Ingesting yeast extract causes excitation of neurogenic and myogenic colonic motor patterns in the rat.

Fermented foods play a significant role in the human diet for their natural, highly nutritious and healthy attributes. Our aim was to study the effect of yeast extract, a fermented substance extracted from natural yeast, on colonic motility to better understand its potential therapeutic role. A yeast extract was given to rats by gavage for 3 days, and myogenic and neurogenic components of colonic motility were studied using spatiotemporal maps made from video recordings of the whole colon ex vivo. A control group received saline gavages. The yeast extract caused excitation of the musculature by increasing the propagation length and duration of long-distance contractions, the major propulsive activity of the rat colon. The yeast extract also evoked rhythmic propulsive motor complexes (RPMCs) which were antegrade in the proximal and mid-colon and retrograde in the distal colon. RPMC activity was evoked by distention-induced neural activity, but it was myogenic in nature since we showed it to be generated by bethanechol in the presence of tetrodotoxin. In conclusion, ingestion of yeast extract stimulates rat colon motility by exciting neurogenic and myogenic control mechanisms.

Role of Hydrogen Sulfide in the Development of Colonic Hypomotility in a Diabetic Mouse Model Induced by Streptozocin.

Hydrogen sulfide (H2S), a novel gasotransmitter, is involved in the regulation of gut motility. Alterations in the balance of H2S play an important role in the pathogenesis of diabetes. This study was conducted to investigate the role of H2S in the colonic hypomotility of mice with streptozotocin (STZ)-induced diabetes. A single intraperitoneal injection of STZ was used to induce the type 1 diabetes model. Male C57BL/6 mice were randomized into a control group and an STZ-treated group. Immunohistochemistry, Western blotting, H2S generation, organ bath studies and whole-cell patch clamp techniques were carried out in single smooth muscle cells (SMCs) of the colon. We found that STZ-induced diabetic mice showed decreased stool output, impaired colonic contractility, and increased endogenous generation of H2S (p < 0.05). H2S-producing enzymes were upregulated in the colon tissues of diabetic mice (p < 0.05). The exogenous H2S donor sodium hydrosulfide (NaHS) elicited a biphasic action on colonic muscle contraction with excitation at lower concentrations and inhibition at higher concentrations. NaHS (0.1 mM) increased the currents of voltage-dependent calcium channels (VDCCs), while NaHS at 0.5 mM and 1.5 mM induced inhibition. Furthermore, NaHS reduced the currents of both voltage-dependent potassium (KV) channels and large conductance calcium-activated potassium (BK) channels in a dose-dependent manner. These results show that spontaneous contraction of colonic muscle strips from diabetic mice induced by STZ was significantly decreased, which may underlie the constipation associated with diabetes mellitus (DM). H2S overproduction with subsequent suppression of muscle contraction via VDCCs on SMCs may contribute in part to the pathogenesis of colonic hypomotility in DM. SIGNIFICANCE STATEMENT: Hydrogen sulfide may exhibit a biphasic effect on colonic motility in mice by regulating the activities of voltage-dependent calcium channels and voltage-dependent and large conductance calcium activated potassium channels. H2S overproduction with subsequent suppression of muscle contraction via VDCCs may contribute to the pathogenesis of colonic hypomotility in diabetes mellitus.

Colitis aggravated by Mrgprb2 knockout is associated with altered immune response, intestinal barrier function and gut microbiota.

NEW FINDINGS: What is the central question of this study? What is the role of mas-related G protein-coupled receptor X2 (MRGPRX2/Mrgprb2) in ulcerative colitis in relation to the intestinal flora, intestinal barrier and immune response? What is the main finding and its importance? Knockout of mouse Mrgprb2 aggravates dextran sulfate sodium (DSS)-induced colitis, which is associated with altered gut microbiota and immune response and disruption of the intestinal barrier. MRGPRB2 may have a protective effect on DSS-induced colitis. ABSTRACT: Ulcerative colitis (UC) is a chronic immune-related disease, and changes in the intestinal microbiota and damage to the intestinal barrier contribute to its pathogenesis. Mast cells (MCs) are widely distributed in the gastrointestinal tract and are thought to be related to the pathogenesis of UC. Human mas-related G protein-coupled receptor X2 (MRGPRX2) and its mouse homologue, Mrgprb2, are selectively expressed on MCs to recruit immune cells and modulate host defence against microbial infection. To investigate the role of Mrgprb2 in UC in mice, we compared the differences between Mrgprb2 knockout (b2KO) male mice and wild-type (WT) male mice with dextran sulfate sodium (DSS)-induced colitis in the severity of clinical symptoms, inflammatory cell infiltration, degree of intestinal barrier damage and composition of the intestinal flora. The results showed that weight loss, disease activity index score, colon shortening and colonic pathological damage were significantly increased in b2KO mice while MC activation, cytokine and chemokine secretion, and inflammatory cell infiltration were decreased. In addition, the abundance and diversity of the intestinal microbiota were reduced in b2KO mice. B2KO mice also exhibited a reduction of probiotics such as norank_f_Muribaculaceae and Lactobacillus and increase of harmful bacteria like Escherichia-Shigella. Intestinal mucosal barrier damage of b2KO mice was more severe than that of WT mice due to the attenuated expression of mucin-2 and occludin. These results demonstrated that MRGPRB2 may have a protective effect on DSS-induced colitis by altering the intestinal flora, participating in barrier repair and recruiting inflammatory cells to eliminate pathogens.

Effects and underlying mechanisms of L-arginine on spontaneous muscle contraction of rat colon.

Arginine (Arg), as a basic amino acid, has been reported to be involved in regulation of gut motility. However, the evidence is limited and the underlying mechanism is not fully understood. Our study was conducted to investigate the effects of L-Arg on spontaneous contraction of the longitudinal muscle strip (LMS) of the rat colon and the relevant mechanisms. An organ bath system was used to detect the contractile force of the LMS. Whole-cell voltage-clamp techniques were applied to observe alterations in the currents of large conductance Ca2+-activated K+ (KCa) channels, voltage-dependent potassium (KV) channels, and L-type Ca2+ channels (LTCCs) in smooth muscle cells (SMCs) of the colon. We found that L-Arg within the physiological concentration had no effect on contraction of LMS, while 1 mM L-Arg significantly increased both the amplitude and frequency of LMS contractility. And the increase in force was mucosa-dependent, whereas changes in frequency as well as in amplitude were inhibited by atropine. In addition, L-Arg (1 mM) activated the LTTCs and inhibited both KCa channels and KV channels on SMCs. Thus, L-Arg above the physiological concentration exerted an excitatory effect on colonic LM contraction, and stimulation by L-Arg was mediated by ACh. In addition, LTCCs, KCa channels, and KV channels on SMCs were involved in the action of L-Arg.

The excitatory effect of hydrogen sulfide on rat colonic muscle contraction and the underlying mechanism.

H2S is a well-known relaxant regulator in muscle contraction but little attention has been paid to its excitatory effect on colonic motility. To investigate the excitation of H2S on rat colonic contraction and the underlying mechanism, the muscle contractile activity was assessed by an organ bath system, the level of substance P (SP) in the colon was detected using enzyme immunoassay kits, L-type Ca2+ channel currents (ICa,L) and large conductance Ca2+-activated K+ channel currents (IBK) in smooth muscle cells (SMCs) were measured by patch-clamp electrophysiology. The results show that the H2S donor NaHS (100 µM) reversed the relaxation of the NO donor SNP on colonic muscle contraction. Pretreatment with the TRPV1 antagonist and the neurokinin receptor antagonists attenuated the NaHS-induced excitation. Incubation of colon with NaHS increased the SP level. In freshly isolated SMCs, NaHS exerted a biphasic effect on ICa,L and concentration-dependently inhibited the IBK. And 100 µM NaHS partially reversed the SNP-induced changes in ICa,L and IBK. We concluded that exogenous H2S exerts a potential excitatory effect on colonic motility, which may be achieved by activating SP release from afferent nerves in combination with a direct activation of ICa,L and suppression of IBK in SMCs.

KISS-1, Mediated by Promoter Methylation, Suppresses Esophageal Squamous Cell Carcinoma Metastasis via MMP2/9/MAPK Axis.

BACKGROUND AND AIMS: KISS-1 is an established tumor suppressor that inhibits metastases in various malignancies. However, little is known regarding its role in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to identify the possible mechanisms of KISS-1 in ESCC metastasis. METHODS: The expression levels of KISS-1 mRNA and protein in ESCC samples and cell lines were analyzed by qRT-PCR, IHC, and western blotting. Bisulfite sequencing PCR (BSP) and methylation-specific PCR (MSP) were used to analyze the methylation pattern of KISS-1 promoter in ESCC cells with or without 5-Aza-dC treatment. The role of KISS-1 in the progression and metastasis of ESCC was analyzed through in vitro functional assays. RESULTS: KISS-1 mRNA and protein were markedly downregulated in ESCC tissues and cell lines compared to the respective controls. Hypermethylation of KISS-1 promoter correlated to its lower expression levels in ESCC, and KISS-1 demethylation inhibited tumor progression. Ectopic KISS-1 overexpression inhibited tumor cell metastasis in vitro. In addition, KISS-1 overexpression downregulated the matrix metalloproteinase 2 and 9 (MMP2 and 9) and inhibited epithelial-mesenchymal transition (EMT). Finally, KISS-1 downregulated phosphorylated extracellular regulated protein kinase 1/2 (ERK1/2) and phosphorylated p38 mitogen-activated protein kinase (MAPK) without affecting their total expression levels in the ESCC cells. MAPK/ERK and p38 MAPK agonists reversed the suppressive effects of KISS-1. CONCLUSIONS: The hypermethylation of KISS-1 promoter partly contributed to its downregulation in ESCC. KISS-1 inhibits the metastasis of ESCC cells by targeting the MMP2/9/ERK/p38 MAPK axis.

CaMKII Mediates TGFß1-Induced Fibroblasts Activation and Its Cross Talk with Colon Cancer Cells.

INTRODUCTION: Cancer-associated fibroblasts (CAFs), as the activated fibroblasts in tumor stroma, are important modifiers of tumor progression. TGFß1 has been the mostly accepted factor to fuel normal fibroblasts transformation into CAFs. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is thought to play an important role in fibroblasts activation induced by TGFß1. The aim of this study is to investigate the potential role of CaMKII in TGFß1-induced fibroblasts activation and CAF-like differentiation. Cross talk between CaMKII-dependent fibroblasts and colon cancer in colon cancer progression also was addressed RESULTS: Immunostaining demonstrated that in colon cancer stroma, CaMKII overexpressed in stromal CAFs. In vitro, TGFß1 increased CAF markers expression in human colon fibroblasts CCD-18Co, but not in CaMKII depletion fibroblasts. CaMKII knockdown by CaMKII shRNA significantly inhibited TGFß1-induced fibroblasts activation and CAF-like differentiation. Smad3, AKT, and MAPK were targeted in TGFß1-CaMKII-mediated pathway. Human colon cancer cell line HCT-116 activated fibroblasts directly, whereas CaMKII depletion dragged CCD-18Co fibroblasts undergoing CAF-associated trans-differentiation. Furthermore, increased proliferation, migration, and invasion of colon cancer cells were stimulated when co-cultured with normal fibroblasts, but not with CaMKII depletion fibroblasts. CONCLUSIONS: These findings provide evidence that CaMKII is a critical mediator in TGFß1-induced fibroblasts activation and is involved in the cross talk with colon cancer cells. CaMKII is a potentially effective target for future treatment of colon cancer.

Dysfunction of apoptosis and autophagy correlates with local recurrence in esophageal squamous cell carcinoma after definitive chemoradiation.

OBJECTIVE: Definitive chemoradiotherapy (dCRT) is one of the standard treatments for esophageal squamous cell carcinoma (ESCC), but local recurrence is the main cause of treatment failure. The changes in apoptosis and autophagy in recurrent tumors of patients with ESCC following dCRT have been poorly estimated. Thus, this study aimed to investigate the expressions of key regulators of apoptosis and autophagy in matched paired samples of primary and recurrent ESCC. METHODS: The medical records of patients with locally advanced ESCC who developed local recurrence after dCRT were reviewed, and the expression profiling of apoptosis-related genes, cell apoptosis, autophagy and autophagy-related proteins were detected in normal esophageal squamous epithelium and paired samples of primary and recurrent ESCC. RESULTS: A total of 126 patients were enrolled, and 52.4% of them had stage III disease. The 1-, 3- and 5-year local recurrence-free survival (LRFS) rates were 54.8, 19.8 and 14.3%, respectively, with a median LRFS of 13.0 months. Patients with T2 tumor or stage II disease showed a significantly prolonged LRFS compared with that of patients with T3-4 tumor or stage III disease. The Apoptotic Machinery key genes expression profiling identified 5 upregulated and 7 downregulated apoptosis-related genes in recurrent tumors compared with their expression levels in the matched primary ESCC tumors. High expression of CD40, TRAF4 and BCL2A1, and low expression of CARD6 and TNFRSF21 were associated with increased risk of early local recurrence after dCRT. No differences in apoptotic index between primary and recurrent samples were detected. However, typical morphological features of autophagosomes and elevated LC3-II protein expression were detected in recurrent tumor samples, and positive LC3-II expression was correlated with increased risk of early local recurrence. CONCLUSION: Our findings indicated that apoptosis and autophagy dysfunction correlated with early local recurrence in patients with locally advanced ESCC receiving dCRT. Further studies are necessary to understand the biology of tumor recurrence in esophageal cancer.

[Effect of L-cysteine on colonic motility and the underlying mechanism].

The purpose of the present study is to investigate the effect of L-cysteine on colonic motility and the underlying mechanism. Immunohistochemical staining and Western blot were used to detect the localization of the H2S-generating enzymes cystathionine-ß-synthase (CBS) and cystathionine-γ-lyase (CSE). Organ bath system was used to observe the muscle contractile activities. Whole-cell patch-clamp technique was applied to record ionic channels currents in colonic smooth muscle cells. The results showed that both CBS and CSE were localized in mucosa, longitudinal and circular muscle and enteric neurons. L-cysteine had a dual effect on colonic contraction, and the excitatory effect was blocked by pretreatment with CBS inhibitor aminooxyacetate acid (AOAA) and CSE inhibitor propargylglycine (PAG); L-cysteine concentration-dependently inhibited L-type calcium channel current (ICa,L) without changing the characteristic of L-type calcium channel (P < 0.01); In contrast, the exogenous H2S donor NaHS increased ICa,L at concentration of 100 µmol/L, but inhibited ICa,L and modified the channel characteristics at concentration of 300 µmol/L (P < 0.05); Furthermore, L-cysteine had no effect on large conductance calcium channel current (IBKCa), but NaHS significantly inhibited IBKCa (P < 0.05). These results suggest that L-cysteine has a potential dual effect on colonic smooth muscle and the inhibitory effect might be directly mediated by L-type calcium channel while the excitatory effect might be mediated by endogenous H2S.

[IL-6 inhibits colonic longitudinal muscle contraction by inactivating L-type calcium channel in rats with pancreatitis].

The aim of this study was to investigate the effect of interleukin 6 (IL-6) on the contraction of colon longitudinal muscle strips in rats with acute pancreatitis (AP) and its underlying mechanism. Rat AP model was established by combined injection (i. p.) of ceruletide and lipopolysaccharide. The effect of IL-6 on spontaneous contraction of longitudinal smooth muscle strips of rat colon was observed by biological function experiment system. The level of serum IL-6 was detected by ELISA, the expression and distribution of IL-6 in colon were observed by histochemical staining, and the effect of IL-6 on L-type calcium channel in colon smooth muscle cells was observed by whole cell patch clamp technique. The results showed that, compared with the control group, AP group exhibited reduced contractile amplitude and longer contraction cycle of colon smooth muscle strips. IL-6 prolonged the contraction cycle of colon smooth muscle strips, but did not affect their spontaneous contraction amplitude. Serum IL-6 concentration in AP group was significantly higher than that in control group (P > 0.05). IL-6 was diffusely distributed in the colon of the control group, but the expression of IL-6 was significantly up-regulated in the colon gland, mucosa and submucosa of the AP group. IL-6 significantly decreased the peak current density of L-type calcium channel in rat colon smooth muscle cells. These results suggest that the colon motility of AP rats is weakened, and the mechanism may be that up-regulated IL-6 inactivates L-type voltage-dependent calcium channels, and then inhibits the contraction of colon longitudinal smooth muscle.

miR-331-3p functions as an oncogene by targeting ST7L in pancreatic cancer.

Pancreatic cancer (PC) is a highly invasive tumor with early metastasis and poor prognosis, yet the mechanisms for tumor progression have not been fully elucidated. Emerging evidence indicates that microRNA-331-3p (miR-331-3p) plays an important role in the progression of diverse human cancers. Here, we found that miR-331-3p was significantly upregulated in tumor specimens of PC patients and PC cell lines. Functional studies showed that downregulation of miR-331-3p inhibited PC cell proliferation and epithelial-mesenchymal transition (EMT)-mediated metastasis in vitro. Furthermore, suppression of tumorigenicity 7 like (ST7L) was identified as a novel target gene of miR-331-3p. Tumor promotion effects of miR-331-3p were partially reversed by ST7L re-expression. In addition, miR-331-3p antagomir suppressed PC tumor growth and metastasis via upregulation of ST7L in xenograft mice. In summary, these results demonstrate that miR-331-3p is a tumor-promoting microRNA (miRNA) in PC cells and a promising biomarker for PC.

Diallyl trisulfide regulates rat colonic smooth muscle contractions by inhibiting L-type calcium channel currents.

Diallyl trisulfide (DATS) is an active organosulfide component of allicin and has several beneficial effects, including antimicrobial, antioxidant, cardioprotective and anticancer effects. Few studies have shown the modulatory effect of DATS on L-type calcium channels in rat colonic smooth muscle cells and colonic motility. To investigate the modulatory effect of DATS on L-type calcium channels in rat colonic smooth muscle and colonic contraction, L-type calcium channel currents were recorded, and colonic contractility in longitudinal and circular smooth muscle strips was measured. DATS attenuated L-type calcium channel currents without affecting steady-state activation or inactivation kinetics and inhibited the spontaneous contractions of both longitudinal and circular smooth muscle strips dose-dependently. In conclusion, DATS has an inhibitory effect on the contractions of colonic muscle strips that is related to its regulation of L-type calcium channels.

Brain-Derived Neurotrophic Factor Contributes to Colonic Hypermotility in a Chronic Stress Rat Model.

BACKGROUND: Brain-derived neurotrophic factor (BDNF) has prokinetic effects on gut motility and is increased in the colonic mucosa of irritable bowel syndrome. AIMS: We aimed to investigate the possible involvement of BDNF in stress-induced colonic hypermotility. METHODS: Male Wistar rats were exposed to daily 1-h water avoidance stress (WAS) or sham WAS for 10 consecutive days. The presence of BDNF and substance P (SP) in the colonic mucosa was determined using enzyme immunoassay kits. Immunohistochemistry and western blotting were performed to assess the expression of BDNF and its receptor, TrkB. The contractions of muscle strips were studied in an organ bath system. RESULTS: Repeated WAS increased the fecal pellet expulsion and spontaneous contractile activities of the colonic muscle strips. Both BDNF and SP in the colonic mucosa were elevated following WAS. Immunohistochemistry revealed the presence of BDNF and TrkB in the mucosa and myenteric plexus. BDNF and TrkB were both up-regulated in colon devoid of mucosa and submucosa from the stressed rats compared with the control. BDNF pretreatment caused an enhancement of the SP-induced contraction of the circular muscle (CM) strips. TrkB antibody significantly inhibited the contraction of the colonic muscle strips and attenuated the excitatory effects of SP on contractions of the CM strips. Repeated WAS increased the contractile activities of the CM strips induced by SP after BDNF pretreatment, and this effect was reversed by TrkB antibody. CONCLUSIONS: The colonic hypermotility induced by repeated WAS may be associated with the increased expression of endogenous BDNF and TrkB. BDNF may have potential clinical therapeutic use in modulating gut motility.

Low expression of microRNA-126 is associated with poor prognosis in colorectal cancer.

MicroRNA-126 (miR-126) has been reported to be a tumor suppressor that targets CXCR4 in colorectal cancer (CRC) cells. This study investigated whether miR-126 has any prognostic impact in patients with CRC. MiR-126 and CXCR4 mRNA expression in 92 pairs of CRC and adjacent nontumorous tissues was examined using quantitative real-time PCR, and CXCR4 protein expression was assessed by immunohistochemistry (IHC) and Western blotting. The correlation between miR-126 and CXCR4 protein expression and clinicopathological features and overall survival rate was determined. MiR-126 was downregulated in CRC tissues that expressed high levels of CXCR4 mRNA. IHC and Western blotting detected high expression of CXCR4 protein in CRC tissues. An inverse correlation was observed between miR-126 and CXCR4 protein expression in CRC tissues. Moreover, low miR-126 and high CXCR4 protein expression was associated with distant metastasis, clinical TNM stage, and poor survival. Multivariate analysis indicated that miR-126 was an independent prognostic factor for overall survival, suggesting its clinical significance as a prognostic predictor in CRC patients.

[Actions of endogenous hydrogen sulfide on colonic hypermotility in a rat model of chronic stress].

The present study was designed to investigate the potential role of endogenous hydrogen sulfide (H2S) in chronic stress-induced colonic hypermotility. Male Wistar rats were submitted daily to 1 h of water avoidance stress (WAS) or sham WAS (SWAS) for 10 consecutive days. The total number of fecal pellets was counted at the end of each 1 h of WAS or SWAS session. Organ bath recordings were used to test the colonic motility. H2S production of colon was determined, and immunohistochemistry and Western blot were performed on rat colonic samples to detect the distribution and expression of H2S-producing enzymes. The results showed that i) repeated WAS increased the number of fecal pellets per hour and the area under the curve (AUC) of the spontaneous contractions of colonic strips (P < 0.05), ii) repeated WAS decreased the endogenous production of H2S and the expression of H2S-producing enzymes in the colon devoid of mucosa and submucosa (P < 0.001), iii) cystathionine-γ-lyase (CSE) was strongly expressed in the cytosols of the circular and longitudinal smooth muscle cells and the nucleus of the myenteric plexus neurons, iv) cystathionine-ß-synthase (CBS) was primarily localized in the cytosols of myenteric plexus neurons and weakly localized in the epithelial cells and v) inhibitors of H2S-producing enzymes increased the contractile activity of colonic strips in the SWAS rats (P < 0.001). In conclusion, the results suggest that the colonic hypermotility induced by repeated WAS may be associated with the decreased production of endogenous H2S.

[Modulatory role and mechanism of BDNF and its receptor TrkB in colonic motility disorder in chronic stress rat].

OBJECTIVE: To investigate the role and mechanism of BDNF and its receptor TrkB in the disorder of colonic motility in chronic stress rats. METHODS: A total of 20 male Wistar rats were randomly divided into two groups using to completely random method after weighed, with 10 rats in each group. Chronic water avoidance stress model was established. Then the fecal pellets of water avoidance stress (WAS) group and sham water avoidance stress (SWAS) group were recorded. Enzyme linked immunosorbent assay (ELISA), real time PCR, Western blot and immunohistochemistry were used to detect the expression of BDNF and TrkB in serum and colon muscle. The amplitudes of contractions of circular smooth muscle strips of each group were recorded after the treatment of TTX, BDNF and K252a. RESULTS: The number of fecal pellets had obviously increased in WAS group comparing with SWAS group (P < 0.05). The level of serum BDNF in WAS group was higher than that of SWAS group ((158.30 ± 9.82) vs (84.68 ± 7.80) pg/ml). And the expression of TrkB in the colon muscle in WAS group was higher than that in SWAS group (0.44 ± 0.03 vs 0.30 ± 0.02, P < 0.05). There was no significant difference between the two groups in expression of BDNF mRNA in colon muscle (P > 0.05). TrkB was mainly expressed in the cell nucleus of muscular layer neurons, and the expression of TrkB had obviously increased in WAS rats. The amplitudes of contractions of circular smooth muscle in WAS rats had significantly increased compared with SWAS rats ((0.35 ± 0.02) vs (0.22 ± 0.03) g, P < 0.05). After adding TTX to block the function of enteric nervous, the difference was remaining ((0.89 ± 0.07) vs (0.53 ± 0.06) g, P < 0.05). BDNF was added to the bath and the R value at different time was recorded. The difference had statistically significant at 6 min and 12 min (both P < 0.05). BDNF could induced the contraction peak of the circular smooth muscle. The contraction peak induced by BDNF was delayed and reduced when K252a was added to the bath 30 min before adding BDNF. CONCLUSION: BDNF plays a modulatory role in the disorder of colonic motility in chronic stress rat by acting on its receptor TrkB.

[Effect of substance P on the potassium and calcium currents of colonic smooth muscle cells].

OBJECTIVE: To investigate the effect of substance P(SP) on the spontaneous contractile activity of smooth muscle cells,the large-conductance calcium-activated potassium channel currents (IBKCa) and the L-type calcium channel currents (ICaL) in rat smooth muscle cells of the proximal colon. METHODS: A total of 24 healthy male Wista rats were used in this test. The change of smooth muscle strips spontaneous contraction of rat proximal colon after adding SP was recorded by a physiological signal stystem (RM6240). The IBKCa and ICaL were measured via the whole cell patch-clamp technique. RESULTS: The longitudinal muscle contraction was obviously increased concentration-dependently after adding different concentrations of SP (10(-7)-10(-6) mol/L), so as the circular muscle while adding SP(10(-8)-10(-6) mol/L) (all P<0.05). Compared with the control group, IBKCa was decreased after adding SP(10(-6) mol/L). Under the stimulating voltage of 60 mV, the IBKCa current density was (11.71±1.65) pA/pF, which was significantly lower compared with the control group (14.42±2.89) pA/pF (P<0.05). The ICaL) was apparently increased. Under the stimulating voltage of 0 mV, the ICaL) currents density was (-5.04±0.67) pA/pF, compared with the control group (-4.25±0.46) pA/pF, which was significantly increased (P<0.01). CONCLUSIONS: SP can promote the spontaneous contractile activity of colon smooth muscle of rats in vitro.And SP decrease IBKCa representatively while apparently increase ICaL). That is probably one of the mechanism SP regulate the gastrointestinal motility.

[Effects of hydrogen sulfide on colonic contraction of rats and ion channel mechanisms].

OBJECTIVE: To explore the effects of hydrogen sulfide (H2S) on colonic contraction of rats at low concentration and ion channel mechanisms. METHODS: Organ bath recordings were used to examine the contraction of colonic smooth muscle strips. The whole-cell patch-clamp technique was used to record the currents of L-type calcium and large conductance Ca²âº-activated K⁺ (BKCa) channels in smooth muscle cells isolated from 30 male Wistar rats. RESULTS: The H2S donor NaHS ((1-12) × 10⁻5 mol/L) increased the spontaneous contractions of longitudinal and circular muscle strips in a dose-dependent manner (all P<0.05) and the effect could not be blocked by tetrodotoxin. NaHS (6 × 10⁻5 and 12 × 10⁻5 mol/L) reversibly increased the L-type calcium current (ICa,L) in a dose-dependent manner. And the peak of ICa,L at 0 mV increased from (-3.16 ± 0.47) to (-3.33 ± 0.54) and (-3.65 ± 0.66) pA/pF respectively (n=6, both P<0.05). Current-voltage (I-V) curve had no shift after NaHS treatment and H2S donor caused no change in the curves of steady-state activation. Likewise BKCa channel was significantly inhibited by NaHS (6 × 10⁻5 and 12 × 10⁻5 mol/L) in a dose-dependent manner. And IBKCa at 60 mV decreased from (16.68 ± 1.23) to (15.26 ± 2.67) and (13.80 ± 3.04) pA/pF respectively(both P<0.05). CONCLUSIONS: H2S at low concentrations increases the spontaneous contraction of rat colonic smooth muscle in a dose-dependent manner. Such an effect may be due to a direct activation of L-type calcium channel and an inhibition of BKCa channel in smooth muscle cells.

Efficacy and safety of cinitapride in the treatment of mild to moderate postprandial distress syndrome-predominant functional dyspepsia.

GOALS AND BACKGROUND: Functional dyspepsia (FD) is a complex disease with a variety of dyspeptic symptoms. Little is known about the clinical efficacy of cinitapride, a 5-HT4 agonist and D2 antagonist, in treating FD. STUDY: This randomized, double-blind, double-dummy, positive-controlled study compared the efficacy and safety of cinitapride (1 mg) and domperidone (10 mg) tid for 4 weeks in 383 consecutive patients with mild to moderate, postprandial distress syndrome-predominant dyspeptic symptoms according to Rome III criteria. The primary endpoint was the noninferiority of cinitapride compared with domperidone in relief of symptoms. The overall patient evaluation of treatment and open gastric emptying effects of both drugs were treated as the secondary endpoints. RESULTS: The rates of symptom relief by cinitapride and domperidone after 4 weeks did not differ significantly on intension-to-treat analysis (85.8% vs. 81.8%, P=0.332). Cinitapride significantly reduced the overall severity of postprandial fullness, early satiation, and bloating (4.3±3.9 vs. 17.8±6.6, P<0.001); and it was superior to the effects of domperidone (5.4±4.9 vs. 18.4±6.9, P<0.001; P=0.021 between groups). Cinitapride also decreased the mean half-gastric emptying time from 131.1±119.4 to 86.5±18.7 minutes (P=0.0002). There was a positive relationship between symptoms and gastric emptying time (r=0.332, P=0.041). Cinitapride-related adverse events were observed in 9.1% of patients, including 1 patient with extrapyramidal symptoms. No patient experienced QT interval prolongation. CONCLUSIONS: This phase III trial has confirmed a noninferior efficacy of cinitapride over domperidone for patients with mild to moderate, postprandial distress syndrome-predominant FD. Cinitapride usage is well tolerated, but its cardiovascular events need further evaluation.

Chronic gastritis in China: a national multi-center survey.

BACKGROUND: Chronic gastritis is one of the most common findings at upper endoscopy in the general population, and chronic atrophic gastritis is epidemiologically associated with the occurrence of gastric cancer. However, the current status of diagnosis and treatment of chronic gastritis in China is unclear. METHODS: A multi-center national study was performed; all patients who underwent diagnostic upper endoscopy for evaluation of gastrointestinal symptoms from 33 centers were enrolled. Data including sex, age, symptoms and endoscopic findings were prospectively recorded. RESULTS: Totally 8892 patients were included. At endoscopy, 4389, 3760 and 1573 patients were diagnosed to have superficial gastritis, erosive gastritis, and atrophic gastritis, respectively. After pathologic examination, it is found that atrophic gastritis, intestinal metaplasia and dysplasia were prevalent, which accounted for 25.8%, 23.6% and 7.3% of this patient population. Endoscopic features were useful for predicting pathologic atrophy (PLR = 4.78), but it was not useful for predicting erosive gastritis. Mucosal-protective agents and PPI were most commonly used medications for chronic gastritis. CONCLUSIONS: The present study suggests non-atrophic gastritis is the most common endoscopic finding in Chinese patients with upper GI symptoms. Precancerous lesions, including atrophy, intestinal metaplasia and dysplasia are prevalent in Chinese patients with chronic gastritis, and endoscopic features are useful for predicting pathologic atrophy.