Purinergic inhibitory regulation of esophageal smooth muscle is mediated by P2Y receptors and ATP-dependent potassium channels in rats.

Purines such as ATP are regulatory transmitters in motility of the gastrointestinal tract. The aims of this study were to propose functional roles of purinergic regulation of esophageal motility. An isolated segment of the rat esophagus was placed in an organ bath, and mechanical responses were recorded using a force transducer. Exogenous application of ATP (10-100 µM) evoked relaxation of the esophageal smooth muscle in a longitudinal direction under the condition of carbachol (1 µM) -induced precontraction. Pretreatment with a non-selective P2 receptor antagonist, suramin (500 µM), and a P2Y receptor antagonist, cibacron blue F3GA (200 µM), inhibited the ATP (100 µM) -induced relaxation, but a P2X receptor antagonist, pyridoxal phosphate-6-azophenyl-2,4-disulfonic acid (50 µM), did not affect it. A blocker of ATP-dependent potassium channels (KATP channels), glibenclamide (200 µM), inhibited the ATP-induced relaxation and application of an opener of KATP channels, nicorandil (50 µM), produced relaxation. The findings suggest that ATP is involved in inhibitory regulation of the longitudinal smooth muscle in the muscularis mucosae of the rat esophagus via activation of P2Y receptors and then opening of KATP channels.

Mechanism of Mulberry Leaves and Black Sesame in Alleviating Slow Transit Constipation Revealed by Multi-Omics Analysis.

Traditional Chinese medicine (TCM) possesses the potential of providing good curative effects with no side effects for the effective management of slow transit constipation (STC), an intestinal disease characterized by colonic dyskinesia. Mulberry leaves (Morus alba L.) and black sesame (Sesamum indicum L.), referred to as SH, are processed and conditioned as per standardized protocols. SH has applications as food and medicine. Accordingly, we investigated the therapeutic potential of SH in alleviating STC. The analysis of SH composition identified a total of 504 compounds. The intervention with SH significantly improved intestinal motility, reduced the time for the first black stool, increased antioxidant activity, and enhanced water content, thereby effectively alleviating colon damage caused by STC. Transcriptome analysis revealed the SH in the treatment of STC related to SOD1, MUC2, and AQP1. The analysis of 16S rRNA gene sequences indicated notable differences in the abundance of 10 bacteria between the SH and model. Metabolomic analysis further revealed that SH supplementation increased the levels of nine metabolites associated with STC. Integrative analysis revealed that SH modulated amino acid metabolism, balanced intestinal flora, and targeted key genes (i.e., SOD1, MUC2, AQP1) to exert its effects. SH also inhibited the AQP1 expression and promoted SOD1 and MUC2 expression.

Inhibition of calcium-sensing receptor by its antagonist promotes gastrointestinal motility in a Parkinson's disease mouse model.

BACKGROUND: The Calcium-sensing receptor (CaSR) participates in the regulation of gastrointestinal (GI) motility under normal conditions and might be involved in the regulation of GI dysmotility in patients with Parkinson's disease (PD). METHODS: CaSR antagonist-NPS-2143 was applied in in vivo and ex vivo experiments to study the effect and underlying mechanisms of CaSR inhibition on GI dysmotility in the MPTP-induced PD mouse model. FINDINGS: Oral intake of NPS-2143 promoted GI motility in PD mice as shown by the increased gastric emptying rate and shortened whole gut transit time together with improved weight and water content in the feces of PD mice, and the lack of influence on normal mice. Meanwhile, the number of cholinergic neurons, the proportion of serotonergic neurons, as well as the levels of acetylcholine and serotonin increased, but the numbers of nitrergic and tyrosine hydroxylase immunoreactive neurons, and the levels of nitric oxide synthase and dopamine decreased in the myenteric plexus in the gastric antrum and colon of PD mice in response to NPS-2143 treatment. Furthermore, the numbers of c-fos positive neurons in the nucleus tractus solitarius (NTS) and cholinergic neurons in the dorsal motor nucleus of the vagus (DMV) increased in NPS-2143 treated PD mice, suggesting the involvement of both the enteric (ENS) and central (CNS) nervous systems. However, ex vivo results showed that NPS-2143 directly inhibited the contractility of antral and colonic strips in PD mice via a non-ENS mediated mechanism. Further studies revealed that NPS-2143 directly inhibited the voltage gated Ca2+ channels, which might, at least in part, explain its direct inhibitory effects on the GI muscle strips. INTERPRETATION: CaSR inhibition by its antagonist ameliorated GI dysmotility in PD mice via coordinated neuronal regulation by both ENS and CNS in vivo, although the direct effects of CaSR inhibition on GI muscle strips were suppressive.

Huanglian-banxia promotes gastric motility of diabetic rats by modulating brain-gut neurotransmitters through MAPK signaling pathway.

BACKGROUND: Gastric motility disorder is an increasingly common problem among people with diabetes. Neurotransmitters have been recognized as critical regulators in the process of gastric motility. Previous study has shown that herb pair huanglian-banxia (HL-BX) can improve gastric motility, but the underlying mechanism is still unclear. The aim of this study was to further investigate the role of HL-BX in modulating brain-gut neurotransmission to promote gastric motility in diabetic rats, and to explore its possible mechanism. METHODS: The diabetic rats were divided into five groups. Gastric emptying rate, intestinal propulsion rate, body weight, and average food intake were determined. Substance P (SP), 5- hydroxytryptamine (5-HT), and glucagon-like peptide -1 (GLP-1) in the serum were measured by enzyme-linked immunosorbent assay. Dopamine (DA) and norepinephrine (NE) in the brain were analyzed by high-pressure liquid chromatography with a fluorescence detector. Protein expression of the tissues in the stomach and brain was determined by Western blot. KEY RESULTS: HL-BX reduced average food intake significantly, increased body weight, and improved gastric emptying rate and intestinal propulsion rate. HL-BX administration caused a significant increase in SP, GLP-1, and 5-HT, but a significant decrease in DA and NE. Interestingly, HL-BX regulated simultaneously the different expressions of MAPK and its downstream p70S6K/S6 signaling pathway in the stomach and brain. Moreover, berberine exhibited a similar effect to HL-BX. CONCLUSIONS: These results indicated that HL-BX promoted gastric motility by regulating brain-gut neurotransmitters through the MAPK signaling pathway. HL-BX and MAPK provide a potential therapeutic option for the treatment of gastroparesis.

Mind shift I: Fructus Aurantii - Rhizoma Chuanxiong synergistically anchors stress-induced depression-like behaviours and gastrointestinal dysmotility cluster by regulating psycho-immune-neuroendocrine network.

BACKGROUND: Researchers have not studied the integrity, orderly correlation, and dynamic openness of complex organisms and explored the laws of systems from a global perspective. In the context of reductionism, antidepressant development formerly focused on advanced technology and molecular details, clear targets and mechanisms, but the clinical results were often unsatisfactory. PURPOSE: MDD represents an aggregate of different and highly diverse disease subtypes. The co-occurrence of stress-induced nonrandom multimorbidity is widespread, whereas only a fraction of the potential clusters are well known, such as the MDD-FGID cluster. Mapping these clusters, and determining which are nonrandom, is vital for discovering new mechanisms, developing treatments, and reconfiguring services to better meet patient needs. STUDY DESIGN: Acute stress 15-minute forced swimming (AFS) or CUMS protocols can induce the nonrandom MDD-FGID cluster. Multiple biological processes of rats with depression-like behaviours and gastrointestinal dysmobility will be captured under conditions of stress, and the Fructus Aurantii-Rhizoma Chuanxiong (ZQCX) decoction will be utilized to dock the MDD-FGID cluster. METHODS/RESULTS: Here, Rhizoma Chuanxiong, one of the seven components of Chaihu-shugan-San, elicited the best antidepressant effect on CUMS rats, followed by Fructus Aurantii. ZQCX reversed AFS-induced depression-like behaviours and gastrointestinal dysmobility by regulating the glutamatergic system, AMPAR/BDNF/mTOR/synapsin I pathway, ghrelin signalling and gastrointestinal nitric oxide synthase. Based on the bioethnopharmacological analysis strategy, the determined meranzin hydrate (MH) and senkyunolide I (SI) by UPLC-PDA, simultaneously absorbed by the jejunum and hippocampus of rats, have been considered major absorbed bioactive compounds acting on behalf of ZQCX. Cotreatment with MH and SI at an equivalent dose in ZQCX synergistically replicated over 50.33 % efficacy of the parent formula in terms of antidepressant and prokinetic actions by modulating neuroinflammation and ghrelin signalling. CONCLUSION: Brain-centric mind shifts require the integration of multiple central and peripheral systems and the elucidation of the underlying neurobiological mechanisms that ultimately contribute to novel therapeutic options. Ghrelin signalling and the immune system may partially underlie multimorbidity vulnerability, and ZQCX anchors stress-induced MDD-FGID clusters by docking them. Combining the results of micro details with the laws of the macro world may be more effective in finding treatments for MDD.

Prokinetics-safety and efficacy: The European Society of Neurogastroenterology and Motility/The American Neurogastroenterology and Motility Society expert review.

BACKGROUND: Prokinetics are a class of pharmacological drugs designed to improve gastrointestinal (GI) motility, either regionally or across the whole gut. Each drug has its merits and drawbacks, and based on current evidence as high-quality studies are limited, we have no clear recommendation on one class or other. However, there remains a large unmet need for both regionally selective and/or globally acting prokinetic drugs that work primarily intraluminally and are safe and without systemic side effects. PURPOSE: Here, we describe the strengths and weaknesses of six classes of prokinetic drugs, including their pharmacokinetic properties, efficacy, safety and tolerability and potential indications.

Does L-carnitine prevent cadmium-induced damage in gastrointestinal contractility and histological changes in prepubertal rat / ¿La L-carnitina previene el daño inducido por cadmio en la contractilidad gastrointestinal y los cambios histológicos en ratas prepúberes?

SUMMARY: Cadmium (Cd) is the industrial and environmental toxic heavy metal which is found in air, water and soil. Cd, adversely affects many organs in humans such as kidney, intestine, liver, testis and lungs. L-carnitine (LC) is an important agent that plays essential role in energy metabolism. In our study, we aimed to work out whether LC application has any protective effect on intestinal contractility and morphologic damage of prepubertal rat duodenum on Cd-induced toxicity. Twenty eight prepubertal female Wistar rats were divided into four groups. The first group is control (C), second group; Cd group; Cadmium chloride was given 2 mg/kg 28 days with a one-day break by i.p. The third group; Cd+LC, which cadmium chloride was given 2 mg/kg i.p. and LC was given orally by gastric lavage. The LC dose was given as 75 mg/kg. The fourth group; LC, which only LC was given orally. The intestinal segments were isolated and suspended in tissue bath. Contractile responses were induced by acetylcholine (ACh) and relaxation was achieved with phenylephrine. Also the segments were examined for histological changes by light microscopy. Ach-induced contractions were higher in Cd+LC, LC, and control group compared to the Cd group in duodenal segments. The phenylephrine-induced relaxations were lower in Cd groups as compared with Control, Cd+LC and LC group in duodenal segments. In Cd group intestinal morphology was observed to be severely damaged whereas in Cd+LC group the damage was noticeably lower. Cd administration caused severe cellular damage and decreased gastrointestinal motility. Treatment with the LC has affected the gastrointestinal contractility and reduced the damage in intestinal morphology, which occured after Cd application.

El cadmio (Cd) es el metal pesado tóxico industrial y ambiental que se encuentra en el aire, el agua y el suelo. El Cd afecta negativamente a muchos órganos humanos, como los riñones, los intestinos, el hígado, los testículos y los pulmones. La L-carnitina (LC) es un agente importante que juega un rol esencial en el metabolismo energético. El objetivo de este estudio fue determinar si la aplicación de LC tiene algún efecto protector sobre la contractilidad intestinal y el daño morfológico del duodeno de rata prepuberal sobre la toxicidad inducida por Cd. Veintiocho ratas Wistar hembras prepúberes se dividieron en cuatro grupos. El primer grupo control (C), segundo grupo; grupo cd; Se administró cloruro de cadmio 2 mg/kg durante 28 días con un descanso de un día por vía i.p. El tercer grupo; Cd+LC, al que se administró cloruro de cadmio 2 mg/kg i.p. y LC se administró por vía oral mediante lavado gástrico. La dosis de LC se administró como 75 mg/kg. El cuarto grupo; LC, al cual solo LC se administraba por vía oral. Los segmentos intestinales fueron aislados y suspendieron en baño de tejido. Las respuestas contráctiles fueron inducidas por acetilcolina (ACh) y la relajación se logró con fenilefrina. También se examinaron los segmentos en busca de cambios histológicos mediante microscopía óptica. Las contracciones inducidas por Ach fueron mayores en Cd+LC, LC y el grupo control en comparación con el grupo Cd en los segmentos duodenales. Las relajaciones inducidas por fenilefrina fueron menores en los grupos Cd en comparación con el grupo Control, Cd+LC y LC en los segmentos duodenales. En el grupo Cd se observó que la morfología intestinal estaba severamente dañada mientras que en el grupo Cd+LC el daño fue notablemente menor. La administración de Cd causó daño celular severo y disminución de la motilidad gastrointestinal. El tratamiento con LC afectó la contractilidad gastrointestinal y redujo el daño en la morfología intestinal, que ocurría después de la aplicación de Cd.

Neuropilin 2 Is a Novel Regulator of Distal Colon Contractility.

Appropriate coordination of smooth muscle contraction and relaxation is essential for normal colonic motility. The impact of perturbed motility ranges from moderate, in conditions such as colitis, to potentially fatal in the case of pseudo-obstruction. The mechanisms underlying aberrant motility and the extent to which they can be targeted pharmacologically are incompletely understood. This study identified colonic smooth muscle as a major site of expression of neuropilin 2 (Nrp2) in mice and humans. Mice with inducible smooth muscle-specific knockout of Nrp2 had an increase in evoked contraction of colonic rings in response to carbachol at 1 and 4 weeks following initiation of deletion. KCl-induced contractions were also increased at 4 weeks. Colonic motility was similarly enhanced, as evidenced by faster bead expulsion in Nrp2-deleted mice versus Nrp2-intact controls. In length-tension analysis of the distal colon, passive tension was similar in Nrp2-deficient and Nrp2-intact mice, but at low strains, active stiffness was greater in Nrp2-deficient animals. Consistent with the findings in conditional Nrp2 mice, Nrp2-null mice showed increased contractility in response to carbachol and KCl. Evaluation of selected proteins implicated in smooth muscle contraction revealed no significant differences in the level of α-smooth muscle actin, myosin light chain, calponin, or RhoA. Together, these findings identify Nrp2 as a novel regulator of colonic contractility that may be targetable in conditions characterized by dysmotility.

Effect of the liquid form of traditional Chinese medicine, Hozen-S, on gastric motility in dogs.

Juzen-taiho-to, a traditional Chinese herbal medicine, is used for patients with anorexia and fatigue in human medicine. In our previous study, granulated Juzen-taiho-to improved vincristine-induced gastrointestinal adverse effects through increasing gastric motility in dogs. As the effect of Hozen-S, the sweet liquid form of Juzen-taiho-to, on dog gastric motility has not been investigated, we examined the effect of administration of Hozen-S on gastric motility. Furthermore, we assessed dog plasma ghrelin level to further elucidate the mechanism of the effect of Hozen-S on gastric contraction. Finally, we assessed the palatability of Hozen-S compared to granulated Juzen-taiho-to and its effect on body weight in dogs. Administration of Hozen-S significantly increased gastric motility, plasma ghrelin concentration, and body weight. A palatability evaluation revealed that the dogs preferred Hozen-S to granulated Juzen-taiho-to. In conclusion, Hozen-S administration to dogs promoted gastric motility by raising plasma ghrelin levels. Considering these functional and palatability data, Hozen-S may replace granulated type Juzen-taiho-to and become a prominent traditional Chinese veterinary medicament.

Bifidobacterium lactis BL-99 modulates intestinal inflammation and functions in zebrafish models.

This study was designed to explore the therapeutics and the mechanisms of a patented and marked gastric acid and intestine juice-resistant probiotics Bifidobacterium lactis BL-99 (B. lactis BL-99) on the intestinal inflammation and functions in the zebrafish models. After feeding for 6 hours, B. lactis BL-99 was fully retained in the larval zebrafish intestinal tract and stayed for over 24 hours. B. lactis BL-99 promoted the intestinal motility and effectively alleviated aluminum sulfate-induced larval zebrafish constipation (p < 0.01). Irregular high glucose diet induced adult zebrafish intestinal functional and metabolic disorders. After fed with B. lactis BL-99, IL-1ß gene expression was significantly down-regulated, and IL-10 and IL-12 gene levels were markedly up-regulated in this model (p < 0.05). The intestinal lipase activity was elevated in the adult zebrafish intestinal functional disorder model after B. lactis BL-99 treatment (p < 0.05), but tryptase content had no statistical changes (p > 0.05). B. lactis BL-99 improved the histopathology of the adult zebrafish intestinal inflammation, increased the goblet cell numbers, and up-and-down metabolites were markedly recovered after treatment of B. lactis BL-99 (p < 0.05). These results suggest that B. lactis BL-99 could relieve intestinal inflammation and promote intestinal functions, at least in part, through modulating intestinal and microbial metabolism to maintain intestinal health.

The underlying rationality of Chinese medicine herb pair Coptis chinensis and Dolomiaea souliei: From the perspective of metabolomics and intestinal function.

ETHNOPHARMACOLOGICAL RELEVANCE: The combination of Coptis chinensis (RC) and Dolomiaea souliei (VR) has long been used as a classic herb pair for the treatment of gastrointestinal diseases, but the underlying mechanisms remain unknown. MATERIALS AND METHODS: In this study, the rationality of evidence-based RC and VR combination was explored from the perspective of metabolism, gut microbiota and gastrointestinal function. RESULTS: After 5 weeks treatment, VR extracts (700 mg/kg) and RC alkaloids (800 mg/kg) showed no toxic effect on mice. However, RC administration significantly decreased the body weight of mice. Gastric emptying, gastrointestinal motility function and the absorption of FITC dextran were retarded in the mice of RC group, taking RC along with low dose VR (RC-VRL) and high dose VR (RC-VRH) reversed the impaired gastrointestinal function caused by RC. RC administration significantly increased villus height/crypt depth value. Notably, VR administration increased the number of crypts in mice ileum and reduced villus height/crypt depth value in VR and RC combination group. RC treatment significantly increased the expression of occludin compared to NC group; RC-VRL treatment reversed this tendency. While, VR administration increased ZO1 expression by 99.4% compared to NC mice. As for gut microbiota, RC gavage decreased the gut microbiota diversity, but gut microbiota in VR group was similar to NC group, and VR and RC combination increased gut microbiota diversity. RC administration obviously increased the proportion of Akkermansia muciniphila, Bacteroides thetaiotaomicron, Parabacteroides distasonis, and Escherichia coli, compared to NC mice. VR treatment increased the richness of Bacteroides thetaiotaomicron, Parabacteroides distasonis. RC-VRL and RC-VRH treatment dose-dependently increased the richness of Rikenellaceae RC9, Lactobacillus, and decreased the abundance of Psychrobacter, Bacteroides and Ruminococcus in mice. Serum metabolomic analysis revealed that RC gavage significantly down regulated 76 metabolites and up regulated 31 metabolites. VR treatment significantly down regulated 30 metabolites and up regulated 12 metabolites. Weight loss caused by RC may attribute to the elevated methylxanthine level in mice. The potential adverse effects caused by high dose RC intake may partially alleviate by high serum contents of adenosine, inosine and urolithin A resulted from VR coadministration. CONCLUSION: VR may alleviate RC caused "fluid retention" via normalizing gastrointestinal function, gut microbiota and modulating the perturbed metabolism.

Evaluation of the antidiarrheal activity of 80% methanol extract and solvent fractions of the leaf of Bersama abyssinica fresen (Melianthaceae) in mice.

INTRODUCTION: The use of traditional medicinal plants in the management of diarrhea has long been practiced in Ethiopia. B. abyssinica fresen is one of the plants traditionally used to treat diarrhea whereas an in vivo study had not yet been conducted. Thus, this study aimed to evaluate the antidiarrheal activity of crude extract and solvent fractions of the leaf of B. abyssinica in mice. METHODS: Cold maceration within 80% methanol was used to extract the leaf powder and extract of the leaf was fractionated using n-hexane, chloroform, and distilled water. The in vivo antidiarrheal activity of crude extracts and solvent fractions were tested in experimental models of castor oil-induced diarrhea, enteropooling, and antimotility test. Five groups each with 6 mice were used under the three antidiarrheal models. Positive controls were treated with loperamide 3 mg/kg and atropine 5 mg/kg and 2% tween 80 was used in the treatment of negative controls. The extract and solvent fractions were administered at doses of 100, 200, and 400 mg/kg. Time of onset of diarrhea, number and weight of total and wet feces, the percent reduction in the number of wet feces, weight and volume of intestinal contents, and percent inhibition of intestinal motility were recorded. Data were analyzed using SPSS version 20. RESULT: Defecation of castor oil-induced diarrheal or loose stools was inhibited (p < 0.01 to p < 0.001) at 200 mg/kg and 400 mg/kg of crude extract and aqueous fraction. The crude extract and the aqueous fraction at three doses (p < 0.01 to p < 0.001), the chloroform fraction at 200 mg/kg and 400 mg/kg (p < 0.01 to p < 0.001), and the n-hexane fraction at 400 mg/kg (p < 0.05) reduced intraluminal fluid accumulation compared with the negative control. Castor oil-induced intestinal motility was significantly suppressed with the three-doses of aqueous fraction (p < 0.05 to p < 0.001), 200 mg/kg and 400 mg/kg of crude extract (p < 0.05 to p < 0.01), 400 mg/kg of chloroform and n-hexane (p < 0.01 to p < 0.001) compared with negative control. CONCLUSION: The crude extract, aqueous, and chloroform fractions of B. abyyssinica leaves have promising anti-diarrheal effects, supporting the plant's traditional use to treat diarrhea.

Lemon balm (Melissa officinalis L.) essential oil and citronellal modulate anxiety-related symptoms - In vitro and in vivo studies.

ETHNOPHARMACOLOGICAL RELEVANCE: Besides psyche-related symptoms, patients with anxiety disorders can have a large number of somatic symptoms as well. Although the treatment of these disorders is mainly focused on resolving their mental component, one cannot neglect the need for the treatment of accompanying somatic symptoms. Melissa officinalis L. (lemon balm), in various formulations, has been extensively used as an ethnomedicinal remedy for the treatment of different psyche-related symptoms, and its use is considered relatively safe. AIM OF THE STUDY: In the present study, the activity of M. officinalis (MO) essential oil was evaluated in several in vitro and in vivo models mimicking or involving anxiety-related somatic symptoms. MATERIALS AND METHODS: To address the effect of MO essential oil on the gastrointestinal and heart-related symptoms accompanying anxiety disorders, in vitro models were utilized that follow the function of the isolated mouse ileum and atria tissues, respectively, after exposure to MO essential oil. Effects of MO essential oil on BALB/c mice motor activity was estimated using the open field, rota-rod, and horizontal wire tests. Additionally, the essential oil was assayed for its potential in inhibiting acetylcholinesterase activity. RESULTS: The performance of mice treated with 25 mg/kg of the oil showed a statistically significant decrease in the motor impairment arising from acute anxiety (open field test), while there was a prolonged latency and a reduction of the frequency of falling from a rotating rod and/or a horizontal wire (signs of muscle weakness/spasms). Concentrations of the essential oil higher than 1 µg/mL were found to inhibit both spontaneous and induced ileum contractions. Moreover, the essential oil and citronellal were found to decrease isolated mouse atria contraction frequency, as well as contraction force. However, the oil was found to be a very weak acetylcholinesterase inhibitor. CONCLUSION: The modulation of anxiety-related symptoms by the oil was found not to be mediated through the inhibition of the acetylcholinesterase, nonetheless, the mechanistic studies involving the ileum and cardiac tissues, revealed that the activity of MO and citronellal might be related to the modification of either voltage-gated Ca2+ channels or muscarinic receptors. Mice locomotion, balance, and muscle strength were not impacted by the essential oil; however, its main constituent, citronellal, was found to exert a certain degree of muscle function inhibition. All these results suggest that the activity of MO essential oil arises from synergistic and/or antagonistic interactions of its constituents, and is not completely dependent on the oil's main constituent.

Centrally Administered Neuropeptide-S Alleviates Gastrointestinal Dysmotility Induced by Neonatal Maternal Separation.

BACKGROUND: Neuropeptide-S (NPS) regulates autonomic outflow, stress response, and gastrointestinal (GI) motor functions. This study aimed to investigate the effects of NPS on GI dysmotility induced by neonatal maternal separation (MS). METHODS: MS was conducted by isolating newborn pups from dams from postnatal day 1 to day 14. In adulthood, rats were also exposed to chronic homotypic stress (CHS). Visceral sensitivity was assessed by colorectal distension-induced abdominal contractions. Gastric emptying (GE) was measured following CHS, whereas fecal output was monitored daily. NPS or NPS receptor (NPSR) antagonist was centrally applied simultaneously with electrocardiography and gastric motility recording. Immunoreactivities for NPS, NPSR, corticotropin-releasing factor (CRF), choline acetyltransferase (ChAT), tyrosine hydroxylase (TH), and c-Fos were assessed by immunohistochemistry. KEY RESULTS: NPS alleviated the MS-induced visceral hypersensitivity. Under basal conditions, central exogenous or endogenous NPS had no effect on GE and gastric motility. NPS restored CHS-induced gastric and colonic dysmotility in MS rats while increasing sympatho-vagal balance without affecting vagal outflow. NPSR expression was detected in CRF-producing cells of hypothalamic paraventricular nucleus, and central amygdala, but not in Barrington's nucleus. Moreover, NPSR was present in ChAT-expressing neurons in dorsal motor nucleus of the vagus (DMV), and nucleus ambiguus (NAmb) in addition to the TH-positive neurons in C1/A1, and locus coeruleus (LC). Neurons adjacent to the adrenergic cells in LC were found to produce NPS. NPS administration caused c-Fos expression in C1/A1 cells, while no immunoreactivity was detected in DMV or NAmb. CONCLUSIONS: NPS/NPSR system might be a novel target for the treatment of stress-related GI dysmotility.

Positive allosteric modulation of endogenous delta opioid receptor signaling in the enteric nervous system is a potential treatment for gastrointestinal motility disorders.

Allosteric modulators (AMs) are molecules that can fine-tune signaling by G protein-coupled receptors (GPCRs). Although they are a promising therapeutic approach for treating a range of disorders, allosteric modulation of GPCRs in the context of the enteric nervous system (ENS) and digestive dysfunction remains largely unexplored. This study examined allosteric modulation of the delta opioid receptor (DOR) in the ENS and assessed the suitability of DOR AMs for the treatment of irritable bowel syndrome (IBS) symptoms using mouse models. The effects of the positive allosteric modulator (PAM) of DOR, BMS-986187, on neurogenic contractions of the mouse colon and on DOR internalization in enteric neurons were quantified. The ability of BMS-986187 to influence colonic motility was assessed both in vitro and in vivo. BMS-986187 displayed DOR-selective PAM-agonist activity and orthosteric agonist probe dependence in the mouse colon. BMS-986187 augmented the inhibitory effects of DOR agonists on neurogenic contractions and enhanced reflex-evoked DOR internalization in myenteric neurons. BMS-986187 significantly increased DOR endocytosis in myenteric neurons in response to the weakly internalizing agonist ARM390. BMS-986187 reduced the generation of complex motor patterns in the isolated intact colon. BMS-986187 reduced fecal output and diarrhea onset in the novel environment stress and castor oil models of IBS symptoms, respectively. DOR PAMs enhance DOR-mediated signaling in the ENS and have potential benefit for the treatment of dysmotility. This study provides proof of concept to support the use of GPCR AMs for the treatment of gastrointestinal motility disorders.NEW & NOTEWORTHY This study assesses the use of positive allosteric modulation as a pharmacological approach to enhance opioid receptor signaling in the enteric nervous system. We demonstrate that selective modulation of endogenous delta opioid receptor signaling can suppress colonic motility without causing constipation. We propose that allosteric modulation of opioid receptor signaling may be a therapeutic strategy to normalize gastrointestinal motility in conditions such as irritable bowel syndrome.

Bamboo shavings derived O-acetylated xylan alleviates loperamide-induced constipation in mice.

BSH-1 is an O-acetylated xylan obtained from bamboo shavings. This study determined the protective effects of BSH-1 against loperamide (Lop)-induced constipation in mice. Mice received BSH-1 by gavage daily for 14 days. In constipated mice, BSH-1 significantly shortened the defecation time and raised the gastrointestinal (GI) transit rate, stool production, and cecal concentration of short-chain fatty acids (SCFAs). BSH-1 regulated the serum levels of gut hormones and neurotransmitters. BSH-1 also significantly altered the cecal microbiota of the constipated mice by increasing the abundance of potentially beneficial bacteria (e.g., Lactobacillus, Roseburia, and Bacteroidales_S24-7) and decreasing potentially pathogenic bacteria (e.g., Alloprevotella and Staphylococcus). Furthermore, colonic transcriptome analysis revealed that BSH-1 significantly reversed the expression changes of genes related to intestinal motility, water and ion transport, inflammation and cancer in constipated mice. Our findings indicated that BSH-1 effectively relieved Lop-induced constipation in mice and could be potentially used for constipation treatment.

The effects of L-carnitine on gastrointestinal contractility and histological changes in rat intestinal ischemia-reperfusion Injury / Efectos de la l-carnitina sobre la contractilidad gastrointestinal y los cambios histológicos en la lesión por isquemia-reperfusión intestinal de rata

SUMMARY: Ischemia-reperfusion (I/R) of the small intestine causes serious abdominal pathologies including tissue dysfunction and organ failure. L-carnitine (L-C), a powerful antioxidant, may help lessen the severity of these pathological effects since it plays a key role in energy metabolism. In this work we aimed to study the effects of L-C on the isolated ileal and duodenal contractility and histological changes in intestinal ischemia and reperfusion injury. Twenty eight Wistar rats were divided into four groups. The first group is the control group. Second group, I/R group, had rats submitted to 45-minutes of intestinal ischemia and to 45-minutes reperfusion. The third group, I/R+ L-C group, rats were treated with L-C 5 minutes before reperfusion and than submitted to ischemia. The fourth group, included rats that were treated with L-C without ischemia or reperfusion. Intestinal ischemia was conducted by obstructing superior mesentery arteries by silk loop. The ileal and duodenal segments were isolated and suspended in tissue bath. Contractile responses were induced by acetylcholine (Ach) and relaxation was achieved with phenylephrine. At the same time the terminal ileal and duodenal segments were examined for histological changes. Ach-induced contraction responses were higher in the I/R+L-C group, the L-C group, and the control group compared to the I/R group, in both ileal and duodenal segments. On the other hand, the phenylephrine-induced relaxations were higher in the I/R+L-C and L-C groups, especially in duodenal segments. In I/R group intestinal morphology was observed to be severely damaged whereas in I/R+L-C group the damage was noticeably lower possibly due to protective properties of L-C. I/R injury caused severe cellular damage response within the muscularis resulting in decreased gastrointestinal motility. Treatment with the L-C has significantly affected the gastrointestinal contractility. Also L-C treatment reduced the damage in intestinal morphology that occurs after IR injury.

RESUMEN: La isquemia-reperfusión (I/R) del intestino delgado provoca graves patologías abdominales que incluyen disfunción tisular y falla orgánica. La L-carnitina (L-C), un poderoso antioxidante, puede ayudar a disminuir la gravedad de estos efectos patológicos, ya que desempeña un papel clave en el metabolismo energético. El objetivo de este trabajo fue estudiar los efectos de L-C sobre la contractilidad ileal y duodenal aislada y los cambios histológicos en la lesión por isquemia y reperfusión intestinal. Se dividieron 28 ratas Wistar en cuatro grupos. El primer grupo fue el control. El segundo grupo, grupo I/R, de ratas sometidas durante 45 minutos de isquemia intestinal y a 45 minutos de reperfusión. El tercer grupo, grupo I/R+ L-C, las ratas se trataron con L-C, 5 minutos antes de la reperfusión y luego se sometieron a isquemia. El cuarto grupo, las ratas fueron tratadas con L-C sin isquemia ni reperfusión. La isquemia intestinal se realizó obstruyendo la arteria mesentérica superior con un asa de seda. Los segmentos ileal y duodenal se aislaron y suspendieron en un baño de tejido. Las respuestas contráctiles fueron inducidas por acetilcolina (Ach) y la relajación se logró con fenilefrina. Al mismo tiempo, se examinaron cambios histológicos de los segmentos del íleon terminal y del duodeno. Las respuestas de contracción inducidas por Ach fueron mayores en el grupo I/R+L-C, el grupo L-C y el grupo control en comparación con el grupo I/R, tanto en el segmento ileal como en el duodenal. Por otra parte, las relajaciones inducidas por fenilefrina fueron mayores en los grupos I/R+L-C y L-C, especialmente en los segmentos duodenales. En el grupo I/R se observó que la morfología intestinal estaba dañada significativamente, mientras que en el grupo I/R+L-C el daño fue notablemente menor, posiblemente debido a las propiedades protectoras de L-C. La lesión por I/R causó una respuesta de daño celular severo dentro de la capa muscular que resultó en una disminución de la motilidad gastrointestinal. El tratamiento con L-C afectó significativamente la contractilidad gastrointestinal. Por otra parte, el tratamiento L-C redujo el daño en la morfología intestinal que ocurre después de la lesión por IR.

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.

Aberrant enteric neuromuscular system and dysbiosis in amyotrophic lateral sclerosis.

Amyotrophic Lateral Sclerosis is a neuromuscular disease characterized by the progressive death of motor neurons and muscle atrophy. The gastrointestinal symptoms in ALS patients were largely ignored or underestimated. The relationship between the enteric neuromuscular system and microbiome in ALS progression is unknown. We performed longitudinal studies on the enteric neuron system (ENS) and microbiome in the ALS human-SOD1G93A (Superoxide Dismutase 1) transgenic mice. We treated age-matched wild-type and ALS mice with butyrate or antibiotics to investigate the microbiome and neuromuscular functions. We examined intestinal mobility, microbiome, an ENS marker GFAP (Glial Fibrillary Acidic Protein), a smooth muscle marker (SMMHC, Smooth Muscle Myosin Heavy Chain), and human colonoids. The distribution of human-G93A-SOD1 protein was tested as an indicator of ALS progression. At 2-month-old before ALS onset, SOD1G93A mice had significantly lower intestinal mobility, decreased grip strength, and reduced time in the rotarod. We observed increased GFAP and decreased SMMHC expression. These changes correlated with consistent increased aggregation of mutated SOD1G93A in the colon, small intestine, and spinal cord. Butyrate or antibiotics treated SOD1G93A mice had a significantly longer latency to fall in the rotarod test, reduced SOD1G93A aggregation, and enhanced enteric neuromuscular function. Feces from 2-month-old SOD1G93A mice significantly enhanced SOD1G93A aggregation in human colonoids transfected with a SOD1G93A-GFP plasmid. Longitudinal studies of microbiome data further showed the altered bacterial community related to autoimmunity (e.g., Clostridium sp. ASF502, Lachnospiraceae bacterium A4), inflammation (e.g., Enterohabdus Muris,), and metabolism (e.g., Desulfovibrio fairfieldensis) at 1- and 2-month-old SOD1G93A mice, suggesting the early microbial contribution to the pathological changes. We have demonstrated a novel link between the microbiome, hSOD1G93A aggregation, and intestinal mobility. Dysbiosis occurred at the early stage of the ALS mice before observed mutated-SOD1 aggregation and dysfunction of ENS. Manipulating the microbiome improves the muscle performance of SOD1G93A mice. We provide insights into the fundamentals of intestinal neuromuscular function and microbiome in ALS.

In vivo acute toxicity, laxative and antiulcer effect of the extract of Dryopteris Ramose.

Dryopteris ramosa (D. ramosa) is one of the most traded medicinally important plants of Himalayan region. Apart from other uses, D. ramosa is traditionally also used to treat gastric ulcers and as a laxative. The present study was designed to investigate the role of methanolic crude extract of Dryopteris Ramosa (MEDR) in acute toxicity, against loperamide induced constipated mice model, antiulcer effect of methanolic extract of D. Ramosa and cholinomimetic like effect of methanolic extract of D. Ramosa. The crude extract was investigated for the presence of active compounds (secondary metabolites) such as alkaloids, flavonoids, carbohydrates, glycosides, terpenoids, phenolic compounds, saponins, and tannins following the standard methods. The antiulcer effect was investigated in mice using the ethanol induced ulcer model at various doses i.e. 50 mg/kg, 100 mg/kg and 200 mg/kg doses. Constipation was induced in the mice via loperamide (3mg/kg body weight). The control group received normal saline. Different doses of plant extracts (50, 100, 150 and 200 mg/kg body weight/day) were administered for 7 days. Various parameters like feeding characteristics, gastrointestinal transit ratio, body weight, fecal properties and the possible mechanism of action of D. Ramosa on intestinal motility were monitored. Various Phytochemicals like saponins, glycosides, flavonoids, tannins, phenols, carbohydrate, alkaloids and triterpenes were found in D. Ramosa. The acute toxicity study showed that MEDR was associated with no mortality except mild and moderate sedation at the highest tested doses (1500 and 2000 mg/kg). MEDR also showed significant antiulcer activity against ethanol-induced ulcerogenesis. The extract enhanced the intestinal motility, normalized the body weight of constipated mice and increased the fecal volume which are indications of laxative property of the herb. The 200 mg/kg body weight dose of the extract was found effective. The presence of various Phytochemicals such as flavonoids, glycosides and tannins might be responsible for the antiulcer activity of D. Ramosa. This study provides the scientific background for the folkloric use of D. Ramosa as antiulcer agent. The laxative action of the extract compares positively with Duphalac, (standard laxative drug). These findings have therefore evidence scientific background to the folkloric use of the herb as a laxative agent.