Vasodilator Activity Research Articles

Nyctanthes arbor-tristis Improves Blood Pressure via Endothelial Pathway: In Silico, Ex Vivo, and In Vivo Evidence.

Systemic hypertension, a common metabolic disorder, poses significant health risks despite the availability of antihypertensive drugs. Nyctanthes arbor-tristis has garnered increasing attention for its perceived efficacy and safety, though its mechanisms of action and the bioactive compounds responsible for its antihypertensive effects remain elusive. Therefore, this study aims to elucidate the antihypertensive activity of N. arbor-tristis leaves in rats and explore associated mechanism through in silico, in vitro, ex vivo, and in vivo studies. The methanolic extract of N. arbor-tristis leaves (MENAT) was fractionated and subjected to qualitative and quantitative phytochemical screening, including total phenolic content (Folin-Ciocalteu method), total flavonoid content (Aluminum chloride method), and total alkaloid content (spectrometric method). Antioxidant studies were conducted using DPPH, FRAP, and H2O2 assays. The most promising fraction (WNAT) was analyzed using LC-MS, and the identified compounds were used for molecular docking studies against cGMP and eNOS. Further, aortic ring assays were conducted to assess ex vivo vasorelaxant activity (rat aortic strip assay) and the underlying mechanisms of WNAT. Later, in vivo studies using a DOCA-salt-induced hypertension model in Wistar rats, along with molecular analyses (RT-PCR), were performed to validate the antihypertensive claims of N. arbor-tristis. In vitro studies demonstrated that the water extract of N. arbor-tristis leaves (WNAT) exhibited strong antioxidant activity and contained key phytochemicals. LC-MS analysis revealed the presence of 19 major compounds, including betulinic acid and arbortristosides. Molecular docking studies indicated that arborside C exhibited a strong affinity for both eNOS and cGMP. Ex vivo studies involving rat aortic strips showed that WNAT induced vasodilatory activity, which is associated with parasympathetic and nitric oxide-related pathways. In vivo experiments further supported WNAT's antihypertensive properties through improvements via amelioration of rat blood pressure and histological features, biochemical markers, morphometric parameters, and gene expression in hypertensive rats. In conclusion, WNAT effectively lowers blood pressure through modulation of the endothelial pathway and warrants further studies to attain its clinical utility in hypertensive subjects.

The influence of the daily salt-intake on the antihypertensive action and atrial natriuretic peptide level in patietns with angiotensin receptor neprilysin inhibition

Abstract Background The angiotensin receptor–neprilysin inhibitor (ARNI) is a drug which acts through angiotensin receptor blocking effect and the increase in atrail natriuretic peptide (ANP) through neprilysin inhibitor in hypertension (HT). These combined effects result in a reduced risk of hospitalization for heart failure or death from cardiovascular causes. ANP is also known for its various cardioprotective effects including vasodilator and natriuretic action. Acording to Guyton's pressure-natriuresis curve, the efficacy of angiotensin receptor blocker drugs is diminished in HT cases with high daily salt inatke. However, whether the effect of ARNI on HT is attenuated in patients with high daily salt intake remains unclear. Purpose The present study investigated the influence of a daily salt intake on the antihypertensive action and ANP level in patients with ARNI. Methods Fourty-four consecutive essential HT patients on ARNI were enrolled. Blood pressure and ANP level were measured at baseline (before taking ARNI) and 3 weeks later. ARNI (200mg) was prescribed and maintained during the study. In addtion, the daily salt intake was calculated using creatinine and natrium levels in urine, age, and body weight according to Japanese hypertensive guideline at baseline and 3 weeks later. Results The average age was 70±8 years old. About 50% (N=23) was male. The mean sytolic and diastolic blood pressure was 148±14mmHg and 89±10mmHg, respectively. The mean daily salt intake was 9.5±2.2 g/day at baseline. The mean ANP level was 529±300pg/ml. At follow up (3 weeks later), the mean systolic and diastolic blood pressure significanly went down to 132± 18 mmHg and 70± 9 mmHg, respectively (p=0.03). ANP level also increased from 529±300pg/ml to 793±580pg/ml. However, the mean daily salt intake was almost same as the baseline at 9.4±3.2 g/day. The patients were divided into 2 groups; high daily salt intake (N=20 with mean daily salt intake 10.5±1.7g/day)) and low daily salt intake (N=24 with 8.4±3.1g/day) groups compared to the baseline. The absolute and percentage changes in systolic blood pressure were almost same in the high and low daily salt intake groups (-12.7±15.8mmHg vs -13.7±14.2mmHg, p=0.75; -5.8±6.5% vs.-7.0±9.6%, p=0.58, respectively). However, the change rate in ANP level was significantly higer in the high daily salt intake group than in the low daily salt intake group (155±63 vs. 12±16%, p=0.01). Conclusion ARNI demonstrates effectiveness in lowering the blood pressure even in patients with higher salt intake, unlike angiotensin receptor blocker. In cases with high salt intake, the notable increase in ANP levels may contribute to decreasing blood pressure through vasodilator and natriuretic action.

Dual prostacyclin infusions: A case report of a patient symptom-driven transition from high-dose intravenous epoprostenol to subcutaneous treprostinil for the treatment of pulmonary arterial hypertension.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. A case of successful transition from high-dose epoprostenol to high-dose subcutaneous treprostinil for treatment of pulmonary arterial hypertension (PAH) is reported. PAH is a chronically progressive disease characterized by pulmonary artery luminal narrowing that causes increased pulmonary artery pressures leading to right ventricular failure. Parenteral prostacyclin analogues, such as epoprostenol and treprostinil, are direct vasodilators and are cornerstones of therapy for patients with severe disease that have been proven to reduce mortality and increase exercise tolerance. These agents must be administered continuously via intravenous or subcutaneous devices and are high-risk medications due to their potent vasodilatory actions. Chronic use of these medications requires constant attention from both providers and patients because of potential complications including central venous catheter infection, thromboembolism, therapy interruptions, and other undesirable consequences. This case report describes management of a 35-year-old male patient on high-dose outpatient intravenous epoprostenol (101ng/kg/min; dosing weight, 47kg) for treatment of PAH who was admitted to the hospital with a malfunctioning central venous catheter. Surrounding manipulation of the central catheter, the patient experienced an ischemic stroke that led to cognitive disability resulting in a lack of ability to manage his previously used home infusion device. The patient was successfully transitioned from intravenous epoprostenol to subcutaneous treprostinil (discharge dose, 200ng/kg/min) over 5 days by infusing both medications simultaneously and adjusting doses based upon patient-reported symptoms. This successful transition from high-dose epoprostenol to high-dose subcutaneous treprostinil demonstrates the importance in considering patient-specific factors during high-risk medication transitions, the value of a patient-directed flexible prostacyclin transition plan, and the benefit of institutional training and education in ensuring the safe use of parenteral prostacyclin analogues.

Treatment practice of vasospasm during endovascular thrombectomy: an international survey

Background and aimThe clinical importance and management of vasospasm as a complication during endovascular stroke treatment (EVT) has not been well studied. We sought to investigate current expert opinions in...

Abstract 57: Macrolides for KCNJ5–mutated Aldosterone-Producing Adenoma (MAPA): a Study for Personalized Management of Primary Aldosteronism

Background: Somatic mutations in the KCNJ5 potassium channel involve up to 70% of the patients presenting with primary aldosteronism (PA) caused by an aldosterone-producing adenoma (APA). Macrolides corrected the altered function of the two common mutations G151R and L168R, in vitro suggesting their potential usefulness for personalized management of patients with KCNJ5-mutated APA. Hence, we investigated if the macrolide roxithromycin that restored the KCNJ5 channel function could lower plasma aldosterone and blood pressure (BP) in KCNJ5-mutated APA patients. Methods and Design: In a within-patient study we assessed changes of plasma aldosterone, active renin, cortisol and BP induced by an oral roxithromycin (150-300 mg) challenge, in consenting consecutive hypertensive patients. In parallel, we investigated the vascular and BP effects of macrolides ex vivo and in vivo in mice. Results: We recruited 425 consecutive patients: 19 had G151R - or L168R - mutated APA, 27 KCNJ5 wild-type APA, and the rest had no identifiable cause of hypertension. Roxithromycin lowered the plasma aldosterone concentration (p<0.001), not BP, in the G151R- and L168R-mutated APA patients, but not in the wild-type. However, an aldosterone-independent BP decrease was seen in the much larger cohort of hypertensive patients without PA. In mice experiments, studies showed that this was accounted far by a significant anti-hypertensive effect of macrolides that involved an endothelium-NO-dependent vasodilatory action. Conclusions: The roxithromycin-induced fall of plasma aldosterone concentration might be a marker of the presence of KCNJ5-mutated APA. Moreover, our studies unveiled an anti-hypertensive effect of macrolides that involves endothelium- and NO-dependent vasodilation.

Abstract P309: Vasodilating Effects of Macrolides: ex vivo and in vivo study

Background: Anecdotal reports showed a decrease in blood pressure (BP) values in subjects assuming macrolide antibiotics when co-administered with calcium channel blockers. Recently, in the MAPA study, in patients with primary hypertension given a single dose of macrolide a decrease in BP was observed. However, whether macrolides induce per se vasorelaxation remains unknown. Aim: To investigate if macrolides induce vasorelaxation and to identify the underlying mechanisms. Methods: The effects of 3 macrolides (roxithromycin, azithromycin, clarithromycin) were investigated in a wire myograph in aortas isolated from C57BL/6J mice, following standard protocols. Relaxation/contraction was evaluated in phenylephrine pre-contracted aorta segments exposed to different macrolide concentrations [10 -10 M to 10 -5 M]. Longer-term effects of azithromycin (50 mg/Kg/d intraperitoneally for 14 days) were investigated in vivo in a mouse model of Ang II-induced hypertension. BP was measured with the tail-cuff method; functional and structural/mechanical properties of the aorta and mesenteric arteries were evaluated with wire or pressure myograph, as appropriate. Results: After exposure to macrolides, phenylephrine pre-contracted mice aorta segments showed relaxation (maximum effect: -15-20% vs DMSO). The vasodilating effect was abolished by the removal of the endothelium, and was blunted by L-NAME. In the vivo studies treatment with azithromycin lowered BP values and prevented Ang II-induced endothelial dysfunction. Conclusions: Macrolides exert a vasodilatory action that involves endothelium-dependent NO release. In a model of Ang II-mediated hypertension, azithromycin exerted a BP-lowering effect.

Vasorelaxant Effects of Ethanolic Extract from Cydonia oblonga Mill. Leaves on Isolated Rat Thoracic Aorta and Potential Mechanism of Action

Objective: Cydonia oblonga Mill . leaves ethanolic extract (CydOL-EE) has shown different cardioprotective effects. However, no previous studies investigated its direct effect on the vascular smooth muscle tone. Therefore, the study aimed to test the potential vasodilator activity of CydOL-EE in ex-vivo rat thoracic aorta preparations with an additional investigation of its mechanistic effects. Methods: CydOL-EE phytochemical profile was first investigated by HPLC-DAD-ESI-MS/MS and then tested for the vasorelaxation/vasoreactivity effects in rat aortic rings. The NO synthase inhibitor N(ω)-nitro-L-arginine methyl ester (L-NAME) and cyclic guanosine monophosphate inhibitor 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) were used to explore of the involvement of NO-dependent pathways. Results: Chromatographic analysis of CydOL-EE revealed the presence of six flavonols and seven hydroxycinnamic acids. Moreover, CydOL-EE showed a decrease in vasoreactivity caused by dose-dependent phenylephrine (PE) (Control, Emax = 104.29 ± 3.67 vs CydOL-EE, Emax = 70.73 ± 3.67, P < .0001) and a direct relaxing activity to precontraction with PE (Emax = 79.63 ± 3.67%). These responses were abolished during e-NOS inhibition, demonstrating that the mechanism of action was predominately controlled by the participation of an endothelium-dependent system. Conclusion: The results of our study show that CydO-EE demonstrates vasorelaxation and reduction of vasoreactivity through a NO-dependent pathway. These findings provide scientific evidence for further understanding of CydOL-EE use in the treatment of cardiovascular disease.

Mailuoning oral liquid ameliorates vasculitis in thromboangiitis obliterans rats via inactivating cGAS-STING-IRF3 and TLR4-MAPKs/NF-κB signaling pathways

Ethnopharmacological relevanceMailuoning oral liquid (MLN O), one traditional Chinese patent medicine, has a good therapeutic effect on thromboangiitis obliterans (TAO) in clinical practice. However, the underlying mechanism remains unclear. Aim of the studyThis study aimed to explore the effects and potential mechanisms of MLN O against TAO based on network pharmacology and experimental verification. Materials and methodsNetwork pharmacology was used to identify the intersectional targets and signaling pathways of MLN O and TAO. In vivo, the TAO model was established by injecting sodium laurate and dihydrotestosterone (DHT) into the femoral arteries of Wistar rats. Rats were given the indicated drugs by intragastric administration (i.g.), intravenous injection (i.v.), or subcutaneous injection (s.c.) per day for 21 days since a week before surgery. In vitro, HUVECs, RAW264.7, and THP-1 cells were stimulated by LPS and DHT to simulate the pathological changes of TAO. The anti-inflammatory, anticoagulant, and immunomodulatory effects of MLN O were evaluated by histological observation, blood biochemical indexes detection, H&E staining, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), qRT-PCR, western blotting and immunofluorescence assays. Furthermore, the vascular ring test was applied to explore the vasodilatory activity of MLN O. ResultsMLN O significantly improved the pathological signs in TAO rats through its excellent anti-inflammatory, anticoagulant, immunomodulatory, and vasodilatory effects. Specifically, MLN O alleviated the gangrene and reduced the thrombosis in TAO rats, meanwhile, suppressed the expressions of inflammatory factors and clotting factors, which is related to the inactivations of cGAS-STING-IRF3 and TLR4-MAPKs/NF-κB signaling pathways. However, the superphysiological dose of DHT deteriorated the pathological development of TAO in vitro and in vivo. Moreover, the results of network pharmacology are consistent with the experimental verification. ConclusionCollectively, this study indicates for the first time that MLN O could alleviate TAO by inhibiting cGAS-STING-IRF3 and TLR4-MAPKs/NF-κB signaling pathways, which sheds light on a novel clinical therapeutic strategy for TAO.

3-methoxycatechol causes vasodilation likely via KV channels: ex vivo, in silico docking and in vivo study

Substituted catechols include both natural and synthetic compounds found in the environment and foods. Some of them are flavonoid metabolites formed by the gut microbiota which are absorbed afterwards. Our previous findings showed that one of these metabolites, 4-methylcatechol, exerts potent vasorelaxant effects in rats. In the current study, we aimed at testing of its 22 structural congeners in order to find the most potent structure and to investigate the mechanism of action. 3-methoxycatechol (3-MOC), 4-ethylcatechol, 3,5-dichlorocatechol, 4-tert-butylcatechol, 4,5-dichlorocatechol, 3-fluorocatechol, 3-isopropylcatechol, 3-methylcatechol and the parent 4-methylcatechol exhibited high vasodilatory activities on isolated rat aortic rings with EC50s ranging from ∼10 to 24 μM. Some significant sex-differences were found. The most potent compound, 3-MOC, relaxed also resistant mesenteric artery but not porcine coronary artery, and decreased arterial blood pressure in both male and female spontaneously hypertensive rats in vivo without affecting heart rate. It potentiated the vasodilation mediated by cAMP and cGMP, but did not impact L-type Ca2+-channels. By using two inhibitors, activation of voltage-gated potassium channels (KV) was found to be involved in the mechanism of action. This was corroborated by docking analysis of 3-MOC with the KV7.4 channel. None of the most active catechols decreased the viability of the A-10 rat embryonic thoracic aorta smooth muscle cell line. Our findings showed that various catechols can relax vascular smooth muscles and hence could provide templates for developing new antihypertensive vasodilator agents without affecting coronary circulation.

Topical amlodipine-loaded solid lipid nanoparticles for enhanced burn wound healing: A repurposed approach

Burn wounds are a complicated process with ongoing psychological and physical issues for the affected individuals. Wound healing consists of multifactorial molecular mechanisms and interactions involving; inflammation, proliferation, angiogenesis, and matrix remodeling. Amlodipine (ADB), widely used in cardiovascular disorders, demonstrated antioxidant and anti-inflammatory effects in some non-cardiovascular studies. It was reported that amlodipine is capable of promoting the healing process by regulation of collagen production, extracellular matrix, re-epithelialization and wound healing through its vasodilation and angiogenic activity. The objective of the current study is to appraise the wound healing capacity of amlodipine-loaded SLN (ADB-SLN) integrated into a hydrogel. The in-vitro characterization revealed that the optimized formulation was nanometric (190.4 ± 1.6 nm) with sufficiently high entrapment efficiency (88 % ± 1.4) and sustained ADB release (85.45 ± 4.45 % after 12 h). Furthermore, in-vivo evaluation was conducted on second-degree burns induced in male Sprague-Dawley rats. ADB-SLN gel revealed a high wound contraction rate and a significant improvement in skin regeneration and inflammatory biomarkers levels, confirming its efficiency in enhancing wound healing compared to other tested and commercial formulations. To conclude, the present findings proved that ADB-SLN integrated hydrogel offers a promising novel therapy for burn wound healing with a maximum therapeutic value.

Design of Novel TRPA1 Agonists Based on Structure of Natural Vasodilator Carvacrol-In Vitro and In Silico Studies.

Considering the escalating global prevalence and the huge therapeutic demand for the treatment of hypertension, there is a persistent need to identify novel target sites for vasodilator action. This study aimed to investigate the role of TRPA1 channels in carvacrol-induced vasodilation and to design novel compounds based on carvacrol structure with improved activities. In an isolated tissue bath experiment, it was shown that 1 µM of the selective TRPA1 antagonist A967079 significantly (p < 0.001) reduced vasodilation induced by 3 mM of carvacrol. A reliable 3D-QSAR model with good statistical parameters was created (R2 = 0.83; Q2 = 0.59 and Rpred2 = 0.84) using 29 TRPA1 agonists. Obtained results from this model were used for the design of novel TRPA1 activators, and to predict their activity against TRPA1. Predicted pEC50 activities of these molecules range between 4.996 to 5.235 compared to experimental pEC50 of 4.77 for carvacrol. Molecular docking studies showed that designed molecules interact with similar amino acid residues of the TRPA1 channel as carvacrol, with eight compounds showing lower binding energies. In conclusion, carvacrol-induced vasodilation is partly mediated by the activation of TRPA1 channels. Combining different in silico approaches pointed out that the molecule D27 (2-[2-(hydroxymethyl)-4-methylphenyl]acetamide) is the best candidate for further synthesis and experimental evaluation in in vitro conditions.

Exploring the Therapeutic Potential of C-Type Natriuretic Peptide for Preeclampsia.

Preeclampsia is a serious condition of pregnancy, complicated by aberrant maternal vascular dysfunction. CNP (C-type natriuretic peptide) contributes to vascular homeostasis, acting through NPR-B (natriuretic peptide receptor-B) and NPR-C (natriuretic peptide receptor-C). CNP mitigates vascular dysfunction of arteries in nonpregnant cohorts; this study investigates whether CNP can dilate maternal arteries in ex vivo preeclampsia models. Human omental arteries were dissected from fat biopsies collected during cesarean section. CNP, NPR-B, and NPR-C mRNA expression was assessed in arteries collected from pregnancies complicated by preeclampsia (n=6) and normotensive controls (n=11). Using wire myography, we investigated the effects of CNP on dilation of arteries from normotensive pregnancies. Arteries were preconstricted with either serum from patients with preeclampsia (n=6) or recombinant ET-1 (endothelin-1; vasoconstrictor elevated in preeclampsia; n=6) to model vasoconstriction associated with preeclampsia. Preconstricted arteries were treated with recombinant CNP (0.001-100 µmol/L) or vehicle and vascular relaxation assessed. In further studies, arteries were preincubated with NPR-B (5 µmol/L) and NPR-C (10 µmol/L) antagonists before serum-induced constriction (n=4-5) to explore mechanistic signaling. CNP, NPR-B, and NPR-C mRNAs were not differentially expressed in omental arteries from preeclamptic pregnancies. CNP potently stimulated maternal artery vasorelaxation in our model of preeclampsia (using preeclamptic serum). Its vasodilatory actions were driven through the activation of NPR-B predominantly; antagonism of this receptor alone dampened CNP vasorelaxation. Interestingly, CNP did not reduce ET-1-driven omental artery constriction. Collectively, these data suggest that enhancing CNP signaling through NPR-B offers a potential therapeutic strategy to reduce systemic vascular constriction in preeclampsia.

Dissolving microneedles loaded with nimodipine for prevention of sleep disorders at a high altitude

Sleep disorders are one of the most common acute reactions on the plateau, which can cause serious complications. However, there is no effective and safe treatment currently available. Nimodipine (NMD) is a dihydropyridine calcium channel blocker with neuroprotective and vasodilating activity, mainly used for the treatment of ischemic brain injury. Commercial oral or injectable NMD formulations are not a good option for central neuron diseases due to their poor brain delivery. In this study, nimodipine dissolving microneedles (NDMNs) were prepared for the prevention of sleep disorders caused by hypoxia. NDMNs were composed of NMD and polyvinyl pyrrolidone (PVP) K90 with a conical morphology and high rigidity. After administration of NDMNs on the back neck of mice, the concentration of NMD in the brain was significantly higher than that of oral medication as was confirmed by the fluorescent imaging on mouse models. NDMNs enhanced cognitive function, alleviated oxidative stress, and improved the sleep quality of mice with high-altitude sleep disorders. The blockage of calcium ion overloading may be an important modulation mechanism. NDMNs are a promising and user-friendly formulation for the prevention of high-altitude sleep disorders.

Chemical constituents from uncaria laevigata and their vasodilatory activities in vitro and action mechanism

A new triterpenoid compound 1* (scandine A1) was obtained from 95% ethanol extract of Uncaria laevigata. Meanwhile, eleven described compounds were also isolated for the first time from Uncaria laevigata. Herein, compound 2 exhibited strong diastolic cardio-cerebrovascular activity (EC50BA = 9.22 μM and EC50CA = 14.65 μM), which was not been previously described. Compound 1* also showed certain diastolic cardio-cerebrovasculary activity. Network pharmacology indicated that the diastolic cardio-cerebrovascular activity of compound 2 was most correlated with the Ras signalling pathway. Molecular docking confirmed that it exhibited strong binding activity with target protein (matrix metalloproteinase inhibitor-1). Moreover, compound 2 demonstrated significant potential on cardio-cerebrovascular activity in vitro. Overall, compounds 1* and 2 with good diastolic cardio-cerebrovascular activity were discovered in this work.

Quantum-chemical calculation, antibiotic potentiating activity, evaluation of efflux pump inhibition against S. aureus multi-resistant strains and molecular docking of the drugs isoniazid and hydralazine

In recent years, due to the uncontrolled use of antibiotics and natural evolution, many pathogenic microorganisms have acquired resistance to currently available drugs. Consequently, the number of infections caused by these microorganisms, considered multi-resistant to antimicrobial drugs, has increased, becoming a serious global public health problem. In the search for alternative therapies, drug repositioning represents a promising way to introduce new medicines. Hydralazine exhibits antihypertensive and peripheral vasodilatory action and isoniazid is a prodrug used as the first choice for the chemotherapy treatment of tuberculosis. In this work, microbiological tests were performed to investigate the modulator potential and efflux pump inhibition on S. aureus multi-resistant strains of the drugs isoniazid and hydralazine. In addition, the Density Functional Theory was used to determine the electronic and reactivity properties. Association of Ciprofloxacin with hydralazine on the K2068 strain proved to be better than the association of Norfloxacin with this antihypertensive on the 1199B strain of S. aureus. Association of isoniazid with ciprofloxacin in the K2068 strain was irrelevant and may have generated antagonism. The opposite effect was observed when associated with Norfloxacin in strain 1199B, where a significant reduction in the MIC of Norfloxacin was observed when associated with isoniazid. Regarding the association of hydralazine and isoniazid with EtBr, the results of this study showed that only hydralazine was able to positively modify the MIC of bromide on strains 1199B and K2068, presenting better results with this last strain, while in tests with to isoniazid. Molecular docking was used to verify the feasibility of forming receptor-ligand complexes and the replicability of the results. The molecular docking study against MepA indicated a possible synergistic effect between hydralazine and the antibiotic ciprofloxacin. Regarding NorA, the data indicated that hydralazine could act through competitive inhibition with the control norfloxacin, since it interacts in the same region of the antibiotic binding site through interactions in common with residues Glu-222, Tyr-225 and Val -302.

Loss of anoctamin 1 reveals a subtle role for BK channels in lymphatic muscle action potentials.

Ca2+ signalling plays a crucial role in determining lymphatic muscle cell excitability and contractility through its interaction with the Ca2+-activated Cl- channel anoctamin 1 (ANO1). In contrast, the large-conductance (BK) Ca2+-activated K+ channel (KCa) and other KCa channels have prominent vasodilatory actions by hyperpolarizing vascular smooth muscle cells. Here, we assessed the expression and contribution of the KCa family to mouse and rat lymphatic collecting vessel contractile function. The BK channel was the only KCa channel consistently expressed in fluorescence-activated cell sorting-purified mouse lymphatic muscle cell lymphatic muscle cells. We used a pharmacological inhibitor of BK channels, iberiotoxin, and small-conductance Ca2+-activated K+ channels, apamin, to inhibit KCa channels acutely in ex vivo isobaric myography experiments and intracellular membrane potential recordings. In basal conditions, BK channel inhibition had little to no effect on either mouse inguinal-axillary lymphatic vessel (MIALV) or rat mesenteric lymphatic vessel contractions or action potentials (APs). We also tested BK channel inhibition under loss of ANO1 either by genetic ablation (Myh11CreERT2-Ano1 fl/fl, Ano1ismKO) or by pharmacological inhibition with Ani9. In both Ano1ismKO MIALVs and Ani9-pretreated MIALVs, inhibition of BK channels increased contraction amplitude, increased peak AP and broadened the peak of the AP spike. In rat mesenteric lymphatic vessels, BK channel inhibition also abolished the characteristic post-spike notch, which was exaggerated with ANO1 inhibition, and significantly increased the peak potential and broadened the AP spike. We conclude that BK channels are present and functional on mouse and rat lymphatic muscle cells but are otherwise masked by the dominance of ANO1. KEY POINTS: Mouse and rat lymphatic muscle cells express functional BK channels. BK channels make little contribution to either rat or mouse lymphatic collecting vessel contractile function in basal conditions across a physiological pressure range. ANO1 limits the peak membrane potential achieved in the action potential and sets a plateau potential limiting the voltage-dependent activation of BK. BK channels are activated when ANO1 is absent or blocked and slightly impair contractile strength by reducing the peak membrane potential achieved in the action potential spike and accelerating the post-spike repolarization.

IMPACT OF THIAZIDES AND DIHYDROPYRIDINES ON HEART FAILURE AMONG HYPERTENSIVE PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMISED CONTROLLED TRIALS

Objective: Background: Hypertension (HTN) can lead to heart failure (HF) if left uncontrolled or poorly managed over time. Thiazide diuretics have a more significant antihypertensive effect than loop diuretics and are commonly prescribed for managing fluid retention in HTN. In contrast, dihydropyridine calcium channel blockers predominantly have peripheral vasodilatory actions that primarily target blood vessels to control HTN. However, there is a lack of sufficient data when it comes to evaluating the cardiovascular clinical outlook (including HF) for hypertensive patients treated with calcium channel blockers and diuretics. Objective To review the literature systematically and perform meta-analyses on impact of thiazides and dihydropyridines on HF incidents among hypertensive patients. Design and method: We searched the four major databases of MEDLINE, EMBASE, Web of Science and Cochrane (from 1993 – October 2023) for randomised controlled trials (RCTs) of thiazides or dihydropyridines. We included RCTs with at least 100 hypertensive participants and a minimum follow-up period of one year. Two authors independently selected the included RCTs, assessed the risk of bias, and collected data on HF. Meta-analyses were performed to summarise the pooled risk ratios (RRs) of HF between treatment arms. Results: The initial literature search identified 1896 records. After duplicates were removed, 1653 records were left, and a full-text review of the 403 eligible studies led to the exclusion of 396 RCTs. In the end, seven RCTs with a total of 49,409 participants were included in our meta-analysis. As to the effect of thiazides and dihydropyridines on HF, the point estimate for statins was less than 1, but it did not reach statistical significance in the overall analysis (the pooled RR in the fixed-effect model was 0.77 [95% CI: 0.70,0.84; I2=53%; X2 p &lt; 0.00001]). Conclusions: There is a statistically significant difference between thiazides and dihydropyridines in terms of HF incidents among hypertensive patients, but there are positive implications for clinical guidance. Further research and analytical investigations are necessary to corroborate and reinforce the findings gathered from various studies.

Vasodilation Effects of Ketapang (&lt;i&gt;Terminalia catappa&lt;/i&gt; Linn) Fruit on Aortic Rings Rat

Hypertension is an important risk factor for cardiovascular disease. Hypertension requires long-term treatment to keep blood pressure under control. Exploration found that antihypertensive drugs have economic value. East Kalimantan is rich in medicinal plant diversity and needs to be explored to discover new drugs for hypertension. Ketapang fruit (Terminalia catappa Linn) has the potential to have a vasodilation effect so research is needed to explore vasodilation activity in vitro. This research to determine the vasodilation activity of Terminalia catappa fruit using isolated aortic ring bioassay. Twelve Wistar rats were used for bioassays isolated aortic ring with endothelium. The aortic rings is precontracted with phenylephrine. This study used two test groups, Control group and Terminalia catappa fruit ethanol extract group (FTC). The FTC and Control concentrations were given cumulatively in chamber of isolated aortic ring. Log concentration -2 FTC (-11.8 ± 3.5)% and Control (0.0 ± 0.0)%, p = 0,002; log concentration -1,5 FTC (-22.8 ± 2.5)% and Control (0.0 ± 0.0)%, p = 0,002; log concentration -1,0 FTC (-41.5 ± 2.8)% and Control (0.0 ± 0.0)%, p = 0,002; log concentration -0,5 FTC (-58.7 ± 3.1)% and Control (0.0 ± 0.0)%, p = 0,002; log concentration 0 FTC (-79.0 ± 3.4)% and Control (0.0 ± -1.9)%, p = 0,001; log concentration 0,5 FTC (-93.8 ± 3.0)% and Control (0.2 ± 1.5)%, p = 0,002. FTC causes vasodilation in isolated rat aortic rings with endothelium.

Antihypertensive Effect of New Agonist of Adenosine Receptor in Spontaneously Hypertensive Rats.

Systemic arterial hypertension is a risk factor for cardiac, renal, and metabolic dysfunction. The search for new strategies to prevent and treat cardiovascular diseases led to the synthesis of new N-acylhydrazones to produce antihypertensive effect. Adenosine receptors are an alternative target to reduce blood pressure because of their vasodilatory action and antioxidant properties, which may reduce oxidative stress characteristic of systemic arterial hypertension. To evaluate the antihypertensive profile of novel selenium-containing compounds designed to improve their interaction with adenosine receptors. Vascular reactivity was evaluated by recording the isometric tension of pre-contracted thoracic aorta of male Wistar rats after exposure to increasing concentrations of each derivative (0.1 to 100 μM). To investigate the antihypertensive effect in spontaneously hypertensive rats, systolic, diastolic, and mean arterial pressure and heart rate were determined after intravenous administration of 10 and 30 μmol/kg of the selected compound LASSBio-2062. Compounds named LASSBio-2062, LASSBio-2063, LASSBio-2075, LASSBio-2076, LASSBio-2084, LASSBio-430, LASSBio-2092, and LASSBio-2093 promoted vasodilation with mean effective concentrations of 15.5 ± 6.5; 14.6 ± 2.9; 18.7 ± 9.6; 6.7 ± 4.1; > 100; 6.0 ± 3.6; 37.8 ± 11.8; and 15.9 ± 5.7 μM, respectively. LASSBio-2062 (30 μmol/kg) reduced mean arterial pressure in spontaneously hypertensive rats from 124.6 ± 8.6 to 72.0 ± 12.3 mmHg (p < 0.05). Activation of adenosine receptor subtype A3 and potassium channels seem to be involved in the antihypertensive effect of LASSBio-2062. The new agonist of adenosine receptor and activator of potassium channels is a potential therapeutic agent to treat systemic arterial hypertension.

Structurally diverse phthalides from fibrous roots of Ligusticum chuanxiong Hort. and their biological activities

Falonolide A (1) and B (2), two novel polyyne hybrid phthalides resulting from unprecedented carbon skeleton polymerized by Z-ligustilide and falcarindiol, along with six new related phthalides (3–8), were isolated from Ligusticum chuanxiong Hort. Their structures were elucidated by spectroscopic analysis, computer-assisted structure elucidation (CASE) analysis, DP4+ probability analysis and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway for 1–8 was proposed, and the production mechanism of 2 was revealed by density functional theory (DFT) method. Compounds 4 and 6 exhibited significant vasodilatory activity with EC50 of 8.00 ± 0.86 and 6.92 ± 1.02 μM, respectively. Compound 4 also displayed significant inhibitory effect of NO production with EC50 value of 8.82 ± 0.30 μM. Based on the established compounds library, structure-activity relationship analysis of phthalides was explored to provide insights into the drug development of vasodilators and anti-flammatory