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World Journal of Gastroenterology Apr 2015To investigate the effect of hydrogen sulfide (H2S) on smooth muscle motility in the gastric fundus.
AIM
To investigate the effect of hydrogen sulfide (H2S) on smooth muscle motility in the gastric fundus.
METHODS
The expression of cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) in cultured smooth muscle cells from the gastric fundus was examined by the immunocytochemistry technique. The tension of the gastric fundus smooth muscle was recorded by an isometric force transducer under the condition of isometric contraction with each end of the smooth muscle strip tied with a silk thread. Intracellular recording was used to identify whether hydrogen sulfide affects the resting membrane potential of the gastric fundus in vitro. Cells were freshly separated from the gastric fundus of mice using a variety of enzyme digestion methods and whole-cell patch-clamp technique was used to find the effects of hydrogen sulfide on voltage-dependent potassium channel and calcium channel. Calcium imaging with fura-3AM loading was used to investigate the mechanism by which hydrogen sulfide regulates gastric fundus motility in cultured smooth muscle cells.
RESULTS
We found that both CBS and CSE were expressed in the cultured smooth muscle cells from the gastric fundus and that H2S increased the smooth muscle tension of the gastric fundus in mice at low concentrations. In addition, nicardipine and aminooxyacetic acid (AOAA), a CBS inhibitor, reduced the tension, whereas Nω-nitro-L-arginine methyl ester, a nonspecific nitric oxide synthase, increased the tension. The AOAA-induced relaxation was significantly recovered by H2S, and the NaHS-induced increase in tonic contraction was blocked by 5 mmol/L 4-aminopyridine and 1 μmol/L nicardipine. NaHS significantly depolarized the membrane potential and inhibited the voltage-dependent potassium currents. Moreover, NaHS increased L-type Ca(2+) currents and caused an elevation in intracellular calcium ([Ca(2+)]i).
CONCLUSION
These findings suggest that H2S may be an excitatory modulator in the gastric fundus in mice. The excitatory effect is mediated by voltage-dependent potassium and L-type calcium channels.
Topics: Animals; Calcium Channel Agonists; Calcium Channels, L-Type; Calcium Signaling; Cells, Cultured; Cystathionine gamma-Lyase; Dose-Response Relationship, Drug; Enzyme Inhibitors; Gastric Fundus; Gastrointestinal Motility; Hydrogen Sulfide; Lyases; Male; Membrane Potentials; Mice, Inbred ICR; Muscle Contraction; Muscle, Smooth; Myocytes, Smooth Muscle; Nitric Oxide Synthase; Potassium Channel Blockers; Potassium Channels, Voltage-Gated; Time Factors
PubMed: 25944997
DOI: 10.3748/wjg.v21.i16.4840 -
Scientific Reports Nov 2015H2S is produced mainly by two enzymes:cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), using L-cysteine (L-Cys) as the substrate. In this study, we...
H2S is produced mainly by two enzymes:cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), using L-cysteine (L-Cys) as the substrate. In this study, we investigated the role of H2S in gastric accommodation using CBS(+/-) mice, immunohistochemistry, immunoblot, methylene blue assay, intragastric pressure (IGP) recording and electrical field stimulation (EFS). Mouse gastric fundus expressed H2S-generating enzymes (CBS and CSE) and generated detectable amounts of H2S. The H2S donor, NaHS or L-Cys, caused a relaxation in either gastric fundus or body. The gastric compliance was significantly increased in the presence of L-Cys (1 mM). On the contrary, AOAA, an inhibitor for CBS, largely inhibited gastric compliance. Consistently, CBS(+/-) mice shows a lower gastric compliance. However, PAG, a CSE inhibitor, had no effect on gastric compliances. L-Cys enhances the non-adrenergic, non-cholinergic (NANC) relaxation of fundus strips, but AOAA reduces the magnitude of relaxations to EFS. Notably, the expression level of CBS but not CSE protein was elevated after feeding. Consistently, the production of H2S was also increased after feeding in mice gastric fundus. In addition, AOAA largely reduced food intake and body weight in mice. Furthermore, a metabolic aberration of H2S was found in patients with functional dyspepsia (FD). In conclusion, endogenous H2S, a novel gasotransmitter, involves in gastric accommodation.
Topics: Animals; Cystathionine beta-Synthase; Cystathionine gamma-Lyase; Cysteine; Dyspepsia; Eating; Electric Stimulation; Gasotransmitters; Gastric Fundus; Gastric Mucosa; Guanidines; Humans; Hydrogen Sulfide; Male; Mice; Mice, Inbred BALB C; Mice, Transgenic; Microscopy, Fluorescence; Muscle Contraction; Pyridoxal; Signal Transduction; Stomach; Substrate Specificity; Sulfides; Tacrolimus
PubMed: 26531221
DOI: 10.1038/srep16086 -
Experimental Physiology Jul 2017What is the central question of this study? The present study investigated the relationship between H S and NO in regulation of gastric fundus tension. What is the main...
What is the central question of this study? The present study investigated the relationship between H S and NO in regulation of gastric fundus tension. What is the main finding and its importance? Endogenous or exogenous H S and NO have opposite effects on fundus tension, and H S-induced gastric fundus tension enhancements are mediated by inhibition of NO generation through the phosphoinositide 3-kinase/Akt pathway. These results are very important in exploring the mechanism of physiological accommodation and accommodation disorder. Hydrogen sulphide (H S) is considered a new gasotransmitter, along with NO and CO. It was recently confirmed that H S and NO play important roles in the regulation of gastrointestinal smooth muscle tension. The present study was designed to elucidate the interactions between H S and NO with respect to the regulation of gastric fundus smooth muscle tension using Western blotting, physiological and electrochemical techniques. Real-time H S and NO generation was detected in gastric smooth muscle tissue. NaHS, an H S donor, enhanced fundus smooth muscle tension, whereas SNP, an NO donor, decreased fundus smooth muscle tension in a dose-dependent manner. NaHS-induced increases in fundus smooth muscle tension were suppressed by l-NAME, an NO synthase inhibitor. Aminooxyacetic acid (AOAA), a cystathionine β-synthase inhibitor, exerted inhibitory effects on fundus smooth muscle tension; these effects were also suppressed by l-NAME. Real-time NO generation was significantly potentiated by AOAA. Endothelial nitric oxide synthase (eNOS) phosphorylation at serine 1177 and Akt phosphorylation at serine 308 and threonine 473 were significantly inhibited by NaHS. LY294002, a phosphoinositide 3-kinase inhibitor, blocked these NaHS-mediated effects. However, eNOS phosphorylation at serine 1177 and Akt phosphorylation at serine 308 and threonine 473 were significantly potentiated by AOAA. Cystathionine β-synthase siRNA interference significantly increased eNOS phosphorylation at serine 1177 and Akt phosphorylation at serine 308 and threonine 473. Cystathionine β-synthase siRNA interference also increased total eNOS protein expression levels but did not significantly change total Akt kinase protein expression levels. These results suggest that H S-induced enhancement of gastric fundus tension is mediated by inhibition of NO generation through the phosphoinositide 3-kinase/Akt pathway.
Topics: Animals; Gastric Fundus; Hydrogen Sulfide; Male; Mice; Muscle Contraction; Muscle Tonus; Muscle, Smooth; Nitric Oxide Synthase Type III; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction
PubMed: 28383821
DOI: 10.1113/EP086288 -
Saudi Pharmaceutical Journal : SPJ :... Mar 2023It has been reported diabetic gastroparesis is related to diabetic autonomic neuropathy of the gastrointestinal tract, and berberine (BBR) could ameliorate diabetic...
BACKGROUND
It has been reported diabetic gastroparesis is related to diabetic autonomic neuropathy of the gastrointestinal tract, and berberine (BBR) could ameliorate diabetic central and peripheral neuropathy. However, the influence of BBR on the function and motility of the gastric fundus nerve is unclear.
METHODS
A diabetic rat model was constructed, and HE staining was used to observe the morphological changes in the gastric fundus. The changes in cholinergic and nitrogen-related neurochemical indexes and the effects of BBR on them were measured using Elisa. The effects of BBR on the neural function and motility of gastric fundus were investigated by electric field stimulation (EFS) induced neurogenic response in vitro.
RESULTS
In the early stage of STZ-induced diabetic rats, the contractile response of gastric fundus induced by EFS was disorder, disturbance of contraction amplitude, and the cell bodies of neurons in the myenteric plexus of gastric fundus presented vacuolar lesions. Administration with BBR could improve the above symptoms. BBR further enhanced the contraction response in the presence of a NOS inhibitor or the case of inhibitory neurotransmitters removal. Interestingly, the activity of ACh could affect NO release directly and the enhancement of BBR on contractile response was canceled by calcium channel blockers completely.
CONCLUSIONS
In the early stage of STZ-induced diabetic rats, the neurogenic contractile response disorder of the gastric fundus is mainly related to cholinergic and nitrergic nerve dysfunction. BBR promotes the release of ACh mainly by affecting the calcium channel to improve the neurological dysfunction of the gastric fundus.
PubMed: 37026044
DOI: 10.1016/j.jsps.2023.01.010 -
British Journal of Pharmacology Mar 19981. The effects of the antioxidants ascorbic acid and alpha-tocopherol and of the metal chelator ethylenediaminetetraacetic acid (EDTA) were studied on relaxations in...
1. The effects of the antioxidants ascorbic acid and alpha-tocopherol and of the metal chelator ethylenediaminetetraacetic acid (EDTA) were studied on relaxations in response to S-nitrosothiols, authentic nitric oxide (NO) and nitrergic non-adrenergic non-cholinergic stimulation of the rat gastric fundus. 2. The S-nitrosothiols S-nitrosocysteine (1-100 nM), S-nitrosoglutathione (0.01-3 microM) and S-nitroso-N-acetylpenicillamine (0.01-3 microM) induced concentration-dependent relaxations of the rat gastric fundus muscle strips, which were precontracted with prostaglandin F2alpha. The relaxations to all S-nitrosothiols were concentration-dependently enhanced by the antioxidants ascorbic acid (0.1-3 microM) and alpha-tocopherol (3-30 microM) and inhibited by the metal chelator EDTA (26 microM). 3. Ascorbic acid and alpha-tocopherol alone did not induce a relaxation of the precontracted rat gastric fundus muscle strip. However, when ascorbic acid (1 microM) or alpha-tocopherol (1 microM) were injected in the organ bath 1 minute after S-nitrosoglutathione (0.1 microM) or after S-nitroso-N-acetylpenicillamine (0.1 microM), they induced an immediate, sharp and transient relaxation. This relaxation was inhibited by the superoxide generator pyrogallol (2 microM). Such a relaxation to ascorbic acid or alpha-tocopherol was not observed in the presence of S-nitrosocysteine (10 nM). 4. Electrical field stimulation (0.5-4 Hz) of the precontracted rat gastric fundus strips induced frequency-dependent nitrergic relaxations which were mimicked by authentic NO (3-300 nM) and by acidified sodium nitrite NaNO2 (0.3-10 microM). Ascorbic acid (0.33-3 microM), alpha-tocopherol (3-30 microM) or EDTA (26 microM) did not affect the relaxations to nitrergic stimulation, NO or NaNO2. 5. In summary, relaxations to S-nitrosothiols in the rat gastric fundus are enhanced by the antioxidants ascorbic acid and alpha-tocopherol and inhibited by the metal chelator EDTA. However, relaxations to nitrergic stimulation of the rat gastric fundus or those to authentic NO were not affected by the antioxidants or by the metal chelator. These results indicate that antioxidants and metal chelators have a different effect on the biological activity of S-nitrosothiols and on that of the nitrergic neurotransmitter. Therefore, our results suggest that S-nitrosothiols do not act as intermediate compounds in nitrergic neurotransmission in the rat gastric fundus.
Topics: Animals; Antioxidants; Ascorbic Acid; Chelating Agents; Edetic Acid; Gastric Fundus; In Vitro Techniques; Male; Nitric Oxide; Rats; Rats, Wistar; Sulfhydryl Compounds; Vitamin E
PubMed: 9559884
DOI: 10.1038/sj.bjp.0701692 -
Endoscopy Dec 2023
Topics: Humans; Gastric Fundus; Endoscopic Mucosal Resection; Traction; Endoscopes; Gastroscopy; Treatment Outcome; Stomach Neoplasms; Gastric Mucosa
PubMed: 36513103
DOI: 10.1055/a-1974-9792 -
Archives of Pathology & Laboratory... Feb 2014Multiphoton microscopy (MPM) based on 2-photon excitation fluorescence and second-harmonic generation allows simultaneous visualization of cellular details and... (Comparative Study)
Comparative Study
CONTEXT
Multiphoton microscopy (MPM) based on 2-photon excitation fluorescence and second-harmonic generation allows simultaneous visualization of cellular details and extracellular matrix components of fresh, unfixed, and unstained tissue. Portable multiphoton microscopes, which could be placed in endoscopy suites, and multiphoton endomicroscopes are in development, but their clinical utility is unknown.
OBJECTIVE
To examine fresh, unfixed endoscopic biopsies obtained from the distal esophagus and gastroesophageal junction to (1) define the MPM characteristics of normal esophageal squamous mucosa and gastric columnar mucosa, and (2) evaluate whether diagnosis of intestinal metaplasia/Barrett esophagus (BE) could be made reliably with MPM.
DESIGN
The study examined 35 untreated, fresh biopsy specimens from 25 patients who underwent routine upper endoscopy. A Zeiss LSM 710 Duo microscope (Carl Zeiss, Thornwood, New York) coupled to a Spectra-Physics (Mountain View, California) Tsunami Ti:sapphire laser was used to obtain a MPM image within 4 hours of fresh specimen collection. After obtaining MPM images, the biopsy specimens were placed in 10% buffered formalin and submitted for routine histopathologic examination. Then, the MPM images were compared with the findings in the hematoxylin-eosin-stained, formalin-fixed, paraffin-embedded sections. The MPM characteristics of the squamous, gastric-type columnar and intestinal-type columnar epithelium were analyzed. In biopsies with discrepancy between MPM imaging and hematoxylin-eosin-stained sections, the entire tissue block was serially sectioned and reevaluated. A diagnosis of BE was made when endoscopic and histologic criteria were satisfied.
RESULTS
Based on effective 2-photon excitation fluorescence of cellular reduced pyridine nucleotides and flavin adenine dinucleotide and lack of 2-photon excitation fluorescence of mucin and cellular nuclei, MPM could readily identify and distinguish among squamous epithelial cells, goblet cells, gastric foveolar-type mucous cells, and parietal cells in the area of gastroesophageal junction. Based on the cell types identified, the mucosa was defined as squamous, columnar gastric type (cardia/fundic-type), and metaplastic columnar intestinal-type/BE. Various types of mucosa seen in the study of 35 biopsies included normal squamous mucosa only (n = 14; 40%), gastric cardia-type mucosa only (n = 2; 6%), gastric fundic mucosa (n = 6; 17%), and both squamous and gastric mucosa (n = 13; 37%). Intestinal metaplasia was identified by the presence of goblet cells in 10 of 25 cases (40%) leading to a diagnosis of BE on MPM imaging and only in 7 cases (28%) by histopathology. In 3 of 35 biopsies (9%), clear-cut goblet cells were seen by MPM imaging but not by histopathology, even after the entire tissue block was sectioned. Based on effective 2-photon excitation fluorescence of elastin and second-harmonic generation of collagen, connective tissue in the lamina propria and the basement membrane was also visualized with MPM.
CONCLUSIONS
Multiphoton microscopy has the ability to accurately distinguish squamous epithelium and different cellular elements of the columnar mucosa obtained from biopsies around the gastroesophageal junction, including goblet cells that are important for the diagnosis of BE. Thus, use of MPM in the endoscopy suite might provide immediate microscopic images during endoscopy, improving screening and surveillance of patients with BE.
Topics: Adenine Nucleotides; Barrett Esophagus; Biopsy; Cardia; Connecticut; Endoscopy, Gastrointestinal; Esophagogastric Junction; Esophagus; Gastric Fundus; Gastric Mucosa; Goblet Cells; Hospitals, University; Humans; Lasers; Materials Testing; Metaplasia; Microscopy, Fluorescence, Multiphoton; Mucous Membrane; Point-of-Care Systems; Spectroscopy, Near-Infrared
PubMed: 24476518
DOI: 10.5858/arpa.2012-0675-OA -
The Journal of Physiology Oct 2022Enteric neurotransmission is critical for coordinating motility throughout the gastrointestinal (GI) tract. However, there is considerable controversy regarding the...
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 and post-junctional electrical responses to neural stimulation. ICC-IM were highly active, generating intracellular Ca -transients that occurred stochastically, from multiple independent sites in single ICC-IM. Ca -transients were not entrained in single ICC-IM or between neighbouring ICC-IM. Activation of enteric motor neurons produced a dominant inhibitory response that abolished Ca -transients in ICC-IM. This inhibitory response was often preceded by a summation of Ca -transients that led to a global rise in Ca . Individual ICC-IM responded to nerve stimulation by a global rise in Ca followed by inhibition of Ca -transients. The inhibition of Ca -transients was blocked by the nitric oxide synthase antagonist l-NNA. The global rise in intracellular Ca was inhibited by the muscarinic antagonist, atropine. Simultaneous intracellular microelectrode recordings with video-imaging revealed that the rise in Ca was temporally associated with rapid excitatory junction potentials and the inhibition of Ca -transients with inhibitory junction potentials. These data support the premise of serial innervation of ICC-IM in excitatory and inhibitory neuroeffector transmission in the proximal stomach. KEY POINTS: The cells responsible for mediating enteric neuroeffector transmission remain controversial. In the stomach intramuscular interstitial cells of Cajal (ICC-IM) were the first ICC reported to receive cholinergic and nitrergic neural inputs. Utilization of a cell specific calcium biosensor, GCaMP6f, the activity, and neuroeffector responses of ICC-IM were examined. ICC-IM were highly active, generating stochastic intracellular Ca -transients. Stimulation of enteric motor nerves abolished Ca -transients in ICC-IM. This inhibitory response was preceded by a global rise in intracellular Ca . Individual ICC-IM responded to nerve stimulation with a rise in Ca followed by inhibition of Ca -transients. Inhibition of Ca -transients was blocked by the nitric oxide synthase antagonist l-NNA. The global rise in Ca was inhibited by the muscarinic antagonist atropine. Simultaneous intracellular recordings with video imaging revealed that the global rise in intracellular Ca and inhibition of Ca -transients was temporally associated with rapid excitatory junction potentials followed by more sustained inhibitory junction potentials. The data presented support the premise of serial innervation of ICC-IM in excitatory and inhibitory neuroeffector transmission in the proximal stomach.
Topics: Animals; Atropine Derivatives; Calcium; Calcium, Dietary; Gastric Fundus; Interstitial Cells of Cajal; Mice; Muscarinic Antagonists; Nitric Oxide Synthase; Synaptic Transmission
PubMed: 36057845
DOI: 10.1113/JP282876 -
BMJ Case Reports Oct 2013Gastric xanthelasma is a rarely encountered finding in upper gastrointestinal (GI) endoscopy. It is characterised by yellowish-white plaque in the stomach especially in... (Review)
Review
Gastric xanthelasma is a rarely encountered finding in upper gastrointestinal (GI) endoscopy. It is characterised by yellowish-white plaque in the stomach especially in the antrum or the pyloric region. Histologically it consists of foamy macrophages in the lamina propria. It is a benign condition but its appearance mimics malignancy and it is found to be associated with various conditions, some of which are considered premalignant so, histological confirmation is necessary. We present a case of a 44-year-old man who presented to the medicine outpatient department for intermittent pain in epigastrium for the last 2 years. His physical examination was normal. His haematological and biochemical investigations were also normal. His upper GI endoscopy revealed yellowish-white plaque in fundus of the stomach, which was diagnosed as gastric xanthelasma by histological examination with associated chronic gastritis.
Topics: 2-Pyridinylmethylsulfinylbenzimidazoles; Adult; Biopsy, Needle; Chronic Disease; Follow-Up Studies; Gastric Fundus; Gastritis; Gastroscopy; Humans; Immunohistochemistry; India; Male; Pantoprazole; Rare Diseases; Risk Assessment; Stomach Diseases; Treatment Failure; Xanthomatosis
PubMed: 24165503
DOI: 10.1136/bcr-2013-201017 -
Biochemical Pharmacology Feb 2024Flavonoids, ubiquitously distributed in the plant world, are regularly ingested with diets rich in fruit, vegetables, wine, and tea. During digestion, they are partially...
Electrophysiology, molecular modelling, and functional analysis of the effects of dietary quercetin and flavonoid analogues on K6.1 channels in rat stomach fundus smooth muscle.
Flavonoids, ubiquitously distributed in the plant world, are regularly ingested with diets rich in fruit, vegetables, wine, and tea. During digestion, they are partially absorbed in the stomach. The present work aimed to assess the in vitro effects of quercetin and ten structurally related flavonoids on the rat gastric fundus smooth muscle, focussing on ATP-dependent K (K6.1) channels, which play a central role in the regulation of resting membrane potential, membrane excitability and, consequently, of gastric motility. Whole-cell currents through K6.1 channels (I) were recorded with the patch-clamp technique and the mechanical activity of gastric fundus smooth muscle strips was studied under isometric conditions. Galangin ≈ tamarixetin > quercetin > kaempferol > isorhamnetin ≈ luteolin ≈ fisetin > (±)-taxifolin inhibited pinacidil-evoked, glibenclamide-sensitive I in a concentration-dependent manner. Morin, rutin, and myricetin were ineffective. The steric hindrance of the molecule and the number and position of hydroxyl groups on the B ring played an important role in the activity of the molecule. Molecular docking simulations revealed a possible binding site for flavonoids in the C-terminal domain of the K6.1 channel subunit SUR2B, in a flexible loop formed by residues 251 to 254 of chains C and D. Galangin and tamarixetin, but not rutin relaxed both high K- and carbachol-induced contraction of fundus strips in a concentration-dependent manner. Furthermore, both flavonoids shifted to the right the concentration-relaxation curves to either pinacidil or L-cysteine constructed in strips pre-contracted by high K, rutin being ineffective. In conclusion, I inhibition exerted by dietary flavonoids might counterbalance their myorelaxant activity, affect gastric accommodation or, at least, some stages of digestion.
Topics: Rats; Animals; Pinacidil; Vasodilator Agents; Gastric Fundus; Quercetin; Molecular Docking Simulation; Potassium Channels; Muscle, Smooth; Electrophysiology; Rutin; Diet; Sulfonylurea Receptors
PubMed: 38086489
DOI: 10.1016/j.bcp.2023.115969