Luteolin ameliorates loperamide-induced functional constipation in mice

Functional constipation (FC) is one of the most common gastrointestinal disorders characterized by hard stools and infrequent bowel movements, which is associated with dysfunction of the enteric nervous system and intestinal motility. Luteolin, a naturally occurring flavone, was reported to possess potential pharmacological activities on intestinal inflammation and nerve injury. This study aimed to explore the role of luteolin and its functional mechanism in loperamide-induced FC mice. Our results showed that luteolin treatment reversed the reduction in defecation frequency, fecal water content, and intestinal transit ratio, and the elevation in transit time of FC models. Consistently, luteolin increased the thickness of the muscular layer and lessened colonic histopathological injury induced by loperamide. Furthermore, we revealed that luteolin treatment increased the expression of neuronal protein HuC/D and the levels of intestinal motility-related biomarkers, including substance P (SP), vasoactive intestinal polypeptide (VIP), and acetylcholine (ACh), as well as interstitial cells of Cajal (ICC) biomarker KIT proto-oncogene, receptor tyrosine kinase (C-Kit), and anoctamin-1 (ANO1), implying that luteolin mediated enhancement of colonic function and contributed to the anti-intestinal dysmotility against loperamide-induced FC. Additionally, luteolin decreased the upregulation of aquaporin (AQP)-3, AQP-4, and AQP-8 in the colon of FC mice. In summary, our data showed that luteolin might be an attractive option for developing FC-relieving medications.

Effect of Dahuang Lingxian prescription on the scf/c-kit signaling pathway in gallbladder interstitial cells of Cajal in a guinea pig model of cholesterol gallstone / 临床肝胆病杂志

Objective To investigate the expression levels of scf and c-kit under the regulation of Dahuang Lingxian prescription and the possible mechanism of its effect on gallbladder dynamics, and to provide a theoretical basis for Dahuang Lingxian prescription in preventing the development and recurrence of cholesterol gallstone. Methods A total of 45 specific pathogen-free healthy male guinea pigs were randomly divided into normal group, model group, and traditional Chinese medicine (TCM) group. The guinea pigs in the normal group were fed with normal diet, and those in the model group and the TCM group were fed with high-fat lithogenic diet. After 8 weeks of feeding, 5 guinea pigs were randomly selected from each group, and successful modeling was determined if gallstone was observed with the naked eye in more than 4 guinea pigs. After successful modeling, the guinea pigs in the TCM group were given Dahuang Lingxian prescription by gavage, and those in the model group were given an equal volume of normal saline by gavage. After 8 consecutive weeks of administration by gavage, gallbladder tissue samples were collected, and HE staining was used to observe the pathological changes of gallbladder tissue; Western blot was used to measure the expression level of tumor necrosis factor-α (TNF-α) in gallbladder tissue; immunohistochemistry was used to measure the protein expression levels of scf and c-kit in gallbladder smooth muscle tissue. A one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups, and the least significant difference multiple comparison method was used for further comparison between two groups. Results HE staining showed marked inflammation of gallbladder tissue in the model group, and compared with the model group, the TCM group had a significantly lower degree of inflammation. Western blot showed that the model group had the highest expression level of TNF-α in gallbladder tissue, followed by the TCM group and the normal group ( P < 0.05); immunohistochemistry showed that compared with the model group, the normal group and the TCM group had significantly higher protein expression levels of scf and c-kit in gallbladder smooth muscle tissue ( P < 0.05). Conclusion Dahuang Lingxian prescription can enhance the dynamic function of the gallbladder, possibly by upregulating the scf/c-kit signaling pathway in interstitial cells of Cajal in gallbladder.

Banxia Xiexintang Regulates Autophagy of Interstitial Cells of Cajal in Gastric Antrum of Rats with Gastric Electric Dysrhythmia / 中国实验方剂学杂志

ObjectiveTo observe the effect of Banxia Xiexintang on the autophagy of interstitial cells of Cajal （ICCs） in the gastric antrum of rats with gastric electric dysrhythmia， and explore the protective effect and regulatory mechanism. MethodThirty-two SD rats were randomly assigned into a normal group， a model group， a Banxia Xiexintang （24.68 g·kg-1） group， and a positive drug （2.7 mg·kg-1） group. The rat model of gastric electric dysrhythmia was established by the method of dieting every other day and drinking dilute hydrochloric acid， and Banxia Xiexintang and the positive drug were administrated for intervention. The body weight of each rat was recorded weekly. The gastric electric activity was recorded by the biological function experimental system. The ultrastructural changes of the gastric antrum tissue were observed by a transmission electron microscope. The co-expression of receptor tyrosine kinase （c-kit）/mammalian homolog of yeast Atg6 （Beclin1） in the gastric antrum tissue was detected by double immunofluorescence labeling method. The expression of microtubule-associated protein 1 light chain 3B （LC3B） and p62 protein in the gastric antrum tissue was determined by Western blot， and the LC3BⅡ/Ⅰ ratio was calculated. ResultCompared with the normal group， the modeling reduced the body weight （P<0.01） and decreased the dominant frequency and dominant power of gastric electricity （P<0.01）. In addition， the modeling caused ultrastructural damage of ICCs in gastric antrum， degeneration and necrosis of organelles， and appearance of a small number of autophagic vesicles. The results of double immunofluorescence labeling showed that the modeling inhibited the positive expression of c-kit and promoted the positive expression of Beclin1 in gastric antrum tissue. Western blot results showed that the modeling increased the ratio of LC3BⅡ/Ⅰ （P<0.01） and down-regulated the expression of p62 protein （P<0.01） in the gastric antrum tissue. Compared with the model group， Banxia Xiexintang and the positive drug increased the body weight （P<0.01） and the dominant frequency and dominant power of gastric electricity （P<0.01）， repaired the ultrastructural damage of ICCs in gastric antrum tissue， promoted the positive expression of c-kit and inhibited the positive expression of Beclin1 in the gastric antrum tissue. Furthermore， Banxia Xiexintang up-regulated the expression of p62 （P<0.05） and inhibited the transformation of LC3BⅠ into LC3BⅡ in gastric antrum tissue （P<0.05）. ConclusionBy regulating the expression of autophagy-related proteins， Banxia Xiexintang can reduce the autophagy and regulate the number and structure of ICCs and thus improve the gastric electric rhythm of rats， which preliminarily explains the mechanism of Banxia Xiexintang in the treatment of epigastric stuffiness.

Gist sincrónico con adenomioma gástrico: Reporte de caso y revisión de la literatura / Synchronous gist with gastric adenomyoma: Case report and literature review

Introducción: La colisión de dos tumores de diferente estirpe celular en un mismo órgano es infrecuente; a pesar de las asociaciones descritas en la literatura, el hallazgo de GIST con adenomioma en sincronismo, llama aún más la atención debido a sus distintos orígenes celulares. Reporte de caso: Presentamos el caso de una paciente mujer de 57 años de edad, quien es sometida a cirugía de resección doble en cuña, y distintos exámenes incluido el anátomo-patológico. Conclusión: Se demuestra la presencia de tumores sincrónicos, GIST gástrico y adenomioma gástrico, a pesar de la infrecuencia de este hallazgo.

Background:The collision of two tumors of different cell lines in the same organ is infrequent; even though, the associations described in the literature, the finding of synchronous GISTwith adenomyoma draws even more attention due to its different cellular origins. We present the case of a 57-year-Case report:old female patient who underwent double wedge resection surgery and various examinations, including pathology. Conclusion:The presence of synchronous tumors, gastric GIST and gastric adenomyoma is demonstrated,despite the infrequency of this finding.

Protective Effect of Tangshen Formula () on Interstitial Cells of Cajal in Colon of Diabetic Rats / 中国结合医学杂志

OBJECTIVE@#To explore the effect of Tangshen Formula (, TSF), a Chinese herbal medicine, on interstitial cells of Cajal (ICC) in the colon of diabetic rats.@*METHODS@#Fifty-four male Wistar rats were randomly divided into normal control (NC, n=14) and high-fat diet (HFD) groups (n=40). After 6 weeks, the rats in the HFD group were injected intraperitoneally streptozotocin once (30 mg/kg). Thirty rats with fasting blood glucose higher than 11.7 mmol/L were randomly divided into diabetes (DM) and TSF groups, 15 rats in each group. Rats in the NC and DM groups were intragastrically administered with saline, and those in the TSF group were given with TSF (2.4 g/kg) once daily for 20 weeks. Expression levels of Bax, Bcl-2, and caspase-3 in colonic smooth muscle layer were measured by Western blotting and immunohistochemical staining. The number of ICC was determined by immunohistochemical staining. Immunofluorescence was used for analyzing the ratio of classically activated macrophages (M1) and alternatively activated macrophages (M2) to total macrophages. Electron microscopy was used to observe the epithelial ultrastructure and junctions.@*RESULTS@#TSF appeared to partially prevented loss of ICC in DM rats (P<0.05). Compared with the NC group, expression levels of Bcl-2, Bax, caspase-3, and TNF-α as well as the ratio of M1 to total macrophages increased in DM rats (all P<0.05), and the ratio of M2 to total macrophages decreased (P<0.05 or P<0.01). Compared with the DM group, TSF decreased the expression levels of abovementioned proteins and restore M2 to total macrophages ratio (P<0.05 or P<0.01). TSF appeared to attenuate the ultrastructural changes of epithelia and improve the tight and desmosome junctions between epithelia reduced in the DM rats.@*CONCLUSION@#Reduced number of ICC in DM rats may be associated with damage of the intestinal barrier. The protective effects of TSF on ICC may be through repair of the epithelial junctions, which attenuates inflammation and inflammation-initiated apoptosis in colon of DM rats.

Expression and significance of HERG protein in Cajal interstitial cells of gallbladder tissue in patients with gallbladder stones / 中华肝胆外科杂志

Objective:To investigate the expression and significance of human ether-a-go-go related gene (HERG) protein in interstitial cells of Cajal (ICC) in patients with gallbladder stones.Methods:The gallbladder tissues of 60 patients with gallbladder diseases who underwent cholecystectomy from January 2018 to December 2020 in the Faculty of Hepato-Pancreato-Biliary Surgery, Chinese PLA General Hospital were collected, including 36 males and 24 females, aged (46.0±14.0) years. They were divided into two groups according to whether there were gallstones: gallstone group and control group (patients with gallbladder polyps and gallbladder adenomyosis), with 30 cases in each group. Color ultrasound was used to detect and calculate the gallbladder contraction rate. The neck, body and bottom tissues of the gallbladder were excised and sectioned. The expression of HERG protein and CD117 ( marker of ICC) was detected by immunofluorescence staining, immunohistochemistry and Western blot.Results:The gallbladder contraction rate in the gallstone group was (65.8±4.1)%, lower than that in the control group (73.8±5.3)%, with a statistically significant difference ( t=4.14, P<0.001). Immunohistochemistry showed that HERG protein was mainly distributed in the mucosal layer of gallbladder tissue, which was pale brown. The relative expression of HERG protein at the bottom of gallbladder in the gallstone group was (0.293±0.102), lower than that in the control group (0.694±0.059), with a statistically significant difference ( t=3.38, P=0.027). Immunofluorescence staining showed that HERG protein was mainly distributed in ICC of gallbladder epithelium. HERG protein expression in ICC at the bottom of gallbladder in gallstone group was lower than that in control group, while HERG protein expression at the neck and body of gallbladder had no significant difference. Conclusion:There are ICC and HERG protein in gallbladder tissue of patients with gallstone. The decrease of gallbladder contraction rate may be related to the decrease of HERG protein expression in ICC in gallbladder bottom tissue.

Study on the mechanism of Dahuangfuzi decoction in improving intestinal motility disorder of rats with severe acute pancreatitis / 中华急诊医学杂志

Objective:To explore the mechanism of Dahuangfuzi decoction on intestinal motility disorder by observing its effect on serum motilin, Cajal interstitial cells and motilin receptor in rats with severe acute pancreatitis (SAP).Methods:Eighteen clean male Sprague-Dawley rats were randomly divided into the control group, SAP group and Dahuangfuzi group ( n=6 each group). The SAP rat model was prepared by retrogradely injected 4% sodium taurocholate into cholangiopancreatic duct. The rats in the SAP group were given 2 mL normal saline (37℃) enema at 12 and 24 h after operation. The rats in the Dahuangfuzi group was given 2 mL Dahuangfuzi decoction (37℃) enema at 12 and 24 h respectively. For the control group, the pancreas was exposed in the same way and then the abdomen was closed. Forty-eight h after operation, the abdominal aorta blood samples were taken for determination of serum endotoxin and amylase, and for detection of serum motilin by enzyme-linked immunosorbent assay (ELISA); the pathological changes of pancreas and ileum were observed by hematoxylin-eosin (HE) staining. The expression of c-kit and motilin receptor protein in ICC in ileum tissue was detected by immunohistochemistry. Results:Compared with the control group, the levels of serum endotoxin and amylase in the SAP group were significantly higher [(504.98±88.81) pg/mL vs. (17.76±5.01) pg/mL; (532.28±66.53) vs. (69.45±3.61) U/L, P<0.05], while the levels of serum motilin were significantly lower [(195.4±6.7) ng/L vs. (301±8.10) ng/L, P<0.05], and the scores of c-kit and motilin receptor protein were decreased ( P<0.05); compared with the SAP group, the levels of serum endotoxin and amylase in the Dahuangfuzi group were significantly reduced [(189.9±38.23) pg/mL vs. (504.98±88.81) pg/mL; (294.23±25.66) vs. (532.28±66.53) U/L, P<0.05], while the levels of serum motilin were significantly increased [(264.2±8.3) ng/L vs. (195.4±6.7) ng/L, P<0.05], and the scores of c-kit and motilin receptor protein were increased ( P<0.05). Conclusions:Dahuangfuzi decoction can improve the intestinal motility of SAP rats by promoting the secretion of motilin, increasing the activity of ICC cells and the expression of motilin receptor.

Regulative effect of Rhubarb dispensing granule on autophagy and gastrointestinal motility of Cajal interstitial cells in rats with chronic transit constipation / 国际中医中药杂志

Objective:To study the regulative effect of Rhubarb dispensing granule on autophagy and gastrointestinal motility of Cajal interstitial cells in rats with chronic transit constipation (STC).Methods:A total of 75 rats were randomly divided into control group, model group, low, medium and high dose groups with 15 rats in each group. Except for the control group, the STC rat models were established by intragastric administration of compound diphenoxylate suspension. Rats in low, medium and high dose groups were given Rhubarb dispensing granule of 1, 2 and 4 g/kg by gavage respectively, while rats in control group and model group were given normal saline with the same volume by gavage, once a day for 14 consecutive days. Fecal moisture content and intestinal propulsion rate were measured. The serum levels of substance P (SP), vasoactive intestinal peptide (VIP), NO and NOS were detected by ELISA. The pathological changes of colon tissue were observed by HE staining. The c-kit level in colon tissue was detected by immunohistochemistry. The mRNA and protein levels of c-kit and Beclin1 in colon tissue were detected by PCR and Western blot.Results:Compared with the model group, the fecal moisture content, the carbon pushing distance and the intestinal pushing rate of the low, medium and high dose groups were significantly increased ( P<0.05), the serum SP level was increased ( P<0.05), the serum VIP, NO and NOS levels of the low, medium and high dose groups were decreased ( P<0.05), and the average expression score of c-kit in colon tissue of the low, medium and high dose groups was significantly increased ( P<0.05). The levels of c-kit mRNA (2.33 ± 0.35, 3.04 ± 0.17, 3.83 ± 0.23 vs. 0.61 ± 0.07) and protein (0.42 ± 0.06, 0.60 ± 0.07, 0.79 ± 0.08 vs. 0.22 ± 0.04)in colon tissue of rats in low, medium and high dose groups were increased ( P<0.05), and Beclin1 mRNA (4.17 ± 0.37, 3.35 ± 0.44, 1.05 ± 0.28 vs. 6.04 ± 0.31) and protein (0.76 ± 0.11, 0.57 ± 0.08, 0.43 ± 0.05 vs. 0.91 ± 0.06) were decreased ( P<0.05). Conclusion:Rhubarb dispensing granule could significantly increase the fecal moisture, intestinal motility rate, serum SP level and colonic tissue c-kit level, decrease serum VIP, NO, NOS level and colonic tissue Beclin1 level in rats with chronic transit constipation, and then inhibit autophagy of Cajal interstitial cells and regulate gastrointestinal motility in rats with chronic transit constipation.

Effect of electroacupuncture on calcium-activated chloride channel currents in interstitial cells of Cajal in rats with diabetic gastroparesis / 针灸推拿医学（英文版）

Objective: To investigate the mechanisms of electroacupuncture (EA) at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) in intervening diabetic gastroparesis (DGP) based on calcium-activated chloride channel. Methods: Forty Sprague-Dawley rats were randomly divided into four groups, including a normal control group (group A), a model group (group B), an EA group (group C) and a metoclopramide group (group D), with 10 rats in each group. A single intraperitoneal injection of 2％ streptozotocin (STZ) combined with 8-week high-glucose high-fat diet was used to establish a DGP rat model. After intervention, gastrointestinal propulsive rate was observed; the expression level of transmembrane protein 16A (TMEM16A) was examined by immunohistochemistry; the Ca2+ concentration in interstitial cells of Cajal (ICCs) was detected by immunofluorescence; and whole-cell patch-clamp technique was applied to detect the current intensity of calcium-activated chloride channel (ICaCC) in ICCs in gastric antrum. Results: After modeling, the blood glucose levels in group B, group C and group D were significantly increased compared with group A (all P<0.01); after intervention, compared with group B, the blood glucose levels in group C and group D were significantly decreased (P<0.05, P<0.01); the intra-group comparison of blood glucose level between after modeling and after intervention found significant difference only in group C (P<0.01). The gastrointestinal propulsive rates in group B, group C and group D were significantly different from that in group A (P<0.01 or P<0.05); the gastrointestinal propulsive rates were markedly higher in group C and group D than in group B (P<0.01, P<0.01). The expressions of TMEM16A in group B and group C were decreased compared with group A (P<0.01, P<0.05); the expressions of TMEM16A in group C and group D were increased compared with group B (P<0.01, P<0.05). The fluorescence intensity of Ca2+ was significantly lower in group B than in group A (P<0.01); the fluorescence intensity of Ca2+ was significantly higher in group C and group D than in group B (P<0.01, P<0.05). ICaCC in ICCs in group B was significantly decreased compared with group A; ICaCC in group C and group D were increased compared with group B. Conclusion: EA at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) can significantly improve gastrointestinal motility in DGP rats by up-regulating the ICaCC in ICCs.

Efficacy of Zhizhuwan Decoction and Its Ingredient-contained Serums on Proliferation and Apoptosis of Rat Colon Interstitial Cells of Cajal / 中国实验方剂学杂志

Objective:To explore the efficacy and molecular mechanism of Zhizhuwan decoction and its ingredient-contained serums on the proliferation and apoptosis of rat colon interstitial cells of cajal (ICC), and make a molecule-level analysis of the possible mechanism of traditional Chinese medicine (TCM) purgation-tonifying therapy in treating slow transit constipation (STC). Method:A total of 40 rats were divided into Atractylodis Macrocephalae Rhizoma(AMR) group, Aurantii Fructus Immaturus（AFI） group, Zhizhuwan group and blank serum group on random basis, with 10 in each group. Baizhu group was given 17.7 g·kg-1·d-1 of AMR decoction by gavage, AFI group was given 8.9 g·kg-1·d-1 AFI decoction by gavage, Zhizhuwan group was given 26.4 g·kg-1·d-1 Zhizhuwan decoction by gavage, and blank serum group was given 3 mL sterile distilled water for 7 consecutive days, once a day. Drug-contained serums and blank serum were collected from blood of the above groups and diluted to 5%, 10%, 15% and 20% concentrations. Each concentration was intervened for 24 h and 48 h, and the amount and status of ICC were observed. The best intervening concentration and time for each group with cell counting kit-8 (CCK-8) were determined. Rat colon ICC was divided into blank control group, blank serum group, AMR group, AFI group and Zhizhuwan group. ICC proliferation for each group was detected with EdU, ICC apoptosis for each group was detected by flow cytometry, and expressions of X-linked inhibitor of apoptosis protein (XIAP) and proliferating cell nuclear antigen (PCNA) were detected by Western blot. Result:Compared with the normal group, the best intervention concentration for blank serum group, AMR group and AFI group was 10%, while that for Zhizhuwan group was 5%. The best intervention times for the above groups were all 24 h. No distinct difference between the effect of blank control group and blank serum group on the proliferation and apoptosis of ICC was observed. In comparison with blank control group and blank serum group, AMR group, AFI group and Zhizhuwan group showed significant changes in ICC proliferation rate (P<0.05，P<0.01). There was a greater increase in ICC proliferation rate of Zhizhuwan group than that of AMR group and Zhizhu group (P<0.05，P<0.01), with no distinct difference between the changes of ICC proliferation rates in AMR group and AFI group. There was no significant difference between the changes of ICC apoptosis rates in AMR group, AFI group and Zhizhuwan group than in blank control group and blank serum group. There were significant increases in the expressions of XIAP and PCNA in AMR group, AFI group and Zhizhuwan group than in blank control group and blank serum group (P<0.05，P<0.01)， but with little difference among the three groups. Conclusion:At certain concentrations, Zhizhuwan, AFI and AMR all have the effect in improving ICC proliferation by increasing XIAP and PCNA expressions, with no evident effect on the apoptosis of ICC, based on TCM purgation-tonifying therapy, Zhizhuwan has the effect in improving ICC proliferation, with a better effect than single administration with AFI or AMR.

Phenotypic changes of interstitial cells of Cajal after intestinal obstruction in rat model

The objective was to study the effect of mechanical intestinal obstruction in rats on the phenotype of interstitial cells of Cajal (ICC). Healthy Wistar rats were randomly divided into sham-operation group (C), one day obstruction group (M1), two days obstruction group (M2), and three days obstruction group (M3), with 10 rats in each group. The expression of SCF mRNA and c-Kit protein in intestinal tissue was investigated by RT-PCR and immunohistochemistry. Compared with the sham-operation group, the relative expression of SCF mRNA and the expression of c-Kit protein in intestinal tissue were significantly decreased in both obstruction groups. Levels decreased gradually with the prolongation of obstruction time, and significantly decreased on the 3rd day after obstruction (P<0.05). Immunohistochemical staining of the small intestine showed that the number of ICC in the sham-operation group was the highest, and they were gradually decreased with the extension of obstruction time in the M1 to M3 groups. There was a significant difference between groups (P<0.05). Intestinal obstruction caused a decrease in the concentrations of SCF mRNA and c-Kit protein in ICC. With the prolongation of intestinal obstruction, the number of ICCs gradually decreased.

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

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

Control of Motility in the Internal Anal Sphincter

The internal anal sphincter (IAS) plays an important role in the maintenance of fecal continence since it generates tone and is responsible for > 70% of resting anal pressure. During normal defecation the IAS relaxes. Historically, tone generation in gastrointestinal muscles was attributed to mechanisms arising directly from smooth muscle cells, ie, myogenic activity. However, slow waves are now known to play a fundamental role in regulating gastrointestinal motility and these electrical events are generated by the interstitial cells of Cajal. Recently, interstitial cells of Cajal, as well as slow waves, have also been identified in the IAS making them viable candidates for tone generation. In this review we discuss four different mechanisms that likely contribute to tone generation in the IAS. Three of these involve membrane potential, L-type Ca²⁺ channels and electromechanical coupling (ie, summation of asynchronous phasic activity, partial tetanus, and window current), whereas the fourth involves the regulation of myofilament Ca²⁺ sensitivity. Contractile activity in the IAS is also modulated by sympathetic motor neurons that significantly increase tone and anal pressure, as well as inhibitory motor neurons (particularly nitrergic and vasoactive intestinal peptidergic) that abolish contraction and assist with normal defecation. Alterations in IAS motility are associated with disorders such as fecal incontinence and anal fissures that significantly decrease the quality of life. Understanding in greater detail how tone is regulated in the IAS is important for developing more effective treatment strategies for these debilitating defecation disorders.

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

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

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

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

Effect of Houpu Sanwu Tang on Small Intestine Interstitial Cells of Cajal and iNOS in Postoperative Ileus Rats / 中国实验方剂学杂志

Objective: To evaluate the effect of Houpu Sanwu Tang on the postoperative ileus (POI), and observe its underlying mechanisms of action on interstitial cells of cajal (ICC) and inducible nitric oxide synthase(iNOS) regulation of POI. Method: Totally 87 healthy adult male SD rats were randomly divided into sham operation group, saline control group and Houpu Sanwu Tang group at low, medium and high doses. Houpu Sanwu Tang low, middle and high dose groups received orally Houpu Sanwu Tang(2.25,4.5,9 g·kg-1); Sham operation group (Sham operation) and saline control group (Saline control) received orally normal saline. Surgical procedure was used to induce the postoperative ileus. Changes in intestinal propulsion rate, intestinal mucosal injury and small intestine expression of c-kit and iNOS among these groups were detected. Result: Intestinal propulsion rate was significantly higher in Houpo Sanwu Tang group than that in Saline control group (PPPPConclusion: Houpu Sanwu Tang can improve the intestinal propulsion rate and the recovery in POI rats. The mechanisms are related to the inhibition of the generation of iNOS, the alleviation of inflammatory response, and increase of the number of ICC, so as to ensure its normal function, and improve the intestinal dynamic disorder.

TNF-α inhibits SCF, ghrelin, and substance P expressions through the NF-κB pathway activation in interstitial cells of Cajal

Ulcerative colitis is a chronic inflammatory disease of the colon where intestinal motility is disturbed. Interstitial cells of Cajal (ICC) are required to maintain normal intestinal motility. In the present study, we assessed the effect of tumor necrosis factor-alpha (TNF-α) on viability and apoptosis of ICC, as well as on the expression of stem cell factor (SCF), ghrelin, and substance P. ICC were derived from the small intestines of Swiss albino mice. Cell viability and apoptosis were measured using CCK-8 assay and flow cytometry, respectively. ELISA was used to measure the concentrations of IL-1β, IL-6, ghrelin, substance P, and endothelin-1. Quantitative RT-PCR was used to measure the expression of SCF. Western blotting was used to measure the expression of apoptosis-related proteins, interleukins, SCF, and NF-κB signaling pathway proteins. TNF-α induced inflammatory injury in ICC by decreasing cell viability and increasing apoptosis and levels of IL-1β and IL-6. TNF-α decreased the levels of SCF, ghrelin, and substance P, but had no effect on endothelin-1. TNF-α down-regulated expressions of SCF, ghrelin, and substance P by activating the NF-κB pathway in ICC. In conclusion, TNF-α down-regulated the expressions of SCF, ghrelin, and substance P via the activation of the NF-κB pathway in ICC.

Effects of ATP on Pacemaker Activity of Interstitial Cells of Cajal from the Mouse Small Intestine / 전남의대학술지

Purinergic receptors play an important role in regulating gastrointestinal (GI) motility. Interstitial cells of Cajal (ICCs) are pacemaker cells that regulate GI smooth muscle activity. We studied the functional roles of external adenosine 5′-triphosphate (ATP) on pacemaker activity in cultured ICCs from mouse small intestines by using the whole-cell patch clamp technique and intracellular Ca²⁺ ([Ca²⁺]ᵢ) imaging. External ATP dose-dependently depolarized the resting membrane and produced tonic inward pacemaker currents, and these effects were antagonized by suramin, a purinergic P2 receptor antagonist. ATP-induced effects on pacemaker currents were suppressed by an external Na⁺-free solution and inhibited by the nonselective cation channel blockers, flufenamic acid and niflumic acid. The removal of external Ca²⁺ or treatment with thapsigargin (inhibitor of Ca²⁺ uptake into endoplasmic reticulum) inhibited the ATP-induced effects on pacemaker currents. Spontaneous [Ca²⁺]ᵢ oscillations were enhanced by external ATP. These results suggest that external ATP modulates pacemaker activity by activating nonselective cation channels via external Ca²⁺ influx and [Ca²⁺]ᵢ release from the endoplasmic reticulum. Thus, it seems that activating the purinergic P2 receptor may modulate GI motility by acting on ICCs in the small intestine.

Role of High-affinity Choline Transporter 1 in Colonic Hypermotility in a Rat Model of Irritable Bowel Syndrome

BACKGROUND/AIMS: Irritable bowel syndrome (IBS) is a common disease characterized by intestinal dysmotility, the mechanism of which remains elusive. We aim to determine whether the high-affinity choline transporter 1 (CHT1), a determinant of cholinergic signaling capacity, modulates intestinal motility associated with stress-induced IBS. METHODS: A rat IBS model was established using chronic water avoidance stress (WAS). Colonic pathological alterations were evaluated histologically and intestinal motility was assessed by intestinal transit time and fecal water content (FWC). Visceral sensitivity was determined by visceromotor response to colorectal distension. RT-PCR, western blotting, and immunostaining were performed to identify colonic CHT1 expression. Contractility of colonic muscle strips was measured using isometric transducers. enzyme-linked immunosorbent assay was used to measure acetylcholine (ACh). We examined the effects of MKC-231, a choline uptake enhancer, on colonic motility. RESULTS: After 10 days of WAS, intestinal transit time was decreased and fecal water content increased. Visceromotor response magnitude in WAS rats in response to colorectal distension was significantly enhanced. Protein and mRNA CHT1 levels in the colon were markedly elevated after WAS. The density of CHT1-positive intramuscular interstitial cells of Cajal and myenteric plexus neurons in WAS rats was higher than in controls. Ammonium pyrrolidine dithiocarbamate partly reversed CHT1 upregulation and alleviated colonic hypermotility in WAS rats. Pharmacological enhancement of CHT1 activity by MKC-231 enhanced colonic motility in control rats via upregulation of CHT1 and elevation of ACh production. CONCLUSION: Upregulation of CHT1 in intramuscular interstitial cells of Cajal and myenteric plexus neurons is implicated in chronic stress-induced colonic hypermotility by modulation of ACh synthesis via nuclear factor-kappa B signaling.

Regulation of Intracellular Calcium by Endoplasmic Reticulum Proteins in Small Intestinal Interstitial Cells of Cajal

BACKGROUND/AIMS: We investigated the role of representative endoplasmic reticulum proteins, stromal interaction molecule 1 (STIM1), and store-operated calcium entry-associated regulatory factor (SARAF) in pacemaker activity in cultured interstitial cells of Cajal (ICCs) isolated from mouse small intestine. METHODS: The whole-cell patch clamp technique applied for intracellular calcium ions ([Ca²+]i) analysis with STIM1 or SARAF overexpressed cultured ICCs from mouse small intestine. RESULTS: In the current-clamping mode, cultured ICCs displayed spontaneous pacemaker potentials. External carbachol exposure produced tonic membrane depolarization in the current-clamp mode, which recovered within a few seconds into normal pacemaker potentials. In STIM1-overexpressing cultured ICCs pacemaker potential frequency was increased, and in SARAF-overexpressing ICCs pacemaker potential frequency was strongly inhibited. The application of gadolinium (a non-selective cation channel inhibitor) or a Ca2+-free solution to understand Orai channel involvement abolished the generation of pacemaker potentials. When recording intracellular Ca²+ concentration with Fluo 3-AM, STIM1-overexpressing ICCs showed an increased number of spontaneous intracellular Ca²+ oscillations. However, SARAF-overexpressing ICCs showed fewer spontaneous intracellular Ca2+ oscillations. CONCLUSION: Endoplasmic reticulum proteins modulated the frequency of pacemaker activity in ICCs, and levels of STIM1 and SARAF may determine slow wave patterns in the gastrointestinal tract.