Comparison of the effects of T-1815, yohimbine and naloxone on mouse colonic propulsion

Effects of probiotics on loperamide-induced constipation in rats

The role of probiotics in mitigating constipation, gut immunity, and gut microbiota has not been well studied. We aimed to evaluate the effects of probiotics on loperamide (LP)-induced constipation in Sprague-Dawley rats. Altogether, 150 male Sprague-Dawley rats (age 8 weeks) were used in the experiments following a 12-day acclimatisation period and were randomly divided into three treatment groups (groups 1, 2, and 3). Spastic constipation was induced via oral LP administration (3 mg/kg) for 6 days, 1 h before administering each test compound in groups 1 and 2. A probiotic solution (4 mL/kg body weight) was orally administered once a day for 6 days in group 2. In group 1, a phosphate buffer solution was orally administered once a day for 6 days, 1 h after each LP administration. In group 3, a phosphate buffer solution was orally administered once a day for 6 days. In the probiotic group, faecal parameters improved; faecal n-butyric acid, acetic acid, and IgA concentrations were increased; intestinal transit time was shortened; and disturbance of intestinal microbiota was inhibited. Our findings suggest that this probiotic was useful in improving various symptoms caused by constipation.

Aster tataricus alleviates constipation by antagonizing the binding of acetylcholine to muscarinic receptor and inhibiting Ca2+ influx

BACKGROUND

The dried root and rhizome of Aster tataricus (RA), is a traditional Chinese medicine has been used for more than 2000 years with the function of antitussive, expectorant and antiasthmatic. Ancient books and modern pharmacological researches demonstrated that RA may have the function of moistening intestines and relieving constipation, but there was a lack of systematic evidence. The aim of this study was to comprehensively evaluate the efficacy and possible mechanisms of ethanol extract of Aster tataricus (ATE) in treating constipation from in vivo to in vitro.

METHODS

In vivo, the ATE was studied in loperamide-induced constipation of mice. In vitro, different concentrations of ATE was tested separately or cumulatively on spontaneous and agonists-induced contractions of isolated rat duodenum strips.

RESULTS

In vivo, at doses of 0.16, 0.8 g/mL, ATE showed significantly promotion of the small intestinal charcoal transit, decrease of the amount of remnant fecal, and increase of the content of fecal water in colon. In addition, ATE could effectively relieve colonic pathological damage caused by loperamide as well. In vitro, with the cumulative concentration increase of ATE from 0.8 to 6.4 mg/mL, it could significantly decrease the contraction caused by KCl or Ach, and gradually restore to near base tension value.Meanwhile, it could also partially but significantly inhibit the contractions induced by Ach and CaCl2 on rat duodenum in a concentration related manner.

CONCLUSIONS

Taking all these findings together, it could be speculated that ATE may attenuate constipation mainly through antagonizing the binding of acetylcholine to muscarinic receptor, inhibiting Ca2+ influx and anti-inflammation.

Changes in the Gut Microbiome after Galacto-Oligosaccharide Administration in Loperamide-Induced Constipation

Unbalanced dietary habits and the consumption of high protein and instant foods cause an increase in constipation. Here, we evaluated the effects of galacto-oligosaccharide (GOS) on a rat model of loperamide-induced constipation by measuring various biological markers and cecal microbiota. The fecal water content and intestinal transit ratio significantly increased in the GOS-administered (GL and GH) groups than in the control group (p < 0.05, p < 0.01, and p < 0.001, respectively). The length of intestinal mucosa (p < 0.05 and p < 0.01, respectively) and area of crypt cells were (p < 0.01, both) significantly increased in the GOS-administered groups compared to the control group. The distribution of interstitial cells of Cajal, which is related to the intestinal movement, showed a significant increase in GOS-administered groups than in the control group (p < 0.01, both). The relative abundance of lactic acid bacteria (LAB), especially Lactobacillus and Lactococcus, significantly increased in the GL group than in the control group. Furthermore, there was a positive correlation between short chain fatty acids (SCFAs) and the gut microbiota in the GL groups. These results demonstrated that GOS administration effectively alleviates constipation by increasing LAB proliferation in the intestinal microbiota and SCFA production.

Lactobacillus paracasei subsp. paracasei NTU 101 lyophilized powder improves loperamide-induced constipation in rats

Constipation is a condition of the digestive system characterized by formation of hard feces that are difficult to eliminate. It has emerged as a new problem that is commonly encountered by many people and lifestyle changes have been unsuccessful in providing a solution. This study aimed to investigate the effects of Lactobacillus paracasei subsp. paracasei NTU 101 on loperamide-induced constipated rats and on gastrointestinal tract function. Sprague-Dawley rats were administered loperamide (2 mg/kg BW) twice daily as well as 1.3, 2.6, and 13.0 mg/kg BW/rat/d of NTU 101 powder. The control, positive control, and NTU 101 powder groups (0.5, 1, 5×) showed improved intestinal mobility with a statistically significant increase of 12.4%, 14.7%, 12.5%, 13.4%, and 15.1%, respectively (p < 0.05); the fecal water content was also significantly increased by 11.7%, 9.0%, 10.0%, 9.3%, and 11.0%, respectively (p < 0.05), compared to the loperamide group. Furthermore, NTU 101 increased the Bifidobactrium spp. and decreased the Clostridium perfringens content in feces; it increased short-chain fatty acid levels, reduced fecal pH value, enhanced the thickness of the colonic mucosa, and increased the number of mucin-producing goblet cells and interstitial cells of Cajal. Thus, NTU 101 powder was found to alleviate loperamide-induced constipation and improve gastrointestinal tract function.

Antioxidant and laxative effects of taurine-xylose, a synthetic taurine-carbohydrate derivative, in loperamide-induced constipation in Sprague-Dawley rats

PURPOSE

In this study, we examined the in vitro antioxidant activities and laxative effects of taurine-xylose (T-X), a synthetic taurine-carbohydrate derivative, in a rat model of constipation induced by loperamide.

METHODS

The animals were divided into four treatment groups: normal untreated rats (NOR group), loperamide-treated control rats (CON group), loperamide and taurine-xylose (15 mg/kg)-treated rats (T-X group), and loperamide and commercial Dulcolax S (5.5 mg/kg)-treated rats (DS group).

RESULTS

In the present study, T-X exhibited potent reducing power and free radical scavenging activities for DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS+ (2,2'-azino-bis (3-ethylbenzothiazoline 6-sulfonic acid ammonium salt) radicals. The laxative effects of T-X were dependent on food, body weight, fecal properties, gastrointestinal transit (GIT) ratio, and serum metabolic parameters. In the T-X group, the number, wet weight, and water content of fecal pellets were noticeably increased compared to those in the loperamide-induced group. T-X treatment significantly increased the activities of hepatic antioxidant enzymes, including those of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT), relative to those in loperamide-induced constipated rats. Furthermore, the GIT ratio and loperamide-induced metabolic parameters in serum, including gastrin (GAS), motilin (MTL), and somatostatin (SS) levels, were significantly improved by T-X treatment.

CONCLUSION

These results suggest that taurine-xylose exerts antioxidant activities and laxative effects on loperamide-induced constipation by promoting gastrointestinal motility.

Laxative effects of triple fermented barley extracts (FBe) on loperamide (LP)-induced constipation in rats

BACKGROUND

Constipation, a common health problem, causes discomfort and affects the quality of life. This study intended to evaluate the potential laxative effect of triple fermented barley (Hordeum vulgare L.) extract (FBe), produced by saccharification, Saccharomyces cerevisiae, and Weissella cibaria, on loperamide (LP)-induced constipation in Sprague-Dawley (SD) rats, a well-established animal model of spastic constipation.

METHODS

Spastic constipation was induced via oral treatment with LP (3 mg/kg) for 6 days 1 h before the administration of each test compound. Similarly, FBe (100, 200 and 300 mg/kg) was orally administered to rats once a day for 6 days. The changes in number, weight, and water content of fecal, motility ratio, colonic mucosa histology, and fecal mucous contents were recorded. The laxative properties of FBe were compared with those of a cathartic stimulant, sodium picosulfate. A total of 48 (8 rats in 6 groups) healthy male rats were selected and following 10 days of acclimatization. Fecal pellets were collected one day before administration of the first dose and starting from immediately after the fourth administration for a duration of 24 h. Charcoal transfer was conducted after the sixth and final administration of the test compounds.

RESULTS

In the present study, oral administration of 100-300 mg/kg of FBe exhibited promising laxative properties including intestinal charcoal transit ratio, thicknesses and mucous producing goblet cells of colonic mucosa with decreases of fecal pellet numbers and mean diameters remained in the lumen of colon, mediated by increases in gastrointestinal motility.

CONCLUSION

Therefore, FBe might act as a promising laxative agent and functional food ingredient to cure spastic constipation, with less toxicity observed at a dose of 100 mg/kg.

Anti-Inflammatory Response and Muscarinic Cholinergic Regulation during the Laxative Effect of Asparagus cochinchinensis in Loperamide-Induced Constipation of SD Rats

Several types of saponins and herbal plants containing saponins have been reported to have anti-inflammatory or laxative activities. To verify the therapeutic effects of saponin-enriched extracts of Asparagus cochinchinensis (SPA) on the anti-inflammatory response and on the cholinergic regulation in the gastrointestinal system, an alteration on the constipation phenotypes, on the inflammatory responses, and on the muscarinic cholinergic regulation were investigated in the transverse colons of Sprague Dawley (SD) rats with loperamide (Lop)-induced constipation after the treatment of SPA. Significant increases were observed on the total number of stools, the gastrointestinal transit, the thickness of the mucosal layer, the flat luminal surface, the number of paneth cells, and the lipid droplets in the Lop + SPA-treated group as compared to the Lop + Vehicle-treated group. SPA treatment induced the recovery of inflammatory cytokines (TNF-α, IL-1β) and IL-6), inflammatory mediators (NF-κB and iNOS), the total number of infiltered mast cells, and mucin secretion. Also, some similar improvements were observed on the levels of acetylcholine esterase (AChE) activity and on the phosphorylation of myosin light chains (MLC) as well as the expression of muscarinic acetylcholine receptors M2/M3 (mAChR M2/M3) and their mediators. The results presented herein provide the first strong evidence that SPA stimulates anti-inflammatory responses and the muscarinic cholinergic regulation when exerting its laxative effects in the chronic constipation of Lop-induced models.

Laxative Effects of Taurine on Loperamide-Induced Constipation in Rats

In the present study, we investigated the laxative effects of taurine in a rat model of loperamide-induced constipation. Rats were divided into six groups of six animals each: normal (NOR), control (CON), loperamide + Dulcolax (5.5 mg/kg, p.o.), and loperamide + various doses of taurine (7.5, 15, and 30 mg/kg, p.o.). Laxative activity was determined based on body weight, feeding characteristics, fecal properties, gastrointestinal transit (GIT) ratio, and the levels of serum gastrointestinal hormones. Taurine supplementation significantly increased the number, wet weight, and water content of fecal pellets in rats with loperamide-induced constipation. GIT ratio and loperamide-induced serum metabolic parameters, such as gastrin (GAS), motilin (MTL), and somatostatin (SS) significantly changed after supplementation with taurine in loperamide-induced constipated rats. We suggest that taurine had a potent effect against loperamide-induced constipation in part by increasing gastrointestinal motility.

Therapeutic effect of protease-activated receptor 2 agonist SLIGRL-NH2 on loperamide-induced Sprague-Dawley rat constipation model and the related mechanism

Purpose

To investigate the therapeutic effects of protease-activated receptor 2 (PAR-2) agonist SLIGRL-NH₂ on loperamide-induced Sprague-Dawley (SD) rat constipation animal models.

Materials and methods

Loperamide was injected subcutaneously to induce constipation twice a day for 3 days. SD rats (n = 30) were randomly divided into five groups: non-constipation group (control, n = 6), constipation group (constipation, n = 6), constipation + SLIGRL-NH₂ low-dosage group (SLIGRL-NH₂ low, n=6), constipation + SLIGRL-NH₂ high-dosage group (SLIGRL-NH₂ high, n = 6), and constipation + prucalopride (positive control, n = 6). The SLIGRL-NH₂ low group and SLIGRL-NH₂ high group were administered with 2.5 μmol/kg and 5 μmol/kg SLIGRL-NH₂, respectively, and the prucalopride group received 2 mg/kg prucalopride. The control and constipation group received 1× PBS under the same pattern. SLIGRL-NH₂ and prucalopride were orally administrated once daily for 7 days. On the final day of oral administration, food intake, water intake, the number of stool pellets, weight, and fecal water content was calculated; moreover, the colons of rats in different groups were collected and histological features were examined by hematoxylin and eosin staining; furthermore, the expression of anoctamin-1 was determined by Immunohistochemical methods, and the expressions of c-kit and PAR-2 were examined using real-time quantitative polymerase chain reaction and Western blot methods; finally, the expressions of neurotransmitter vasoactive intestinal peptide (VIP) and substance P (SP) were examined using enzyme-linked immuno-sorbent assay methods.

Results

The feeding and excretion behaviors, intestinal transit ratio, and the histological feature of the colon in the constipated rats were all improved by SLIGRL-NH₂ treatment; moreover, SLIGRL-NH₂ treatment induced significant increase in the expression of PAR-2 and also increased number of interstitial Cajal cells. Furthermore, SLIGRL-NH₂ also decreased the contents of the inhibitory neurotransmitter VIP and increased the expression of the excitatory neurotransmitter SP. High dose of SLIGRL-NH₂ has shown similar anti-constipation effects as prucalopride.

Conclusion

These results suggested that SLIGRL-NH₂ can enhance gastrointestinal transit and alleviate in rats with loperamide-induced constipation.

Naringenin induces laxative effects by upregulating the expression levels of c-Kit and SCF, as well as those of aquaporin 3 in mice with loperamide-induced constipation

Constipation is a common affliction which causes discomfort and affects the quality of life of affected individuals. Naringenin (NAR), a natural flavonoid widely found in citrus fruits and tomatoes, has been reported to exhibit various pharmacological effects, such as anti-inflammatory, anti-atherogenic, anti-mutagenic, hepatoprotective and anticancer effects. Increasing evidence has indicated that NAR has potential for use in the treatment of constipation. Thus, the aim of this study was to evaluate the laxative effects of NAR in mice with loperamide-induced (Lop-induced) constipation. The data indicated that NAR relieved Lop-induced constipation in mice based on the changes of fecal parameters (numbers, weight and water content), the intestinal charcoal transit ratio and the histological alteration. ELISA revealed that NAR regulated the production levels of gastrointestinal metabolic components, such as motilin (MTL), gastrin (Gas), endothelin (ET), substance P (SP), acetylcholinesterase (AChE) and vasoactive intestinal peptide (VIP) in serum. The expression levels of enteric nerve-related factors, glial cell line-derived neurotrophic factor (GDNF), transient receptor potential vanilloid 1 (TRPV1), nitric oxide synthase (NOS), c-Kit, stem cell factor (SCF) and aquaporin 3 (AQP3) were examined by western blot analysis and RT-PCR analysis. The results of this study suggest that NAR relieves Lop-induced constipation by increasing the levels of interstitial cells of Cajal markers (c-Kit and SCF), as well as AQP3. Thus, NAR may be effective as a candidate in patients suffering from lifestyle-induced constipation.

Vinblastine, an anticancer drug, causes constipation and oxidative stress as well as others disruptions in intestinal tract in rat

The purpose of this study is to examine the gastrointestinal disorders after injection of vinblastine (2 mg kg^-1 b.w. i.v.) in rats. Animals were divided into two equal groups: Group 1 was considered as a control group (NaCl, 0.9%). Group 2 was treated with intravenous injection of vinblastine for 7 days. Loperamide (2 mg kg^-1) was injected in a saline solution subcutaneously to induce constipation in another group of rats during the same period. Fecal parameters of the different groups have been determined. At the end of the experiment, animals were anaesthetized and sacrificed by decapitation. The intestinal mucosa specimens were examined for lipid peroxidation, sulfhydryl groups (-SH) and protein carbonylation as well as antioxidant enzyme activities and intracellular mediators. Gastrointestinal motility was realized by the test meal (10% charcoal in 5% gum arabic). In result, statistically significant decreases in the fecal number and water content collected during 24 h were detected in the vinblastine group, but less important than loperamide control group. The animals treated with vinblastine, showed also a significant decrease (13%) of GIT, lower than that of loperamide (34%). The intestinal tissues from vinblastine-treated rats were showed a significant increase in lipoperoxydation and H₂O₂ production as well as a significant depletion of enzymatic and non-enzymatic antioxidants. Added to that, a disruption of intracellular iron and calcium levels was observed. Therefore, the present study provide the first strong evidence that vinblastine induced numerous disruptions in gastrointestinal which are related to oxidative stress and intracellular mediators disorders.

Uridine stimulate laxative effect in the loperamide-induced constipation of SD rats through regulation of the mAChRs signaling pathway and mucin secretion

Background

Uridine (Urd), which has been reported as a major component of RNA, plays an important role in various biological process including neuroprotection, biochemical modulation and glycolysis, although its role in constipation has yet to be established. Therefore, in this study, we investigated the laxative effects of Urd on chronic constipation.

Methods

The constipation phenotypes and their related mechanisms were investigated in the transverse colons of SD rats with loperamide (Lop)-induced constipation after treatment with 100 mg/kg of Urd.

Results

The number, weight and water contents of stools were significantly higher in the Lop + Urd treated group than the Lop + Vehicle treated group, while food intake and water consumption of the same group were maintained at a constant level. The thickness of the mucosa layer, muscle and flat luminal surface, as well as the number of goblet cells, paneth cells and lipid droplets were enhanced in the Lop + Urd treated group. Furthermore, the expression of the muscarinic acetylcholine receptors M2 and M3 (mAChR M2 and M3) at the transcriptional and translational level was recovered in the Lop + Urd treated group, while some markers such as Gα and inositol triphosphate (IP3) in their downstream signaling pathway were completely recovered by Urd treatment. Moreover, the ability for mucin secretion and the expression of membrane water channel (aquaporine 8, AQP8) were increased significantly in the Lop + Urd treated group compared with Lop + Vehicle treated group. Finally, the activity of Urd was confirmed in primary smooth muscle of rat intestine cells (pRISMC) based on Gα expression and IP3 concentration.

Conclusions

The results of the present study provide the first strong evidence that Urd can be considered an important candidate for improving chronic constipation induced by Lop treatment in animal models.

Toxicological implications and laxative potential of ethanol root extract of Morella serrata in loperamide-induced constipated Wistar rats

CONTEXT

Morella serrata L. (Myricaceae) is commonly used in South Africa to treat several diseases including constipation.

OBJECTIVES

This study investigated toxicological implications and laxative potential of the ethanol root extract of the plant.

MATERIALS AND METHODS

While normal control animals were placed on sterile placebo, the loperamide-constipated rats were treated with the extract at 75, 150 and 300 mg/kg doses for 7 days, and their feeding patterns and faecal properties were monitored. Gastrointestinal transit ratio and the toxicity profile of the tested doses were thereafter evaluated.

RESULTS

The significantly increased faecal volume (192.08%), feed (63.63%), water intake (55.97%) and improved intestinal motility (95.05%) in the constipated rats following treatment with the extract (at 300 mg/kg) suggested laxative potential of the extract. The 1.5-2.0-fold normalization of the platelets, erythrocytes and leukocytes counts in the extract-treated constipated rats suggests its non-haematotoxic tendency. Furthermore, the extract (at the highest investigated dose) reversed the attenuation in the concentrations of the electrolytes (0.5-2-fold), total protein (62.12%) and albumin (55.88%) in the constipated animals as well as attenuated activities of hepatic enzymes (0.5-3.0-fold) and levels of urea (126.67%), creatinine (40.32%), cholesterol (3-fold) and triglycerides (9-fold). These further support its non-toxic and therapeutic attributes against constipation.

CONCLUSION

Overall, the effect exhibited by M. serrata in this study competed well with Senokot (standard drug) and proved that it may be relatively safe and with excellent laxative potential, thus, supporting its pharmacological applications in South Africa.

Constipation enhances the propensity to seizure in pentylenetetrazole-induced seizure models of mice

Epilepsy is characterized by spontaneous recurrent seizures and represents one of the most frequent neurological diseases, affecting about 60 million people worldwide. The cellular and neurocircuit bases of epilepsy are poorly understood. Constipation is a common gastrointestinal disorder characterized by symptoms such as straining, hard stool, and infrequent defecation. Population-based studies have shown that the prevalence of constipation is up to 30% of the population in developed countries. The causal link between seizure and constipation is a common belief among patients and physicians, but there are no scientific data to support this association. The current investigation evaluated the effects of constipation induced by loperamide (a peripheral μ-opioid receptor agonist without effect on central nervous system receptors) and clidinium (a quaternary amine antimuscarinic agent with reduced central nervous system effects) on two different seizure models of mice: (1) myoclonic, clonic, and generalized tonic seizures and death induced by intraperitoneal administration of pentylenetetrazole and (2) clonic seizure threshold induced by intravenous infusion of pentylenetetrazole. We demonstrated that the measured intestinal transit (%intestinal transit) decreased after loperamide or clidinium treatment for 3days. Constipation in mice which was induced by loperamide or clonidine caused a decrease in threshold to clonic seizure in the intravenous pentylenetetrazole seizure model. Moreover loperamide- or clidinium-induced constipation decreased latencies to, clonic, and tonic seizures and death in the intraperitoneal pentylenetetrazole model of mice. Serum ammonia levels were slightly elevated in both loperamide- and clidinium-treated mice. In conclusion, loperamide- or clidinium-induced constipated mice are more prone to seizure which might confirm the belief of patients and physicians about constipation as a trigger of seizure.

Laxative effects of fermented rice extract in rats with loperamide-induced constipation

Constipation is a common problem in males and females. The aim of the present study was to evaluate the laxative effects of fermented rice extract (FRe) on rats with loperamide-induced constipation. FRe (100, 200 and 300 mg/kg) was administered orally once per day for six days following 1 h loperamide treatment. The laxative effects of FRe were compared with those of sodium picosulfate (S. picosulfate). Following the induction of constipation in the rats, a marked decrease was observed in the fecal pellet number and water content discharged over 24 h, the surface mucus thickness in the colonic lumen, intestinal charcoal transit ratio, thickness of the colonic mucosa and the number of mucus-producing cells, while an increase was observed in the number of fecal pellets remaining in the colonic lumen and their mean diameter, as compared with the normal vehicle control rats. These conditions were significantly alleviated following the administration of the three doses of FRe when compared with the loperamide control group. However, the alleviating effects were lower than those of S. picosulfate, with the exception of the intestinal charcoal transit ratio. Similar effects on the intestinal charcoal transit ratio were detected for the three doses of FRe when compared with the S. picosulfate-treated rats. In conclusion, the results indicated that FRe exhibits a laxative effect without causing diarrhea, as compared with sodium picosulfate; thus, FRe may be effective as a complementary medicine in patients suffering from lifestyle-induced constipation.

Synergistic effect of fermented rice extracts on the probiotic and laxative properties of yoghurt in rats with loperamide-induced constipation

Aim. The objective was to evaluate the synergistic effects of fermented rice extracts (FRe) on the laxative and probiotic properties of yoghurt in rats with loperamide-induced constipation. Methods. After constipation induction, yoghurt containing FRe (BFRe; 0.05%, 0.1%, or 1%) was administered orally once per day for 6 days. Results. Loperamide treatment caused marked decreases in fecal pellet numbers and water content discharged, as well as in the surface mucosal thickness of the colonic lumen, intestinal charcoal transit ratio, thickness, and number of mucous-producing goblet cells in the colonic mucosa, whereas it increased the remnant fecal pellet number and the mean diameter of the colonic lumen. However, this loperamide-induced constipation was ameliorated by treatment with FRe, yoghurt single formula, or 0.05%, 0.1%, or 1% BFRe (10 mL/kg). Additionally, the viable numbers of Lactobacillus in the cecal contents and feces were markedly higher than those in constipated rats. Moreover, greater probiotic and laxative effects were detected in BFRe-treated rats than in rats treated with equivalent doses of yoghurt or FRe single formula. Conclusion. The results suggest that addition of FRe to liquid yoghurt will enhance the probiotic and beneficial laxative effects of yoghurt in the digestive tract, without causing side effects.

Metabolomics approach to serum biomarker for loperamide-induced constipation in SD rats

Loperamide has long been known as an opioid-receptor agonist useful as a drug for treatment of diarrhea resulting from gastroenteritis or inflammatory bowel disease as well as to induce constipation. To determine and characterize putative biomarkers that can predict constipation induced by loperamide treatment, alteration of endogenous metabolites was measured in the serum of Sprague Dawley (SD) rats treated with loperamide for 3 days using ¹H nuclear magnetic resonance (¹H NMR) spectral data. The amounts and weights of stool and urine excretion were significantly lower in the loperamide-treated group than the No-treated group, while the thickness of the villus, crypt layer, and muscle layer was decreased in the transverse colon of the same group. The concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatinine (Cr) were also slightly changed in the loperamide-treated group, although most of the serum components were maintained at a constant level. Furthermore, pattern recognition of endogenous metabolites showed completely separate clustering of the serum analysis parameters between the No-treated group and loperamide-treated group. Among 35 endogenous metabolites, four amino acids (alanine, glutamate, glutamine and glycine) and six endogenous metabolites (acetate, glucose, glycerol, lactate, succinate and taurine) were dramatically decreased in loperamide-treated SD rats. These results provide the first data pertaining to metabolic changes in SD rats with loperamide-induced constipation. Additionally, these findings correlate the changes in 10 metabolites with constipation.

Aqueous extracts of Liriope platyphylla induced significant laxative effects on loperamide-induced constipation of SD rats

Background

Liriope platyphylla has long been reported as a therapeutic drug for treatment of various human chronic diseases including inflammation, diabetes, neurodegenerative disorders, obesity, and atopic dermatitis. To investigate the laxative effects of L. platyphylla, alterations in excretion parameters, histological structure, mucin secretion, and related protein levels were investigated in rats with loperamide (Lop)-induced constipation after treatment with aqueous extract of L. platyphylla (AEtLP).

Methods

Alterations on constipation phenotypes were measured in rats with Lop-induced constipation after treatment with AEtLP using excretion parameter analysis, histological analysis, RT-PCR, western blot and transmission electron microscope (TEM) analysis.

Results

The amounts of stool and urine excretion were significantly higher in the Lop + AEtLP-treated group than in the Lop + vehicle-treated group, whereas food intake and water consumption were maintained at constant levels. AEtLP treatment also induced an increase in villus length, crypt layer, and muscle thickness in the constipation model. Total mucin secretion was higher in the Lop + AEtLP-treated group than in the Lop + vehicle-treated group, although mucin secretion per crypt was very similar among all groups. Furthermore, RT-PCR and western blot revealed a dramatic reduction of key factors level on the muscarinic acetylcholine receptors (mAChRs) signaling pathway in the Lop + AEtLP-treated group relative to the Lop + vehicle-treated group. Especially, the accumulation of lipid droplets in enterocytes of crypts following Lop treatment was improved to the level of the No-treated group in response to AEtLP treatment.

Conclusion

These results suggest that AEtLP improves constipation induced by Lop treatment through an increase in crypt layer and stimulation of lipid droplet secretions. These data are the first to show that the laxative effects of AEtLP are closely related to the down-regulation of mAchRs and their downstream signals.

Effect of colic vein ligature in rats with loperamide-induced constipation

Introduction. Medical treatment in chronic constipation is not always successful. Surgery is indicated in unresponsive selected severe cases. This study presents the distal venous colic ligation in rat as a novel surgical approach. Materials and Methods. 16 rats (study group) were evaluated in 3 phases of 6 days each: A (normal conditions), B (loperamide-induced constipation), and C (colic vein legation) and compared with rats treated in phase C with PEG 4,000 (control group). Blood biochemical and physiological parameters, daily fecal water content (FWC), and histological analysis were performed in all study phases. Results. No biochemical and physiological parameters changes were observed. FWC decreased in phase B and increased in phase C in both groups with a grow up to 2.3-fold in study group compared to control (P < 0.0001). Moreover, in study group, a high number of colonic goblet cells were detected (phase C versus phase B: P < 0.001) while no differences were registered in control. Conclusion. By ligature of the colic vein in constipated rats, an increase in FWC and goblet cells higher than in PEG treated rats was detected. The described surgical procedure appeared effective, simple, and safe; further studies in animal models, however, are necessary to assess its clinical applicability.

A novel peripherally restricted cannabinoid receptor antagonist, AM6545, reduces food intake and body weight, but does not cause malaise, in rodents

BACKGROUND AND PURPOSE

Cannabinoid CB(1) receptor antagonists reduce food intake and body weight, but clinical use in humans is limited by effects on the CNS. We have evaluated a novel cannabinoid antagonist (AM6545) designed to have limited CNS penetration, to see if it would inhibit food intake in rodents, without aversive effects.

EXPERIMENTAL APPROACH

Cannabinoid receptor binding studies, cAMP assays, brain penetration studies and gastrointestinal motility studies were carried out to assess the activity profile of AM6545. The potential for AM6545 to induce malaise in rats and the actions of AM6545 on food intake and body weight were also investigated.

KEY RESULTS

AM6545 binds to CB(1) receptors with a K(i) of 1.7 nM and CB(2) receptors with a K(i) of 523 nM. AM6545 is a neutral antagonist, having no effect on cAMP levels in transfected cells and was less centrally penetrant than AM4113, a comparable CB(1) receptor antagonist. AM6545 reversed the effects of WIN55212-2 in an assay of colonic motility. In contrast to AM251, AM6545 did not produce conditioned gaping or conditioned taste avoidance in rats. In rats and mice, AM6545 dose-dependently reduced food intake and induced a sustained reduction in body weight. The effect on food intake was maintained in rats with a complete subdiaphragmatic vagotomy. AM6545 inhibited food intake in CB(1) receptor gene-deficient mice, but not in CB(1)/CB(2) receptor double knockout mice.

CONCLUSIONS AND IMPLICATIONS

Peripherally active, cannabinoid receptor antagonists with limited brain penetration may be useful agents for the treatment of obesity and its complications.

The effect of Aloe ferox Mill. in the treatment of loperamide-induced constipation in Wistar rats

BACKGROUND

Constipation is the most common gastrointestinal complaint all over the world and it is a risk factor of colorectal cancer. In this study, the efficacy of aqueous leaf extract of Aloe ferox Mill. was studied against loperamide-induced constipation in Wistar rats.

METHODS

Constipation was induced by oral administration of loperamide (3 mg/kg body weight) while the control rats received normal saline. The constipated rats were treated with 50, 100 and 200 mg/kg body weight/day of the extract for 7 days during which the feeding characteristics, body weight, fecal properties and gastrointestinal transit ratio were monitored.

RESULTS

The extract improved intestinal motility, increased fecal volume and normalized body weight in the constipated rats, which are indications of laxative property of the herb with the 200 mg/kg body weight of the extract showing the best efficacy.

CONCLUSION

The effect of the extract compares favourably well with senokot, a standard laxative drug. These findings have therefore, lent scientific credence to the folkloric use of the herb as a laxative agent by the people of the Eastern Cape of South Africa.

New views on antidiarrheal effect of wood creosote: is wood creosote really a gastrointestinal antiseptic?

Wood creosote, the principal ingredient in Seirogan, has a long history as a known gastrointestinal microbicidal agent. When administered orally, the intraluminal concentration of wood creosote is not sufficiently high to achieve this microbicidal effect. Through further animal tests, we have shown that antimotility and antisecretory actions are the principal antidiarrheal effects of wood creosote. Wood creosote inhibits intestinal secretion induced by enterotoxins by blocking the Cl(-) channel on the intestinal epithelium. Wood creosote also decreases intestinal motility accelerated by mechanical, chemical, or electrical stimulus by the inhibition of the Ca(2+) influx into the smooth muscle cells. In this overview, the antimotility and antisecretory effects of wood creosote are compared with those of loperamide. Wood creosote was observed to inhibit stimulated colonic motility, but not normal jejunal motility. Loperamide inhibits normal jejunal motility, but not stimulated colonic motility. Both wood creosote and loperamide inhibit intestinal secretion accelerated by acetylcholine. Wood creosote was found to have greater antisecretory effects in the colon than loperamide. Based upon these findings, we conclude that the antidiarrheal effects of wood creosote are due to both antisecretory activity in the intestine and antimotility in the colon, but not due to the microbicidal activity as previously thought. Wood creosote was found to have no effects on normal intestinal activity. These conclusions are supported by the results of a recent clinical study comparing wood creosote and loperamide, which concluded that wood creosote was more efficacious in relieving abdominal pain and comparable to loperamide in relieving diarrhea.

Comparison between partial agonist (ME3412) and antagonist (alosetron) of 5-hydroxytryptamine 3 receptor on gastrointestinal function

Therapeutic use of 5-hydroxytryptamine 3 (5-HT(3)) receptor antagonists for diarrhoea-predominant irritable bowel syndrome may be accompanied by constipation. We hypothesized that ME3412, 5-chloro-2-(1,4-diazacycloheptan-1-yl)-7-methylbenzoxazole, a novel partial agonist of the 5-HT(3) receptor, would minimize constipation without reducing antidiarrhoeal activity. Receptor binding studies showed that ME3412 is highly selective for the human 5-HT(3) receptor (K(i) = 1.51 nmol L(-1)). A 5-HT(3) receptor agonist, 2-methyl-5-HT, caused contractile response in the isolated guinea-pig ileum and accelerated secretion in the guinea-pig colonic mucosal preparation. ME3412 and 5-HT(3) receptor antagonist, alosetron, antagonized the 2-methyl-5-HT-induced responses with similar potency in insurmountable and surmountable manner, respectively. ME3412 caused weak agonism in isolated ileum strips and also in the colonic mucosa with intrinsic activity of 0.09 and 0.59, respectively. In conscious dogs, alosetron (3 microg kg(-1) i.v.) suppressed the migrating motor complex (MMC), whereas a relatively high dose (300 microg kg(-1)) of ME3412 was required for inhibition of MMC. ME3412 and alosetron suppressed 5-HT induced-diarrhoea in mice. In contrast, ME3412 did not significantly affect colonic propulsion compared with alosetron. These results imply that the partial agonist may relieve diarrhoea with low risk of inducing constipation.

Decreased colonic mucus in rats with loperamide-induced constipation

Constipation is a risk factor of colorectal cancer. Mucin is a major component of lumenal mucus, which protects the colorectal mucosa against mechanical and chemical damage. The aim of this study was to evaluate mucus production and to quantitate lumen mucus in a rat model of spastic constipation. We induced constipation with loperamide (1.5 mg/kg), and histochemically evaluated mucus production and the thickness of the mucus layer at the fecal surface. We quantitated the mucus attached to the mucosal surface using colonic perfusion with N-acetylcysteine. While more feces remained in the colon, there was less fecal excretion and lower fecal water content in loperamide-administered rats than in control rats. Crypt epithelial cells contained less mucus in constipated rats than in control rats. The mucus layer at the fecal surface was thinner and less mucus was recovered from the mucosal surface in constipated rats than in control rats. Mucus production of crypt epithelial cells and mucus at the fecal and mucosal surface were reduced by loperamide-induced constipation.

Short chain fatty acids but not lactate or succinate stimulate mucus release in the rat colon

BACKGROUND

Short chain fatty acids (SCFAs) affect various intestinal functions. Mucus is an important physiological component of the intestinal mucosal barrier. However, the effect of SCFAs or other organic acids on the intestinal mucus release is poorly understood. The aim of this study was to investigate whether lumen SCFA stimulates mucus release into the rat colon.

METHODS

A solution of SCFA, lactate or succinate was infused into the colon of anesthetized rats, and we then measured the hexose content of the effluent. We also examined the influence of cholinergic antagonists on the effects of SCFA.

RESULTS

A SCFA mixture (75 mM acetate, 35 mM propionate and 20 mM butyrate) or individual SCFAs (130 mM) increased the mucus release into the colon in a similar manner. The individual SCFAs, but not lactate or succinate, stimulated colonic mucus secretion in similar concentration-dependent manners. Butyrate stimulated colonic mucus secretion at 20 mM, but acetate, propionate, lactate and succinate at this concentration did not. Pretreatment with an anti-cholinergic agent diminished the stimulatory effects of SCFAs on mucus secretion.

CONCLUSIONS

Lumen SCFAs, but not lactate or succinate, stimulate mucus release from the rat colon via a cholinergic nerve mechanism.