure.</p><p><b>METHODS</b>30 rat models with acute liver failure were induced with D-galactosamine and another 30 normal rats were used as controls. The indexes of MMC recorded by multi-channel physiological recorder were compared.</p><p><b>RESULTS</b>No significant differences found between the two groups in antral and duodenal MMC cycles and frequencies of duodenal and jejunal MMC III phase. Compared with normal controls, the MMC II phase in the acute liver failure rats was significantly prolonged (t=-3.97, -3.85, P<0.05), the MMC III duration of antrum and duodenum (u=-4.99, t=4.66, P<0.05) was shorter and the MMC III frequency of antrum (u=-4.73, P<0.05) was faster. In addition, the MMC cycle and MMC III phase of jejunum were significantly prolonged (u=-1.63, t=-4.94, P<0.05) and the MMC III phase duration was significantly shorter in the acute liver failure rats (t=5.10, P<0.05).</p><p><b>CONCLUSION</b>Significantly prolonged MMC II phase characterized by migrating clustered contraction, shortened MMC III phase and extended jejunal MMC cycles were probably the major contributors to the gastrointestinal motility disorders in the rats with acute liver failure.</p>

Effects of neurotrophin 3 on interdigestive migrating motor complex in rats with acute liver injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of neurotrophin 3(NT-3)on interdigestive migrating motor complex (MMC) in rats with D-galactosamine induced acute liver injury.</p><p><b>METHODS</b>Twenty-four specific pathogen-free purebred rats were equally randomized into control and acute liver injury groups. The control group was injected with equal volume of normal saline via tail vein. Acute liver injury model of the rats was induced by D-galactosamine injection via the tail vein in the acute liver injury group. And the indexes of interdigestive MMC before and after NT-3 injection were recorded by a polygraph and analyzed in model group. The serum NT-3 concentration was assayed in the two groups.</p><p><b>RESULTS</b>There were no significant changes of gastrointestinal MMC cycle and jejunal phase I MMC after NT-3 injection. Compared with the acute liver injury rats before NT-3 injection , the antral phases I, III and IV MMC were significantly prolonged [(577.44 ± 248.60)s vs (343.58 ± 227.30) s, (80.94 ± 21.15) s vs (24.76 ± 7.41) s, (405.69 ± 131.34) s vs (191.67 ± 128.15) s, P < 0.05] and the phase II MMC was shortened [ (883.94 ± 488.50) s vs (1519.00 ± 831.14) s, P < 0.05] in the acute liver injury group. The duodenal phases I, III and IV MMC were significantly prolonged [ (557.63 ± 335.14) s vs (309.46 ± 220.22) s,(75.91 ± 15.75) s vs (31.15 ± 13.67) s, (423.38 ± 135.22) s vs (209.77 ± 123.83) s, P < 0.05] and MMC II phase was shortened [ (748.81 ± 579.69) s vs (1535.86 ± 930.50) s, P < 0.05] in the acute liver injury rats. In addition, the jejunal MMC III and MMC IV phase was significantly prolonged [ (86.58 ± 23.40) s vs (31.41 ± 16.09) s,(385.18 ± 110.02) s vs (220.59 ± 159.30) s, P < 0.05] and phase II MMC was shortened [ (876.89 ± 652.01) s vs (1870.89 ± 1010.35) s, P < 0.05 ] in the acute liver injury rats. The serum NT-3 level was significantly higher in model group than in control group.</p><p><b>CONCLUSION</b>NT-3 could enhance the gastrointestinal motility in acute liver injury rats.</p>