Emptying In Mice Research Articles

Structural characteristics of wheat bran insoluble dietary fiber with various particle size distributions and their influences on the kinetics of gastrointestinal emptying in mice

Wheat bran is an abundant yet underutilized agricultural byproduct. Herein, the insoluble dietary fiber from wheat bran (WBIDF) was ultra-milled to investigate its impact on physicochemical properties and gastrointestinal emptying. SEM and CLSM showed that the laminar structure of WBIDF was disrupted as the particle size was significantly reduced. In the similar characteristic peaks appearing at 3410, 2925, 1635, 1041, and 895 cm−1 in the FT-IR spectra and at 2940, 1593, 1080, and 526 cm−1 in the Raman spectra, the peak intensity was increased as the particle size decreased. It may be that the hydrogen bonding between cellulose, hemicellulose, or other macromolecules was enhanced. X-ray diffraction showed cellulose type I results for all five samples. Correspondingly, the water-holding, swelling, and oil-holding capacities increased by 75.33 %, 52.62 %, and 75.00 %, respectively, in WBIDF-CW1.8 compared with WBIDF-CWy. Additionally, smaller particle sizes had lower viscosity, thereby enhancing intestinal propulsion and gastric emptying rates. Enhanced contact of the cecal tissue growth factor with the intestinal mucosa delayed ghrelin secretion and stimulated the secretion of motilin, gastrin, and cholecystokinin. In conclusion, the particle sizes of WBIDF were reduced through ultramicro-grinding, leading to altered structure, enhanced hydration and oil-holding capacities, decreased viscosity, and improved gastrointestinal emptying capacity.

Zn-Fe primary battery-enabled controlled hydrogen release in stomach for improving insulin resistance in obesity-associated type 2 diabetes

Chronic systemic inflammation in obesity-associated type 2 diabetes (T2D) is a key inducing factor of insulin resistance (IR). Hydrogen molecule (H2) has been proved to be a safe and effective anti-inflammatory agent, but conventional H2 administration methods cannot provide a high dosage and a long duration of H2 treatment in IR-related tissues and thus lead to limited therapeutic efficacies. We here propose a new strategy of controlled H2 release to match the time window of gastric emptying for maximizing the bioavailability and therapeutic outcome of H2. This work enhances the hydrolysis rate of Zn by constructing a Zn-Fe primary-battery micro-/nano-structure, and the H2-releasing rate is adjusted by tuning the ratio of Zn to Fe. The Zn-Fe micro-/nano-structure is orally administrated once daily to alleviate obesity-associated T2D in a leptin-deficient (ob/ob) mouse model. The H2 generation time of the Zn-Fe primary-battery micro-/nano-structure with the Fe/Zn ratio of 1:100 in gastric acid is about 3 h, just matching with the time window of gastric emptying in mice. In vivo monitoring results show that H2 generated by Zn-Fe micro-/nano-structure in stomach can effectively accumulate in major IR-sited tissues including liver, adipose tissue, and skeletal muscle at a high dose for a relatively long time compared to H2-rich water drinking. Oral administration of Zn-Fe micro-/nano-structure at 200 mg/kg body weight has realized an efficient IR improvement and remarkably ameliorated systemic inflammation in ob/ob mice. In addition, a high-dose administration of Zn-Fe shows no visible toxicity in mice. This work provides a new strategy to maximize the outcome of hydrogen therapy.

The 16α-hydroxylated Bile Acid, Pythocholic Acid Decreases Food Intake and Increases Oleoylethanolamide in Male Mice.

Modulation of bile acid (BA) structure is a potential strategy for obesity and metabolic disease treatment. BAs act not only as signaling molecules involved in energy expenditure and glucose homeostasis, but also as regulators of food intake. The structure of BAs, particularly the position of the hydroxyl groups of BAs, impacts food intake partly by intestinal effects: (1) modulating the activity of N-acyl phosphatidylethanolamine phospholipase D, which produces the anorexigenic bioactive lipid oleoylethanolamide (OEA) or (2) regulating lipid absorption and the gastric emptying-satiation pathway. We hypothesized that 16α-hydroxylated BAs uniquely regulate food intake because of the long intermeal intervals in snake species in which these BAs are abundant. However, the effects of 16α-hydroxylated BAs in mammals are completely unknown because they are not naturally found in mammals. To test the effect of 16α-hydroxylated BAs on food intake, we isolated the 16α-hydroxylated BA pythocholic acid from ball pythons (Python regius). Pythocholic acid or deoxycholic acid (DCA) was given by oral gavage in mice. DCA is known to increase N-acyl phosphatidylethanolamine phospholipase D activity better than other mammalian BAs. We evaluated food intake, OEA levels, and gastric emptying in mice. We successfully isolated pythocholic acid from ball pythons for experimental use. Pythocholic acid treatment significantly decreased food intake in comparison to DCA treatment, and this was associated with increased jejunal OEA, but resulted in no change in gastric emptying or lipid absorption. The exogenous BA pythocholic acid is a novel regulator of food intake and the satiety signal for OEA in the mouse intestine.

Metformin acts as a dual glucose regulator in mouse brain.

Aims: Metformin improves glucose regulation through various mechanisms in the periphery. Our previous study revealed that oral intake of metformin activates several brain regions, including the hypothalamus, and directly activates hypothalamic S6 kinase in mice. In this study, we aimed to identify the direct effects of metformin on glucose regulation in the brain. Materials and methods: We investigated the role of metformin in peripheral glucose regulation by directly administering metformin intracerebroventricularly in mice. The effect of centrally administered metformin (central metformin) on peripheral glucose regulation was evaluated by oral or intraperitoneal glucose, insulin, and pyruvate tolerance tests. Hepatic gluconeogenesis and gastric emptying were assessed to elucidate the underlying mechanisms. Liver-specific and systemic sympathetic denervation were performed. Results: Central metformin improved the glycemic response to oral glucose load in mice compared to that in the control group, and worsened the response to intraperitoneal glucose load, indicating its dual role in peripheral glucose regulation. It lowered the ability of insulin to decrease serum glucose levels and worsened the glycemic response to pyruvate load relative to the control group. Furthermore, it increased the expression of hepatic G6pc and decreased the phosphorylation of STAT3, suggesting that central metformin increased hepatic glucose production. The effect was mediated by sympathetic nervous system activation. In contrast, it induced a significant delay in gastric emptying in mice, suggesting its potent role in suppressing intestinal glucose absorption. Conclusion: Central metformin improves glucose tolerance by delaying gastric emptying through the brain-gut axis, but at the same time worsens it by increasing hepatic glucose production via the brain-liver axis. However, with its ordinary intake, central metformin may effectively enhance its glucose-lowering effect through the brain-gut axis, which could surpass its effect on glucose regulation via the brain-liver axis.

TAAR1 Agonist Ulotaront Improves Glycemic Control and Reduces Body Weight in Rodent Models of Diabetes, Obesity, and Iatrogenic Weight Gain

AbstractIntroductionPreclinical evidence has identified the trace amine-associated receptor 1 (TAAR1) as a novel regulator of metabolic control. Ulotaront is a TAAR1 and 5-HT1A agonist currently in Phase 3 clinical trials for the treatment of schizophrenia. Here we summarize preclinical results assessing the effects of ulotaront on weight and metabolic parameters.MethodsEffects of ulotaront administration were evaluated on oral glucose tolerance (oGTT), gastric emptying, and in rodent models of weight gain (high-fat diet [HFD]-, corticosterone-, and olanzapine-induced).ResultsFollowing 15-day oral administration of ulotaront, rats on HFD showed dose-dependent reduction in body weight, food intake, and liver triglyceride content compared to controls. In addition, a more rapid reversal of olanzapine-induced weight gain and food intake was observed in rats switched to ulotaront (vs. vehicle). Consistent with weight-lowering effects in rats, chronic ulotaront treatment normalized corticosterone-induced weight gain in mice. Assessment of oGTT showed a dose-dependent reduction of glucose excursion in response to acute ulotaront administration in naive and diabetic db/db mice. Ulotaront administration also delayed gastric emptying in mice—a likely mechanism driving reductions in glucose excursions during the oGTT. Whole-brain c-fos imaging of ulotaront-treated mice revealed increased neuronal activity in several brain regions associated with regulation of food intake and metabolic signals.ConclusionsThe data indicate that ulotaront not only lacks metabolic liabilities typically associated with antipsychotics but can reduce body weight and improve glucose tolerance in rodent models. The underlying mechanisms may include TAAR1-mediated peripheral effects on glucose homeostasis and/or direct modulation of homeostatic and hedonic neurocircuits regulating energy balance. The beneficial metabolic effects of ulotaront may suggest a substantially improved risk-benefit profile compared to established antipsychotics.FundingSunovion Pharmaceuticals Inc. and Otsuka Pharmaceutical Development & Commercialization, Inc.

Magnetic resonance imaging as a non-invasive tool to assess gastric emptying in mice.

Methods to study gastric emptying in rodents are time consuming or terminal, preventing repetitive assessment in the same animal. Magnetic resonance imaging (MRI) is a non-invasive technique increasingly used to investigate gastrointestinal function devoid of these shortcomings. Here, we evaluated MRI to measure gastric emptying in control animals and in two different models of gastroparesis. Mice were scanned using a 9.4 Tesla MR scanner. Gastric volume was measured by delineating the stomach lumen area. Control mice were scanned every 30 min after ingestion of a 0.2 g meal and stomach volume was quantified. The ability of MRI to detect delayed gastric emptying was evaluated in models of morphine-induced gastroparesis and streptozotocin-induced diabetes. Magnetic resonance imaging reproducibly detected increased gastric volume following ingestion of a standard meal and progressively decreased with a half emptying time of 59 ± 5 min. Morphine significantly increased gastric volume measured at t= 120 min (saline: 20 ± 2 vs morphine: 34 ± 5 mm3 ; n= 8-10; p< 0.001) and increased half emptying time using the breath test (saline: 85 ± 22 vs morphine: 161 ± 46 min; n= 10; p< 0.001). In diabetic mice, gastric volume assessed by MRI at t= 60 min (control: 23 ± 2 mm3 ; n= 14 vs diabetic: 26 ± 5 mm3 ; n= 18; p= 0.014) but not at t= 120 min (control: 21 ± 3 mm3 ; n= 13 vs diabetic: 18 ± 5 mm3 ; n= 18; p= 0.115) was significantly increased compared to nondiabetic mice. Our data indicate that MRI is a reliable and reproducible tool to assess gastric emptying in mice and represents a useful technique to study gastroparesis in disease models or for evaluation of pharmacological compounds.

2-Arachidonoyl glycerol suppresses gastric emptying via the cannabinoid receptor 1-cholecystokinin signaling pathway in mice.

2-Monoacylglycerol (2-MAG) is one of the digestion products of dietary lipids. We recently demonstrated that a 2-MAG, 2-arachidonoyl glycerol (2-AG) potently stimulated cholecystokinin (CCK) secretion via cannabinoid receptor 1 (CB1) in a murine CCK-producing cell line, STC-1. CCK plays a crucial role in suppressing postprandial gastric emptying. To examine the effect of 2-AG on gastric emptying, we performed acetaminophen and phenol red recovery tests under oral or intraperitoneal administration of 2-AG in mice. Orally administered 2-AG (25mg/kg) suppressed the gastric emptying rate in mice, as determined by the acetaminophen absorption test and phenol red recovery test. Intraperitoneal administration of a cholecystokinin A receptor antagonist (0.5 mg/kg) attenuated the gastric inhibitory emptying effect. In addition, both oral (10 mg/kg) and intraperitoneal (0.5 mg/kg) administration of a CB1 antagonist counteracted the 2-AG-induced gastric inhibitory effect. Furthermore, intraperitoneal 2-AG (25mg/kg) suppressed gastric emptying. These results indicate that 2-AG exhibits an inhibitory effect on gastric emptying in mice, possibly mediated by stimulating both CCK secretion via CB1 expressed in CCK-producing cells and acting on CB1 expressed in the peripheral nerves. Our findings provide novel insights into the 2-MAG-sensing mechanism in enteroendocrine cells and the physiological role of 2-MAG.

Iron tablets delay gastric emptying, which is ameliorated by 5-HT&lt;sub&gt;3&lt;/sub&gt; receptor antagonist.

Gastrointestinal symptoms, including nausea and vomiting, are common adverse effects of oral iron tablets, but the mechanism of iron-induced nausea and vomiting is not yet known. Studies have shown that there are close relationships between gastrointestinal motility and gastrointestinal symptoms such as nausea, vomiting, and diarrhea, with more than 90% of patients with delayed gastric emptying experiencing nausea and vomiting. However, the effect of iron on gastrointestinal motility has not yet been investigated. In the present study, we aimed to elucidate the effects of iron on gastrointestinal motility using sodium ferrous citrate (SFC), the most commonly used iron tablets. Gastric emptying in mice was assessed by 13C-octanoic acid breath test to examine the effect of SFC (3-30 mg Fe/kg, p.o.) with or without the 5-HT3 receptor antagonist, palonosetron hydrochloride (5 mg/kg. s.c.). Colon transit was also measured by the beads method. The results showed that SFC delayed the gastric emptying, which was ameliorated by administration of palonosetron hydrochloride. It was also confirmed that ingredients of the tablets had no effect on gastric emptying. SFC also had no effect on the colon transit in vivo. These results lead the possibility that the iron-induced delayed gastric emptying may be mediated through nausea and vomiting.

679-P: The Novel GIP, GLP-1, and Glucagon Triple Receptor Agonist LY3437943 Exhibits Robust Efficacy in Preclinical Models of Obesity and Diabetes

The ever-growing prevalence of obesity and its associated comorbidities (T2D, NASH/NAFLD) is driving the need to discover new therapies for improving metabolic health. Recently, multi-receptor agonists have offered promise for meeting this need. Here, we characterize LY3437943, a novel single agent tri-agonist at the GIP, GLP-1, and glucagon (Gcg) receptors (R). Pharmacologic analysis of LY3437943 in cAMP assays using recombinant cell lines expressing the individual receptors indicated a potency balance favoring GIPR agonism (1.7- and 2.5-fold less potent at the GLP-1R and GcgR, respectively, but 7-fold more potent at the GIPR; all potencies in relation to the native ligands). In endogenous cells, LY3437943 regulated adipocyte lipolysis and hepatocyte glucose output. In vivo studies demonstrated regulation of multiple metabolic endpoints. Acute treatment with LY3437943 dose-dependently inhibited semi-liquid gastric emptying in mice and enhanced glucose dependent insulin secretion in rat IVGTT experiments. Chronic studies in diet induced obese mice reduced food intake and body weight (45% weight loss primarily via reduced fat mass) superior to other GIPR and GLP-1R agonists. In these experiments, LY3437943 lowered blood glucose and plasma insulin, indicating improved insulin sensitivity. Additionally, chronic administration improved biomarkers of liver health, decreasing both plasma alanine aminotransferase and liver triglycerides. Rodent and cynomolgus monkey PK modeling also suggested the potential for weekly dosing in humans. Taken these findings together, LY3437943 is a novel tri-agonist at the GIPR, GLP-1R, and GcgR, producing superior weight loss and glycemic control compared with other incretin receptor-targeting molecules and offers additional benefit for liver health. These findings prompt evaluation of the potential clinical benefit of LY3437943 in patients with obesity and metabolic diseases. Disclosure T. Coskun: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. F. S. Willard: Employee; Self; Eli Lilly and Company. J. V. Ficorilli: None. O. Cabrera: None. S. Urva: Employee; Self; Eli Lilly and Company. F. Norouziyan cooper: None. L. Guo: Employee; Self; Eli Lilly and Company. J. Alsina-fernandez: None. H. Qu: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. J. S. Moyers: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. W. C. Roell: Employee; Self; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company. L. O’farrell: None. A. Regmi: Employee; Self; Eli Lilly and Company. X. Ruan: None. A. D. Showalter: None. K. Sloop: Employee; Self; Eli Lilly and Company. D. B. Wainscott: Employee; Self; Eli Lilly and Company, Employee; Spouse/Partner; Eli Lilly and Company, Stock/Shareholder; Self; Eli Lilly and Company, Stock/Shareholder; Spouse/Partner; Eli Lilly and Company. Funding Eli Lilly and Company

Usefulness of a Kampo Medicine on Stress‐Induced Delayed Gastric Emptying in Mice

Anxiety and depression often occur with gastrointestinal symptoms. Although the Japanese traditional medicine (Kampo medicine) bukuryoingohangekobokuto (BGH) is approved for treating anxiety, neurotic gastritis, and heartburn, its effect on gastrointestinal motility remains poorly known. This study aimed to examine the effect of BGH on delayed gastric emptying in stress model mice and clarified its action mechanism. Seven-week-old C57BL/6 male mice were acclimated for a week and fasted overnight. Stress hormone, corticotropin-releasing factor (CRF), was intracerebroventricularly injected to mice, and solid nutrient meal (ground chow and distilled water) was orally administered 1 hour after. Gastric contents were collected to evaluate gastric emptying rates by measuring its dry weight. Injection of CRF (0.3 or 1.0 μg/mouse) significantly delayed the 2-hour gastric emptying in mice. BGH (1.0 g/kg), which was administered 30 minutes before the CRF injection, significantly ameliorated the delayed gastric emptying induced by CRF (0.3 μg/mouse). BGH (0.5, 1.0 g/kg) significantly enhanced the 1-hour gastric emptying and slightly increased the 2-hour gastric emptying in mice without CRF injection. In vitro functional assays showed that components of BGH antagonized or inhibited CRF type-2, dopamine D2/D3, neuropeptide Y Y2 receptors, or acetylcholinesterase. In conclusion, the components of BGH may exert synergistic effects on improving gastric emptying via various targets. BGH is considered to be potentially useful for treating gastrointestinal dysmotility with psychological symptoms.

1187-P: The Novel Biguanide NT1195 Is an Oral Antidiabetes Drug for Patients with Kidney Disease

Metformin, the most prescribed drug for T2D, has significant deficiencies in potency, pharmacokinetics (PK) and safety, especially in patients with kidney disease. Despite these deficiencies no improvements have been made to the biguanide (BIG) drug class. Novel BIGs with greater efficacy and without the risk of lactic acidosis are needed for T2D in patients with impaired renal function. A library of novel BIGs was screened for functional activity against a panel of organic cation transporters (OCTs). This OCT activity profile has allowed us to select BIGs with increased potency, improved PK properties and reduced elimination in urine. NT1195 was identified from this library and examined in more detail. This BIG is 5-10x more potent in mouse OGTT than metformin and is potent in the db:db mouse model, lowering plasma glucose after 8 days of dosing when metformin did not. NT1195 is more effective at elevating GLP-1 levels and inhibited gastric emptying in mice, where metformin did not. Improved potency alone is not sufficient to create the next generation of BIG therapeutics; it is also important to improve drug safety and to reduce the risk of lactic acidosis. Detailed PK studies in mice show that NT1195 has a 28.5h half-life (metformin = 1.97h), high levels of exposure (6x &amp;gt;metformin) and renal clearance that is 50x less than metformin. This latter finding suggests an increase in the safety of NT1195 in patients with impaired renal function, since we anticipate that NT1195 will be cleared by non-renal processes and that drug levels will not be affected by kidney disease. PK studies in cynomolgus monkeys provide similar findings for NT1195 with good exposure and a long half-life after oral administration. Also, NT1195 was found to increases glucose disposal in an IVGTT in insulin resistant monkeys. Safety studies are underway that will prepare NT1195 for a micro-dose study in T2D patients with and without kidney disease. Disclosure K.W. Batchelor: None. J.N. Livingston: Consultant; Self; CohBar, Inc. Employee; Self; NovoTarg Therapeutics. K.K. Brown: None. K. Kavanagh: Research Support; Self; Takeda Development Centre Europe Ltd. J.E. Cobb: Consultant; Self; NovaTarg Therapeutics. Funding National Institute of Diabetes and Digestive and Kidney Diseases

Intestinal TGR5 agonism improves hepatic steatosis and insulin sensitivity in Western diet-fed mice.

Takeda G protein-coupled receptor 5 (TGR5) agonists induce systemic release of glucagon-like peptides (GLPs) from intestinal L cells, a potentially therapeutic action against metabolic diseases such as nonalcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD), and Type 2 diabetes. Historically, TGR5 agonist use has been hindered by side effects, including inhibition of gallbladder emptying. Here, we characterize RDX8940, a novel, orally administered TGR5 agonist designed to have minimal systemic effects and investigate its activity in mice fed a Western diet, a model of NAFLD and mild insulin resistance. Agonist activity, binding selectivity, toxicity, solubility, and permeability of RDX8940 were characterized in standard in vitro models. RDX8940 pharmacokinetics and effects on GLP secretion, insulin sensitivity, and liver steatosis were assessed in C57BL/6 mice fed normal or Western diet chow and given single or repeated doses of RDX8940 or vehicle, with or without dipeptidyl peptidase-4 (DPP4) inhibitors. Gallbladder effects were assessed in CD-1 mice fed normal chow and given RDX8940 or a systemic TGR5 agonist or vehicle. Our results showed that RDX8940 is minimally systemic, potent, and selective, and induces incretin (GLP-1, GLP-2, and peptide YY) secretion. RDX8940-induced increases in plasma active GLP-1 (aGLP-1) levels were enhanced by repeated dosing and by coadministration of DPP4 inhibitors. RDX8940 increased hepatic exposure to aGLP-1 without requiring coadministration of a DPP4 inhibitor. In mice fed a Western diet, RDX8940 improved liver steatosis and insulin sensitivity. Unlike systemic TGR5 agonists, RDX8940 did not inhibit gallbladder emptying. These results indicate that RDX8940 may have therapeutic potential in patients with NAFLD/NASH.NEW & NOTEWORTHY Takeda G protein-coupled receptor 5 (TGR5) agonists have potential as a treatment for nonalcoholic steatohepatitis and nonalcoholic fatty liver disease (NAFLD) but have until now been associated with undesirable side effects associated with systemic TGR5 agonism, including blockade of gallbladder emptying. We demonstrate that RDX8940, a potent, selective, minimally systemic oral TGR5 agonist, improves liver steatosis and insulin sensitivity in a mouse model of NAFLD and does not inhibit gallbladder emptying in mice.

Change in Populations of Macrophages Promotes Development of Delayed Gastric Emptying in Mice

Muscularis propria macrophages lie close to cells that regulate gastrointestinal motor function, including interstitial cells of Cajal (ICC) and myenteric neurons. In animal models of diabetic gastroparesis, development of delayed gastric emptying has been associated with loss of macrophages that express cytoprotective markers and reduced networks of ICC. Mice with long-term diabetes and normal gastric emptying have macrophages that express anti-inflammatory markers and have normal gastric ICC. Mice homozygous for the osteopetrosis spontaneous mutation in the colony-stimulating factor 1 gene (Csf1op/op) do not have macrophages; when they are given streptozotocin to induce diabetes, they do not develop delayed gastric emptying. We investigated whether population of the gastric muscularis propria of diabetic Csf1op/op mice with macrophages is necessary to change gastric emptying, ICC, and myenteric neurons and investigated the macrophage-derived factors that determine whether diabetic mice do or do not develop delayed gastric emptying. Wild-type and Csf1op/op mice were given streptozotocin to induce diabetes. Some Csf1op/op mice were given daily intraperitoneal injections of CSF1 for 7 weeks; gastric tissues were collected and cellular distributions were analyzed by immunohistochemistry. CD45+, CD11b+, F4/80+ macrophages were dissociated from gastric muscularis propria, isolated by flow cytometry and analyzed by quantitative real-time polymerase chain reaction. Cultured gastric muscularis propria from Csf1op/op mice was exposed to medium that was conditioned by culture with bone marrow-derived macrophages from wild-type mice. Gastric muscularis propria from Csf1op/op mice given CSF1 contained macrophages; 11 of 15 diabetic mice given CSF1 developed delayed gastric emptying and had damaged ICC. In non-diabetic Csf1op/op mice, administration of CSF1 reduced numbers of gastric myenteric neurons but did not affect the proportion of nitrergic neurons or ICC. In diabetic Csf1op/op mice given CSF1 that developed delayed gastric emptying, the proportion of nitrergic neurons was the same as in non-diabetic wild-type controls. Medium conditioned by macrophages previously exposed to oxidative injury caused damage to ICC in cultured gastric muscularis propria from Csf1op/op mice; neutralizing antibodies against IL6R or TNF prevented this damage to ICC. CD45+, CD11b+, and F4/80+ macrophages isolated from diabetic wild-type mice with delayed gastric emptying expressed higher levels of messenger RNAs encoding inflammatory markers (IL6 and inducible nitric oxide synthase) and lower levels of messenger RNAs encoding markers of anti-inflammatory cells (heme oxygenase 1, arginase 1, and FIZZ1) than macrophages isolated from diabetic mice with normal gastric emptying. In studies of Csf1op/op and wild-type mice with diabetes, we found delayed gastric emptying to be associated with increased production of inflammatory factors, and reduced production of anti-inflammatory factors, by macrophages, leading to loss of ICC.

Effects of electroacupuncture at acupoints with different nerve segments on gastric emptying in OT gene knockout mice

To observe the effects of electroacupuncture (EA) at acupoints with different nerve segments on gastric emptying in oxytocin (OT) gene knockout mice, and to explore the role of paraventricular nucleus OT in EA regulating gastric function. Twenty OT knockout mice and twenty wild-type mice (8-9 weeks old, male and female in half) were divided into a control group, a Zusanli (ST 36) group, a Neiguan (PC 6) group and a Weishu (BL 21) group randomly, 5 mice in each group. The mice in the control group received no acupuncture; the mice in the Zusanli (ST 36) group, Neiguan (PC 6) group and Weishu (BL 21) group were treated with EA at unilateral "Zusanli" (ST 36), "Neiguan" (PC 6) and "Weishu" (BL 21) for 15 min respectively. Subsequently, the mice were treated with intragastric administration with milk loaded with technetium-99m diethylene triamine pentaacetic acid (99mTc-DTPA), immediately followed by scanning of single photon emission computed tomography (SPECT) to test gastric emptying for 50 min; the original data was collected and analyzed to obtain the half gastric emptying time (GET 1/2), 50-min stomach residue rate and gastric emptying curve. The wild-type mice group:compare with the control group, after EA at "Zusanli" (ST 36) and "Neiguan" (PC 6), the GET 1/2 and 50-min stomach residue rate were significantly reduced, which could improve the gastric emptying of wild-type mice (P<0.01, P<0.05); after EA at "Weishu" (BL 21), the GET 1/2 and 50-min stomach residue rate were significantly increased, which could inhibit the gastric emptying of wild-type mice (P<0.01, P<0.05). The OT gene knockout mice group:compared with the control group, EA at "Zusanli" (ST 36) and "Neiguan" (PC 6) had no significant effects on gastric emptying (both P>0.05); after EA at "Weishu" (BL 21), the GET 1/2 and 50-min stomach residue rate were significantly increased, which could inhibit the gastric emptying of OT gene knockout mice (both P<0.01). Gastric emptying curve:the gastric emptying of OT gene knockout mice was significantly faster than that of wild-type mice. The effects of EA at acupoints with different nerve segments on gastric emptying in mice are different, and the knockout of OT gene could accelerate the gastric emptying, and influence the acupuncture effect of several acupoints. It is suggested the paraventricular nucleus OT neurons, as the initiating device of autonomic nervous pathways, might participate in EA regulating the gastric function to inhibit the gastric emptying, with the form of neural and neuroendocrine.

Evaluation of anti-diabetic effect and gall bladder function with 2-thio-5-thiomethyl substituted imidazoles as TGR5 receptor agonists

A novel series of 2-thio-5-thiomethyl substituted imidazoles was discovered to be potent TGR5 agonists that possessed glucose-lowering effects while inhibiting gall bladder emptying in mice.

Circulating Ghrelin Acts on GABA Neurons of the Area Postrema and Mediates Gastric Emptying in Male Mice.

Ghrelin is known to act on the area postrema (AP), a sensory circumventricular organ located in the medulla oblongata that regulates a variety of important physiological functions. However, the neuronal targets of ghrelin in the AP and their potential role are currently unknown. In this study, we used wild-type and genetically modified mice to gain insights into the neurons of the AP expressing the ghrelin receptor [growth hormone secretagogue receptor (GHSR)] and their role. We show that circulating ghrelin mainly accesses the AP but not to the adjacent nucleus of the solitary tract. Also, we show that both peripheral administration of ghrelin and fasting induce an increase of c-Fos, a marker of neuronal activation, in GHSR-expressing neurons of the AP, and that GHSR expression is necessary for the fasting-induced activation of AP neurons. Additionally, we show that ghrelin-sensitive neurons of the AP are mainly γ-aminobutyric acid (GABA)ergic, and that an intact AP is required for ghrelin-induced gastric emptying. Overall, we show that the capacity of circulating ghrelin to acutely induce gastric emptying in mice requires the integrity of the AP, which contains a population of GABA neurons that are a target of plasma ghrelin.

Anethole restores delayed gastric emptying and impaired gastric accommodation in rodents

Functional dyspepsia (FD), a functional gastrointestinal disorder, is characterized by persistent or recurrent postprandial upper abdominal discomfort and epigastric pain. The high prevalence of FD and associated healthcare costs suggests that treatment of this condition by methods other than prescribed medicines, such as natural products, could be beneficial. Delayed gastric emptying and impaired gastric accommodation play important roles in the development of FD. Anethole (1-methoxy-4-((E)-propenyl)-benzene), a major component of essential fennel oil, has been used as a flavoring, in alcoholic beverage production and in pharmaceutical formulations for many years. In this study, we examined the effects of anethole on delayed gastric emptying and impaired gastric accommodation in rodents. Oral administration of anethole improved clonidine-induced delayed gastric emptying but did not affect normal gastric emptying in mice. Fennel oil and Anchu-san (a Japanese herbal medicine containing anethole) also restored delayed gastric emptying. Furthermore, oral administration of anethole stimulated gastric accommodation in rats. These results suggest that anethole could be beneficial for the treatment of FD.

Fasting does not induce gastric emptying in rats

To evaluate the effect of fasting on gastric emptying in mice. Twenty-eight mice were distributed into three study groups: a normal group (N=4): normal standard animals; a total fasting group (N=12): subjected to food and water deprivation and a partial fasting group (N=12): subjected to food deprivation only. The fasting groups were subdivided into three subgroups of four animals each, according to the date of euthanasia: 24, 48 and 72 hours. Was analyzed: the gastric volume, degree of the gastric wall distention and the presence of food debris in gastrointestinal tract. The mean gastric volume was 1601 mm3 in the normal group, 847 mm3 in total fasting group and 997 mm3 in partial fasting group. There was difference between the fasting groups in any analyzed period (p<0.05). Regarding the presence of food debris in the gastrointestinal tract and the degree of distension of the stomach, there was no difference between the groups that underwent total or partial fasting (p>0.05). Total fasting or only-solids deprivation does not induce gastric emptying in mice.

Endogenous elevation of plasma cholecystokinin does not prevent gallstones.

Regular gall bladder contraction reduces bile stasis and prevents gallstone formation. Intraduodenal administration of exogenous pancreatic secretory trypsin inhibitor-I (PSTI-I, also known as monitor peptide) causes cholecystokinin (CCK) secretion. We proposed that stimulation of CCK release by PSTI would produce gall bladder contraction and prevent gallstones in mice fed a lithogenic diet. Therefore, we tested the effect of overexpression of rat PSTI-I in pancreatic acinar cells on plasma CCK levels and gall bladder function in a transgenic mouse line (TgN[Psti1]; known hereafter as PSTI-I tg). Importantly, PSTI tg mice had elevated fasting and fed plasma CCK levels compared to wild-type (WT) mice. Only mice fed the lithogenic diet developed gallstones. Both fasting and stimulated plasma CCK levels were substantially reduced in both WT and PSTI-I tg mice on the lithogenic diet. Moreover, despite higher CCK levels PSTI-I tg animals developed more gallstones than WT animals. Together with the previously observed decrease in CCK-stimulated gall bladder emptying in mice fed a lithogenic diet, our findings suggest that a lithogenic diet causes gallstone formation by impaired CCK secretion in addition to reduced gall bladder sensitivity to CCK.

Pharmacological reduction of mucosal but not neuronal serotonin opposes inflammation in mouse intestine

ObjectiveEnterochromaffin cell-derived serotonin (5-HT) promotes intestinal inflammation. We tested hypotheses that peripheral tryptophan hydroxylase (TPH) inhibitors, administered orally, block 5-HT biosynthesis and deplete 5-HT from enterochromaffin cells sufficiently to ameliorate...