Symptom effects and central mechanism of acupuncture in patients with functional gastrointestinal disorders: a systematic review based on fMRI studies.

BACKGROUND: Functional gastrointestinal disorders (FGIDs) are closely related to disorders of brain-gut interaction. FGIDs are the dominant disease of acupuncture treatment, which can improve the symptoms and emotional state. AIM: To evaluate the results and quality of the available clinical evidence and to summarize the central mechanism and effect of acupuncture on FGIDs. METHODS: PubMed, EMBASE, Web of science, Cochrane Library, China National Knowledge Infrastructure (CNKI) were searched by computer to collect the randomized controlled trials (RCTs), which contained central mechanisms via fMRI research of acupuncture in the treatment of FGIDs patients. The search time limit was from the establishment of the database to June 22, 2022. Two researchers independently screened the literature, extracted data, and evaluated the quality. RESULTS: Ten RCTs involving fMRI data were included in this study, including 4 Functional dyspepsia (FD) studies, 3 irritable bowel syndrome (IBS) studies, and 3 functional constipation (FC) studies. The score of improvements in both gastrointestinal symptoms and psychological symptoms showed that acupuncture could significantly improve the clinical symptoms of FGIDs patients, including abdominal pain, abdominal distension, frequency of defecation, and stool characteristics, and could relieve anxiety and depression symptoms of patients. Acupuncture could regulate brain functional connections and functional activity in FGIDs patients, mainly including insula, anterior cingulate cortex, prefrontal cortex, thalamus, hippocampus, amygdala and other brain regions. CONCLUSION: Acupuncture can improve gastrointestinal symptoms and psychological status in FGIDs patients, and regulate functional connectivity and activity of brain regions such as insula, ACC, PFC, thalamus, HIPP, amygdala, etc. These changes in brain activity may related to visceral sensation, pain regulation, emotion, but further studies of high quality are still necessary.

Transcutaneous electrical stimulation for gastrointestinal motility disorders.

BACKGROUND/PURPOSE: Gastrointestinal (GI) dysmotility is categorized by muscle or nerve dysfunctions in any portion of the GI tract, which leads to abnormalities in GI motor and sensory function. Symptoms may vary depending on the organ affected and can be debilitating. Treatment usually involves diet and lifestyle changes. Pharmacotherapy is limited in effectiveness with various side effects. Transcutaneous electrical stimulation (TES), a noninvasive, needleless technique that provides electrical stimulation using cutaneous non-needle electrodes, has become increasingly popular. It has been shown to be beneficial in treating GI motility disorders. METHODS: This review paper navigates through the different TES techniques, including transcutaneous peripheral nerve (vagal/sacral/tibial nerves) electrical stimulation, transcutaneous electrical acustimulation (stimulation via acupuncture point), transcutaneous interferential current therapy, and transcutaneous electrical nerve stimulation. KEY RESULTS: As we delve deeper, we explore the promising effects of TES on dysphagia, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, postoperative ileus, constipation, and irritable bowel syndrome. The literature at hand speaks volumes about the therapeutic prowess of this noninvasive technique. CONCLUSION & INFERENCES: The time is ripe to evaluate further the full therapeutic potential of TES, a noninvasive, nonpharmaceutical, nonsurgical, and home-based self-administrative technique in managing GI motility disorders.

Review article: Functional dyspepsia and pregnancy-Effects and management in a special population.

BACKGROUND: Around 10% of Americans meet the Rome IV criteria for functional dyspepsia (FD), with a significantly higher rate in women. FD also has a higher prevalence in women below the age of 50, suggesting that women who are affected are likely to be of reproductive age. Unfortunately, there is a lack of research or evidence-based guidelines on managing FD in pregnancy. AIMS AND METHODS: To address this issue, we aimed to perform a systematic review of the interactions between FD and pregnancy and managing pre-existing FD in the peripartum and post-partum phases using current lifestyle, pharmacological, non-pharmacological and alternative medicine interventions. RESULTS: Due to the lack of Rome IV FD-specific data in pregnancy, we instead performed a narrative review on how existing FD interventions could be extrapolated to the pregnant population. Where possible we use the highest level of available evidence or official guidelines to answer these questions, which often involves synthesising treatment and safety evidence of these interventions in other diseases during pregnancy. Finally, we highlight current substantial knowledge gaps requiring further research for the safe management of a pregnant patient with pre-existing FD. CONCLUSIONS: Overall, despite the paucity of knowledge of treating FD during pregnancy, providers can mitigate this uncertainty by planning ahead with the patient. Patients should ideally minimise treatment until after breastfeeding. However, interdisciplinary resources are available to ensure that minimal-risk interventions are maximised, while interventions with more risks, if necessary, are justifiable by both the patient and the care team. Future investigations should continue to elicit the mechanistic relationship between FD and pregnancy while cautiously expanding prospective research on promising and safe therapies in pregnant patients with pre-existing FD.

Corrigendum: Wenshen-Jianpi prescription, a Chinese herbal medicine, improves visceral hypersensitivity in a rat model of IBS-D by regulating the MEK/ERK signal pathway.

[This corrects the article DOI: 10.3389/fphar.2022.955421.].

Wenshen-Jianpi prescription, a Chinese herbal medicine, improves visceral hypersensitivity in a rat model of IBS-D by regulating the MEK/ERK signal pathway.

The goal of the study was to analyze whether WJP can alleviate visceral hypersensitivity in IBS-D model rats. In this study, 36 Sprague-Dawley (SD) rats aged 4 weeks old were randomly divided into two groups: the model group (n = 27) and the control group (n = 9). The rat model of IBS-D was established by modified compound methods for 4 weeks. After the modification, IBS-D rats were randomly divided into three groups, namely, the IBS-D model group (n = 9), the positive drug group (n = 9), and the WJP group (n = 9), with different interventions, respectively. The control group was fed and allowed to drink water routinely. The Bristol stool scale scores were used to assess the severity of diarrhea. Abdominal withdrawal reflex (AWR) scores were used to assess visceral sensitivity. Expression of TNF-α was measured, and histopathological examinations were performed to assess colon inflammation in IBS-D model rats. Key factors of the MEK/ERK signal pathway in the tissue of the colon and hippocampus were measured to analyze the mechanism of WJP. Compared with the control group, the Bristol stool scale scores in the model group were significantly increased (p < 0.0001). The scores of the WJP group were significantly decreased compared with the model group (p = 0.0001). Compared with the control group, AWR scores in the model group at each pressure level were significantly increased (p = 0.0003, p < 0.0001, p = 0.0007, and p = 0.0009). AWR scores of the WJP group were significantly decreased compared with the model group (p = 0.0003, p = 0.0007, p = 0.0007, and p = 0.0009). Compared with the control group, the model group had significantly higher expression of TNF-α in the colon tissue (p < 0.0001). However, the WJP group had significantly lower level of TNF-α compared with the model group (p < 0.0001). Meanwhile, compared with the control group, the relative expression of the proteins of p-MEK1/2, p-ERK1, and p-ERK2 in the colon tissue was significantly increased in the model group (p < 0.0001). Compared with the model group, the relative expression of the proteins in the colon tissue were significantly decreased in the WJP group (p < 0.0001, p = 0.0019, and p = 0.0013). Compared with the control group, the relative expression of the proteins of p-MEK1/2, p-ERK1, and p-ERK2 in the hippocampus tissue were significantly increased in the model group (p < 0.0001). Compared with the model group, the relative expression of the proteins in the hippocampus tissue were significantly decreased in the WJP group (p = 0.0126, p = 0.0291, and p = 0.0145). The results indicated that WJP can alleviate visceral hypersensitivity in IBS-D model rats, possibly mediated by downregulating the expression of TNF-α, p-MEK1/2, p-ERK1, and p-ERK2 in the colon tissue. At the same time, WJP also affects downregulating the expression of p-MEK1/2, p-ERK1, and p-ERK2 in the hippocampus tissue.

Placebo Response Rates in Acupuncture Therapy Trials for Functional Dyspepsia: A Systematic Review and Meta-Analysis.

BACKGROUND: Functional dyspepsia (FD) is a functional digestive disease with limited management selection. Previous studies revealed that acupuncture therapy is effective for FD. However, because sham controls were not implemented in most clinical trials following acupuncture therapy, it is difficult to differentiate overall treatment responses from placebo. This study aims to quantify placebo responses in clinical trials in which FD patients received sham manual acupuncture (MA) and sham electroacupuncture (EA). MATERIALS AND METHODS: Randomized controlled trials of MA and EA for FD patients were searched in PubMed, Web of Science, Cochrane Library, and Embase databases, as well as 4 Chinese language databases from inception to January 2021. RevMan 5.20 software was used for pooled analysis of symptom scores and quality of life. The symptom scores were combined using standard mean difference (SMD) or weighted mean difference (WMD) with a 95% confidence interval (CI). The quality of included studies was tested using modified Jadad scale and Standards for Reporting Interventions in Controlled Trials of Acupuncture (STRICTA) checklist. Egger's test, Begg's test, and sensitivity analyses were conducted using Stata 11.0 statistical software. The protocol of this study is registered in PROSPERO as CRD42021233858. RESULTS: After screening, the current systematic review included 13 randomized controlled trials, of which 8 studies were used in the meta-analysis. Regarding subjective outcomes, the combined effect of sham MA on FD symptoms was [SMD=-0.42, 95% CI (-0.72, -0.12); P=0.005], whereas sham EA treatment was [SMD=-0.54, 95% CI (-0.81, -0.27); P<0.001]. The combined effect on FD quality of life of post-sham MA group was [SMD=-0.32, 95% CI (-0.52, -0.12); P=0.002]. With regard to objective outcomes, the combined effect of sham EA on dominant frequency was [WMD=-0.11, 95% CI (-0.30, -0.08); P=0.24], while the combined effect of sham EA on dominant power was [WMD=-3.35, 95% CI (-8.04, 1.35); P=0.16]. CONCLUSIONS: Sham MA and sham EA remarkably improve symptoms and quality of life scores of FD without influencing objective outcomes, highlighting the significance of sham controls in acupuncture therapy clinical trials.

Acupuncture in Inflammatory Bowel Disease.

Scientific research into the effects and mechanisms of acupuncture for gastrointestinal diseases including inflammatory bowel disease has been rapidly growing in the past several decades. In this review, we discuss the history, theory, and methodology of acupuncture and review potentially beneficial mechanisms of action of acupuncture for managing inflammatory bowel disease. Acupuncture has been shown to decrease disease activity and inflammation via increase of vagal activity in inflammatory bowel disease. Acupuncture has demonstrated beneficial roles in the regulation of gut dysbiosis, intestinal barrier function, visceral hypersensitivity, gut motor dysfunction, depression/anxiety, and pain, all of which are factors that can significantly impact quality of life in patients with inflammatory bowel disease. A number of clinical trials have been performed to investigate the therapeutic effects of acupuncture in ulcerative colitis and Crohn's disease. Although the data from these trials are promising, more studies are needed given the heterogeneous and multifactorial aspects of inflammatory bowel disease. There is also an important need to standardize acupuncture methodology, study designs, and outcome measurements.

Central and Peripheral Effects of Transcutaneous Acupuncture Treatment for Nausea in Patients with Diabetic Gastroparesis.

BACKGROUND/AIMS: Nausea, an unpleasant symptom of diabetic gastroparesis (DMGP), has been reported to be alleviated by needleless transcutaneous electrical acupuncture (TEA). Our study was designed to utilize electroencephalography (EEG) and electrogastrography (EGG) recordings to investigate the central and peripheral responses of TEA in the treatment of nausea in DMGP patients. METHODS: Eleven DMGP subjects underwent simultaneous EEG and EGG testing while grading the severity of nausea following 30-minute intervals of: (1) baseline, (2) visual stimulation (VS) to provoke more nausea, (3) active VS together with TEA, and (4) TEA alone, and a final 15-minute recording without any intervention. RESULTS: The nausea score was increased to 5.9 ± 1.5 with VS (P < 0.05, vs 3.5 ± 1.0 at baseline), then reduced to 3.5 ± 1.2 with VS plus TEA, and to 2.5 ± 1.3 with TEA alone, while it continued at a score of 2.9 ± 1.0 post TEA (all significant, P < 0.05, vs VS without TEA). The mean percentage of normal gastric slow waves was decreased to 60.0 ± 5.7% with VS (P < 0.05, vs 66.6 ± 4.5% at baseline), then improved to 69.2 ± 4.8% with VS plus TEA, and maintained at 70 ± 3.6% with TEA alone. During initial VS, EEG signals showed right inferior frontal activity as the prominent finding, but during VS with TEA, left inferior frontal activity predominated. CONCLUSIONS: In DMGP, TEA improves gastric dysrhythmia and ameliorates nausea. TEA treatment of nausea provoked by VS resulted in a change of dominance from right to left inferior frontal lobe activity. These data provide new understandings of peripheral and central mechanisms for nausea, and potential future directions for DMGP treatment approaches.

Chronic gastric electrical stimulation leads to weight loss via modulating multiple tissue neuropeptide Y, orexin, α-melanocyte-stimulating hormone and oxytocin in obese rats.

OBJECTIVES: Gastric electrical stimulation (GES) has great potential for the treatment of obesity. We investigated the impact of chronic GES on the alteration of adipose tissue and the regulation of neuropeptide Y (NPY), orexin (OX), α-melanocyte-stimulating hormone (α-MSH) and oxytocin (OXT), and their receptors in several tissues. MATERIAL AND METHODS: Most of the experiments included three groups of diet-induced obesity rats: (1) sham-GES (SGES); (2) GL-6mA (GES with 6 mA, 4 ms, 40 Hz, 2 s on, 3 s off at lesser curvature); and (3) SGES-PF (SGES rats receiving pair feeding to match the consumption of GL-6mA rats). Chronic GES was applied for 2 h every day for 4 weeks. During treatment with GES, food intake and body weight were monitored weekly. The alteration of epididymal fat weight, gastric emptying, and expression of peptides and their receptors in several tissues were determined. RESULTS: GL-6mA was more potent than SGES-PF in decreasing body weight gain, epididymal fat tissue weight, adipocyte size and gastric emptying. Chronic GES significantly altered NPY, OX, α-MSH and OXT and their receptors in the hypothalamus, adipose tissue and stomach. CONCLUSIONS: Chronic GES effectively leads to weight loss by reducing food intake, fat tissue weight and gastric emptying. NPY, α-MSH, orexin and OXT, and their receptors in the hypothalamus, adipose tissue and stomach appear to be involved in the anti-obesity effects of chronic GES.

Ameliorating effects and autonomic mechanisms of needle-less transcutaneous electrical stimulation at ST36 on stress-induced impairment in gastric slow waves.

BACKGROUND AND AIM: Stress has long been documented to alter gastrointestinal motility. The effects of electroacupuncture (EA) on stress and gastric motility are relatively well known; however, whether EA has an ameliorating effect on stress-induced dysmotility remained unclear. This study aims to investigate the effects and mechanisms of needle-less transcutaneous electroacupuncture (TEA) on stress-induced impairment in gastric slow waves. METHODS: A watch-size digital stimulator was developed. Ten healthy volunteers were involved in a four-session study (control, cold stress, TEA, and sham TEA). Electrogastrograpy was used to assess gastric slow waves, and electrocardiogram was recorded for the assessment of autonomic functions. The recordings were made in each session with/without stress and with TEA at ST36 or sham points. RESULTS: The results are as follows: (i) Cold stress-induced gastric dysrhythmia and impaired normal slow waves (P < 0.01). TEA showed a preventive effect on cold stress-induced impairment in gastric slow waves. TEA at ST36, but not sham TEA, normalized slow waves (P = 0.03 vs stress; P = 0.44 vs control), attributed to the suppression of gastric dysrhythmia; (ii) Postprandially, there was a decrease in vagal activity in both control (P = 0.004) and stress (P = 0.002) sessions; this decrease was prevented with TEA (P < 0.05). Similarly, there was a postprandial increase in sympathetic activity in both control (P = 0.01) and stress (P = 0.002) sessions, and this increase was suppressed with TEA. CONCLUSIONS: Needle-less TEA at ST36 using a watch-size stimulator is able to improve stress-induced impairment in gastric slow waves, possibly mediated via the autonomic mechanism. Home-based needle-less TEA may be a viable therapy for stress-induced impairment in gastric motility functions.

Gastric electrical stimulation optimized to inhibit gastric motility reduces food intake in dogs.

AIMS: The aim of this study was to test the hypothesis that that a method of gastric electrical stimulation (GES) optimized to inhibit gastric motility was effective in reducing food intake in dogs. METHODS: Female dogs with a gastric cannula and gastric serosal electrodes were studied in three experiments: (1) to determine the best parameters and locations of GES in inhibiting gastric tone, slow waves, and contractions in dogs;( 2) to investigate the reproducibility of the inhibitory effects of GES; and (3) to study the effect of the GES method on food intake in dogs. RESULTS: (1) For GES to exert significant effects on gastric motility, a pulse width of ≥2 ms was required, and with other appropriate inhibitory parameters, GES was able to increase gastric volume by 190.4 %, reduce antral contractions by 39.7 %, and decrease the percentage of normal slow waves by 47.6 %. In addition, the inhibitory effect of GES was more potent with the stimulation electrodes placed along the lesser or greater curvature than placed in the middle, and more potent with the electrodes placed in the distal stomach than in the proximal stomach; (2) the inhibitory effects of GES on gastric motility were reproducible; (3) the GES method optimized to inhibit gastric motility produced a 20 % reduction in food intakes in non-obese dogs. CONCLUSION: GES with appropriate parameters inhibits gastric motility, and the effects are reproducible. The GES method optimized to inhibit gastric motility reduces food intake in healthy dogs and may have a therapeutic potential for treating obesity.

Electroacupuncture improves impaired gastric motility and slow waves induced by rectal distension in dogs.

Rectal distension (RD) is known to induce upper gastrointestinal (GI) symptoms. The aim of this study was to investigate the effects and underlying mechanisms of RD on gastric slow waves (GSW) and motor activity and furthermore to investigate the effects and mechanisms of electroacupuncture (EA) on GSW and motor activity. Eight female hound dogs chronically implanted with gastric serosal electrodes and a gastric fistula were studied in six separate sessions. Antral motility, GSW, heart rate variability, and rectal pressure were evaluated for the above purposes. 1) RD at a volume of 120 ml suppressed antral motility significantly. Guanethidine blocked the inhibitory effect of RD. EA at ST36 was able to restore the suppressed antral contractions induced by RD (16.6+/-1.7 vs. 8.0+/-1.4, P<0.001). Naloxone partially blocked the effect of EA on antral contractions. 2) RD reduced the percentage of normal GSW from 98.8+/-0.8% at baseline to 76.1+/-8.6% (P<0.05) that was increased to 91.8+/-3.0% with EA. The effects of EA on the GSW were nullified by the presence of naloxone. 3) EA did not show any significant effect on rectal pressure, suggesting that the ameliorating effects of EA on RD-induced impaired gastric motility were not due to a decrease in rectal pressure. 4) EA increased the vagal activity suppressed by RD. In conclusion, RD inhibits postprandial gastric motility and impairs GSW in dogs, and the inhibitory effects are mediated via the adrenergic pathways. EA at ST36 is able to restore the RD-induced impaired GSW and motor activities, possibly by enhancing vagal activity, and is partially mediated via the opioid pathway. EA may have therapeutic potential for functional gastrointestinal disorders.

Effects of gastric electrical stimulation with short pulses and long pulses on gastric dysrhythmia and signs induced by vasopressin in dogs.

AIMS: This study was to investigate the effect of gastric electrical stimulation (GES) with short pulses, long pulses, short-pulse trains or long-pulse trains on gastric dysrhythmia and motion-sickness signs induced by vasopressin. METHODS: Seven male beagle dogs implanted with four pairs of electrodes on gastric serosa were studied. The study was performed in six sessions in a randomized order. In session 1 or 2, either saline or vasopressin was infused without GES. In session 3, 4, 5 and 6, GES with short pulses, long pulses, trains of short pulses or trains of long pulses was performed before and during vasopressin infusion. Gastric slow waves and motion-sickness signs were recorded in each session. RESULTS: (1) Vasopressin induced gastric dysrhythmia and motion sickness-like signs (ANOVA, P < 0.001). (2) GES with short pulses or trains of short pulses was capable of preventing vasopressin-induced emetic response (P < 0.001), but did not normalize gastric dysrhythmia. (3) GES with long pulses or trains of long pulses was able to normalize gastric dysrhythmia induced by vasopressin (P < 0.001), but showed no effects on vasopressin-induced motion-sickness signs. CONCLUSION: GES with short pulses or trains of short pulses prevents vasopressin-induced emetic response with no improvement in gastric dysrhythmia. GES with long pulses or trains of long pulses normalizes gastric dysrhythmia induced by vasopressin with no effects on signs.

Synchronized gastric electrical stimulation improves delayed gastric emptying in nonobese mice with diabetic gastroparesis.

The aim of this study was to investigate the effect and mechanism of synchronized gastric electrical stimulation (SGES) on gastric emptying in nonobese mice with diabetic gastroparesis (DB-GP). Eight control mice and 48 nonobese diabetic (NOD) mice with two pairs of gastric electrodes were used in this study. The study included seven groups in a randomized order [control, diabetes (DB), DB-GP, DB + SGES, DB-GP + SGES, DB-GP + Atropine, and DB-GP + SGES + Atropine groups]. In the control, DB, DB-GP, and DB-GP + Atropine groups, gastric emptying was measured in BLAB/cJ mice (control group) or NOD mice with a duration of diabetes of 0-7 days (DB group) or 28-35 days (DB-GP or DB-GP + Atropine group). In the DB + SGES, DB-GP + SGES, and DB-GP + SGES + Atropine groups, the experiment was the same as the corresponding DB, DB-GP, and DB-GP + Atropine groups except that SGES was applied during the experiment. SGES was applied via the proximal pair of electrodes and synchronized with the intrinsic gastric slow waves. The following results were obtained: 1) gastric emptying was delayed in NOD mice with a duration of diabetes of 28-35 days; 2) SGES was able to significantly increase gastric emptying in both diabetic mice and diabetic gastroparetic mice; and 3) the excitatory effect of SGES was completely blocked by atropine. SGES accelerates gastric emptying in NOD mice with diabetic gastroparesis. The effect of SGES on gastric emptying is mediated via the cholinergic pathway. These findings suggest that SGES may have a therapeutic potential for treating patients with diabetic gastroparesis.

Effects and mechanisms of vaginal electrical stimulation on rectal tone and anal sphincter pressure.

PURPOSE: This study was designed to evaluate the effect of vaginal electrical stimulation on rectal tone and compliance and anal sphincter pressure and to explore possible mechanisms involved in the effects of vaginal electrical stimulation on rectal tone in conscious dogs. METHODS: Seven dogs inserted with a probe with two ring electrodes were studied. The study included two experiments. The first experiment was composed of two series of sessions rectal tone and compliance; and anal sphincter pressure. Each series included three sessions: vaginal electrical stimulation with long pulses, vaginal electrical stimulation with trains of long pulses, and vaginal electrical stimulation with trains of short pulses. The second experiment was performed in two sessions: vaginal electrical stimulation with long pulses plus guanethidine, and vaginal electrical stimulation with trains of long pulses plus guanethidine. In each session, rectal tone was recorded. RESULTS: 1) Vaginal electrical stimulation with long pulses or trains of long pulses but not trains of short pulses significantly decreased rectal tone and increased anal sphincter pressure. 2) None of the vaginal electrical stimulation methods altered rectal compliance. 3) The inhibitory effect of vaginal electrical stimulation on rectal tone was abolished by guanethidine. CONCLUSIONS: Vaginal electrical stimulation with long pulses or trains of long pulses but not trains of short pulses reduces rectal tone and increases anal sphincter pressure. The inhibitory effect of vaginal electrical stimulation on rectal tone is mediated by the sympathetic pathway. These findings suggest that vaginal electrical stimulation may be a potential therapy for fecal incontinence.

Effects of retrograde gastric electrical stimulation with pulse trains on gastric emptying of solids and plasma hormones in dogs.

BACKGROUND: Retrograde gastric electrical stimulation (RGES) is proposed as a novel therapy for obesity. However, mechanisms of RGES are not fully investigated. The aim of this study was to investigate the effects of RGES with trains of pulses on gastric slow waves, gastric emptying of solids, and plasma concentrations of satiety-related peptides and glucose. METHODS: Seven female beagle dogs implanted with 4 pairs of gastric electrodes on the gastric serosa were studied (control and RGES). Gastric emptying, gastric slow waves, and signs were recorded in each session. Plasma leptin, insulin, glucagons, and glucose were also measured. RESULTS: RGES with pulse trains (a pulse width of 2 milliseconds) significantly decreased gastric emptying of solids and plasma insulin but has no effect on plasma leptin, glucagons, and glucose. CONCLUSION: Acute gastric electrical stimulation with pulse trains is able to decrease gastric emptying of solids and plasma insulin but has no effects on plasma leptin, glucagons, and glucose.

Gastric electrical stimulation using endoscopically placed mucosal electrodes reduces food intake in humans.

BACKGROUND: Implantable gastric stimulation (IGS) has been proposed for treating obesity. The aim of this study was to investigate the effects of temporary mucosal electrical stimulation on water and food intake as well as gastric emptying in healthy humans. METHODS: The study was designed to study the effects of temporary gastric electrical stimulation (GES) on symptoms, gastric accommodation, food intake, and gastric emptying. It was performed in 12 healthy volunteers on 3 consecutive days. GES was performed using mucosal electrodes endoscopically placed in the fundus. RESULTS: The amount of maximum water intake was reduced with GES (894 +/- 326 mL) compared with sham-GES (1,093 +/- 417 mL, p = 0.01). The food intake was also reduced with GES (p = 0.012). In comparison with sham stimulation, GES delayed gastric emptying during the first 45 min after the meal but not during the remaining time. GES with parameters effective in reducing water and food intake and delaying gastric emptying did not induce significant dyspeptic symptoms, compared with sham stimulation. CONCLUSIONS: GES using temporary mucosal electrodes decreases food intake as well as maximum intake of water, and has a tendency of delaying gastric emptying. It may have a potential application for the treatment of obesity.

Two-channel gastric electrical stimulation accelerates delayed gastric emptying induced by vasopressin.

The aim of this study was to investigate the effects of two-channel gastric electrical stimulation (GES) on delayed gastric emptying, gastric dysrhythmias, and motion sickness-like symptoms induced by vasopressin. Seven dogs implanted with four pairs of gastric electrodes and a duodenal cannula were studied in four randomized sessions (saline, vasopressin, single-channel GES, and two-channel GES). The experiment in each session was conducted sequentially as follows: 30-min baseline, ingestion of a liquid meal, 30-min iv infusion of vasopressin or saline, and two 30-min postprandial recordings. In the GES sessions, GES was applied via the first pair of electrodes for single-channel GES or the first and third pairs of electrodes for two-channel GES. Gastric emptying was collected every 15 min via the cannula for a period of 90 min. Results were as follows. (1) Vasopressin induced gastric dysrhythmias, motion sickness-like symptoms, and delayed gastric emptying (P < 0.01, ANOVA). (2) GES normalized gastric dysrhythmias (P < 0.01) but showed no effects on vasopressin-induced emetic response. (3) Two-channel GES improved delayed gastric emptying induced by vasopressin. In comparison with the vasopressin session, two-channel GES, but not single-channel GES, significantly increased gastric emptying at 30 min (43.9+/-12.6 vs. 27.5+/-7.7%; P < 0.03), 60 min (75.3+/-15.1 vs. 54.0+/-17.8%; P < 0.05), and 90 min (91.6+/-9.8 vs. 80.3+/-9.0%; P < 0.05). GES with long pulses is able to normalize gastric dysrhythmias. Two-channel GES improves delayed gastric emptying induced by vasopressin.