L-NG-nitroarginine Methyl Ester Research Articles

Current insights and future perspectives of flavonoids: A promising antihypertensive approach.

Hypertension, or high blood pressure (BP), is a complex disease influenced by various risk factors. It is characterized by persistent elevation of BP levels, typically exceeding 140/90 mmHg. Endothelial dysfunction and reduced nitric oxide (NO) bioavailability play crucial roles in hypertension development. L-NG-nitro arginine methyl ester (L-NAME), an analog of L-arginine, inhibits endothelial NO synthase (eNOS) enzymes, leading to decreased NO production and increased BP. Animal models exposed to L-NAME manifest hypertension, making it a useful design for studying the hypertension condition. Natural products have gained interest as alternative approaches for managing hypertension. Flavonoids, abundant in fruits, vegetables, and other plant sources, have potential cardiovascular benefits, including antihypertensive effects. Flavonoids have been extensively studied in cell cultures, animal models, and, to lesser extent, in human trials to evaluate their effectiveness against L-NAME-induced hypertension. This comprehensive review summarizes the antihypertensive activity of specific flavonoids, including quercetin, luteolin, rutin, troxerutin, apigenin, and chrysin, in L-NAME-induced hypertension models. Flavonoids possess antioxidant properties that mitigate oxidative stress, a major contributor to endothelial dysfunction and hypertension. They enhance endothelial function by promoting NO bioavailability, vasodilation, and the preservation of vascular homeostasis. Flavonoids also modulate vasoactive factors involved in BP regulation, such as angiotensin-converting enzyme (ACE) and endothelin-1. Moreover, they exhibit anti-inflammatory effects, attenuating inflammation-mediated hypertension. This review provides compelling evidence for the antihypertensive potential of flavonoids against L-NAME-induced hypertension. Their multifaceted mechanisms of action suggest their ability to target multiple pathways involved in hypertension development. Nonetheless, the reviewed studies contribute to the evidence supporting the useful of flavonoids for hypertension prevention and treatment. In conclusion, flavonoids represent a promising class of natural compounds for combating hypertension. This comprehensive review serves as a valuable resource summarizing the current knowledge on the antihypertensive effects of specific flavonoids, facilitating further investigation and guiding the development of novel therapeutic strategies for hypertension management.

Antinociception induced by rosuvastatin in mice: Modulation by opioid receptor antagonists, risperidone and l-name

Statins are widely used in cardiovascular disease as cholesterol lowering drugs. However, they also have other actions (pleiotropic effects) including antiproliferative, antithrombotic, neuroprotective, immunomodulatory, anti-inflammatory and antinociceptive activity. The aim of this study was to determine the antinociception properties of rosuvastatin in two murine models of pain and the involvement of opioid antagonists (naltrexone, naltrindole, norbinaltorphimine), risperidone, and L-NAME (L-NG-nitro arginine methyl ester) in this effect. Rosuvastatin was chosen among available statins because it is commonly prescribed and has high potency, efficacy, and an acceptable safety profile. Rosuvastatin antinociception was evaluated in the acetic acid writhing test and the formalin hind paw test by dose-response curves, before and after the i.p. administration of opioid antagonists, risperidone, and L-NAME. This work demonstrates that the assayed drugs modulate the antinociceptive effect of rosuvastatin in both experimental murine pain tests. The antinociception effect described for rosuvastatin may be due to a particular modulation induced by the opioid antagonists, risperidone and L-NAME. Given the broad effects of rosuvastatin, the results of this study may have novel clinical implications in the therapy of pain.

Correlational Study of Aminopeptidase Activities between Left or Right Frontal Cortex versus the Hypothalamus, Pituitary, Adrenal Axis of Spontaneously Hypertensive Rats Treated with Hypotensive or Hypertensive Agents.

It has been suggested that the neuro-visceral integration works asymmetrically and that this asymmetry is dynamic and modifiable by physio-pathological influences. Aminopeptidases of the renin-angiotensin system (angiotensinases) have been shown to be modifiable under such conditions. This article analyzes the interactions of these angiotensinases between the left or right frontal cortex (FC) and the same enzymes in the hypothalamus (HT), pituitary (PT), adrenal (AD) axis (HPA) in control spontaneously hypertensive rats (SHR), in SHR treated with a hypotensive agent in the form of captopril (an angiotensin-converting enzyme inhibitor), and in SHR treated with a hypertensive agent in the form of the L-Arginine hypertensive analogue L-NG-Nitroarginine Methyl Ester (L-NAME). In the control SHR, there were significant negative correlations between the right FC with HPA and positive correlations between the left FC and HPA. In the captopril group, the predominance of negative correlations between the right FC and HPA and positive correlations between the HPA and left FC was maintained. In the L-NAME group, a radical change in all types of interactions was observed; particularly, there was an inversion in the predominance of negative correlations between the HPA and left FC. These results indicated a better balance of neuro-visceral interactions after captopril treatment and an increase in these interactions in the hypertensive animals, especially in those treated with L-NAME.

Endothelium-dependent vasorelaxation effects of F5 fraction of Crinum amabile chloroform extract

BackgroundVascular dysfunction can lead to many health problems including hypertension and heart disease. The complexities of vascular dysfunction and vascular disorder-related diseases have prompted the search for many new biologically active compounds in the efforts of resolving the problems. Previous studies have shown that Amaryllidaceae alkaloids exert multiple biological activities, including the vasorelaxation effect. Crinum amabile, which is a family member of Amaryllidaceae, is believed to possess a promising pharmacological activity as a vasorelaxant.MethodThe vasorelaxation activities of Crinum amabile extracts and fractions were determined using in vitro models of phenylephrine pre-contracted intact and denuded rat aortic rings. The mechanistic pathways of vasorelaxation were investigated by pre-treatment of endothelium-intact rat aortic rings with L-NG Nitro Arginine Methyl Ester (L-NAME), methylene blue (MB), indomethacin, atropine and propranolol, respectively.ResultsThe results showed that chloroform extract (CE) of Crinum amabile exhibited the highest vasorelaxation activity, and further fractionation of CE found that its F5 fraction exerted the strongest activity. An in-depth study on the mechanistic pathway revealed that the endothelium-dependent vasorelaxation induced by F5 fraction was primarily achieved through stimulation of prostaglandin (PGI2) production and partially associated with NO/cGMP activation pathway.ConclusionFindings from this study suggest that Crinum amabile can serve as a promising candidate for the discovery and development of the new vasorelaxant drug.

Abstract P209: Six Weeks Oral Losartan Treatment Improves Endothelium-dependent Dilation In Normotensive Women With A History Of Preeclampsia

Women with a history of preeclampsia have a 4-fold increased risk of cardiovascular disease compared to women who had a healthy pregnancy. These women demonstrate microvascular endothelial dysfunction, mediated by reduced nitric oxide (NO)-dependent dilation and increased sensitivity to angiotensin II. We hypothesized that systemic angiotensin II type 1 receptor (AT 1 R) inhibition would improve endothelium- and NO-dependent dilation in the microvasculature of women with a history of preeclampsia. Seven normotensive (seated SBP 118±6; DBP 78±6 mmHg) women (33±6 years of age, 11±7 months postpartum) with a history of preeclampsia participated in a double-blind placebo-controlled crossover study. Following 6 weeks of placebo and losartan treatment (50 mg/day), participants wore a 24-hour blood pressure monitor and completed 1 study visit in which 2 intradermal microdialysis fibers were placed in the skin of the ventral forearm for graded infusions of acetylcholine (ACh, 10 -7 -10 2 mM) or ACh + 15 mM N G nitro L-arginine methyl ester (L-NAME; NO synthase inhibitor) to assess endothelium- and NO-dependent dilation, respectively. Red blood cell flux was measured over each microdialysis site by laser-Doppler flowmetry. Cutaneous vascular conductance was calculated (CVC=Doppler flux/mean arterial pressure) and normalized to maximum (%max; 28 mM SNP + 43°C). Systemic losartan treatment augmented endothelium-dependent (losartan: 96±4 vs placebo: 70±14%max; P <0.001) and NO-dependent (losartan: 35±14 vs placebo: 23±8%; P <0.001) dilation. There was no effect of treatment on 24-hour systolic blood pressure (losartan: 117±4 vs placebo: 117±8 mmHg), diastolic blood pressure (losartan: 72±5 vs placebo: 71±5 mmHg) or mean arterial pressure (losartan: 92±4 vs placebo: 92±6 mmHg; all P>0.05 ). Losartan treatment increased endothelium-dependent vasodilation via NO-mediated pathways in the absence of changes in blood pressure in women with a history of preeclampsia. These data suggest that systemic AT 1 R inhibition may be a viable therapeutic approach to treat persistent microvascular dysfunction in otherwise healthy women who have had preeclampsia.

Standardized seed extract of Cajanus cajan (L) Millsp. produced antinociceptive and anti-inflammatory actions through inhibition of inflammatory mediators and activation of opioidergic signaling

Background and PurposePeripheral tissue damage and diseases could lead to persistent pain beyond possible resolution suggestive of disease-promoting condition which gives rise to chronic pain. The inability of current medications to manage some chronic inflammatory and painful conditions necessitate the need for better treatment options. Natural products have been a veritable source for the discovery of more efficacious and safer therapeutics. Cajanus cajan (L) Millsp, (Fabaceae) is used in traditional African medicines for the treatment of painful, gut disturbance and inflammatory conditions. Hence, the current study aims to investigate the anti-inflammatory and antinociceptive actions of the ethanol seed extract of Cajanus cajan (CC) in rodents and possible mechanisms of action. MethodsHigh performance liquid chromatography coupled with diode-array detection (HPLC-DAD) was used to identify 8 major flavonoids in CC. Antinociceptive activity was investigated using the acetic acid-induced writhing reflex, biphasic formalin-induced flinching behaviour and supraspinal hot plate-evoked nociception in mice. Carrageenan-induced rat paw oedema test was used to evaluate the anti-inflammatory action of CC in rats. Possible mechanism of antinociception and anti-inflammatory actions were examined using both in vivo model and molecular docking procedures against µ-opioid receptor (MOR), cyclooxygenase-2 (COX-2) and phospholipase A2 (PLA2) proteins, respectively. ResultsThe chromatographic procedure qualitatively and quantitatively confirmed the presence of rutin, quercetin, gallic acid, luteolin, pinostrobin, BiochaninA, formononetin and apigenin in CC. The in vivo nociceptive assay, showed that CC (50, 100, or 200 mg/kg, p.o.) significantly decreased mean number of writhing reflex with peak effect at 50 mg/kg (72% inhibition) when compared with vehicle control in mouse writhing test. Similarly, the biphasic formalin-induced nociception was significantly reduced by CC (50 mg/kg) with 24.61 and 66.73% inhibition of nociceptive reactions in both the early and late phases of formalin-induced inflammatory pain, respectively. In addition, CC significantly increased supraspinal thermally mediated pain threshold with maximum possible effects of 42.25 and 52.16% at CC 50 and 100 mg/kg, respectively, in hot-plate test. Similarly, CC100mg/kg caused time course inhibition of carrageenan-induced paw oedema in rat with peak effect (65.78%, CC 100 mg/kg; 6 h). Interestingly, the antinociceptive action of CC was blocked by the pre-treatment of mice with l-NG-nitro arginine methyl ester (L-NAME) or naloxone. The molecular docking analysis revealed prominent interactions of pinostrobin, physcion and lupeol with MOR, COX-2, and PLA2, respectively. ConclusionFindings from this study showed that Cajanus cajan seeds extract possesses anti-nociceptive and anti-inflammatory through inhibition of inflammatory mediators (PLA2/COX-2) and activation of opioidergic signalling.

CNS sites controlling the gastric pyloric sphincter: Neuroanatomical and functional study in the rat.

The pyloric sphincter receives parasympathetic vagal innervation from the dorsal motor nucleus of the vagus (DMV). However, little is known about its higher-order neurons and the nuclei that engage the DMV neurons controlling the pylorus. The purpose of the present study was twofold. First, to identify neuroanatomical connections between higher-order neurons and the DMV. This was carried out by using the transneuronal pseudorabies virus PRV-152 injected into rat pylorus torus and examining the brains of these animals for PRV labeling. Second, to identify the specific sites within the DMV that functionally control the motility and tone of the pyloric sphincter. For these studies, experiments were performed to assess the effect of DMV stimulation on pylorus activity in urethane-anesthetized male rats. A strain gauge force transducer was sutured onto the pyloric tonus to monitor tone and motility. L-glutamate (500pmol/30 nL) was microinjected unilaterally into the rostral and caudal areas of the DMV. Data from the first study indicated that neurons labeled with PRV occurred in the DMV, hindbrain raphe nuclei, midbrain Edinger-Westphal nucleus, ventral tegmental area, lateral habenula, and arcuate nucleus. Data from the second study indicated that microinjected L-glutamate into the rostral DMV results in contraction of the pylorus blocked by intravenously administered atropine and ipsilateral vagotomy. L-glutamate injected into the caudal DMV relaxed the pylorus. This response was abolished by ipsilateral vagotomy but not by intravenously administered atropine or L-NG-nitroarginine methyl ester (L-NAME). These findings identify the anatomical and functional brain neurocircuitry involved in controlling the pyloric sphincter. Our results also show that site-specific stimulation of the DMV can differentially influence the activity of the pyloric sphincter by separate vagal nerve pathways.

Zinc induced regulation of PCR1 gene for cadmium stress resistance in rice roots

In this study, the interaction between zinc (Zn) and cadmium (Cd) was investigated in rice roots to evaluate how Zn can protect the plants from Cd stress. Rice seedlings were treated with Cd (100 μM) and Zn (100 μM) in different combinations (Cd alone, Zn alone, Zn+ Cd, Zn+ Cd+ L-NAME, Zn+ Cd+ L-NAME+ SNP). Rice roots treated with only Zn also displayed similar toxic effects, however when combined with Cd exhibited improved growth. Treating the plant with Zn along with Cd distinctly reduced Cd concentration in roots while increasing its own accumulation due to modulation in expression of Zinc-Regulated Transporter (ZRT)-/IRT-Like Protein (OsZIP1) and Plant Cadmium Resistance1 (OsPCR1). Cd reduced plant biomass, cell viability, pigments, photosynthesis and causing oxidative stress due to inhibition in ascorbate-glutathione cycle. L-NAME (NG-nitro L-arginine methyl ester), prominently suppressed the beneficial impacts of Zn against Cd stress, whereas the presence of a NO donor, sodium nitroprusside (SNP), significantly reversed this effect of L-NAME. Collectively, results point that NO signalling is essential for Zn- mediated cross-tolerance against Cd stress via by modulating uptake of Cd and Zn and expression of OsZIP1 and OsPCR1, and ROS homeostasis due to fine tuning of ascorbate-glutathione cycle which finally lessened oxidative stress in rice roots. The results of this study can be utilized to develop new varieties of rice through genetic modifications which will be of great significance for maintaining crop productivity in Cd-contaminated areas throughout the world.

Licofelone Attenuates Acetic Acid-Induced Colitis in Rats Through Suppression of the Inflammatory Mediators.

Licofelone is a dual Cyclooxygenase 1,2 (COX1,2)/5-lipoxygenase) 5-LOX (inhibitor with analgesic and anti-inflammatory effects with possible functions on inflammatory bowel disease (IBD), which is a chronic recurrent condition with no particular treatment. This study evaluated the anti-inflammatory effects of licofelone on acetic acid-induced colitis in rats. Ten groups of male Wistar rats (n = 6) were used. Sham, control group, licofelone at doses of 2.5, 5, and 10 mg/kg, L-NG-nitro arginine methyl ester (L-NAME) (10 mg/kg, i.p.), aminoguanidine (AG) (100 mg/kg, i.p.), 30 min before using licofelone (10 mg/kg). Also, three groups received L-NAME, aminoguanidine, or dexamethasone. Macroscopic, microscopic, and biochemical analysis of myeloperoxidase (MPO), and nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), superoxide dismutase (SOD), reactive oxygen species (ROS), and Toll-like receptor 4 (TLR-4) were assessed in colon tissue. Licofelone at a dose of 10 mg/kg attenuated colitis, increased SOD activity, and significantly reduced colonic levels of the abovementioned inflammatory factors. In addition, licofelone improved macroscopic and microscopic symptoms in the acetic acid-induced colitis model. Moreover, the concurrent use of nitric oxide synthase (NOS) inhibitors with 10 mg/kg of licofelone reversed the observed positive effects, demonstrating the function of nitric oxide in IBD pathogenesis and the probable mechanism for licofelone in the healing process of induced colitis. A reduced level of inflammatory factors confirmed the anti-inflammatory activity of licofelone as a dual COX1,2/5-LOX inhibitor. Furthermore, outcomes revealed the protective role of licofelone in treating experimental colitis. The findings are suggestive of the potential use of licofelone in IBD.

(081) Comparing the Contributions of Nitric Oxide and Estrogen to Methamphetamine-Induced Alterations of Vaginal Blood Flow in Rats

Abstract Introduction Vaginal dryness is a frequent complaint, especially in post-menopausal women. The physiology underlying the production of vaginal lubrication in response to arousing stimuli is established; however, no current pharmacological agents successfully target mechanisms utilizing this physiology. Previous research from our lab has demonstrated that female methamphetamine (meth) users experience the production of excessive vaginal lubrication immediately following an intravenous injection of methamphetamine, and we have recapitulated this in an anesthetized rodent model. We have also found that this vaginal lubrication, as well as vaginal blood flow increased by meth, are heavily nitric oxide dependent. Objective The purpose of the current study is to determine if increased vaginal blood flow correlates with increased vaginal lubrication in response to meth, and to determine if alterations in this blood flow are dependent upon nitric oxide, estrogen, or both. Methods Adult female Wistar rats were implanted with chronic indwelling jugular catheters and allowed at least one week to recover from surgery. Rats anesthetized with isoflurane gas were intravenously infused with meth or saline via the implanted catheter. Vaginal blood flow, measured using a Periflux System 5000 and a small laser probe inserted 5-10 mm into the vaginal canal, was continuously recorded before and for at least twenty minutes following drug administration. After establishing meth-induced alterations in vaginal blood flow, rats were pre-treated with L-NG-Nitro arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor or fulvestrant, an estrogen receptor antagonist, followed by meth administration using the same procedure for measuring blood flow to determine the contribution of nitric oxide and estrogen. Results Meth immediately increases vaginal blood flow, followed by a decrease in perfusion, which is characteristic of a drug that induces such profound sympathetic activation. L-NAME reduced meth-induced increases in vaginal blood flow, and we predict that fulvestrant will be less effective. Conclusions Nitric oxide and estrogen are molecules critical to the production of vaginal lubrication. Nitric oxide, important for the vasodilation cascade leading to the production of vaginal transudate, contributes to meth-induced increases in vaginal blood flow and vaginal lubrication. Estrogen signaling likely contributes to meth-induced increases in vaginal blood flow, and thus, vaginal lubrication, but not as substantially as nitric oxide, making nitric oxide a better potential target for those suffering from vaginal dryness. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Embera NeuroTherapeutics & JanOne, both affiliations unrelated to current research

364 Beneficial Actions of SGLT2 Inhibition and H2S Therapy in Heart Failure with Preserved Ejection Fraction

OBJECTIVES/GOALS: SGLT2i therapy is currently a cornerstone in heart failure with preserved ejection fraction (HFpEF) therapy. Similarly, H2S has been shown to be beneficial in preclinical models of heart failure. With this in mind, we sought to investigate the effects of the SGLT2i and H2S donor therapy alone or in combination in a rodent model of cardiometabolic HFpEF. METHODS/STUDY POPULATION: Male C57BL/6N mice (9 weeks of age) were fed a high fat, Western diet (HFD) and received L-NG-Nitro arginine methyl ester (L-NAME) in the drinking water (0.5 g/L) to induce HFpEF. At 5 weeks, animals were randomized to either control, H2S donor (SG-1002, 90 mg/kg/d, P.O), Empagliflozin (155 mg/L, P.O), or the combination of SG-1002 and Empagliflozin for an additional 5 weeks while being maintained on HFD and L-NAME. Echocardiography, left ventricular invasive LV and systemic hemodynamics, and exercise capacity testing were performed to assess cardiovascular disease severity. Fasted glucose, circulating triglyceride and cholesterol content were similarly measured to quantify key clinical metabolic parameters. H2S and its metabolite, sulfane sulfur, were quantified to assure adequate H2S donation. RESULTS/ANTICIPATED RESULTS: Administration of SG-1002 restored H2S and sulfane sulfur to normal circulating levels. All treatment groups exhibited similar improvements in LV diastolic dysfunction as measured by E/E’and LVEDP. Combination therapy significantly improved exercise capacity whereas the monotherapy groups did not. Treatment with SG-1002 decreased fasting glucose and circulating cholesterol while all treatment groups displayed decreased circulating triglycerides and body weight compared to HFpEF control. DISCUSSION/SIGNIFICANCE: These data indicate that restoring H2S or treatment with an SGLT2i in this preclinical HFpEF model attenuates pathology. Combination of both drugs exhibited greater benefit than either monotherapy in important HFpEF parameters such as exercise capacity. Further studies are underway to characterize the benefits observed from combination therapy.

Antidepressant- and anxiolytic-like actions of Cajanus cajan seed extract mediated through monoaminergic, nitric oxide-cyclic GMP and GABAergic pathways.

The seeds of Cajanus cajan (L) Millsp, are used in Traditional medicine for the treatment of anxiety and other neurological disorders. Hence, this study is designed to investigate the antidepressant- and anxiolytic-like properties of ethanol seed extract of Cajanus cajan (CC) in mice. CC (50, 100 or 200mg/kg, p.o.) was administered 1h before subjecting the animals to different behavioral models: forced swim test (FST) and tail suspension test (TST) (depressive-like behaviour), open field test (OFT), elevated plus maze (EPM), light-dark test (LDT) and hole-board test (HBT) for anxiety-like behaviour. To ascertain the pharmacodynamic of CC mice were pretreated with monoaminergic, nitrergic and GABAergic receptors antagonists. As well as molecular docking analysis of about 19 flavonoids present in CC on GABAA, α2 adrenoceptors and 5-HT2A receptors. CC (50, 100 or 200mg/kg, p.o.) treatment significantly reduced immobile time in both FST and TST when compared with vehicle-treated control. However, the pretreatment of mice with prazosin/yohimbine (α1/2 adrenoceptor antagonists, respectively), WAY100635 (5-HT1A receptor antagonist), ketanserin (5-HT2A receptor antagonist), sulpiride (dopamine D2 receptor antagonist), L-NG-Nitro arginine methyl ester (L-NAME), or methylene blue reversed the antidepressant-like effect of CC. In anxiety model, CC produced significant (p<0.05) increase in open arms exploration and head dipping behavior which was reversed by flumazenil (benzodiazepine receptor antagonist) in the EPM. Docking analysis showed significant binding affinity of orientin, vitexin, pinostrobin and quercetin with 5HT2A, α2-adrenoceptor and GABAA receptors. Findings from this study showed that C.cajan seeds extract exerts antidepressant-like effect through participation of monoaminergic systems (5-HT2 receptor, α1/α2-adrenoceptors, and dopamine D2-receptors), nitric oxide-cyclic GMP pathway and anxiolytic-like effect via GABAA benzodiazepine receptors. Moreso, presence of flavonoids with significant binding energies with monoaminergic and GABAergic systems support the potential of the extract in the management of mixed anxiety-depressive illness.

Effect of Calamintha officinalis on Vascular Contractility and Angiotensinconverting Enzyme-2.

The study aimed to assess the antihypertensive activity of Calamintha officinalis. Calamintha officinalis (CO) is a medicinal and aromatic herb as well as an antihypertensive plant that is widely used for its medicinal properties in several regions. This study aimed to evaluate the effect of the aqueous extract of Calamintha officinalis (AECO) on vasorelaxant activity and arterial blood pressure under normal and hypertensive states in rats. Additionally, the effect of AECO on vascular angiotensin-converting enzyme 2 (ACE-2) was assessed. In the current study, AECO (100 mg/Kg) was prepared, and its antihypertensive ability was assessed in L-NG-Nitro arginine methyl ester (L-NAME)-induced hypertensive rats. Blood pressure and heart rate were recorded for 6 h for the acute experiment and during seven days for the subchronic treatment. The results indicated that AECO reduced the systolic, diastolic, and mean arterial blood pressure in hypertensive rats. In addition, the study showed that AECO exerts a vasorelaxant ability through the sGC-cGMP induction pathway, vascular cyclooxygenase pathway, and the opening of K+ channels. However, AECO had no inhibitory effect on aortic ACE-2. The study illustrates the beneficial action of AECO as an antihypertensive and vasorelaxant agent.

Vascular Effects of the Fetal Hemoglobin Inducer Agent 3-(1,3-Dioxoisoindolin-2-yl) Benzyl Nitrate.

Vascular endothelium is a protective layer of cells lining the lumen of blood vessels that plays important roles by releasing factors responsible for controlling the vascular tone, regulating the expression of pro-inflammatory cytokines, and expressing adhesion molecules involved in vascular hemostasis. Imbalance of vascular properties leads to endothelial dysfunction (ED) and cardiovascular damage. Some diseases, such as sickle cell anemia, are characterized by ED with reduction in the levels of nitric oxide (NO). Previously, we have shown that the fetal hemoglobin inducer agent 3-(1,3-dioxoisoindolin-2-yl) benzyl nitrate (Lapdesf-4c) could act as NO donor, inhibiting platelet aggregation and reducing the inflammation associated with SCA. However, the vascular effect of this compound was not yet studied. Herein, we evaluated the effects of Lapdesf-4c in vascular reactivity experiments using aortic rings from male Wistar rats (300 g/90 days). We have found that Lapdesf-4c induced vasodilation in the presence (E+) or absence of endothelium (E-) with an average of EMax values of 101.8 ± 3.33% and 111.8 ± 3.21%. The mechanism of action was studied using 1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one (ODQ), L-NG-nitroarginine methyl ester (L-NAME), and hydroxocobalamin. The EMax values for those pathways were hydroxocobalamin (30.6 ± 2.21%), ODQ (4.75 ± 0.51%), and L-NAME (109 ± 3.65), suggesting that Lapdesf-4c exhibits NO-dependent mechanisms. Lapdesf-4c was able to prevent angiotensin-induced ED after incubation of aorta rings for 1 h. We found based on the concentration-effect curve using acetylcholine (ACh) that pEC50 values for the control, Ang II, and combination of (Ang II + Lapdesf-4c) were 6.73, 6.46, and 7.15, respectively. In conclusion, Lapdesf-4c has emerged as a new drug candidate that can promote vasodilation and act as a protective agent against ED, being useful to prevent vascular damage.

Iterative analysis of metabolic modulation in the cyanobacterium Aphanizomenon flos-aquae 2012 KM1/D3 upon nitric oxide synthase derived NO induction

Nitric oxide synthase (NOS) in mammals is recognized for its essentialities in several metabolism including blood vascular relaxation and nerves transmission etc. yet their functionalities in prokaryotes are largely unknown. Our study aimed to evaluate the putative role of nitric oxide synthase (NOS) derived nitric oxide (NO) during oxidative burst in the cyanobacterium, Aphanizomenon flos-aquae 2012/KM1/D3. Here, the accumulation of NO was dramatically reduced upon NOS inhibitor L-NG-Nitro arginine methyl ester (L-NAME) supplementation, exhibiting significant NO synthesis by NOS, whereas addition of L-arginine increase NOS derived NO in a dose dependent manner. Moreover, the reduction in the growth and metabolic activities of the cyanobacterium were evident upon L-NAME treatment that possibly pertained to decline in photopigments, PSII efficiency, loss in membrane integrity and DNA damage due to oxidative burst which culminated into cell death. Besides, the increment in carbohydrates and lipid content ensued with a decrease in protein content, indicating gluconeogenesis. Additionally, NOS inhibition disrupted the fatty acid and hydrocarbon profile, suggesting diminished membrane fluidity and cell integrity. However, higher content of flavonoids, phenolics, thiols and proline in L-NAME treated cells was also observed. Furthermore, L-arginine supplementation enhanced pigment content, photosynthetic efficiency, and reduced oxidative stress, thereby enhancing cyanobacterial growth. Further, L-arginine supplementation maintained Asc/DHAsc and GSH/GSSG ratio, conferred redox homeostasis. These results suggest that the NOS activity plays a critical role in protecting cyanobacteria from oxidative burst, maintaining their physiological balance.

Abstract P333: Influence Of RSK2 On Blood Pressure In Aging

Hypertension (HTN) is highly prevalent and is a significant risk factor for CVD. Excessive vasoconstriction contributes to HTN. Recently, p90 ribosomal S6 kinase, isoform 2 (RSK2) signaling has been shown to play a significant role in the regulation of basal vascular tone and BP control by phosphorylating RLC20 to promote smooth muscle contractility. Young adult Rsk2 KO mice have lower BP than WT littermates. Here, we examine the role of RSK2 in a geriatric HTN mouse model. Male &gt;2-year old WT and Rsk2 KO mice underwent daily BP measurements using tail cuff manometry. After 2 weeks of training, baseline (BL) BP was recorded, followed by 2 weeks of HTN induced by 20 mg/kg/day of L-N G -Nitroarginine methyl ester (L-NAME) via drinking water. Echocardiographic studies were performed at BL. WT mice had significant mortality (7 of 11 died), not seen in KO (1 of 8 died). At BL, WT mice had a significantly higher SBP compared to KOs (123±10 vs. 99±12 mmHg). L-NAME elevated SBP in WT but not KO mice (137±2 vs. 97±8 mmHg). Echocardiographic studies at BL showed no differences between genotypes. However, when ejection fraction (EF) was correlated with SBP, EF was negatively correlated with SBP in WT (-0.94 %/mmHg, p = 0.046, R 2 = 0.59, n = 6) but not KO mice (p = 0.15, n = 7). Clinically, HTN-associated mortality and morbidity primarily affects older populations. Here, we show that the loss of RSK2 reduces BP in geriatric mice, similar to findings in young adult mice, and that it also abolished the hypertensive effects of L-NAME. Aged Rsk2 KO mice appear to be protected from cardiovascular effects of aging. RSK2 is a potential target for pharmacologic inhibition to treat HTN and related risks in geriatric populations.

Physalis angulata Leaf Ethanol Extract Reduces Oxidative Stress and Improves Endothelial Progenitor Cells in L-NAME-Induced Hypertensive Rats

This study aimed to evaluate the effects of ciplukan (Physalis angulata L.) leaf ethanol extract on L-NG-nitroarginine methyl ester (L-NAME)-induced hypertensive rats. We randomly divided twenty-five Wistar rats into five groups. The sham group was given a PBS injection. The hypertensive group was injected with L-NAME on days 1 to 28. Three groups of hypertensive rats were given the extract on days 4 to 28. Blood pressure was measured using the tail-cuff method on days 0, 4, 10, and 27. The endothelial progenitor cells (EPCs) in the blood were measured by flow cytometry as a percentage of circulating angiogenic cells (CACs, CD34+/CD309+/CD45+) and endothelial colony-forming cells (ECFCs, CD34+/CD309+/CD45-). Serum NO and MDA levels, as well as serum SOD activity, were measured colorimetrically. Serum TNF-α levels were measured by the ELISA method. The ciplukan leaf extract reduced systolic and diastolic blood pressure, reduced the percentage of EPCs in the blood, increased serum NO levels, reduced MDA levels, increased serum SOD activity, and reduced serum TNF-α levels in L-NAME-induced hypertensive rats. It is concluded that ciplukan ethanol leaf extract exerts protective effects on L-NAME-induced hypertensive rats. These study results can strengthen the scientific basis of using ciplukan leaf ethanol extract to treat hypertension.

Methamphetamine-Induced Alterations of Vaginal Blood Flow in Rats

ABSTRACT Introduction Those suffering with vaginal dryness, whether experienced once or chronically, frequently experience painful and unpleasurable sexual experiences and diminished self-esteem as a result. Although the physiology of vaginal transudate production is long established, no pharmacological treatment other than estrogen has shown promise in attenuating vaginal dryness. Previously, our lab has shown that methamphetamine (meth) induced vaginal lubrication in adult women and anesthetized rats. The production of these vaginal secretions was shown to be dose-, as well as nitric oxide-dependent. As the secretion of vaginal lubrication is immensely dependent on local hemodynamics and the resulting increased blood flow to the genital tissues, determining meth-induced alterations in blood flow to these tissues is paramount. Objective The purpose of the current study is to determine if increased vaginal blood flow correlates with increased vaginal lubrication in response to meth, and to determine if alterations in this blood flow are nitric oxide-dependent. Methods Adult female Wistar rats were implanted with chronic indwelling jugular catheters and allowed at least one week to recover from surgery. Rats anesthetized with isoflurane gas were intravenously infused with meth (0.06-0.96 mg/kg) or saline via the implanted catheter. Vaginal blood flow, measured using a Periflux System 5000 and a small laser probe inserted 5-10 mm into the vaginal canal, was continuously recorded before and for at least twenty minutes following drug administration. After establishing meth-induced alterations in vaginal blood flow, pre-treatment with L-NG-Nitro arginine methyl ester (L-NAME), a non-specific nitric oxide synthase inhibitor, followed by meth administration following the same procedure for measuring blood flow allowed us to determine the contribution of nitric oxide to the observed changes in blood flow. Results Preliminary findings show that an IV infusion of meth induces an immediate increase in vaginal blood flow, followed by decreased blood flow due to vasoconstriction via increased sympathetic tone. We anticipate inhibition of nitric oxide production will reduce the increase in blood flow immediately after meth administration since this decreased vaginal lubrication in response to the same treatment. Conclusions These findings provide insight into the meth-induced vaginal lubrication we have previously reported, and that meth, whose sympathomimetic action traditionally induces vasoconstriction, produces increased blood flow in vaginal tissues, which is likely the driving force for the increased transudate produced. This advancement is critical for uncovering a mechanism that may serve as the optimal pharmacological target to treat vaginal dryness. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Embera NeuroTherapeutics &amp; JanOne

Leukotriene Receptor Antagonist, Montelukast Ameliorates L-NAME-Induced Pre-eclampsia in Rats through Suppressing the IL-6/Jak2/STAT3 Signaling Pathway.

Aims: To investigate the potential protective role of montelukast (Mont) in the pre-eclampsia rat model induced by L-NG-Nitro arginine methyl ester (L-NAME). Methods and materials: Thirty-two pregnant female albino Wistar rats were assigned to four groups: the control group: pregnant rats received vehicles; the Mont group: pregnant rats received Mont (10 mg/kg/day, p.o.) from the 6th to the 18th day of gestation; the L-NAME group: pregnant rats received L-NAME (50 mg/kg/day, i.p.) from the 9th to the 18th day of gestation; the Mont/L-NAME group: pregnant rats received Mont (10 mg/kg/day, p.o.) from the 6th to the 18th day of gestation and L-NAME (50 mg/kg/day, i.p.) from the 9th to the 18th day of gestation. Placental, hepatic, and renal malondialdehyde (MDA), total nitrites (NOx), interleukin 6 (IL-6), and tumor necrosis factor (TNF)-α were determined. Serum alanine transaminase (ALT), aspartate transaminase (AST), creatinine, urea, 24-h urinary protein, and the placental growth factor (PGF) were measured. Histopathological examinations of the placental, hepatic, and renal tissues were also performed. In addition, placental, hepatic, and renal Janus kinase 2 (Jak2) and signal transducer and activator of transcription 3 (STAT3) immunoblotting were performed. Key findings: Mont improves oxidative stress, IL-6, TNF-α, ALT, AST, creatinine, urea, 24-h urinary protein, PGF, Jak2, and STAT3 which were all affected by L-NAME. Moreover, the histopathological assessment indicated that Mont restored the normal architecture that was markedly disturbed by L-NAME. Significance: Mont exerted the biochemical and histopathological amelioration of L-NAME-caused pre-eclampsia through its anti-inflammatory, anti-oxidant function and suppression of the IL-6/Jak2/STAT3 signaling pathway.

Composite biscuits from sandpaper and acha flour restore the altered activity of arginase, cholinergic, and purinergic enzymes in hypertensive-diabetic rats.

Hypertension is one of the common co-morbidities in diabetes. Thus, the present study sought to study the effects of composite biscuits from the mixture of acha (Digitaria exilis) and sandpaper (Fiscus exasperata) leaf flours (ASLF) on mean arterial blood pressure (MABP), arginase, cholinergic, purinergic enzymatic cascade, and nitric oxide (NO) levels as well as oxidative status in streptozotocin (STZ)/L-NG -nitro arginine methyl ester (L-NAME)-induced hypertensive/diabetic rats. Experimental rats were distributed randomly into 7 groups (n=5). Group I-III rats were placed on the basal diet; IV-VII rats were placed on composite biscuits designated as A, B, C, and D respectively for 14 days. On the 13th day, the MABP of the experimental rats was monitored and recorded. Thereafter, the rats were sacrificed, tissues of interest were harvested, and homogenized. Subsequently, the activity of arginase cholinesterase and purinergic enzymes, as well as NO levels were evaluated in the experimental rats. However, hypertensive/diabetic rats placed on the formulated diet exhibited reduced MABP when compared with the untreated hypertensive/diabetic rats. Also, altered activity of arginase, cholinergic and purinergic were restored in diet-treated hypertensive/diabetic rats when compared with hypertensive/diabetic rats. Similarly, the NO level and antioxidant status of the treated hypertensive/diabetic rats were notably enhanced when compared with hypertensive/diabetic rats. It could be inferred that composite biscuits exhibited an ameliorative effect in hypertensive/diabetic states via their reductive effect on the MABP, arginase, cholinesterase, and purinergic enzymes and enhanced NO levels in hypertensive/diabetic rats. Meanwhile, the biscuit designated as D had seems better when their effects were compared holistically. PRACTICAL APPLICATIONS: Acha grains and sandpaper leaf have been used in the folklore for disease treatment. However, the production of composite biscuits from these naturally available recipes for the management of hypertensive diabetics proved therapeutic since their effect on hypertensive diabetic rats is positive. Therefore, the composite biscuit will offer nutraceutical benefits to both healthy and disease individuals.