Potential Antihypertensive Activity of the Aqueous Extract of Ammi visnaga and its Effect on ACE-2 in Rats.

AIMS: This work aimed to investigate the antihypertensive activity of Ammi visnaga. BACKGROUND: The aqueous extract of Ammi visnaga has traditionally been used to treat hypertension in Morocco. OBJECTIVE: The objective of this investigation was to evaluate the effect of Ammi visnaga aqueous extract (AVAE) on arterial blood pressure, systolic blood pressure (SBP), mean blood pressure (MBP), diastolic blood pressure (DBP), and heart rate (HR) in normotensive and hypertensive rats. In addition, the effect of the aqueous extract of Ammi visnaga on vasodilatation was assessed in isolated rat aortic rings with functional endothelium pre-contracted with epinephrine EP or KCl. METHODS: AVAE was obtained, and its antihypertensive ability was pharmacologically investigated in L-NAME hypertensive and normotensive rats. The rats received oral AVAE at two selected doses of 70 and 140 mg/kg for six hours (acute experiment) and seven days (sub-chronic). Thereafter, systolic, diastolic, mean arterial blood pressure and heart rate were evaluated. Moreover, the vasorelaxant activity of AESA was performed in thoracic aortic ring rats. In addition, the mechanisms of action involved in the vasorelaxant effect were studied. RESULTS: AVAE lowered blood pressure only in L-Name-induced hypertensive rats. Furthermore, AVAE (0.375-1.375 mg/ml) showed a vasodilator effect in isolated aortic rats. In addition, not all of the medications used in our study were responsible for the signaling pathway. As a result, additional pharmaceuticals are required to confirm the mechanism of this signaling pathway. CONCLUSION: The aqueous extract of Ammi visnaga exerts an interesting antihypertensive activity, which could be mediated through its vasorelaxant activity. The study supports its use as a medicinal plant against hypertension in Morocco.

[Mechanism of Jiming Powder in ameliorating heart failure with preserved ejection fraction based on metabolomics].

In this study, untargeted metabolomics was conducted using the liquid chromatography-tandem mass spectrometry(LC-MS/MS) technique to analyze the potential biomarkers in the plasma of mice with heart failure with preserved ejection fraction(HFpEF) induced by a high-fat diet(HFD) and nitric oxide synthase inhibitor(Nω-nitro-L-arginine methyl ester hydrochloride, L-NAME) and explore the pharmacological effects and mechanism of Jiming Powder in improving HFpEF. Male C57BL/6N mice aged eight weeks were randomly assigned to a control group, a model group, an empagliflozin(10 mg·kg~(-1)·d~(-1)) group, and high-and low-dose Jiming Powder(14.3 and 7.15 g·kg~(-1)·d~(-1)) groups. Mice in the control group were fed on a low-fat diet, and mice in the model group and groups with drug intervention were fed on a high-fat diet. All mice had free access to water, with water in the model group and Jiming Powder groups being supplemented with L-NAME(0.5 g·L~(-1)). Drugs were administered on the first day of modeling, and 15 weeks later, blood pressure and cardiac function of the mice in each group were measured. Heart tissues were collected for hematoxylin-eosin(HE) staining to observe pathological changes and Masson's staining to observe myocardial collagen deposition. Untargeted metabolomics analysis was performed on the plasma collected from mice in each group, and metabolic pathway analysis was conducted using MetaboAnalyst 5.0. The results showed that the blood pressure was significantly lower and the myocardial concentric hypertrophy and left ventricular diastolic dysfunction were significantly improved in both the high-dose and low-dose Jiming Powder groups as compared with those in the model group. HE and Masson staining showed that both high-dose and low-dose Jiming Powder significantly alleviated myocardial fibrosis. In the metabolomics experiment, 23 potential biomarkers were identified and eight strongly correlated metabolic pathways were enriched, including linoleic acid metabolism, histidine metabolism, alpha-linolenic acid metabolism, glycerophospholipid metabolism, purine metabolism, porphyrin and chlorophyll metabolism, arachidonic acid metabolism, and pyrimidine metabolism. The study confirmed the pharmacological effects of Jiming Powder in lowering blood pressure and ameliorating HFpEF and revealed the mechanism of Jiming Powder using the metabolomics technique, providing experimental evidence for the clinical application of Jiming Powder in treating HFpEF and a new perspective for advancing and developing TCM therapy for HFpEF.

1,8-Cineole ameliorates endothelial injury and hypertension induced by L-NAME through regulation of autophagy via PI3K/mTOR signaling pathway.

Our previous data confirmed that 1,8-Cineole had an antihypertensive effect in animal models. However, it is unclear whether antihypertension is dependent on the protective effect of 1,8-Cineole on endothelial function and structure. At present, the purpose was to investigate the protective effects of 1,8-Cineole on vascular endothelial tissue in hypertensive rats and human umbilical vein endothelial cells (HUVECs). Our results showed that 1,8-Cineole significantly reduced the blood pressure and improved the vascular endothelial lesion, attenuated vascular oxidative stress and inflammation induced by Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) in rats. Pretreatment with 1,8-Cineole was able to inhibit the increase in malondialdehyde (MDA) and reactive oxygen species (ROS) induced by L-NAME, and increased the release and expression of superoxide dismutase (SOD) and nitric oxide (NO). In addition, 1,8-Cineole also reversed the increase of autophagy-associated protein LC3Ⅱ/LC3Ⅰ and the decrease of P62 in vivo and in vitro respectively. There was a synergistic effect between PI3K agonists and drugs, while PI3K inhibitors blocked the efficacy of 1,8-Cineole. The addition of autophagy inhibitor chloroquine increases the expression of eNOS. Taken together, our results indicate that 1,8-Cineole has potential beneficial promising antihypertension depending on the integrity of vascular endothelial structure and function induced by L-NAME, and the mechanism involves ameliorating autophagy by regulating of PI3K/mTOR.

Nitric oxide synthase inhibitors as potential therapeutic agents for gliomas: A systematic review.

INTRODUCTION: Gliomas represent the most prevalent form of brain tumors, among which glioblastomas are the most malignant subtype. Despite advances in comprehending their biology and treatment strategies, median survival remains disappointingly low. Inflammatory processes involving nitric oxide (NO), critically contribute to glioma formation. The inducible isoform of NO synthase (iNOS) is highly overexpressed in gliomas and has been linked to resistance against temozolomide (TMZ) treatment, neoplastic transformation, and modulation of immune response. While both in vitro and in vivo studies showed the potential of iNOS inhibitors as effective treatments for gliomas, no clinical trials on gliomas have been published. This review aims to summarize the available evidence regarding iNOS as a target for glioma treatment, focusing on clinically relevant data. METHODS: Following PRISMA guidelines, we conducted a systematic review by searching PubMed/Medline, and Embase databases in May 2023. We included studies that investigated the impact of NOS inhibitors on glioma cells using L-NMMA, CM544, PBN, 1400W or l-NAME either alone or combined with TMZ. We extracted data on the NOS inhibitor used, subtype, study setting, animal model or cell lines employed, obtained results, and safety profile. Our inclusion criteria encompassed original articles in English or Spanish, studies with an untreated control group, and a primary outcome focused on the biological effects on glioma cells. RESULTS: Out of 871 articles screened from the aforementioned databases, 37 reports were assessed for eligibility. After excluding studies that did not utilize glioma cells or address the designated outcome, 11 original articles satisfied the inclusion and exclusion criteria. Although no NOS inhibitor has been tested in a published clinical trial, three inhibitors have been evaluated using in vivo models of intracranial gliomas. l-NAME, 1400W, and CM544 were tested in vitro. Co-administration of l-NAME, or CM544 with TMZ showed superior results in vitro compared to individual agent testing. CONCLUSION: Glioblastomas remain a challenging therapeutic target. iNOS inhibitors exhibit substantial potential as treatment options for oncologic lesions, and they have demonstrated a safe toxicity profile in humans for other pathological conditions. Research endeavors should be focused on investigating their potential effects on brain tumors.

Ammodaucus leucotrichus Acts as an Antihypertensive and Vasorelaxant Agent Through sGC and Prostaglandin Synthesis Pathways.

BACKGROUND: Ammodaucus leucotrichus is a medicinal plant used in traditional medicine to treat various ailments, including hypertension. AIMS: The study aimed to determine the antihypertensive activity of Ammodaucus leucotrichus. OBJECTIVE: The study aimed to investigate the antihypertensive and vasorelaxant activities of the aqueous extract of Ammodaucus leucotrichus fruits (ALAE) in rats. METHODS: ALAE was prepared to study its antihypertensive effect in L-NAME (Nω-L-arginine methyl ester)-induced hypertensive rats and its vasorelaxant activity in isolated thoracic aortas of rats. The acute and subchronic effects of ALAE on systolic, diastolic, mean arterial pressure, and heart rate (HR) were evaluated after oral administration of ALAE (60 and 100 mg/kg body weight) for 6 h for the acute experiment and over 7 days for the subchronic test. Isolated thoracic aortic rings were prepared to examine the vasorelaxant action of ALAE. Several common pharmacological agents were used to test potential pathways implicated in vasorelaxant action. RESULTS: The results showed that ALAE reduced blood pressure parameters (systolic, mean, and diastolic blood pressure) in L-NAME-induced hypertension rats after repeated oral treatment over seven days without affecting normotensive rats. Furthermore, in thoracic aortic rings pre-contracted with epinephrine (EP) (10 µM) or KCl (80 mM), ALAE (0.250-1.625 mg/ml) showed a vasorelaxant effect. In isolated rat thoracic aortas, blockage of soluble guanylyl cyslase with blue methylene (P < 0.01) partially decreased this vasorelaxant effect. In addition, blockage of the prostaglandin synthesis pathway with indomethacin (P<0.05) also reduced the vasorelaxant activity of ALAE. Pretreatment of aortic rings with glibenclamide, propanolol, L-NAME, MLN-4760, or nifedipine did not affect ALAE-induced vasorelaxation. CONCLUSION: Ammodaucus leucotrichus is a prescient medicinal plant, able to act as an antihypertensive agent. Moreover, the results suggest that the extract increased cGMP in NO-independent manner.

Influence of lemon (Citrus limon) and lime (Citrus aurantifolia) juices on the erectogenic properties of sildenafil in rats with L-NAME-induced erectile dysfunction.

The use of lemon (Citrus limon) and lime (Citrus aurantifolia) juices for the treatment of erectile dysfunction (ED) is fast becoming common practice, even though there is dearth of information on the effect of such functional food and drug combination in the management of ED. This study evaluated the effect of lemon and lime juices on the erectogenic properties of sildenafil. ED was induced with L-NAME (40 mg/kg body weight). The rats were divided into 11 groups (n = 6) and given various doses of the test samples. Immediately after the sexual behavior studies, the animals were sacrificed and the penile and brain tissues were isolated. The results revealed that lime and lemon juices improved sexual behavior in rats by improving NO production and inhibiting the activities of PDE-5, arginase, ACE, MAO, ATPdase, AMPdase, and activated antioxidant enzymes. Furthermore, lime at 1.0 ml/kg significantly improved the therapeutic properties of sildenafil. While, lemon (0.5 and 1.0 ml/kg) and lime (0.5 ml/kg) did not show any synergistic effect. This study revealed that lime and lemon juices could improve erectile function and combining lime juice with sildenafil could be very effective in the management of ED. PRACTICAL APPLICATIONS: The therapeutic management of erectile dysfunction has involved maximizing NO production through the modulation of macromolecules such as phosphodiesterase-5 and arginase with the use of drugs such as sildenafil. Combining such drugs with functional foods such as lime and lemon juices is becoming common practice. However, there is dearth of report on the effect of lime and lemon juices on the erectogenic potentials of sildenafil. The present study shows that combining 1 ml/kg lime juice (got from 2 lime fruits) with sildenafil will boost the erectogenic properties of the drug. While combining lime (0.5 ml/kg) and lemon (0.5 and 1.0 ml/kg) juices with the drug did not have any synergistic effect.

Nitric oxide synthase inhibitor L-NG-nitroarginine methyl ester (L-NAME) attenuates remobilization-induced joint inflammation.

Shortly after joint remobilization, inflammation is induced in the joint and aggravates joint contracture via subsequent fibrosis. However, the mechanisms involved in remobilization-induced inflammation are not yet fully understood. We hypothesized that joint immobilization followed by remobilization induces hypoxia/reoxygenation, initiating inflammatory reactions through nitric oxide (NO) production via NO synthase 2 (NOS2). This study aimed to investigate whether: 1) administration of the NOS inhibitor L-NG-nitroarginine methyl ester (l-NAME) can attenuate remobilization-induced joint inflammation; and 2) hypoxia/reoxygenation is induced by joint immobilization and followed by remobilization. Unilateral knee joints of rats were immobilized using external fixators for three weeks. After removal of the fixation device, knees were allowed to move freely for one day (remobilization) with or without l-NAME administration. Without l-NAME administration, inflammatory reactions including joint swelling and inflammatory cell infiltration, edema, and upregulation of inflammatory mediator genes in the joint capsule were detected following upregulation of the NOS2 gene after remobilization. These remobilization-induced inflammatory reactions were partially attenuated by administration of l-NAME. Therefore, NOS2/NO elevation has potential as a novel treatment for remobilization-induced joint inflammation. Gene expression of the hypoxia marker hypoxia inducible factor-1α was upregulated after one day of remobilization, rather than after immobilization. These results suggest that upregulation of NOS2 by remobilization might be not due to hypoxia/reoxygenation.

Inhibition of breast tumor growth by N(G)-nitro-l-arginine methyl ester (l-NAME) is accompanied by activation of fibroblasts.

Nitric Oxide (NO) is involved in many physiological and pathological processes. It is generated by a family of NO synthases (NOS), being the inducible isoform, iNOS, responsible for higher amounts of NO. Here, we report that pharmacological inhibition of NO production by l-NAME reduces both viability and MAPK activated signalling pathways in iNOS positive human and murine cancer cell lines. In vivo, using syngeneic models, in parallel with tumor reduction induced by l-NAME, collagen deposition and α-SMA positive stromal cells are observed. This observation takes place only when tumor cells express iNOS. In vitro, l-NAME induces viability and differentiation on fibroblast. Our results reveal that NO inhibition contributes to stimulate proliferation and activation of fibroblasts in parallel with tumor reduction of iNOS positive breast cancer.

Therapy of the rat hemorrhagic cystitis induced by cyclophosphamide. Stable gastric pentadecapeptide BPC 157, L-arginine, L-NAME.

We focused on the cyclophosphamide-induced hemorrhagic cystitis (100 mg/kg/day intraperitoneally throughout three days) as a particular NO-system disturbance, and therapy possibilities. We demonstrated that it may be attenuated by subsequent administration of the NOS substrate L-arginine (100 mg/kg/day intraperitoneally), aggravated by NOS-blocker L-NAME (5 mg/kg/day intraperitoneally), all influenced by the stable gastric pentadecapeptide BPC 157 (10 µg/kg/day, 10 ng/kg/day, intraperitoneally or perorally, in drinking water). Regularly, cyclophosphamide dose- and time-dependently induced severe hemorrhagic cystitis lesions, gross lesions, and corresponding urothelial necrosis, vesical edema, erosion, hemorrhage, inflammation, and ulceration, microscopically. The bladder wet weight dramatically increased. Functionally, already after first cyclophosphamide administration, there is an increased leak point pressure. Until the second cyclophosphamide administration, L-arginine consistently attenuated regular cyclophosphamide-induced severe hemorrhagic cystitis lesions, grossly and microscopically, but not functionally. L-NAME aggravated these lesions and eradicated beneficial effect of L-arginine when combined. BPC 157 administration after cyclophosphamide, given in either dose or in either regimen markedly attenuated all cyclophosphamide lesions, grossly, microscopically. The increase of the bladder wet weight was consistently attenuated. Functionally, increased leak point pressure was reversed to the values noted in normal rats. The similar findings were noted in rats that received BPC 157 together with L-NAME or L-arginine, given alone or combined. Thus, the lesions are NO-related based on the administration of L-NAME as well as administration of L-arginine, and their mutual interaction, and counteraction by BPC 157 application. Likewise, we reveal new therapeutic possibilities, emphasizing stable gastric pentadecapeptide BPC 157 and L-arginine, versus L-NAME in rats underwent cyclophosphamide-induced cystitis.

The effects of extremely low-frequency pulsed electromagnetic fields on analgesia in the nitric oxide pathway.

There is growing interest in the effects of extremely low-frequency electromagnetic fields on mechanisms in biological organisms. This study's goal is to determine the role of the Nitiric Oxide (NO) pathway for thermal pain by intentionally interfering with it using a pulsed electromagnetic field generated by an extremely low-frequency alternating current (ELF-PEMF) in combination with BAY41-2272 (sGC activator), NOS inhibitor l-NAME, and NO donor l-arginine. This study included 72 adult male Wistar albino rats (mean weight of 230 ±â€¯12 g). The rats were kept at room temperature (22 ±â€¯2 °C) in a 12-h light/dark cycle and in a room with sound insulation. PEMF (50 Hz, 5 mT) were applied four times a day for 30 min and at 15-min intervals for 15 days. Analgesic effects were assessed with tail-flick and hot-plate tests. Before the tests, NO donor l-arginine (300 mg/kg), sGC activator BAY41-2272 (10 mg/kg), and NOS inhibitor l-name (40 mg/kg) were injected intraperitoneally into rats in six randomly-selected groups. The maximum analgesic effect of a 5 mT electromagnetic field was on day 7. PEMF significantly increased the analgesia effect when the functioning of the NO pathway was ensured with l-arginine, which is a NO donor, and BAY41-2271, which is the intracellular receptor and sGC activator. However, there was no difference between rats treated with PEMF and the NOS inhibitor l-NAME as compared to rats only treated with PEMF. In conclusion, PEMF generate analgesia by activating the NO pain pathway.

The SAFE pathway is involved in the postconditioning mechanism of oxytocin in isolated rat heart.

Oxytocin (OT) has a postconditioning effect against the ischemia-reperfusion (I/R) injury. However, its precise cardioprotection mechanism at the early reperfusion phase remains under debate. Our previous study revealed that OT postconditioning (OTpost) is cardioprotective by activating the Reperfusion Injury Salvage Kinase (RISK) pathway. Therefore, the present study is aimed to determine the biological effects of OTpost via the OT receptor and the activation of the JAK/STAT3 signaling pathway, mitochondrial adenosine triphosphate-dependent potassium channel (mitoKATP), nitric oxide (NO) release, and its anti-apoptotic effects against I/R injury in an isolated rat heart model. Sixty-three rats were randomly allocated to one of nine groups. OT was perfused 40 min prior to the regional ischemia or 15 min at the early reperfusion phase. AG490 (a JAK/STAT3 inhibitor), 5HD (a mitoKATP blocker), atosiban (an OT receptor antagonist), L-NAME (a nonspecific nitric oxide synthase inhibitor) were applied either alone or in combination with OT during the pre-ischemia phase and/or in the early reperfusion phase. Myocardial infarct size, hemodynamic factor, ventricular arrhythmia, coronary flow, cardiac biochemical marker, and the apoptosis index were determined at the end of reperfusion. Oxytocin postconditioning reduced infarct size, lactate dehydrogenase activity, arrhythmia score, ventricular fibrillation, and apoptosis. Moreover, AG490, 5HD, atosiban, and L-NAME abrogated the cardioprotective effects of OT. Our results demonstrated that the cardioprotective effects of OT are mediated by NO release, and the activation of mitoKATP and the SAFE pathway through the JAK/STAT3 signaling cascade that finally lead to decrease in the apoptosis index during the early reperfusion phase.

The Effect of Chronic NO Synthase Inhibition on the Vasoactive and Structural Properties of Thoracic Aorta, NO Synthase Activity, and Oxidative Stress Biomarkers in Young SHR.

Although the role of nitric oxide (NO) in essential hypertension is still unclear, the effects of long-term NO deficiency have not yet been investigated during the critical juvenile period in spontaneously hypertensive rats (SHR). We aimed to analyze the effects of chronic NO synthase (NOS) inhibition on systolic blood pressure (sBP), vasoactivity, morphological changes and superoxide level in the thoracic aorta (TA), NOS activity in different tissues, and general biomarkers of oxidative stress in plasma of young SHR. Four-week-old SHR were treated with NG-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg/day, p.o.) for 4-5 weeks. L-NAME treatment induced a transient sBP increase only, and surprisingly, slightly inhibited endothelium-dependent relaxation of TA. Hereby, the inhibition of NOS activity varied from tissue to tissue, ranging from the lowest in the TA and the kidney to the highest in the brain stem. In spite of an increased sensitivity of adrenergic receptors, the maximal adrenergic contraction of TA was unchanged, which was associated with changes in elastin arrangement and an increase in wall thickness. The production of reactive oxygen species in the TA was increased; however, the level of selected biomarkers of oxidative stress did not change. Our findings proved that the TA of young SHR responded to chronic NO deficiency by the development of adaptive mechanisms on the functional (preserved NO-derived vasorelaxation, unincreased contraction) and molecular (preserved NOS activity) level.

Orofacial antinociceptive effect of Mimosa tenuiflora (Willd.) Poiret.

Mimosa tenuiflora (Willd.) Poiret, popularly known in Brazil as "jurema-preta" is widely used against bronchitis, fever, headache and inflammation. Its antioxidant, anti-inflammatory and antinociceptive potential has already been reported. To assess the orofacial antinociceptive effect of M. tenuiflora, ethanolic extracts of M. tenuiflora (leaves, twigs, barks and roots) were submitted to in vitro tests of antioxidant activity. The extract with the highest antioxidant potential was partitioned and subjected to preliminary chemical prospecting, GC-MS, measurement of phenolic content and cytotoxicity tests of the fraction with the highest antioxidant activity. The nontoxic fraction with the highest antioxidant activity (FATEM) was subjected to tests of acute and chronic orofacial nociception and locomotor activity. The possible mechanisms of neuromodulation were also assessed. The EtOAc fraction, obtained from the ethanolic extract of M. tenuiflora barks, was the one with the highest antioxidant potential and nontoxic (FATEM), and Benzyloxyamine was the major constituent (34.27%). FATEM did not alter the locomotor system of mice and reduced significantly the orofacial nociceptive behavior induced by formalin, glutamate, capsaicin, cinnamaldehyde or acidic saline compared to the control group. FATEM also inhibited formalin- or mustard oil-induced temporomandibular nociception. In addition, it also reduced mustard oil-induced orofacial muscle nociception. However, FATEM did not alter hypertonic saline-induced corneal nociception. Neuropathic nociception was reversed by treatment with FATEM. The antinociceptive effect of FATEM was inhibited by naloxone, L-NAME and glibenclamide. FATEM has pharmacological potential for the treatment of acute and neuropathic orofacial pain and this effect is modulated by the opioid system, nitric oxide and ATP-sensitive potassium channels. These results lead us to studies of isolation and characterization of bioactive principles.

Counteraction of perforated cecum lesions in rats: Effects of pentadecapeptide BPC 157, L-NAME and L-arginine.

AIM: To study the counteraction of perforated cecum lesion using BPC 157 and nitric oxide (NO) system agents. METHODS: Alongside with the agents' application (after 1 min, medication (/kg, 10 mL/2 min bath/rat) includes: BPC 157 (10 µg), L-NAME (5 mg), L-arginine (100mg) alone or combined, and saline baths (controls)) on the rat perforate cecum injury, we continuously assessed the gross reappearance of the vessels (USB microcamera) quickly propagating toward the defect at the cecum surface, defect contraction, bleeding attenuation, MDA- and NO-levels in cecum tissue at 15 min, and severity of cecum lesions and adhesions at 1 and 7 d. RESULTS: Post-injury, during/after a saline bath, the number of vessels was significantly reduced, the defect was slightly narrowed, bleeding was significant and MDA-levels increased and NO-levels decreased. BPC 157 bath: the vessel presentation was markedly increased, the defect was noticeably narrowed, the bleeding time was shortened and MDA- and NO-levels remained normal. L-NAME: reduced vessel presentation but not more than the control, did not change defect and shortened bleeding. L-arginine: exhibited less vessel reduction, did not change the defect and prolonged bleeding. In combination, mutual counteraction occurred (L-NAME + L-arginine) or the presentation was similar to that of BPC 157 rats (BPC 157 + L-NAME; BPC 157 + L-arginine; BPC 157 + L-NAME + L-arginine), except the defect did not change. Thereby at day 1 and 7, saline, L-NAME, L-arginine and L-NAME + L-arginine failed (defect was still open and large adhesions present). CONCLUSION: The therapeutic effect was achieved with BPC 157 alone or in combination with L-NAME and L-arginine as it was able to consolidate the stimulating and inhibiting effects of the NO-system towards more effective healing recruiting vessels.

Bypassing major venous occlusion and duodenal lesions in rats, and therapy with the stable gastric pentadecapeptide BPC 157, L-NAME and L-arginine.

AIM: To investigate whether duodenal lesions induced by major venous occlusions can be attenuated by BPC 157 regardless nitric oxide (NO) system involvement. METHODS: Male Wistar rats underwent superior anterior pancreaticoduodenal vein (SAPDV)-ligation and were treated with a bath at the ligated SAPDV site (BPC 157 10 µg, 10 ng/kg per 1 mL bath/rat; L-NAME 5 mg/kg per 1 mL bath/rat; L-arginine 100 mg/kg per 1 mL bath/rat, alone and/or together; or BPC 157 10 µg/kg instilled into the rat stomach, at 1 min ligation-time). We recorded the vessel presentation (filled/appearance or emptied/disappearance) between the 5 arcade vessels arising from the SAPDV on the ventral duodenum side, the inferior anterior pancreaticoduodenal vein (IAPDV) and superior mesenteric vein (SMV) as bypassing vascular pathway to document the duodenal lesions presentation; increased NO- and oxidative stress [malondialdehyde (MDA)]-levels in duodenum. RESULTS: Unlike the severe course in the SAPDV-ligated controls, after BPC 157 application, the rats exhibited strong attenuation of the mucosal lesions and serosal congestion, improved vessel presentation, increased interconnections, increased branching by more than 60% from the initial value, the IAPDV and SMV were not congested. Interestingly, after 5 min and 30 min of L-NAME and L-arginine treatment alone, decreased mucosal and serosal duodenal lesions were observed; their effect was worsened at 24 h, and no effect on the collateral vessels and branching was seen. Together, L-NAME+L-arginine antagonized each other's response, and thus, there was an NO-related effect. With BPC 157, all SAPDV-ligated rats receiving L-NAME and/or L-arginine appeared similar to the rats treated with BPC 157 alone. Also, BPC 157 in SAPDV-ligated rats normalized levels of NO and MDA, two oxidative stress markers, in duodenal tissues. CONCLUSION: BPC 157, rapidly bypassing occlusion, rescued the original duodenal flow through IAPDV to SMV flow, an effect related to the NO system and reduction of free radical formation.

Effects of nitric oxide inhibitors in mice with bladder outlet obstruction

ABSTRACT Purpose To investigate the lower urinary tract changes in mice treated with L-NAME, a non-selective competitive inhibitor of nitric oxide synthase (NOS), or aminoguanidine, a competitive inhibitor of inducible nitric oxide synthase (iNOS), after 5 weeks of partial bladder outlet obstruction (BOO), in order to evaluate the role of constitutive and non-constitutive NOS in the pathogenesis of this experimental condition. Materials and Methods C57BL6 male mice were partially obstructed and randomly allocated into 6 groups: Sham, Sham + L-NAME, Sham + aminoguanidine, BOO, BOO + L-NAME and BOO + aminoguanidine. After 5 weeks, bladder weight was obtained and cystometry and tissue bath contractile studies were performed. Results BOO animals showed increase of non-voiding contractions (NVC) and bladder capacity, and also less contractile response to Carbachol and Electric Field Stimulation. Inhibition of NOS isoforms improved bladder capacity and compliance in BOO animals. L-NAME caused more NVC, prevented bladder weight gain and leaded to augmented contractile responses at muscarinic and electric stimulation. Aminoguanidine diminished NVC, but did not avoid bladder weight gain in BOO animals and did not improve contractile responses. Conclusion It can be hypothesized that chronic inhibition of three NOS isoforms in BOO animals leaded to worsening of bladder function, while selective inhibition of iNOS did not improve responses, what suggests that, in BOO animals, alterations are related to constitutive NOS.

Dual NEP/ECE inhibition improves endothelial function in mesenteric resistance arteries of 32-week-old SHR.

Endothelin 1 (ET-1), a potent vasoconstrictor, pro-mitogenic and pro-inflammatory peptide, may promote development of endothelial dysfunction and arterial remodeling. ET-1 can be formed through cleavage of big-ET-1 by endothelin-converting enzyme (ECE) or neutral endopeptidase (NEP). We investigated whether chronic treatment with the novel dual NEP/ECE inhibitor SOL1 improves functional and structural properties of resistance-sized arteries of 32-week-old male spontaneously hypertensive rats (SHR). SHR received a chronic 4-week treatment with SOL1, losartan or hydralazine. We then compared effects of inhibition of NO synthase (NOS) (100 µM l-NAME), blockade of ETA- and ETB-receptors (10 µM bosentan) and stimulation of the endothelium with 0.001-10 µM acetylcholine (ACh) in isolated third-order mesenteric resistance arteries. Losartan and hydralazine significantly lowered blood pressure. Losartan decreased the media-to-lumen ratio of resistance arteries. l-NAME (1) increased arterial contractile responses to K+ (5.9-40 mM) in the losartan, SOL1 and vehicle group and (2) increased the sensitivity to phenylephrine (PHE; 0.16-20 µM) in the SOL1 group but not in the losartan, hydralazine and vehicle group. Relaxing responses to ACh in the absence or presence of l-NAME during contractions induced by either 10 µM PHE or 40 mM K+ were not altered by any in vivo treatment. Acute treatment with bosentan did, however, significantly improve maximal relaxing responses involving endothelium-derived nitric oxide and -hyperpolarizing factors in the SOL1 group but not in the losartan, hydralazine or vehicle group. Thus, chronic inhibition of NEP/ECE improved basal endothelial function but did not alter blood pressure, resistance artery structure and stimulated endothelium-dependent relaxing responses in 32-week-old SHR.

Effects of nitric oxide inhibitors in mice with bladder outlet obstruction.

PURPOSE: To investigate the lower urinary tract changes in mice treated with L-NAME, a non-selective competitive inhibitor of nitric oxide synthase (NOS), or aminoguanidine, a competitive inhibitor of inducible nitric oxide synthase (iNOS), after 5 weeks of partial bladder outlet obstruction (BOO), in order to evaluate the role of constitutive and non-constitutive NOS in the pathogenesis of this experimental condition. MATERIALS AND METHODS: C57BL6 male mice were partially obstructed and randomly allocated into 6 groups: Sham, Sham + L-NAME, Sham + aminoguanidine, BOO, BOO + L-NAME and BOO + aminoguanidine. After 5 weeks, bladder weight was obtained and cystometry and tissue bath contractile studies were performed. RESULTS: BOO animals showed increase of non-voiding contractions (NVC) and bladder capacity, and also less contractile response to Carbachol and Electric Field Stimulation. Inhibition of NOS isoforms improved bladder capacity and compliance in BOO animals. L-NAME caused more NVC, prevented bladder weight gain and leaded to augmented contractile responses at muscarinic and electric stimulation. Aminoguanidine diminished NVC, but did not avoid bladder weight gain in BOO animals and did not improve contractile responses. CONCLUSION: It can be hypothesized that chronic inhibition of three NOS isoforms in BOO animals leaded to worsening of bladder function, while selective inhibition of iNOS did not improve responses, what suggests that, in BOO animals, alterations are related to constitutive NOS.

Nitric oxide mediates effects of acute, not chronic, naltrexone on LPS-induced hepatic encephalopathy in cirrhotic rats.

Recent studies suggest endogenous opioids and nitric oxide (NO) are involved in the pathophysiology of hepatic encephalopathy (HE). In this study, the interaction between the opioid receptor antagonist and NO was investigated on lipopolysaccharide (LPS)-induced HE in cirrhotic rats. Male rats were divided in the sham- and bile duct ligation (BDL)-operated groups. Animals were treated with saline; naltrexone (10 mg/kg, i.p.); or L-NAME (3 mg/kg, i.p.), alone or in combination with naltrexone. To induce HE, LPS (1 mg/kg, i.p.) was injected 1 h after the final drug treatment. HE scoring, hepatic histology, and plasma NO metabolites levels and mortality rate were recorded. Deteriorated level of consciousness and mortality after LPS administration significantly ameliorated following both acute and chronic treatment with naltrexone in cirrhotic rats. However, acute and chronic administration of L-NAME did not change HE scores in cirrhotic rats. The effects of acute but not chronic treatment of naltrexone on HE parameters were reversed by L-NAME. Plasma NOx concentrations elevated in BDL rats, which were decreased after acute and chronic treatment by naltrexone or L-NAME, significantly. We suggest both acute and chronic treatment with naltrexone improved LPS-induced HE. But, only acute treatment with naltrexone may affect through NO pathway.

Stable gastric pentadecapeptide BPC 157 in the treatment of colitis and ischemia and reperfusion in rats: New insights.

AIM: To provide new insights in treatment of colitis and ischemia and reperfusion in rats using stable gastric pentadecapeptide BPC 157. METHODS: Medication [BPC 157, L-NAME, L-arginine (alone/combined), saline] was bath at the blood deprived colon segment. During reperfusion, medication was BPC 157 or saline. We recorded (USB microscope camera) vessel presentation through next 15 min of ischemic colitis (IC-rats) or reperfusion (removed ligations) (IC + RL-rats); oxidative stress as MDA (increased (IC- and IC + RL-rats)) and NO levels (decreased (IC-rats); increased (IC + RL-rats)) in colon tissue. IC + OB-rats [IC-rats had additional colon obstruction (OB)] for 3 d (IC + OB-rats), then received BPC 157 bath. RESULTS: Commonly, in colon segment (25 mm, 2 ligations on left colic artery and vein, 3 arcade vessels within ligated segment), in IC-, IC + RL-, IC + OB-rats, BPC 157 (10 µg/kg) bath (1 mL/rat) increased vessel presentation, inside/outside arcade interconnections quickly reappeared, mucosal folds were preserved and the pale areas were small and markedly reduced. BPC 157 counteracted worsening effects induced by L-NAME (5 mg) and L-arginine (100 mg). MDA- and NO-levels were normal in BPC 157 treated IC-rats and IC + RL-rats. In addition, on day 10, BPC 157-treated IC + OB-rats presented almost completely spared mucosa with very small pale areas and no gross mucosal defects; the treated colon segment was of normal diameter, and only small adhesions were present. CONCLUSION: BPC 157 is a fundamental treatment that quickly restores blood supply to the ischemically injured area and rapidly activates collaterals. This effect involves the NO system.