Nitric Oxide and the Gastrointestinal Tract

Antispasmodic Activity of Light-Roasted Coffee Extract and Its Potential Use in Gastrointestinal Motility Disorders

Antispasmodic agents are crucial in managing gastrointestinal motility disorders by modulating muscle contractions and reducing symptoms like cramping and diarrhea. This study investigated the antispasmodic potential of different coffee bean extracts, including light coffee (LC), medium coffee (MC), and dark coffee (DC), on ileum contractions induced by potassium chloride (KCl), and elucidated their mechanisms of action using in vitro isolated tissue techniques. The results demonstrated that all coffee extracts reduced spontaneous contractions of rat ileum tissue in a dose-dependent manner. Among these, LC showed the most significant reduction in ileum contractions, particularly at higher concentrations. The key findings reveal that LC at 5 mg/mL significantly reduced CaCl2-induced contractions in isolated rat ileum tissue, indicating that LC may inhibit calcium influx or interfere with calcium signaling pathways. The presence of nifedipine, propranolol, and N-nitro-L-arginine methyl ester (L-NAME) have been confirmed in their involvement; they block calcium influx and calcium channels and activate β-adrenergic pathways as part of LC's mechanism of action. The presence of their active compounds, particularly chlorogenic acid and caffeine, likely contributes to the observed antispasmodic effects. These findings suggest that LC exerts its antispasmodic effects by targeting key mechanisms involved in muscle spasms and intestinal motility, providing a potential for managing such conditions.

Effects of the long-term influence of bisphenol A and bisphenol S on the population of nitrergic neurons in the enteric nervous system of the mouse stomach

Bisphenol A (BPA) is an endocrine disruptor commonly used in the production of plastics. Due to its relatively well-known harmful effects on living organisms, BPA is often replaced by its various analogues. One of them is bisphenol S (BPS), widely used in the plastics industry. Until recently, BPS was considered completely safe, but currently, it is known that it is not safe for various internal organs. However, knowledge about the influence of BPS on the nervous system is scarce. Therefore, the aim of this study was to investigate the influence of two doses of BPA and BPS on the enteric nitrergic neurons in the CD1 strain mouse stomach using the double-immunofluorescence technique. The study found that both substances studied increased the number of nitrergic neurons, although changes under the impact of BPS were less visible than those induced by BPA. Therefore, the obtained results, for the first time, clearly indicate that BPS is not safe for the innervation of the gastrointestinal tract.

Aloe vera gel attenuates acetic acid-induced ulcerative colitis in adult male Wistar rats

Ulcerative colitis is a disease of undetermined etiology and treatment. It affects the colon and rectum and typically involves the mucosa, manifesting as continuous areas of inflammation and ulceration. Aloe gel contains more than a hundred potentially active constituents of different classes. This study investigated the effect of aloe gel on experimentally-induced ulcerative colitis. Male Wistar rats were randomly allocated into groups A to F of six rats each. Ulcerative colitis was induced to rats in groups B to F by single intra-colonic administration of 2 mL of 4% acetic acid with a size 6F pediatrics catheter. In contrast, group A received an equivalent volume of normal saline by the same route. Twenty-four hours after induction, rats in groups B and C received normal saline and 1 mg/kg b. wt. daily dose of dexamethasone, respectively. In contrast, those in groups D, E, and F received 20, 40, and 60 mg/kg b. wt. doses of aloe gel, respectively, for 14 days. They were sacrificed 24 h after the last administration. We assessed disease progression by determining the clinical activity index, gross inflammation, histological alterations, the intensity of DNA in colon cells, and tissue level of nitric oxide. All the parameters but one increased significantly in group B rats. The quantitative distribution of DNA in colon cells reduced significantly in this group. Aloe gel doses significantly reversed these changes in a dose-dependent manner. Dexamethasone showed lesser efficacy relative to 60 mg dose of the Aloe gel extract. We conclude that Aloe vera gel has therapeutic potential in the treatment and management of ulcerative colitis. The most significant effects were observed in the groups treated with the highest dose of Aloe gel (60 mg/kg b. wt.). It is also worth noting that the remediated potential of aloe gel in acetic acid-induced UC surpasses that of dexamethasone.

Gastroprotective Effects of Ganoderma lucidum Polysaccharides with Different Molecular Weights on Ethanol-Induced Acute Gastric Injury in Rats

Ganoderma lucidum is known as a medicine food homology that can ameliorate gastrointestinal diseases. To evaluate the gastroprotective effects on different Ganoderma lucidum polysaccharides (GLPs), GLP was separated into three parts with different molecular weights using 100 kDa, 10 kDa, and 1 kDa membranes. The mitigation effects of different GLPs on ethanol-induced acute gastric injury were observed in rats. After pretreatment with different GLPs, especially GLP above 10 kDa, the symptoms of gastric mucosal congestion and bleeding were improved; serum myeloperoxidase, inflammatory factor, and histamine were decreased; and antioxidant activity and defense factors (NO and EGF) were increased. Results showed that GLP with different molecular weights had a dose-dependent effect in alleviating alcohol-induced gastric injury. The underlying mechanism might be related to regulating anti-oxidation, promoting the release of related defense factors, reducing inflammatory factors, and reducing the level of histamine in serum. The current work indicated that GLPs above 10 kDa could be applied as natural resources for producing new functional foods to prevent gastric injury induced by ethanol.

Antidiarrheal, Antimicrobial, and Antioxidant Properties of the Aqueous Extract of Tunisian Persimmon (Diospyros kaki Thunb.) Fruits

Medicinal plants were used to prevent and treat numerous gastrointestinal disorders owing, in part, to their antioxidant capacity. The protective effects of Diospyros kaki fruit aqueous extract (DKFAE) against castor oil (CO)-induced diarrhea was studied. The in vitro antioxidant and antibacterial properties were investigated using colorimetric and biochemical analyses. In vivo, 60 male rats were divided into 6 groups of 10 animals each (n = 10): control (C), CO, CO+various doses of DKFAE (100, 200, and 400 mg/kg, b.w., p.o.), and CO+loperamide (LOP, 10 mg/kg, b.w., p.o.).The DKFAE was rich in tannins and showed interesting antioxidant and antibacterial activities. The liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis resulted in the identification of 16 phenolic compounds, among which quinic acid was the main one. The in vivo study showed that diarrhea was accompanied by an oxidative stress status as measured by an increase of lipid peroxidation, a decrease of glutathione and thiol group levels, as well as antioxidant enzyme activity depletion, such as glutathione peroxidase, superoxide dismutase, and catalase. The DKFAE administration significantly decreased the gastrointestinal transit in a dose-dependent manner. Besides, DKFAE protected against CO-induced diarrhea and intestinal fluid accumulation. Interestingly, DKFAE pretreatment counteracted all the oxidative stress status deregulation induced by CO intoxication. D. kaki fruit could be suggested for its strong protective effect against CO-induced acute diarrhea, which could be explained, in part, to its antimicrobial and antioxidant properties.

Chemically-Induced Inflammation Changes the Number of Nitrergic Nervous Structures in the Muscular Layer of the Porcine Descending Colon

Simple Summary

The enteric nervous system (ENS) is the part of the nervous system that is located in the wall of the gastrointestinal tract and regulates the majority of the functions of the stomach and intestine. The ENS is characterized by a complex structure and a high degree of independence from the brain. It is known that the ENS changes under the impact of physiological and pathological stimuli. One of the active substances synthetized by enteric neurons is nitric oxide (NO), which is involved in the regulation of intestinal motility, blood flow, secretory activity, and immunological processes in the gastrointestinal tract. In the present study, the influence of chemically-induced inflammatory process on a number of nitrergic neuronal structures located in the muscular layer of the descending colon is investigated. An increase in the number of structures that nitric oxide takes part in is correlated with the inflammatory processes.

Abstract

The enteric nervous system (ENS) is the part of the nervous system that is located in the wall of the gastrointestinal tract and regulates the majority of the functions of the stomach and intestine. Enteric neurons may contain various active substances that act as neuromediators and/or neuromodulators. One of them is a gaseous substance, namely nitric oxide (NO). It is known that NO in the gastrointestinal (GI) tract may possess inhibitory functions; however, many of the aspects connected with the roles of this substance, especially during pathological states, remain not fully understood. An experiment is performed here with 15 pigs divided into 3 groups: C group (without any treatment), C1 group (“sham” operated), and C2 group, in which experimental inflammation was induced. The aim of this study is to investigate the influence of inflammation on nitrergic nervous structures in the muscular layer of the porcine descending colon using an immunofluorescence method. The obtained results show that inflammation causes an increase in the percentage of nitric oxide synthase (nNOS)-positive neurons in the myenteric plexus of the ENS, as well as the number of nitrergic nerve fibers in the muscular layer of the descending colon. The obtained results suggest that NO is involved in the pathological condition of the large bowel and probably takes part in neuroprotective and/or adaptive processes.

The T2 Toxin Produced by Fusarium spp. Impacts Porcine Duodenal Nitric Oxide Synthase (nNOS)-Positive Nervous Structures-The Preliminary Study

T2 toxin synthetized by Fusarium spp. negatively affects various internal organs and systems, including the digestive tract and the immune, endocrine, and nervous systems. However, knowledge about the effects of T2 on the enteric nervous system (ENS) is still incomplete. Therefore, during the present experiment, the influence of T2 toxin with a dose of 12 µg/kg body weight (b.w.)/per day on the number of enteric nervous structures immunoreactive to neuronal isoform nitric oxide synthase (nNOS—used here as a marker of nitrergic neurons) in the porcine duodenum was studied using the double immunofluorescence method. Under physiological conditions, nNOS-positive neurons amounted to 38.28 ± 1.147%, 38.39 ± 1.244%, and 35.34 ± 1.151 of all enteric neurons in the myenteric (MP), outer submucous (OSP), and inner submucous (ISP) plexuses, respectively. After administration of T2 toxin, an increase in the number of these neurons was observed in all types of the enteric plexuses and nNOS-positive cells reached 46.20 ± 1.453% in the MP, 45.39 ± 0.488% in the OSP, and 44.07 ± 0.308% in the ISP. However, in the present study, the influence of T2 toxin on the intramucosal and intramuscular nNOS-positive nerves was not observed. The results obtained in the present study indicate that even low doses of T2 toxin are not neutral for living organisms because they may change the neurochemical characterization of the enteric neurons.

Alcohol and gastric motility: pathophysiological and therapeutic implications

Alcohol has been associated with alterations in gastric motility. The literature identifies that various factors play a role in alcohol's effect on gastric emptying including differences in alcohol concentration, osmolarity, caloric content, amino acids as well as different processing techniques (fermentation vs distillation). Additionally, chronic alcohol consumption has been shown to alter the myenteric nitrergic system resulting in impaired gastrointestinal motor function, and it also has an inhibitory effect on the release of several neurotransmitters that play a key role in gastrointestinal motility, including acetylcholine. Whether social or limited intake of alcohol could have a therapeutic role has not been apparent. Serendipitously, we have identified a therapeutic role for alcohol with a meal in the entity of dumping syndrome (DS) where there is postprandial rapid emptying of voluminous and hyperosmolar gastric contents into the small bowel. In the clinical setting of DS attributed to impaired vagal nerve function, there was normalization of gastric emptying and resolution of accompanying symptoms when drinking a glass of wine before and during meals. We propose that alcohol's anticholinergic effect was augmented in the setting of vagal nerve denervation resulting in slowing of gastric emptying and in alleviation of symptoms of early DS. This review article provides an in-depth analysis of the published literature on alcohol and gastric motility focusing on the accumulated knowledge that may have clinical application and relevance.

Neurochemical Plasticity of nNOS-, VIP- and CART-Immunoreactive Neurons Following Prolonged Acetylsalicylic Acid Supplementation in the Porcine Jejunum

Aspirin, also known as acetylsalicylic acid (ASA), is a commonly used anti-inflammatory drug that has analgesic and antipyretic properties. The side effects are well known, however, knowledge concerning its influence on gastric and intestinal innervation is limited. The enteric nervous system (ENS) innervates the whole gastrointestinal tract (GIT) and is comprised of more than one hundred million neurons. The capacity of neurons to adapt to microenvironmental influences, termed as an enteric neuronal plasticity, is an essential adaptive response to various pathological stimuli. Therefore, the goal of the present study was to determine the influence of prolonged ASA supplementation on the immunolocalization of neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP) and cocaine- and amphetamine- regulated transcript peptide (CART) in the porcine jejunum. The experiment was performed on 8 Pietrain × Duroc immature gilts. Using routine double-labelling immunofluorescence, we revealed that the ENS nerve cells underwent adaptive changes in response to the induced inflammation, which was manifested by upregulated or downregulated expression of the studied neurotransmitters. Our results suggest the participation of nNOS, VIP and CART in the development of inflammation and may form the basis for further neuro-gastroenterological research.

Nitroso-oxidative stress after activation of 5-HT4 receptors under conditions of colitis in rats

Serotonin (5-hydroxytryptamine, 5-HT) plays an important role in the regulation of the functioning of the gastrointestinal tract, including that of the colon. The response of smooth muscles, blood vessels and colon mucosa (CM) to 5-HT is realized through the activation of various types of 5-HT receptors, in particular, 5-HT4 receptors, since the latter are identified on colon cells membranes (enterocytes, smooth muscles and endothelium). The aim of our study was to determine the effect of 5-НT4 receptors agonist (mosapride) on nitrogen (II) oxide production and lipid peroxidation in CM and colon muscle tissue (CMT) under the conditions of experimental ulcerative colitis (UC).

Nitric oxide as an active substance in the enteric neurons of the porcine digestive tract in physiological conditions and under intoxication with bisphenol A (BPA)

Bisphenol A (BPA) is an organic substance, which is commonly used in the production of plastic. It is known that BPA has the negative impact on the living organism, affecting among others the reproductive organs, nervous, endocrine and immune systems. Nevertheless the knowledge about the influence of BPA on the enteric nervous system (ENS) is extremely scanty. On the other hand, nitric oxide is considered to be one of the most important neuronal factors in the ENS. The aim of the study was to investigate the influence of low and high doses of BPA on neuronal isoform nitric oxide synthase - like immunoreactive (nNOS-LI) nervous structures in the various parts of the porcine gastrointestinal (GI) tract using double immunofluorescence technique. The obtained results show that BPA affects nNOS-LI enteric neurons and nerve fibers, and the character and severity of observed changes depend on the fragment of the gastrointestinal tract, part of the ENS and dose of the toxin. It should be pointed out that even relatively low doses of BPA (0.05 mg/kg body weight/day) are not neutral for the organism and may change the number of nitrergic nervous structures in the stomach and intestine. Observed changes are probably connected with neurotoxic activity of BPA, but the exact mechanisms of them still remain unclear.

Impact of Continuous vs Bolus Feeding on Splanchnic Perfusion in Very Low Birth Weight Infants: A Randomized Trial

OBJECTIVE

To detect changes in splanchnic perfusion and oxygenation induced by 2 different feeding regimens in infants with intrauterine growth restriction (IUGR) and those without IUGR.

STUDY DESIGN

This was a randomized trial in 40 very low birth weight infants. When an enteral intake of 100 mL/kg/day was achieved, patients with IUGR and those without IUGR were randomized into 2 groups. Group A (n = 20) received a feed by bolus (in 10 minutes), then, after at least 3 hours, received the same amount of formula by continuous nutrition over 3 hours. Group B (n = 20) received a feed administered continuously over 3 hours, followed by a bolus administration (in 10 minutes) of the same amount of formula after at least 3 hours. On the day of randomization, intestinal and cerebral regional oximetry was measured via near-infrared spectroscopy and Doppler ultrasound (US) of the superior mesenteric artery was performed. Examinations were performed before the feed and at 30 minutes after the feed by bolus and before the feed, at 30 minutes after the start of the feed, and at 30 minutes after the end of the feed for the 3-hour continuous feed.

RESULTS

Superior mesenteric artery Doppler US showed significantly higher perfusion values after the bolus feeds than after the continuous feeds. Near-infrared spectroscopy values remained stable before and after feeds. Infants with IUGR and those without IUGR showed the same perfusion and oxygenation patterns.

CONCLUSION

According to our Doppler US results, bolus feeding is more effective than continuous feeding in increasing splanchnic perfusion.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01341236.

Antidiarrheal effect of Alpinia oxyphylla Miq. (Zingiberaceae) in experimental mice and its possible mechanism of action

ETHNOPHARMACOLOGICAL RELEVANCE

The fructus Alpinia oxyphylla Miq. (AOM) has been used for treating diarrhea with spleen deficiency and gastralgia for thousands of years. A number of traditional Chinese medicine formulae provide AOM as an alternative herbal treatment for diarrhea, but the scientific basis for this usage has not been well defined.

AIM OF THE STUDY

In this study, we tried to investigate the antidiarrheal activity and possible mechanisms of Fructus AOM, aiming to enrich our understanding to the scientific meanings and theoretical significance of Fructus AOM in clinical practice.

MATERIALS AND METHODS

The fructus of AOM collected from Hainan province in China were macerated in the 95% ethanol to obtain the crude 95% ethanol extract, followed by subjected to chromatographic separation over a Diaion HP20 column to obtain 90% and 50% ethanol eluted fractions. The activities of the crude extract and fractions on castor oil induced acute diarrhea, rhubarb induced chronic diarrhea, gastrointestinal transit (GIT) in mice, and contractions of isolated guinea-pig ileum were evaluated. Additionally, nitric oxide (NO), gastrointestinal peptides gastrin (GAS), motilin (MTL) and somatostatin (SS) levels that related to gastrointestinal motilities were detected to demonstrate the potential mechanisms. Ultimately, LC-MS/MS method was utilized to ensure the chemical consistency.

RESULTS

The 95% ethanol extract and 90% ethanol eluted fraction significantly delayed the onset time and decreased the wet faeces proportion compared with control group in the castor oil induced acute diarrhea mice. In terms of further evaluation of antidiarrheal activity, the 95% ethanol extract and 90% ethanol elution displayed significant inhibition of the intestinal propulsion at the two highest oral doses of 20 g crude drug/kg and 1g/kg. Moreover the 95% ethanol extract (10 and 20 g crude drug/kg) and 90% ethanol elution (0.5 and 1g/kg) could significantly inhibit the GIT, which was partially attributed to the increase in NO and SS levels, and the decreased MTL. In vitro spontaneous contractions of the isolated guinea pig ileum induced by carbachol, neostigmine and histamine were attenuated by both the extract and elution. Phytochemical analysis of 95% ethanol extract and its fractions identified the presence of diphenylheptanes, sesquiterpenes, and flavones as the major components.

CONCLUSIONS

Our in vivo and in vitro data could partly support and justify the traditional usage of Fructus AOM on the treatment of diarrhea in traditional medicine.

Nitric oxide released from luminal s-nitroso-N-acetylcysteine increases gastric mucosal blood flow

Nitric oxide (NO)-mediated vasodilation plays a key role in gastric mucosal defense, and NO-donor drugs may protect against diseases associated with gastric mucosal blood flow (GMBF) deficiencies. In this study, we used the ex vivo gastric chamber method and Laser Doppler Flowmetry to characterize the effects of luminal aqueous NO-donor drug S-nitroso-N-acetylcysteine (SNAC) solution administration compared to aqueous NaNO2 and NaNO3 solutions (pH 7.4) on GMBF in Sprague-Dawley rats. SNAC solutions (600 μM and 12 mM) led to a rapid threefold increase in GMBF, which was maintained during the incubation of the solutions with the gastric mucosa, while NaNO2 or NaNO3 solutions (12 mM) did not affect GMBF. SNAC solutions (600 μM and 12 mM) spontaneously released NO at 37 °C at a constant rate of 0.3 or 14 nmol·mL-1·min-1, respectively, while NaNO2 (12 mM) released NO at a rate of 0.06 nmol·mL-1·min-1 and NaNO3 (12 mM) did not release NO. These results suggest that the SNAC-induced GMBF increase is due to their higher rates of spontaneous NO release compared to equimolar NaNO2 solutions. Taken together, our data indicate that oral SNAC administration is a potential approach for gastric acid-peptic disorder prevention and treatment.

Activity of alkaloids on peptic ulcer: what's new?

Peptic ulcer is a common disease characterized by lesions that affect the mucosa of the esophagus, stomach and/or duodenum, and may extend into the muscular layer of the mucosa. Natural products have played an important role in the process of development and discovery of new drugs, due to their wide structural diversity and present, mostly specific and selective biological activities. Among natural products the alkaloids, biologically active secondary metabolites, that can be found in plants, animals or microorganisms stand out. The alkaloids are compounds consisting of a basic nitrogen atom that may or may not be part of a heterocyclic ring. This review will describe 15 alkaloids with antiulcer activity in animal models and in vitro studies.

Black tea extract and its thearubigins relieve the sildenafil-induced delayed gut motility in mice: a possible role of nitric oxide

In this study we hypothesize that a standardized black tea aqueous extract (BTE) and thearubigins, its main polyphenolic pigments, will improve sildenafil-induced delay in gastric emptying (GE) and small intestinal transit (SIT) in mice. Twenty groups of mice (n = 8) were given a phenol red meal, and three sets of experiments were performed. In the first and second sets, effects of different concentrations of BTE, thearubigins (TRs), and sildenafil (SLD), alone and in combinations, on GE and SIT were measured. In the third set, influence of nω -Nitro-l-arginine methyl ester hydrochloride (l-NAME) pretreatment on effects of these treatments was tested. Black tea extract (3% and 4.5%) and thearubigins (50 and 60 mg/kg) dose-dependently increased GE and SIT, whereas BTE 6% and thearubigins 70 mg/kg did not affect them. Sildenafil dose-dependently reduced both GE and SIT. Combination of metoclopramide, BTE 4.5%, thearubigins 60, or l-NAME with sildenafil (5 mg/kg) reversed its motility-delaying effects. Pretreatment with l-NAME followed by BTE 4.5%, thearubigins 60, BTE 4.5% + sildenafil 5, or thearubigins 60 + sildenafil 5 only partially affected the accelerating effects of BTE 4.5% and thearubigins 60. In conclusion, a standardized BTE and its thearubigins improve the sildenafil-induced delayed gut motility in mice. This improvement was partially blocked by l-NAME suggesting a possible role of nitric oxide. Thus, BTE 4.5% or TRs 60 mg/kg solution could be considered a reliever therapy for the sildenafil-induced dyspepsia.

Gastric antisecretory and cytoprotective effects of hydroalcoholic extracts of Plumeria alba Linn. leaves in rats

OBJECTIVE

This study was conducted to evaluate the antiulcerogenic property of hydroalcoholic extract obtained from the leaves of Plumeria alba Linn.

METHODS

Antiulcer assays were performed using the protocols of ulcer induced by non-steroidal anti-inflammatory drugs, ethanol and pylorus ligation. The hydroalcoholic extract (HAPA), and various fractions of HAPA like, n-hexane extract (HPA), ethyl acetate extract (EAPA) and n-butanol extract (BPA) were administered at doses of 200 and 400 mg/kg for HAPA and 100 and 200 mg/kg for fractions of extracts. Parameters of gastric secretion (volume, pH, total protein, and free and total acidity) were determined by the pylorus ligation model. Parameters like aspartate aminotransferase and alanine aminotransferase were also determined in ethanol-induced ulcer model. To determine the mechanism of action, role of nitric oxide was also evaluated.

RESULTS

EAPA and BPA (100 and 200 mg/kg, p.o.) showed gastric ulcer-healing effect in indomethacin-induced ulcer model, while HAPA (200 mg/kg) and HPA showed no significant antiulcer effect. Both EAPA and BPA showed gastric cytoprotective effect in ethanol-induced gastric ulcer and inhibited gastric secretion in pylorus-ligated rats.

CONCLUSION

The results of the present study show that some hydroalcoholic extract of Plumeria alba L. displays antiulcer activity, as demonstrated by the significant inhibition of ulcer formation induced by different models, which is consistent with the literature report in folk medicine.

Evaluation of antiulcer activity of chromanone fraction from Calophyllum brasiliesnse Camb

ETHNOPHARMACOLOGICAL RELEVANCE

Calophyllum brasiliense Camb. (Clusiaceae), popularly known as 'guanandi', is found in the tropical areas and swampy lands. The latex exuding from its bark is used in the treatment of gastric ulcer in folk medicine. Several active compounds have been isolated from its stem bark among them, are the chromanone acids. Therefore, this study aimed to evaluate antiulcer activity and probable mechanism(s) of action of a fraction containing a mixture of chromanone acids (BI), derived by column chromatography fractionation of the hexane extract of the stem bark of Calophyllum brasiliense (HECb), using experimental in vitro and in vivo models.

MATERIALS AND METHODS

Ulcer was induced by oral administration of ethanol (75%, v/v) and indomethacin (50mg/kg). Malondialdehyde, reduced glutathione and catalase activity was measured in stomach tissue after ethanol induced ulcer. In order to evaluate the effect of BI on nitric oxide, ulcer was induced by ethanol in l-NAME pretreated animals. Anti-Helicobacter pylori activity was verified in disk diffusion and broth microdilution in vitro assays, using cagA+ and vacA+ Helicobacter pylori strains.

RESULTS

BI prevented the gastric ulceration caused by ethanol and indomethacin treatments. Its gastroprotective mechanism in ethanol-induced ulcer was partly due to reduction of MDA and CAT levels in the gastric tissue. BI did not affect the GSH levels and its gastroprotective effect was not reversed by pretreatment with l-NAME. BI showed anti-Helicobacter pylori in the both assays.

CONCLUSION

The results indicate that BI is partly responsible for the HECb antiulcer and anti-Helicobacter pylori effects.

The gender difference of selective serotonin reuptake inhibitor, fluoxetine in adult rats with stress-induced gastric ulcer

We investigated the gender difference of selective serotonin reuptake inhibitor, fluoxetine in adult rats with stress-induced gastric ulcer. The rats were randomly divided into six groups: Group I, control males and group II, control females; group III, acute cold restraint stressed males and group IV, acute cold restraint stressed females; group V, fluoxetine-treated stressed males and group VI, fluoxetine-treated stressed females. Acute cold restraint stress was established by fixing the four limbs of the rat and placing it in a refrigerator at 4°C for 3h. Fluoxetine was given intraperitoneal in a single dose of 10mg/kg/day. After 2 weeks, stomach and brain tissues were collected for the assay of gastric malonaldehyde (MDA), catalase, nitric oxide (NO) and cortical gamma aminobutyric acid (GABA). Stressed animals exhibited increased total acidity in association with decreased gastric secretion volume. Gastric MDA was increased while gastric catalase, NO, and cortical GABA were decreased in stressed male rats when compared to stressed females. However, fluoxetine administration attenuated these stress-induced changes especially in stressed male animals. Stressed male rats were more responsive to the antiulcer effect of fluoxetine more than stressed females. However, fluoxetine might be considered to be the first-choice drug in depressive patients with gastric ulcers in the future.