Search

Enteric neurotransmission is critical for coordinating motility throughout the gastrointestinal (GI) tract. However, there is considerable controversy regarding the cells that are responsible for the transduction of these neural inputs. In the present study, utilization of a cell-specific calcium biosensor GCaMP6f, the spontaneous activity and neuroeffector responses of intramuscular ICC (ICC-IM) to motor neural inputs was examined. Simultaneous intracellular microelectrode recordings and high-speed video-imaging during nerve stimulation was used to reveal the temporal relationship between changes in intracellular Ca

This study aims to identify the ideal arteriole size to target in bariatric embolization, with the goal of maximizing weight loss efficacy while maintaining patient safety. Although all published clinical trials of bariatric embolization have used embolic microspheres that were at least 300 μm in diameter, optimal weight loss outcomes have been achieved safely in swine using 50-μm embolics. Human fundal remnants from bariatric surgery were compared with swine fundal sections after bariatric embolization with 50-μm embolic microspheres to assess the ideal fundal vessel size for bariatric embolization. In swine, the 50-μm embolic microspheres deposited in the luminal half of the submucosa with a mean arteriole size of 49 ± 30 μm. The mean arteriole diameter in the corresponding submucosal layer of the human gastric fundi was 40 ± 30 μm. These measurements are intended to inform future clinical trials and direct the development of embolic agents for bariatric embolization.

It has been reported that adiponectin (ADPN) and resistin are co-secreted by white mouse adipocytes and exert similar inhibitory effects in the mouse gastric fundus, in which resistin was observed to increase neuronal nitric oxide synthase (nNOS) expression. On these grounds, the present work aimed to investigate whether the effects of the two adipokines on the neurally-induced relaxant responses potentiate each other and whether there is a possible correlation with changes in nNOS expression in preparations from the mouse gastric fundus. In carbachol (CCh)-precontracted strips, electrical field stimulation elicited nitrergic relaxant responses, whose amplitude was increased by ADPN or resistin, but no additional enhancements were observed in their concomitant presence. Western blot and immunofluorescence analyses revealed that ADPN, like resistin, was able to up-regulate nNOS expression and to increase the percentage of nNOS-positive neurons in the myenteric plexus: co-treatment with the two adipokines did not induce additional changes. The results indicate that the two adipokines modulate nitrergic neurotransmission, and both do so by up-regulating nNOS expression. Therefore, nNOS appears to be a shared target for the two adipokines’ effects, which, rather than mutually reinforcing each other, may represent a dual physiological control mechanism to guarantee gastric fundus relaxation.

Many studies have been conducted to determine the composition of the glycoconjugates of the mucus-secreting cells of the fundic glands of the stomach. However, the chief cells of these glands have been largely ignored because they secrete mainly zymogens with a lower glycosylation. The aim of this work was to analyze the glycoconjugates of the gastric chief cells by a battery of 17 different lectins, recognizing Fucose, N-acetylgalactosamine, Galactose, N-acetylneuraminic acid, N-acetylglucosamine and Mannose containing oligosaccharides. Histochemical techniques were performed with several lectins and also combined with two pre-treatments; β-elimination, which removes O-linked oligosaccharides, and incubation with Peptide-N-Gycosidase F, which removes N-linked oligosaccharides. In addition, acid hydrolysis was performed before WGA histochemistry, and incubation with glucose oxidase before Con A labeling. Many lectins did not stain the chief cells. In addition, the presence of O-glycans in the apical cell membrane was demonstrated with the lectins AAL, HPA, MPA/MPL, PNA, RCA-I, and WGA. Some of these O-glycans were resistant to short-term β-elimination pre-treatments. Mannose-binding lectins stained the basal cytoplasm of the chief cells. The level of glycosylation of the chief cells was lower than that of the mucous cells. The presence of O-glycans in the apical cell membrane is consistent with the presence of mucins such as MUC1 in the apical membrane of chief cells. Moreover, Mannose-binding lectins revealed N-glycosylation in the basal cytoplasm. The knowledge of gastric chief cell glycoconjugates is relevant because of their potential involvement not only in in physiological but also in pathological processes, such as cancer.

Endokinin A/B (EKA/B), the common C-terminal decapeptide in endokinins A and B, is a preferred ligand of the NK1 receptor and regulates pain and itch. The study focused on the effects of EKA/B on rat gastric motility in vivo and in vitro. Gastric emptying was measured to evaluate gastric motility in vivo. Intragastric pressure and the contraction of gastric muscle strips were measured to evaluate gastric motility in vitro. Moreover, various neural blocking agents and neurokinin receptor antagonists were applied to explore the mechanisms. TAC4 and TACR1 mRNAs were expressed throughout rat stomach. EKA/B promoted gastric emptying by intraperitoneal injection in vivo. Correspondingly, EKA/B also increased intragastric pressure in vitro. Additionally, EKA/B contracted the gastric muscle strips from the fundus but not from the corpus or antrum. Further studies revealed that the contraction induced by EKA/B on muscle strips from the fundus could be significantly reduced by NK1 receptor antagonist SR140333 but not by NK2 receptor antagonist, NK3 receptor antagonist, or the neural blocking agents used. Our results suggested that EKA/B might stimulate gastric motility mainly through the direct activation of myogenic NK1 receptors located in the fundus.

PURPOSE: To examine the safety and efficacy of bariatric arterial embolization (BAE) with X-ray-visible embolic microspheres (XEMs) and an anti-reflux catheter in swine. MATERIAL AND METHODS: BAE with selective infusion of XEMs (n = 6) or saline (n = 4, control) into the gastric fundal arteries was performed under X-ray guidance. Weight and plasma hormone levels were measured at baseline and weekly for four weeks after embolization. Cone beam CT (CBCT) images were acquired immediately after embolization and weekly for four weeks. Hormone-expressing cells in the stomach were assessed by immunohistochemical staining. RESULTS: BAE pigs lost weight at one week after embolization followed by significantly impaired weight gain relative to controls (14.3% vs 20.9% at 4 weeks, P = 0.03). Plasma ghrelin levels were significantly lower in embolized animals than those in controls (1221.6 vs 1706.2 at 4 weeks, P < 0.01). XEMs were visible on X-ray and CBCT during embolization and their radiopacity persisted over four weeks (165.5 HU at week-1 vs. 158.5 HU at week-4, P = 0.9). Superficial mucosal ulcerations were noted in 1 of 6 BAE animals. Ghrelin-expressing cell counts were significantly lower in the gastric fundus (17.7 vs 36.8, P < 0.00001) and antrum (24.2 vs 46.3, P < 0.0001) than those in controls. Gastrin-expressing cell counts were markedly reduced in BAE pigs relative to controls (98.5 vs 127.0, P < 0.02). Trichrome staining demonstrated significantly more fibrosis in BAE animals compared with controls (13.8% vs 8.7%, P < 0.0001). CONCLUSION: XEMs enabled direct visualization of the embolic material during and after embolization. BAE with XEMs and anti-reflux microcatheters was safe and effective.

The inhibitory effects of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and linoleic acid (LA) on the contractions induced by five prostanoids and U46619 (a TP receptor agonist) were examined in guinea pig gastric fundus smooth muscle (GFSM). Tension changes were isometrically measured, and the mRNA expression of prostanoid receptors was measured by RT-qPCR. DHA and EPA significantly inhibited contractions induced by the prostanoids and U46619, whereas LA inhibited those induced by prostaglandin D

Transient outward, or “A-type,” currents are rapidly inactivating voltage-gated potassium currents that operate at negative membrane potentials. A-type currents have not been reported in the gastric fundus, a tonic smooth muscle. We used whole cell voltage clamp to identify and characterize A-type currents in smooth muscle cells (SMCs) isolated from murine fundus. A-type currents were robust in these cells with peak amplitudes averaging 1.5 nA at 0 mV. Inactivation was rapid with a time constant of 71 ms at 0 mV; recovery from inactivation at −80 mV was similarly rapid with a time constant of 75 ms. A-type currents in fundus were blocked by 4-aminopyridine (4-AP), flecainide, and phrixotoxin-1 (PaTX1). Remaining currents after 4-AP and PaTX1 displayed half-activation potentials that were shifted to more positive potentials and showed incomplete inactivation. Currents after tetraethylammonium (TEA) displayed half inactivation at −48.1 ± 1.0 mV. Conventional microelectrode and contractile experiments on intact fundus muscles showed that 4-AP depolarized membrane potential and increased tone under conditions in which enteric neurotransmission was blocked. These data suggest that A-type K+ channels in fundus SMCs are likely active at physiological membrane potentials, and sustained activation of A-type channels contributes to the negative membrane potentials of this tonic smooth muscle. Quantitative analysis of Kv4 expression showed that Kcnd3 was dominantly expressed in fundus SMCs. These data were confirmed by immunohistochemistry, which revealed Kv4.3-like immunoreactivity within the tunica muscularis. These observations indicate that Kv4 channels likely form the A-type current in murine fundus SMCs.

In this study, we investigated the possible role of the l-cysteine/hydrogen sulfide pathway in β

Our previous analysis using a mouse metastasis model identified EMI Domain Containing 1 (EMID1) as a potential candidate metastasis-promoting gene. Although EMID1 was isolated as a member of the Emu gene family, which is expressed during mouse embryogenesis, little is known about the molecule. We sought to clarify the molecular function of EMID1 and the protein expression. Overexpression and knockdown studies using mouse cell lines identified two novel functions of EMID1: intracellular signaling involving enhancement of cell growth via cell cycle promotion and suppression of cell motility, and inhibition of cell-matrix adhesion by extracellularly secreted EMID1. EMID1 deposited on the culture dish induced self-detachment of cells that overexpressed the protein and inhibited adhesion of additionally seeded cells. This multifunctional property involving both intracellular signaling and the extracellular matrix suggests that EMID1 may be a matricellular proteins. Expression analysis using immunohistochemical staining revealed expression of EMID1 that was limited to chief cells of the gastric fundic gland and β cells of the pancreatic islets in normal adult human tissues, implying cell-specific functions of this molecule. In addition, increased expression of EMID1 protein detected in some cases of human cancers implies that EMID1 might be a new therapeutic target for cancer treatment.

Some adipokines, such as adiponectin (ADPN), other than being implicated in the central regulation of feeding behavior, may influence gastric motor responses, which are a source of peripheral signals that also influence food intake. The present study aims to elucidate the signaling pathways through which ADPN exerts its actions in the mouse gastric fundus. To this purpose, we used a multidisciplinary approach. The mechanical results showed that ADPN caused a decay of the strip basal tension, which was abolished by the nitric oxide (NO) synthesis inhibitor, L-NG-nitro arginine (L-NNA). The electrophysiological experiments confirmed that all ADPN effects were abolished by L-NNA, except for the reduction of Ca2+ current, which was instead prevented by the inhibitor of AMP-activated protein kinase (AMPK), dorsomorphin. The activation of the AMPK signaling by ADPN was confirmed by immunofluorescence analysis, which also revealed the ADPN R1 receptor (AdipoR1) expression in glial cells of the myenteric plexus. In conclusion, our results indicate that ADPN exerts an inhibitory action on the gastric smooth muscle by acting on AdipoR1 and involving the AMPK signaling pathway at the peripheral level. These findings provide novel bases for considering AMPK as a possible pharmacologic target for the potential treatment of obesity and eating disorders.

In this paper, we proposed and validated a probability distribution guided network for segmenting optic disc (OD) and optic cup (OC) from fundus images. Uncertainty is inevitable in deep learning, as induced by different sensors, insufficient samples, and inaccurate labeling. Since the input data and the corresponding ground truth label may be inaccurate, they may actually follow some potential distribution. In this study, a variational autoencoder (VAE) based network was proposed to estimate the joint distribution of the input image and the corresponding segmentation (both the ground truth segmentation and the predicted segmentation), making the segmentation network learn not only pixel-wise information but also semantic probability distribution. Moreover, we designed a building block, namely the Dilated Inception Block (DIB), for a better generalization of the model and a more effective extraction of multi-scale features. The proposed method was compared to several existing state-of-the-art methods. Superior segmentation performance has been observed over two datasets (ORIGA and REFUGE), with the mean Dice overlap coefficients being 96.57% and 95.81% for OD and 88.46% and 88.91% for OC.

Made available in DSpace on 2020-12-12T02:41:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Background: BALB/c and C57BL/6 mice are widely used in biomedical research; however, the differences between strains are still underestimated. Our aims were to develop an experimental protocol to evaluate the duodenal contractility and gastrointestinal transit in mice using the Alternating Current Biosusceptometry (ACB) technique and to compare gastrointestinal motor function and morphology between BALB/c and C57BL/6 strains. Methods: Male mice were used in experiments (a) duodenal contractility: animals which had a magnetic marker surgically fixed in the duodenum to determine the frequency and amplitude of contractions and (b) gastrointestinal transit: animals which ingested a magnetically marked chow to calculate the Oro-Anal Transit Time (OATT) and the Fecal Pellet Elimination Rate (FPER). The animals were killed after the experiments for organ collection and morphometric analysis. Key Results: BALB/c and C57BL/6 had two different duodenal frequencies (high and low) with similar amplitudes. After 10 hours of monitoring, BALB/c eliminated around 89% of the ingested marker and C57BL/6 eliminated 33%; OATT and FPER were slower for C57BL/6 compared with BALB/c. The OATT and amplitude of low frequency had a strong positive correlation in C57BL/6. For BALB/c, the gastric muscular layer was thicker compared to that measured for C57BL/6. Conclusions and Inferences: The experimental protocol to evaluate duodenal contractility and fecal magnetic pellets output using the ACB technique in mice was successfully established. BALB/c strains had higher duodenal frequencies and a shorter time to eliminate the ingested marker. Our results showed differences in both motor function and gastrointestinal morphology between BALB/c and C57BL/6 strains. Institute of Biosciences São Paulo State University UNESP Institute of Biological Sciences and Health Federal University of Mato Grosso UFMT Alagoas State University of Health Sciences UNCISAL Institute of Biosciences São Paulo State University UNESP

Dysfunction of gastrointestinal (GI) motility is a common complication in patients with diabetes mellitus (DM). Studies related to changes in fundus contraction induced by inhibitors in DM are not well known. Therefore, this study aimed to investigate the signaling pathways involved in the changes in the contraction of fundus smooth muscle obtained from control and DM rats. DM was induced by injecting streptozotocin (65 mg/kg) into Sprague-Dawley rats. The rats were sacrificed after 14 days. Fundus smooth muscle contraction was stimulated using electrical field stimulation (amplitude, 50 V; duration, 1 min; frequency, 2-20 Hz) and acetylcholine (0.1 mM). The inhibitor-mediated cell membrane was pre-treated with atropine, verapamil, methysergide, ketanserin, ondansetron, and GR 113808. Inhibitors related to intracellular signaling, such as U73122, chelerythrine, L-NNA, were also used. ML-9 and Y-27632 were identified as inhibitors of factors of myosin light chain (MLC). The contractility was observed to be lower in the DM group than in the control group. Further, the activities of phospholipase C (PLC), protein kinase C (PKC), and myosin light chain kinase (MLCK) were decreased in the DM group. DM reduced the activity of PLC, PKC, and MLCK, which resulted in a decrease in the contractility of the fundus smooth muscle. Therefore, our results present the mechanism of this DM-mediated GI disorder.

The prevalence of obesity is increasing globally, leading to significantly increased morbidity, mortality, and health care costs. However, there is a lack of effective treatment options that can treat patients with obesity less invasively than with bariatric surgery. Bariatric arterial embolization (BAE) is an image-guided, minimally invasive, percutaneous procedure that is currently being investigated in preclinical animal models and early clinical trials. If successful, BAE may represent a viable interventional approach for obesity treatment. The purpose of this article is to introduce the physiological and anatomical rationale for BAE, review techniques involved in performing BAE for weight modulation, and provide up-to-date preclinical evidence that supports the translation of BAE into patients.

The fundic glands of the stomach contain two types of mucous cells: surface mucous cells (SMCs) located at the surface of the stomach and the pits, and mucous neck cells (MNCs) situated in the neck of the glands. They produce mucins, highly glycosylated proteins. Very little is known about the glycan composition of these mucins and of gastric secretion in general. We used several lectins combined with deglycosylation pretreatments to analyze the glycan composition of SMCs and MNCs. The results showed the presence of terminal sialic acid and subterminal Gal and GalNAc, which is consistent with previous knowledge about glycosylation in mucins. Our results also support previous reports that showed a different expression of mucins in the SMCs, depending on their superficial or deep location in the pit. Some lectins labeled only the perinuclear region of the SMCs, but not the apical region, where the secretory granules are stored. This suggests that the lectins are labeling sugar residues that are accessible to lectins during the first steps of glycan synthesis, which occurs in the endoplasmic reticulum and Golgi apparatus. Our results indicate that SMCs and MNCs produce a mucus secretion with a different glycoconjugate composition. The secretion is more varied in SMCs. As our results coincide with what we know about glycosylation of mucins, we can conclude that most of the glycans detected belong to mucins, and the differences in glycosylation observed in each cell type may be due, mainly, to the different secreted mucins. Anat Rec, 301:2128-2144, 2018. © 2018 Wiley Periodicals, Inc.

Aqueous extract of the spines of the brown bullhead catfish (Ameiurus nebulosus Lesueur, 1819) caused contraction of the guinea-pig small intestine in vitro, a widely-used preparation in pharmacology. The action is dependent on extracellular Ca2+, and probably takes place on the smooth muscle cells. Mouse gastrointestinal preparations were also contracted by the extract. Stings by the spines of this fish species causes a painful sensation in man. We tested the effect of an extract of spines in isolated organ experiments on innervated smooth muscle preparations. In the guinea-pig ileum, the response to the extract was abolished by the Ca2+-channel blocker nifedipine, but only slightly reduced by atropine (a muscarine receptor antagonist) or tetrodotoxin (TTX; a blocker axonal conduction) or antagonists for P2X purinoceptors. Blocking of serotonin or histamine H1 receptors, tachykinin NK1 receptors, functional impairment of capsaicin-sensitive sensory nerve endings or inhibition of cyclo-oxygenases failed to influence the contractile effect of the extract. No inhibitory action of the extract was detected on the ileum subject to electrical motor nerve stimulation.

This study tested the effects of β-methylphenylethylamine (β-MPEA) and octopamine on contractile parameters of the gastrointestinal tract in rats. We hypothesized that some of their effects result from interactions with trace amine (TA)-associated receptors or serotoninergic 5-hydroxytryptamine (5-HT) receptors. β-MPEA-induced contractions in rat gastric fundus strips under resting tonus conditions, but induced relaxation in preparations that were previously contracted with carbachol. Octopamine relaxed gastric fundus strips maintained at resting tonus or contracted with carbachol. The contractile effect of β-MPEA was reduced by cyproheptadine and methiothepin, antagonists of excitatory 5-HT receptors. The relaxing effect of β-MPEA on gastric fundus was insensitive to pretreatment with N-(3-ethoxyphenyl)-4-(1-pyrrolidinyl)-3-(trifluoromethyl)benzamide (EPPTB) and tropisetron, antagonists of TA1 and 5-HT4 receptors, respectively. Both EPPTB and tropisetron inhibited the relaxant effects of octopamine on carbachol-contracted preparations. Contrarily, EPPTB did not reduce the relaxant effects of RO5263397 (TA1 agonist) or zacopride (5-HT4 agonist). Octopamine, but not β-MPEA, delayed the gastrointestinal transit of a liquid test meal in awaken rats. In isolated preparations of the small intestine under resting conditions, β-MPEA did not alter the basal tonus, but octopamine relaxed it. Intestinal preparations previously contracted with carbachol relaxed after the addition of octopamine and decreased the magnitude of their spontaneous rhythmic contractions in a tropisetron-dependent manner. Thus, β-MPEA and octopamine exerted pharmacological actions on the rat gastrointestinal tract. The excitatory effects of β-MPEA involved 5-HT receptors. Octopamine inhibited the rat gut contractility through the likely involvement of 5-HT4 and TA receptors. Overall, octopamine effectively inhibited rat gastrointestinal transit.

The epithelium of the gastric mucosa and its glands in the corpus of rat stomach contains mucous surface cells (MSCs), parietal cells, mucous neck cells (MNCs), zymogenic or chief cells (ZCs), several types of enteroendocrine cells, and intermediate cells with characteristics between MNCs and ZCs also called transitional or prezymogenic cells (pre-ZCs). The aim of our work was to analyze the expression of Mannose (Man) in the rat gastric glands by means of Galanthus nivalis lectin (GNA) histochemistry to identify the differences between MNC, pre-ZCs and ZCs and to establish the relationships between these cells. Most of the cytoplasm of MNCs was negative for GNA histochemistry. Intensity of GNA labeling in the gastric gland showed a graduation from pre-ZCs (weak labeling) to ZCs (moderate labeling). Labeling of ZCs was stronger at the perinuclear and apical cytoplasm. In the last years, strong evidence has been reported supporting that ZCs differentiate from MNCs. Our work also supports the origin of ZCs from MNCs, because the GNA labeling graduation might be due to oligosaccharides which are not expressed in MNCs, start to express in pre-ZCs and are more abundant in ZCs, indicating that differentiation from MNCs to ZCs is a process in which glycans with Man moieties are synthesized.

AIM To investigate whether glucagon-like peptide-2 (GLP-2) influences the neurally-induced responses in gastric strips from mice, since no data are available. METHODS For functional experiments, gastric fundal strips were mounted in organ baths containing Krebs-Henseleit solution. Mechanical responses were recorded via force-displacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrical field stimulation (EFS) was applied via two platinum wire rings through which the preparation was threaded. The effects of GLP-2 (2 and 20 nmol/L) were evaluated on the neurally-induced contractile and relaxant responses elicited by EFS. Neuronal nitric oxide synthase (nNOS) enzyme was evaluated by immunohistochemistry. RESULTS In the functional experiments, electrical field stimulation (EFS, 4-16 Hz) induced tetrodotoxin (TTX)-sensitive contractile responses, which were reduced in amplitude by GLP-2 (P < 0.05). In the presence of the nitric oxide (NO) synthesis inhibitor L-NNA, GLP-2 no longer influenced the neurally-evoked contractile responses (P > 0.05). The direct smooth muscle response to methacholine was not influenced by GLP-2 (P > 0.05). In the presence of guanethidine and carbachol, the addition of GLP-2 to the bath medium evoked TTX-sensitive relaxant responses that were unaffected by L-NNA (P > 0.05). EFS induced a fast NO-mediated relaxation, whose amplitude was enhanced in the presence of the hormone (P < 0.05). Immunohistochemical experiments showed a significant increase (P < 0.05) in nNOS immunoreactivity in the nerve structures after GLP-2 exposure. CONCLUSION The results demonstrate that in gastric fundal strips, GLP-2 influences the amplitude of neurally-induced responses through the modulation of the nitrergic neurotransmission and increases nNOS expression.

Background This study aimed to evaluate the effects of the position of an acetic acid-induced gastric ulcer and the effects of prokinetic drugs on gastric emptying. Materials and Methods Male Sprague-Dawley rats were used in this study. Acetic acid ulcers were induced either in the region between the fundus and pylorus on the anterior wall of the stomach or in the glandular region on the greater curvature of the stomach to determine whether there were regional differences in the effect of the ulcers. Gastric emptying was evaluated with a breath test using [1-13C] acetic acid. In addition, the effects of the prokinetic drugs, metoclopramide and mosapride, on gastric emptying were also evaluated. Results Acetic acid induced ulcers in the region between the fundus and pylorus on the anterior wall of the stomach significantly delayed gastric emptying as compared with control rats, but not the acetic acid induced ulcers in the glandular region on the greater curvature of the stomach. Metoclopramide and mosapride did not improve the delayed gastric emptying even at doses that enhanced gastric emptying in normal rats. Conclusion These findings show that gastric emptying is influenced by the position of the ulcer and the region between the fundus and pylorus on the anterior wall plays an important role in gastric emptying. Moreover, it was found that metoclopramide and mosapride do not improve the delayed gastric emptying caused by acetic acid ulcers induced on the anterior wall in the region between the fundus and pylorus.

Purpose To assess whether the number of fundal arteries embolized and use of gastroprotective agents have an impact on ghrelin suppression and gastric ulceration rates. Materials and Methods Twenty-two healthy, growing swine (mean, 38.4 kg; range, 30.3–47.0 kg) were evaluated. Six control swine underwent a sham procedure. Gastric embolization was performed by the infusion of 40-µm microspheres selectively into some or all gastric arteries supplying the gastric fundus. In group 1, 6 swine underwent embolization of all 4 arteries to the gastric fundus. In group 2, 5 swine underwent embolization of 2 gastric fundal arteries. In group 3, 5 swine underwent embolization of 1 gastric fundal artery. Animals in groups 2 and 3 were treated with gastroprotective agents (sucralfate and omeprazole). Weight and fasting plasma ghrelin levels were analyzed at baseline and at week 4. Upon animal euthanasia, gross analysis was performed for identification of ulcers. Results Only group 1 animals exhibited changes in serum ghrelin levels that rendered them significantly lower than those in control animals ( P = .049). Group 3 animals exhibited marked elevations in serum ghrelin levels compared with control animals ( P = .001). Gross pathologic evaluation revealed 0 ulcers in the control animals, 3 ulcers (50%) in group 1, 2 ulcers (40%) in group 2, and 2 ulcers (40%) in group 3. Conclusions Administration of gastroprotective agents and embolization of fewer arteries to the gastric fundus did not prevent gastric ulceration in treated animals. Only animals that underwent embolization of all gastric arteries exhibited significant decreases in serum ghrelin levels.

Glucagon-like peptide-2 (GLP-2) has been reported to indirectly relax gastric smooth muscle. In the present study we investigated, through a combined mechanical and immunohistochemical approach, whether GLP-2 interferes with the electrical field stimulation (EFS)-induced vipergic relaxant responses and the mechanism through which it occurs. For functional experiments, strips from the mouse gastric fundus were mounted in organ baths for isometric recording of the mechanical activity. Vasoactive intestinal peptide (VIP) immunoreactivity in GLP-2 exposed specimens was also evaluated by immunohistochemistry. In carbachol pre-contracted strips, GLP-2 (20 nM) evoked a tetrodotoxin (TTX)-sensitive relaxation, similar in shape to the TTX-insensitive of 100 nM VIP. In the presence of GLP-2, VIP had no longer effects and no more response to GLP-2 was observed following VIP receptor saturation. EFS (4–16 Hz) induced a fast relaxant response followed, at the higher stimulation frequencies (≥ 8 Hz), by a slow one. This latter was abolished either by GLP-2 or VIP receptor saturation as well as by the VIP receptor antagonist, VIP 6–28 (10 μM). A decrease of VIP-immunoreactive nerve structures in the GLP-2 exposed specimens was observed. These results suggest that, in the mouse gastric fundus, GLP-2 influences the EFS-induced slow relaxant response by promoting neuronal VIP release.

Class-I-antiarrhythmics like ajmaline are known to alter smooth muscle function, which may cause alterations in gastrointestinal motility. The effects of ajmaline on isolated gastric and portal vein smooth muscle and the underlying mechanisms are unknown. We studied the effects of ajmaline on the contractile patterns of isolated preparations of gastric antrum and portal vein from Wistar rats. The organ bath technique was used to measure spontaneous or pharmacologically induced isometric contractions. Changes in force observed after application of ajmaline or under control conditions are reported as % of the amplitude of an initial K+-induced contraction. Electric field stimulation was used to study neurogenic relaxations of gastric fundus smooth muscle. Ajmaline increased the amplitude of spontaneous contractions of muscle strips (portal vein: control 31.1 ± 15.2%, with 100 μM ajmaline 76.6 ± 32.3%, n = 9, p

Statins are determined to have various pleiotropic effects apart from their lipid-lowering properties. Herein, we investigated the direct effects of atorvastatin on gastric smooth muscle tone. Atorvastatin effectively relaxed isolated rat gastric fundus strips precontracted with acetylcholine, potassium chloride, and serotonin. Incubation of the strips with nitric oxide synthase inhibitor, l-NOARG (10

It is generally considered that enteric neuropathy is one of the causative factors in diabetic gastroparesis. Our previous study demonstrated that there is a loss of NOS neurons in diabetic mice. However, the underlying mechanism remains unclear. The present study was designed to clarify the relationship between neuronal P2X7R and NOS neuron damage. The effect of P2X7R on diabetes-induced gastric NOS neurons damage and its mechanism were investigated by using quantitative RT-PCR，immunofluorescence, western blot, isometric force recording, intracellular calcium ([Ca2+]i) measurement and whole-cell patch clamp techniques. The immunohistochemistry and western blot results showed that nNOS expression was significantly down-regulated in diabetic mice, meanwhile, electric field stimulation-induced NOS sensitive relaxation was significantly suppressed. Myenteric neurons expressed P2X7R and pannexin1, and the mRNA and protein level of P2X7R and pannexin1 were up-regulated in diabetic mice. BzATP, a P2X7R activator, evoked [Ca2+]i increase in Hek293 cells with heterologous expression of P2X7R (Hek293-P2X7R cells) and the same dose of ATP-induced [Ca2+]i was more obvious in Hek293-P2X7R cells than in Hek293 cells. Application of BzATP activated an inward current of Hek293-P2X7R in a dose dependent manner. Hek293-P2X7R but not untransfected Hek293 cells could take up of YO-PRO-1. In addition, the uptake of YO-PRO-1 by Hek293-P2X7R was blocked by oxATP, a P2X7 antagonist and CBX, a pannexin1 inhibitor. The results suggest that the P2X7R of enteric neurons may be involved in diabetes-induced NOS neuron damage via combining with pannexin-1 to form transmembrane pores which induce macromolecular substances and calcium into the cells.

Background/Aims: Roux-en-Y Gastric Bypass, RYGB, is the most effective strategy to control body weight in morbid obesity. RYGB leads to rapid improvement of glycemic status and weight loss, which are largely attributed to the alteration of gastrointestinal hormones including ghrelin. The current study examined potential mechanisms of altered ghrelin synthesis after RYGB. Methods: Gastric mammalian target of rapamycin (mTOR) signaling, ghrelin synthesis and secretion were determined in lean or obese male mice with or without RYGB operation, as well as in obese patients pre- and post-RYGB surgery. Ghrelin expression and mTOR signaling were investigated by western blotting and immunohistochemistry. Ghrelin mRNA levels were detected by real-time PCR. Plasma ghrelin was measured by enzyme immunoassay. Results: mTOR activity in the gastric fundus was significantly lower than in the forestomachs. Both of them were decreased after 24h fasting. A significant negative correlation was found between gastric levels of phospho-S6 (phospho-S6 ribosomal protein) and proghrelin during changes of energy status. mTOR activity was activated, whereas ghrelin expression was inhibited by Roux-en-Y Gastric Bypass in both rodents and human beings. Increment of ghrelin synthesis and decline of mTOR signaling induced by rapamycin were significantly reversed by RYGB in both lean and obese mice. Administration of Ad-S6K1 (adenovirus-mediated p70 ribosomal protein subunit 6 kinase 1) from tail vein suppressed the expression of ghrelin in RYGB-operated mice relative to control animals. Conclusion: mTOR is therefore a gastric fuel sensor whose activity is linked to the regulation of ghrelin after Roux-en-Y Gastric Bypass.

β-Phenylethylamine (β-PEA) is a trace amine with chemical proximity to biogenic amines and amphetamines. It is an endogenous agonist of trace amine-associated receptors (TAARs) that acts as a neuromodulator of classic neurotransmitters in the central nervous system. At high concentrations, β-PEA contracts smooth muscle, and a role for TAARs in these responses has been postulated. The high dietary intake of trace amines has been associated with such symptoms as hypertension and migraine, especially after the intake of foods containing such compounds. In gastrointestinal tissues, TAAR expression was reported, although the effect of β-PEA on gastric contractile behaviour is unknown. Here, isolated strips that were obtained from the rat gastric fundus were stimulated with high micromolar concentrations of β-PEA. Under resting tonus, β-PEA induced contractions. In contrast, when the strips were previously contracted with KCl, a relaxant response to β-PEA was observed. The contractile effect of β-PEA was inhibited by 5-hydroxytryptamine (5-HT) receptor antagonists (i.e., cyproheptadine and ketanserin) but not by the TAAR1 antagonist EPPTB. In gastric fundus strips that were previously contracted with 80 mmol/L KCl, the relaxant effect of β-PEA intensified in the presence of 5-HT receptor antagonists, which was inhibited by EPPTB and the adenylyl cyclase inhibitor MDL-12,330A. The guanylyl cyclase inhibitor ODQ did not alter the relaxant effects of β-PEA. In conclusion, β-PEA exerted dual contractile and relaxant effects on rat gastric fundus. The contractile effect appeared to involve the recruitment of 5-HT receptors, and the relaxant effect of β-PEA on KCl-elicited contractions likely involved TAAR1 .

Background For the contraction and relaxation of gastric smooth muscles to occur, the intracellular Ca2+ concentration must be increased and decreased, respectively. The Na+/Ca2+ exchanger (NCX) is a plasma membrane transporter that is involved in regulating intracellular Ca2+ concentrations. Methods To determine the role of NCX in gastrointestinal tissues, we examined electric field stimulation (EFS)-induced relaxations in the circular muscles of the gastric fundus in NCX1 and NCX2 heterozygote knockout mice (HET). Key Results The myenteric plexus layers and the longitudinal and circular muscle layers in the gastric fundus of wild-type mice (WT) were strongly immunoreactive to NCX1 and NCX2. EFS induced a transient relaxation that was apparent during the stimulus and a sustained relaxation that persisted after the end of the stimulus. The amplitudes of EFS-induced transient relaxation and sustained relaxation were greater in NCX1 HET and NCX2 HET than in WT. When an inhibitor of nitric oxide synthase was added following the EFS, neither NCX1 HET nor NCX2 HET exhibited transient relaxation, similar to WT. Furthermore, when a PACAP antagonist was added following the EFS, sustained relaxation in NCX1 HET and NCX2 HET was not observed, similar to WT. Next, we examined the effect of NCX heterozygous deficiency on relaxation in response to NO and PACAP in smooth muscles. The magnitude of NOR-1- and PACAP-induced relaxations in NCX1 HET and NCX2 HET was similar to that of WT. Conclusions & Inferences In this study, we demonstrate that NCX1 and NCX2 expressed in neurons regulate the motility in the gastric fundus.

The aim of the study was to investigate the effect of 2-oxoglutaric acid (2-Ox) supplementation (a precursor of glutamine and hydroxyproline, the most abundant amino acid of collagen) on cartilage and bone in pigs after fundectomy. Pigs at the age of forty days were subjected to fundectomy and divided into two groups depending on 2-Ox supplementation (at the daily dosage of 0.4 g/kg of body weight). Other pigs were sham operated. Pigs were euthanized at the age of eight months. An analysis of the morphometry of trabeculae, growth plate and articular cartilage in fundectomy-induced osteopenic bone was performed. Moreover, the levels of expression of osteocalcin, osteopontin and osteoprotegerin in trabecular bone and osteocalcin in articular cartilage were evaluated. Articular cartilage was thinnest in fundectomized pigs and thickest in 2-Ox-supplemented animals after fundectomy. Moreover, 2-Ox supplementation after fundectomy enhanced the total thickness of the growth plate and trabeculae in fundectomized pigs. The most evident signal for osteocalcin and osteoprotegerin in trabecular bone was in sham-operated and 2-Ox-supplemented pigs; a low reaction was observed in the fundectomized group. Additionally, as a long-term postoperative consequence, a change was observed in the expression of osteocalcin in articular cartilage. It seems that 2-Ox is suitable for use in preventing the negative effects of fundectomy on cancellous bone and cartilage.

Background Severe burn injury has been demonstrated to delay gastric emptying. The aim of this study was to investigate effects and cellular mechanisms of auricular electroacupuncture (AEA) at the acupoints innervated by the auricular branch of vagus nerve on burn-induced gastric dysmotility in rats. Methods Propranolol (β-adrenoceptor antagonist) was injected intraperitoneally after the rats underwent burn injury. All experiments were performed 6 h following burn/sham burn injury. AEA was performed at bilateral auricular acupoints for 45 min. Electrocardiogram was recorded for 30 min. Plasma hormones were measured; cyclooxygenase (COX)-2 expressions in gastric tissue were measured using western blotting and real-time RT-PCR. Key Results (i) Burn injury delayed gastric emptying (p = 0.006) and AEA increased gastric emptying by 49% (p = 0.045). (ii) Burn injury evoked a significant elevation in plasma noradrenaline, which was suppressed by AEA. (iii) Burn injury significantly increased protein and mRNA expressions of COX-2 in gastric fundus and antrum. AEA suppressed burn-induced increase in protein expressions, but not mRNA expressions of COX-2. Conclusions & Inferences Burn injury delays gastric emptying by up-regulating COX-2 attributed to sympathetic overactivity. AEA improves burn-induced delay in gastric emptying, possibly mediated via the sympathetic-COX-2 pathway.

Through-the-scope endoscopic clips are widely used. Several designs of endoscopic clips are marked for different applications. However, no prior reports have been published to aid in comparing success rates of clip deployment and the retention rates at different regions of the stomachs. The aims of the article were to compare success rates of clip deployment and the retention rates at different regions of the stomachs with a novel endoclip. Upper endoscope was inserted into the stomach of five pigs under general anesthesia. In all animals, three regions of the stomachs (gastric fundus, gastric body, and gastric antrum) were chosen as the sites of clip application. Two clips of a novel type were placed along the same gastric site at a distance of 0.5–1 cm from each other. Animals had weekly endoscopies to quantitate clip retention. Success rates of clip deployment were 70 % for gastric fundus, 100 % for gastric body, and 100 % for gastric antrum. Clip retention rates were significantly higher with gastric body than with gastric fundus or gastric antrum at 1–8 weeks. (1) For the clip device, it seems that it is difficult for the clip deployment in gastric fundus (70 %) than that in the gastric body or gastric antrum (100 %), but there is no statistical significance (χ 2 test, p = 0.21). (2) Clips used in the gastric body were retained significantly longer than that in the gastric fundus or gastric antrum. (3) The novel clips were safe, and no complications such as bleeding or weight loss were noted.

Background Rikkunshito (RKT) is a gastroprotective herbal medicine. In this study, we investigated the role of RKT in the relaxation of the gastric body (fundus and corpus) and antrum. Methods We used Suncus murinus, a unique small model animal with similar gastrointestinal motility to humans and dogs. RKT was added at 0.1, 1.0, and 5.0 mg/mL to induce relaxation in vitro; the outcome measure was the intensity of relaxation. The number of spontaneous antral contractions in the absence or the presence of RKT was also counted. Key Results Rikkunshito induced the relaxation of the gastric body and antrum and decreased the number of spontaneous antral contractions in a dose-dependent manner. The responses to RKT (1.0 mg/mL) were not affected by pretreatment with atropine, N-nitro-l-arginine methyl ester, ritanserin, or ondansetron. On the other hand, timolol almost completely reversed the relaxation induced by RKT (1.0 mg/mL) on the gastric body and antrum and the occurrence of the spontaneous antral contractions. Both butoxamine, a β2-adrenoreceptor antagonist, and L 748337, a β3-adrenoreceptor antagonist, but not CGP 20712, a β1-adrenoreceptor antagonist, significantly reversed the RKT-induced (1.0 mg/mL) gastric relaxation. Conclusions & Inferences These results indicate that RKT stimulates and modulates gastric relaxation through β2- and β3-adrenergic, but not β1-adrenergic, pathways in S. murinus.

BACKGROUND Sphingosine and its metabolite sphingosine phosphate (S1P) regulate a multitude of biological functions, including the contractile state of smooth. Gastrointestinal side effects have been reported in patients treated with FTY720, a sphingosine analog that is approved for the treatment of multiple sclerosis. The aim of this study was to characterize the effects of FTY720 on rat gastric fundus smooth muscle under basal conditions and during activation induced by high-K+ solution. METHODS Isometric contractions of isolated circular strips of gastric fundus smooth muscle were recorded using the organ bath method. The effects of FTY720 or vehicle were recorded under control conditions and in the presence of indomethacin, L-NAME, HA-1100, nifedipine, JTE-013, and suramin. Tone and contractions recorded in the presence of FTY720 or vehicle are reported as % of the amplitude of an initial high-K+ contraction obtained under control conditions. KEY RESULTS From a concentration of 10 μmol L-1 onwards, FTY720 increased the tone, reaching 8.9% ± 7.5% at 100 μmol L-1 (P

KEY POINTS: Activation of focal adhesion kinase (FAK) by integrin signalling facilitates smooth muscle contraction by transmitting the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue. Here we report that electrical field stimulation (EFS) of cholinergic motor neurons activates FAK in gastric fundus smooth muscles, and that FAK activation by EFS is atropine‐sensitive but nicardipine‐insensitive. PDBu and calyculin A contracted gastric fundus muscles Ca(2+)‐independently and also activated FAK. Inhibition of FAK activation inhibits the contractile responses evoked by EFS, and inhibits CPI‐17 phosphorylation at T38. This study indicates that mechanical force or tension is sufficient to activate FAK, and that FAK appears to be involved in the activation of the protein kinase C–CPI‐17 Ca(2+) sensitization pathway in gastric fundus smooth muscles. These results reveal a novel role for FAK in gastric fundus smooth muscle contraction by facilitating CPI‐17 phosphorylation. ABSTRACT: Smooth muscle contraction involves regulating myosin light chain phosphorylation and dephosphorylation by myosin light chain kinase and myosin light chain phosphatase. C‐kinase potentiated protein phosphatase‐1 inhibitor of 17 kDa (CPI‐17) and myosin phosphatase targeting subunit of myosin light‐chain phosphatase (MYPT1) are crucial for regulating gastrointestinal smooth muscle contraction by inhibiting myosin light chain phosphatase. Integrin signalling involves the dynamic recruitment of several proteins, including focal adhesion kinase (FAK), to focal adhesions. FAK tyrosine kinase activation is involved in cell adhesion to the extracellular matrix via integrin signalling. FAK participates in linking the force generated by myofilament activation to the extracellular matrix and throughout the smooth muscle tissue. Here, we show that cholinergic stimulation activates FAK in gastric fundus smooth muscles. Electrical field stimulation in the presence of N (ω)‐nitro‐l‐arginine methyl ester and MRS2500 contracted gastric fundus smooth muscle strips and increased FAK Y397 phosphorylation (pY397). Atropine blocked the contractions and prevented the increase in pY397. The FAK inhibitor PF‐431396 inhibited the contractions and the increase in pY397. PF‐431396 also inhibited the electrical field stimulation‐induced increase in CPI‐17 T38 phosphorylation, and reduced MYPT1 T696 and T853, and myosin light chain S19 phosphorylation. Ca(2+) influx was unaffected by PF‐431396. Nicardipine inhibited the contractions but had no effect on the increase in pY397. Phorbol 12,13‐dibutyrate or calyculin A contracted gastric fundus smooth muscle strips Ca(2+) independently and increased pY397. Our findings suggest that FAK is activated by mechanical forces during contraction and reveal a novel role of FAK in the regulation of CPI‐17 phosphorylation.

AIMTo investigate whether the adipocytes derived hormone adiponectin (ADPN) affects the mechanical responses in strips from the mouse gastric fundus.METHODSFor functional experiments, gastric strips from the fundal region were cut in the direction of the longitudinal muscle layer and placed in organ baths containing Krebs-Henseleit solution. Mechanical responses were recorded via force-displacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrical field stimulation (EFS) was applied via two platinum wire rings through which the preparation was threaded. The effects of ADPN were investigated on the neurally-induced contractile and relaxant responses elicited by EFS. The expression of ADPN receptors, Adipo-R1 and Adipo-R2, was also evaluated by touchdown-PCR analysis.RESULTSIn the functional experiments, EFS (4-16 Hz) elicited tetrodotoxin (TTX)-sensitive contractile responses. Addition of ADPN to the bath medium caused a reduction in amplitude of the neurally-induced contractile responses (P < 0.05). The effects of ADPN were no longer observed in the presence of the nitric oxide (NO) synthesis inhibitor L-N-G-nitro arginine (L-NNA) (P > 0.05). The direct smooth muscle response to methacholine was not influenced by ADPN (P > 0.05). In carbachol precontracted strips and in the presence of guanethidine, EFS induced relaxant responses. Addition of ADPN to the bath medium, other than causing a slight and progressive decay of the basal tension, increased the amplitude of the neurally-induced relaxant responses (P < 0.05). Touchdown-PCR analysis revealed the expression of both Adipo-R1 and Adipo-R2 in the gastric fundus.CONCLUSIONThe results indicate for the first time that ADPN is able to influence the mechanical responses in strips from the mouse gastric fundus.

KEY POINTS: Enteric neurotransmission is essential for gastrointestinal (GI) motility, although the cells and conductances responsible for post‐junctional responses are controversial. The calcium‐activated chloride conductance (CaCC), anoctamin‐1 (Ano1), was expressed by intramuscular interstitial cells of Cajal (ICC‐IM) in proximal stomach and not resolved in smooth muscle cells (SMCs). Cholinergic nerve fibres were closely apposed to ICC‐IM. Conductances activated by cholinergic stimulation in isolated ICC‐IM and SMCs were determined. A CaCC was activated by carbachol in ICC‐IM and a non‐selective cation conductance in SMCs. Responses to cholinergic nerve stimulation were studied. Excitatory junction potentials (EJPs) and mechanical responses were evoked in wild‐type mice but absent or greatly reduced with knockout/down of Ano1. Drugs that block Ano1 inhibited the conductance activated by carbachol in ICC‐IM and EJPs and mechanical responses in tissues. The data of the present study suggest that electrical and mechanical responses to cholinergic nerve stimulation are mediated by Ano1 expressed in ICC‐IM and not SMCs. ABSTRACT: Enteric motor neurotransmission is essential for normal gastrointestinal (GI) motility. Controversy exists regarding the cells and ionic conductance(s) that mediate post‐junctional neuroeffector responses to motor neurotransmitters. Isolated intramuscular ICC (ICC‐IM) and smooth muscle cells (SMCs) from murine fundus muscles were used to determine the conductances activated by carbachol (CCh) in each cell type. The calcium‐activated chloride conductance (CaCC), anoctamin‐1 (Ano1) is expressed by ICC‐IM but not resolved in SMCs, and CCh activated a Cl(−) conductance in ICC‐IM and a non‐selective cation conductance in SMCs. We also studied responses to nerve stimulation using electrical‐field stimulation (EFS) of intact fundus muscles from wild‐type and Ano1 knockout mice. EFS activated excitatory junction potentials (EJPs) in wild‐type mice, although EJPs were absent in mice with congenital deactivation of Ano1 and greatly reduced in animals in which the CaCC‐Ano1 was knocked down using Cre/loxP technology. Contractions to cholinergic nerve stimulation were also greatly reduced in Ano1 knockouts. SMCs cells also have receptors and ion channels activated by muscarinic agonists. Blocking acetylcholine esterase with neostigmine revealed a slow depolarization that developed after EJPs in wild‐type mice. This depolarization was still apparent in mice with genetic deactivation of Ano1. Pharmacological blockers of Ano1 also inhibited EJPs and contractile responses to muscarinic stimulation in fundus muscles. The data of the present study are consistent with the hypothesis that ACh released from motor nerves binds muscarinic receptors on ICC‐IM with preference and activates Ano1. If metabolism of acetylcholine is inhibited, ACh overflows and binds to extrajunctional receptors on SMCs, eliciting a slower depolarization response.

What is the central question of this study? Acute acidosis that results from short-term exercise is involved in delayed gastric emptying in rats and the lower responsiveness of gastric fundus strips to carbachol. Does extracellular acidosis decrease responsiveness to carbachol in tissues of sedentary rats? How? What is the main finding and its importance? Extracellular acidosis inhibits cholinergic signalling in the rat gastric fundus by selectively influencing the G

Gastroesophageal reflux disease is a common disorder in humans and has been treated for the last 67 years using fundoplication. However, treatment results have generally not been satisfactory. Physiological and anatomic findings must be taken into account to improve the therapy technique. In this article, these are described using the example of paradoxical sphincters and the effect of NO signal molecules in the gastrointestinal tract.

Objectives: The aim of this study was to evaluate anticholinergic, antihistaminic, and antiserotonergic activity of the n-hexane extract of the seeds of Zanthoxylum alatum (ZAHE) on isolated ileum of rat and guinea pig and fundus of rat. Materials and Methods: ZAHE was prepared using soxhlet extraction and cumulative concentration response curves were constructed using various doses on the tissues for acetylcholine (ACh), 5-hydroxytryptamine (5-HT), and histamine with or without n-hexane extract. Atropine, ketanserin, and pheniramine maleate were used as antagonists for ACh, serotonin, and histamine, respectively. Results: ZAHE-induced concentration-dependent inhibition of isolated ileum and fundus in rat and ileum of guinea pig. The half maximal effective concentration (EC50) of ACh in the presence of atropine (10−6 M; P < 0.05) and ZAHE (1000 μg/ml; P < 0.01) was significantly higher than EC50of ACh alone. The EC50of 5-HT in the presence of ketanserin (10−5 M; P < 0.01) and ZAHE (1000 μg/ml; P < 0.05) was higher than EC50of 5-HT alone. Similarly, the EC50of histamine in the presence of pheniramine maleate (10−6 M; P < 0.01) and ZAHE (300 μg/ml; P < 0.01 and 1000 μg/ml; P < 0.05) was also significantly higher than EC50of histamine alone. Conclusion: From the study, it was observed that ZAHE shows significant anticholinergic, antiserotonergic, and antihistaminic activity. The study provides sufficient evidence that the seeds can be used in gastric disorders, cough, chest infection, etc., as per folklore claims.

Obesity is a public health epidemic in the United States, which results in significant morbidity, mortality, and cost to the healthcare system. Despite advancements in traditional therapeutic options for the obese patients, there is a treatment gap for patients in whom lifestyle modifications alone have not been successful, but for whom bariatric surgery is not a suitable option. Areas covered: This treatment gap needs to be addressed and thus, complimentary or alternative treatments to lifestyle changes and surgery are urgently needed. Recent evidence suggests that embolization of the gastric fundus ('Bariatric Embolization'), which is predominantly supplied by the left gastric artery, may affect energy homeostasis by decreasing ghrelin production. The purpose of this special report is to discuss the background, rationale and latest data on this topic, as well as provide the latest data from the ongoing BEAT Obesity clinical trial. Expert commentary: A multipronged approach is essential in the treatment of obesity. Bariatric embolization looks to treat the hormonal imbalances which contribute to obesity. If proven successful in the long-term, bariatric embolization represents a potential minimally invasive approach to treat obesity offered by interventional radiologists.

Nitric oxide (NO) is a major inhibitory neurotransmitter in the gastrointestinal (GI) tract. Its main effector, NO-sensitive guanylyl cyclase (NO-GC), is expressed in several GI cell types, including smooth muscle cells (SMC), interstitial cells of Cajal (ICC), and fibroblast-like cells. Up to date, the interplay between neurons and these cells to initiate a nitrergic inhibitory junction potential (IJP) is unclear. Here, we investigate the origin of the nitrergic IJP in murine fundus and colon. IJPs were determined in fundus and colon SMC of mice lacking NO-GC globally (GCKO) and specifically in SMC (SM-GCKO), ICC (ICC-GCKO), and both SMC/ICC (SM/ICC-GCKO). Nitrergic IJP was abolished in ICC-GCKO fundus and reduced in SM-GCKO fundus. In the colon, the amplitude of nitrergic IJP was reduced in ICC-GCKO, whereas nitrergic IJP in SM-GCKO was reduced in duration. These results were corroborated by loss of the nitrergic IJP in global GCKO. In conclusion, our results prove the obligatory role of NO-GC in ICC for the initiation of an IJP. NO-GC in SMC appears to enhance the nitrergic IJP, resulting in a stronger and prolonged hyperpolarization in fundus and colon SMC, respectively. Thus NO-GC in both cell types is mandatory to induce a full nitrergic IJP. Our data from the colon clearly reveal the nitrergic IJP to be biphasic, resulting from individual inputs of ICC and SMC.

Ghrelin is a multifunctional peptide that promotes an increase of food intake and stimulates GH secretion. Ghrelin secretion is regulated by nutritional status and nutrients. Although a high-protein (HP) diet increases plasma ghrelin secretion in mammals, the mechanisms and the roles of the elevated ghrelin concentrations due to a HP diet have not been fully established. To clarify the roles of elevated acylated ghrelin upon intake of a HP diet, we investigated the regulation of ghrelin concentrations in plasma and tissues in wethers fed with either the HP diet or the control (CNT) diet for 14 days, and examined the action of the elevated plasma ghrelin by using a ghrelin-receptor antagonist. The HP diet gradually increased the plasma acylated-ghrelin concentrations, but the CNT diet did not. Although the GH concentrations did not vary significantly across the groups, an injection of ghrelin-receptor antagonist enhanced insulin levels in circulation in the HP diet group. In the fundus region of the stomach, the ghrelin levels did not differ between the HP and CNT diet groups, whereas ghrelinO-acyltransferase mRNA levels were higher in the group fed with HP diet than those of the CNT diet group were. These results indicate that the HP diet elevated the plasma ghrelin levels by increasing its synthesis; this elevation strongly suppresses the appearance of insulin in the circulation of wethers, but it is not involved in GH secretion. Overall, our findings indicate a role of endogenous ghrelin action in secretion of insulin, which acts as a regulator after the consumption of a HP diet.

To improve the therapeutic effects of gastric electrical stimulation (GES) for obesity, an animal experiment was conducted using a new type of stimulators. Proper parameters of GES were selected, and the impacts of GES on the food intake and gastric accommodation of canines were observed. Eight beagle dogs were operated on, and GES was performed on them. Firstly, GES was performed to determine the right parameters according to symptoms. Secondly, the so selected parameters were used in a 3-day GES procedure, during which process food intake, body weight, and symptoms were recorded. Thirdly, the gastric capacities before and after GES with different pulse widths were measured by means of a barostat. The selected parameters varied for each dog, with the pulse widths ranging from 0.3 to 6 ms. The food consumption after GES dropped significantly as compared with the amount observed in the sham stimulation. Tolerance to stimulation could be observed during GES. The post-GES gastric fundus capacity increased evidently in comparison with the capacity before GES, suggesting significant distention as compared with sham stimulation. Given an increment of 2 ms in the pulse width twice, the gastric capacity continued to distend each time. GES featuring pulse trains with wider and individualized pulse widths could inhibit food consumption of dogs. The stimulation parameters should be selected individually and adjusted periodically. GES of this mode could also increase the fasting gastric capacity with certain dose-related effects. The new type of stimulators may be more suitable for the treatment of human obesity than traditional stimulators.

In chronic experiments on rabbits, the effect of electric stimulation of the hunger center in the lateral hypothalamus on myoelectric activity of the fundal and antral parts of the stomach was studied under conditions of hunger and satiation in the absence of food. Stimulation of the lateral hypothalamus in rabbits subjected to 24-h food deprivation and in previously fed rabbits produced incessant seeking behavior, which was followed by reorganization of the structure of temporal organization of slow wave electric activity of muscles of the stomach body and antrum specific for hungry and satiated animals. Increased hunger motivation during electric stimulation of the lateral hypothalamus manifested in the structure of temporal organization of slow wave electric activity of the stomach body and antrum muscles in rabbits subjected to 24-h food deprivation in the replacement of bimodal distribution of slow wave periods to a trimodal type typical of 2-day deprivation, while transition from satiation to hunger caused by electric stimulation of the lateral hypothalamus was associated with a shift from monomodal distributions of slow wave periods to a bimodal type typical of 24-h deprivation. Reorganization of the structure of temporal organization of slow wave electric activity of the stomach body and antrum muscles during electric stimulation of the lateral hypothalamus was determined by descending inhibitory influences of food motivational excitation on activity of the myogenic pacemaker of the lesser curvature of the stomach.

Previous studies have identified differences in the expression of proteins that regulate myosin light chain phosphorylation and contraction in tonic and phasic smooth muscle. cGMP plays a critical role in smooth muscle relaxation and is important for optimal function of phasic and tonic smooth muscle. The intracellular cGMP levels are regulated by its hydrolysis via phosphodiesterase 5 (PDE5) and efflux via novel multidrug resistance protein 5 (MRP5). In the present study we tested the hypothesis that the differences in the phasic and tonic behavior of smooth muscles may be related to differences in mechanisms that terminate cGMP signaling. Expression of PDE5 and MRP5 was significantly (more than 2-fold) higher in fundus compared with antrum. The NO donor S-nitrosoglutathione (GSNO) caused an increase in PDE5 activity and intra- and extracellular cGMP levels in both fundus and antrum. Stimulation of PDE5 activity and increase in extracellular cGMP were significantly higher in fundus, whereas increase in intracellular cGMP was significantly higher in antrum. GSNO-induced increase in extracellular cGMP was blocked in dispersed cells by the cyclic nucleotide export blocker probenecid and in cultured muscle cells by depletion of ATP or suppression of MRP5 by siRNA, providing evidence that cGMP efflux was mediated by ATP-dependent export via MRP5. Consistent with the higher expression and activity levels of PDE5 and MRP5, GSNO-induced PKG activity and muscle relaxation were significantly lower in muscle cells from fundus compared with antrum. Thus higher expression of PDE5 and MRP5 in muscle cells from fundus correlates with tonic phenotype of muscle.

Background & Aims It is not clear how nitric oxide (NO) released from enteric neurons relaxes gastrointestinal (GI) smooth muscle. In analogy to the vascular system, NO might directly induce relaxation of smooth muscle cells (SMCs) by acting on its receptor, NO-sensitive guanylyl cyclase (NO-GC). Alternatively, intermediate cells, such as the interstitial cells of Cajal (ICCs), might detect nitrergic signals to indirectly regulate smooth muscle tone, and thereby regulate the motor function of the GI tract. We investigated the role of ICCs and SMCs in nitrergic relaxation using mice with cell-specific disruption of the gene encoding the β 1 subunit of NO-GC ( GUCY1B3 ). Methods We created mice that lack NO-GC specifically in SMCs (SM-guanylyl cyclase knockout [GCKO]), ICCs (ICC-GCKO), or both (SM/ICC-GCKO). We investigated the effects of exogenous and endogenous NO on murine fundus using isometric force studies. Total gut transit time was measured to monitor the functional consequences of NO-GC deletion on GI motility in vivo. Results NO-GC is expressed in ICC and SMC. Deletion of the NO receptor from SMCs incompletely reduced NO-induced fundus relaxation, which was hardly affected after ICC-specific deletion. Gut transit time did not change in SM-GCKO or ICC-GCKO mice compared with control mice. However, nitrergic relaxation was not observed in SM/ICC-GCKO mice, which had increased gut transit time compared with controls. Conclusions In mice, NO-GC is the only NO receptor to relax the fundus; deletion of NO-GC from the combination of SMCs and ICCs blocks nitrergic signaling. Therefore, ICCs and SMCs jointly mediate the relaxant effect of enteric NO.

Acute Helicobacter pylori infection produces hypochlorhydria. The decrease in acid facilitates survival of the bacterium and its colonization of the stomach. The present study was designed to identify the pathways in oxyntic mucosa by which acute H. pylori infection inhibits acid secretion. In rat fundic sheets in an Ussing chamber, perfusion of the luminal surface with H. pylori in spent broth (103–108cfu/ml) or spent broth alone (1:105to 1:100final dilution) caused a concentration-dependent increase in somatostatin (SST; maximal: 200 ± 20 and 194 ± 9% above basal; P < 0.001) and decrease in histamine secretion (maximal: 45 ± 5 and 48 ± 2% below basal; P < 0.001); the latter was abolished by SST antibody, implying that changes in histamine secretion reflected changes in SST secretion. Both responses were abolished by the axonal blocker tetrodotoxin (TTX), the sensory neurotoxin capsaicin, or the CGRP antagonist CGRP8-37, implying that the reciprocal changes in SST and histamine secretion were due to release of CGRP from sensory neurons. In isolated rabbit oxyntic glands, H. pylori inhibited basal and histamine-stimulated acid secretion in a concentration-dependent manner; the responses were not affected by TTX or SST antibody, implying that H. pylori can directly inhibit parietal cell function. In conclusion, acute administration of H. pylori is capable of inhibiting acid secretion directly as well as indirectly by activating intramural CGRP sensory neurons coupled to stimulation of SST and inhibition of histamine secretion. Activation of neural pathways provides one explanation as to how initial patchy colonization of the superficial gastric mucosa by H. pylori can acutely inhibit acid secretion.

Background Resveratrol is a polyphenolic compound that can be isolated from plants and also is a constituent of red wine. Resveratrol induces relaxation of vascular smooth muscle and may prevent cardiovascular diseases. Purpose Impaired gastric accommodation plays an important role in functional dyspepsia and fundic relaxation and is a therapeutic target of functional dyspepsia. Although drugs for fundic relaxation have been developed, these types of drugs are still rare. The purpose of this study was to investigate the relaxant effects of resveratrol in the guinea pig fundus. Study Design We studied the relaxant effects of resveratrol in the guinea pig fundus. In addition, we investigated the mechanism of resveratrol-induced relaxation on the guinea pig fundus by using tetraethylammonium (a non-selective potassium channel blocker), apamine (a selective inhibitor of the small conductance calcium-activated potassium channel), iberiotoxin (an inhibitor of large conductance calcium-activated potassium channels), glibenclamide (an ATP-sensitive potassium channel blocker), KT 5720 (a cAMP-dependent protein kinase A inhibitor), KT 5823 (a cGMP-dependent protein kinase G inhibitor), NG-nitro-L-arginine (a competitive inhibitor of nitric oxide synthase), tetrodotoxin (a selective neuronal Na+ channel blocker), ω-conotoxin GVIA (a selective neuronal Ca2+ channel blocker) and G-15 (a G-protein coupled estrogen receptor antagonist). Results The results of this study showed that resveratrol has potent and dose-dependent relaxant effects on the guinea pig fundic muscle. In addition, the results showed that resveratrol-induced relaxation of the guinea pig fundus occurs through nitric oxide and ATP-sensitive potassium channels. Conclusion This study provides the first evidence concerning the relaxant effects of resveratrol in the guinea pig fundic muscle strips. Furthermore, resveratrol may be a potential drug to relieve gastrointestinal dyspepsia.