Vasorelaxant Agents Research Articles

Bioguided Identification of Polymethoxyflavones as Novel Vascular CaV1.2 Channel Blockers from Citrus Peel

The huge amount of citrus peel produced worldwide represents an economic burden for society. However, this agricultural by-product is a rich source of natural molecules, potentially endowed with interesting pharmacological activities. In this regard, we decided to investigate if the polymethoxyflavones contained in citrus peel waste could be exploited as novel vasorelaxant agents. A hydroalcoholic blond orange (Citrus sinensis) peel extract, obtained by ultrasonication, was partitioned in dichloromethane. Column chromatography allowed for the isolation of four polymethoxyflavones, namely, scutellarein tetramethyl ether, nobiletin, tangeretin, and sinensetin, identified by nuclear magnetic resonance (NMR) spectroscopy and UPLC-HRMS/MS and confirmed by multivariate curve resolution of NMR fractional spectra. The four molecules showed interesting in vitro vasorelaxant activity, at least, in part, due to the blockade of smooth muscle CaV1.2 channels. Molecular modeling and docking analysis elucidated the binding mode of the polymethoxyflavones at the homology model of the rat CaV1.2c subunit and provided the structural basis to rationalise the highest activity of scutellarein tetramethyl ether in the set and the dramatic effect of the additional methoxy group occurring in nobiletin and sinensetin. In conclusion, citrus peel can be considered a freely available, valuable source of vasoactive compounds worthy of pharmaceutical and/or nutraceutical exploitation.

Preparation and Preliminary Structure-Activity Relationship Studies of Schwarzinicine A Analogs as Vasorelaxant Agents.

Schwarzinicines A-D, a series of alkaloids recently discovered from Ficus schwarzii, exhibit pronounced vasorelaxant activity in rat isolated aorta. Building on this finding, a concise synthesis of schwarzinicines A and B has been reported, allowing further investigations into their biological properties. Herein, a preliminary exploration of the chemical space surrounding the structure of schwarzinicine A (1) was carried out aiming to identify structural features that are essential for vasorelaxant activity. A total of 57 analogs were synthesized and tested for vasorelaxant activity in rat isolated aorta. Both efficacy (Emax) and potency (EC50) of these analogs were compared. In addition to identifying structural features that are required for activity or associated with potency enhancement effect, four analogs showed significant potency improvements of up to 40.2-fold when compared to 1. Molecular dynamics simulation of a tetrameric 44-bound transient receptor potential canonical-6 (TRPC6) protein indicated that 44 could potentially form important interactions with the residues Glu509, Asp530, Lys748, Arg758, and Tyr521. These results may serve as a foundation for guiding further structural optimization of the schwarzinicine A scaffold, aiming to discover even more potent analogs.

Salvia aucheri Exhibits Antihypertensive Activity in Hypertensive Rats.

The present work aimed to assess the antihypertensive activity of Salvia aucheri. Salvia aucheri (S. aucheri) is an aromatic and medicinal herb belonging to the Lamiaceae family. In Morocco, this plant is locally used for used to treat stomach, digestive disorders, rheumatism, and hypertension. Nevertheless, the effect of Salvia aucheri on hypertension has not yet been studied. The objective of this investigation was to evaluate the beneficial effect of the aqueous extract of S. aucheri leaves 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 S. aucheri leaves on vasodilatation was assessed in isolated rat aortic rings with functional endothelium precontracted with epinephrine EP or KCl. The aqueous extract of the aerial parts of S. aucheri (AESA) was obtained, and its antihypertensive ability was pharmacologically investigated in L-NAME hypertensive and normotensive rats. The rats received AESA orally at two selected doses of 100 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. The results indicated that AESA significantly reduced the systolic, diastolic, and mean arterial blood pressure in hypertensive rats over both single and repeated oral administration. However, AESA did not change the blood pressure parameters in normotensive rats. Concerning the results of vasorelaxant activity, the results showed that AESA was able to provoke potent vasorelaxant ability, which seems to be mediated through direct nitric oxide (NO) and NO-cyclic guanosine monophosphate pathways. The study elucidates the beneficial action of AESA as an antihypertensive and vasorelaxant agent.

Artificial intelligence-driven identification of morin analogues acting as CaV1.2 channel blockers: Synthesis and biological evaluation

Morin is a vasorelaxant flavonoid, whose activity is ascribable to CaV1.2 channel blockade that, however, is weak as compared to that of clinically used therapeutic agents. A conventional strategy to circumvent this drawback is to synthesize new derivatives differently decorated and, in this context, morin-derivatives able to interact with CaV1.2 channels were found by employing the potential of PLATO in target fishing and reverse screening. Three different derivatives (5a-c) were selected as promising tools, synthesized, and investigated in in vitro functional studies using rat aorta rings and rat tail artery myocytes. 5a-c were found more effective vasorelaxant agents than the naturally occurring parent compound and antagonized both electro- and pharmaco-mechanical coupling in an endothelium-independent manner. 5a, the series’ most potent, reduced also Ca2+ mobilization from intracellular store sites. Furthermore, 5a≈5c > 5b inhibited Ba2+ current through CaV1.2 channels. However, compound 5a caused also a concentration-dependent inhibition of KCa1.1 channel currents.

Novel Labdane Diterpenes-Based Synthetic Derivatives: Identification of a Bifunctional Vasodilator That Inhibits CaV1.2 and Stimulates KCa1.1 Channels.

Sesquiterpenes such as leucodin and the labdane-type diterpene manool are natural compounds endowed with remarkably in vitro vasorelaxant and in vivo hypotensive activities. Given their structural similarity with the sesquiterpene lactone (+)-sclareolide, this molecule was selected as a scaffold to develop novel vasoactive agents. Functional, electrophysiology, and molecular dynamics studies were performed. The opening of the five-member lactone ring in the (+)-sclareolide provided a series of labdane-based small molecules, promoting a significant in vitro vasorelaxant effect. Electrophysiology data identified 7 as a CaV1.2 channel blocker and a KCa1.1 channel stimulator. These activities were also confirmed in the intact vascular tissue. The significant antagonism caused by the CaV1.2 channel agonist Bay K 8644 suggested that 7 might interact with the dihydropyridine binding site. Docking and molecular dynamic simulations provided the molecular basis of the CaV1.2 channel blockade and KCa1.1 channel stimulation produced by 7. Finally, 7 reduced coronary perfusion pressure and heart rate, while prolonging conduction and refractoriness of the atrioventricular node, likely because of its Ca2+ antagonism. Taken together, these data indicate that the labdane scaffold represents a valuable starting point for the development of new vasorelaxant agents endowed with negative chronotropic properties and targeting key pathways involved in the pathophysiology of hypertension and ischemic cardiomyopathy.

The drp-1-mediated mitochondrial fission inhibitor mdivi-1 impacts the function of ion channels and pathways underpinning vascular smooth muscle tone

Mdivi-1 is widely used as a pharmacological tool to inhibit dynamin-related protein-1-mediated mitochondrial fission. Whether this compound may interact directly or indirectly with ion channels or cellular pathways fundamental for the regulation of vascular smooth muscle tone remains unknown. The present study aimed to assess the effect of mdivi-1 on CaV1.2 and KCa1.1 channels, both in vitro and in silico as well as on the mechanical activity of rat aorta rings. Mdivi-1 was an effective CaV1.2 channel blocker, docking in a CaV1.2 channel antagonist binding region, stimulated KCa1.1 channel current, binding to a sensing region common to other stimulators, and possibly inhibited the Rho-kinase pathway. These effects contributed to its vasorelaxant activity observed in rings stimulated with high KCl, phenylephrine, or NaF. Neither structurally different dynamin inhibitors nor a stimulator affected the Ca2+ antagonistic and vasorelaxant activities of the compound. However, mito-tempol reduced its vasorelaxant potency towards phenylephrine. Finally, mdivi-1 antagonized mitochondrial fission triggered by phenylephrine. In conclusion, mdivi-1 is an effective in vitro vasorelaxant agent at concentrations routinely employed to block dynamin-related protein-1. Ion channels and pathways key to the maintenance of vessel active tone are involved in this mechanism. These yet undiscovered off-target effects raise caution for the interpretation of mitochondrial fission signalling.

C72. Peripartum Cardiomyopathy: “Comparison in Management of Two Cases”

Abstract Background Peripartum cardiomyopathy (PPCM) is a pregnancy related cardiomyopathy that associated with high morbidity, mortality, also high probability of partial and often full recovery. The management of PPCM remains challenging. Case Summary The first patient was 33 years old woman, diagnosed with PPCM 3 days after giving birth. The second patient was 30 years old woman with heart failure symptoms since 3 months after giving birth but only seek medical attention 10 months later. Both patients presented with heart failure and LVEF 37%. The difference was acute onset PPCM on the first patient and the second one was already fall to chronic heart failure condition due to untreated PPCM. Both patients were treated with heart failure drugs but no bromocriptine in second patient. Six months follow up showed increased LVEF to 65% in first patient with full recovery but no significant improvement on second patient with LVEF 40 %. Discussion The first patient was presented as acute PPCM. Diagnosis PPCM in the second patient was made after exclusion of other causes of heart failure. Both women presenting after delivery, so can generally be treated according to the ESC Guidelines for heart failure. BOARD scheme therapy (Bromocriptine, Oral heart failure therapies, Anticoagulants, vasoRelaxing agents, Diuretic) were used in first patient but we treated the second patient as common heart failure patient without including bromocriptine in therapy. Full recovery found in patient that was diagnosed and treated earlier. Long term management and counselling is essential for these patients.

C72. Peripartum Cardiomyopathy: “Comparison in Management of Two Cases”

Abstract Background Peripartum cardiomyopathy (PPCM) is a pregnancy related cardiomyopathy that associated with high morbidity, mortality, also high probability of partial and often full recovery. The management of PPCM remains challenging. Case Summary The first patient was 33 years old woman, diagnosed with PPCM 3 days after giving birth. The second patient was 30 years old woman with heart failure symptoms since 3 months after giving birth but only seek medical attention 10 months later. Both patients presented with heart failure and LVEF 37%. The difference was acute onset PPCM on the first patient and the second one was already fall to chronic heart failure condition due to untreated PPCM. Both patients were treated with heart failure drugs but no bromocriptine in second patient. Six months follow up showed increased LVEF to 65% in first patient with full recovery but no significant improvement on second patient with LVEF 40 %. Discussion The first patient was presented as acute PPCM. Diagnosis PPCM in the second patient was made after exclusion of other causes of heart failure. Both women presenting after delivery, so can generally be treated according to the ESC Guidelines for heart failure. BOARD scheme therapy (Bromocriptine, Oral heart failure therapies, Anticoagulants, vasoRelaxing agents, Diuretic) were used in first patient but we treated the second patient as common heart failure patient without including bromocriptine in therapy. Full recovery found in patient that was diagnosed and treated earlier. Long term management and counselling is essential for these patients.

Revisiting the Large-Conductance Calcium-Activated Potassium (BKCa) Channels in the Pulmonary Circulation.

Potassium ion concentrations, controlled by ion pumps and potassium channels, predominantly govern a cell′s membrane potential and the tone in the vessels. Calcium-activated potassium channels respond to two different stimuli-changes in voltage and/or changes in intracellular free calcium. Large conductance calcium-activated potassium (BKCa) channels assemble from pore forming and various modulatory and auxiliary subunits. They are of vital significance due to their very high unitary conductance and hence their ability to rapidly cause extreme changes in the membrane potential. The pathophysiology of lung diseases in general and pulmonary hypertension, in particular, show the implication of either decreased expression and partial inactivation of BKCa channel and its subunits or mutations in the genes encoding different subunits of the channel. Signaling molecules, circulating humoral molecules, vasorelaxant agents, etc., have an influence on the open probability of the channel in pulmonary arterial vascular cells. BKCa channel is a possible therapeutic target, aimed to cause vasodilation in constricted or chronically stiffened vessels, as shown in various animal models. This review is a comprehensive collation of studies on BKCa channels in the pulmonary circulation under hypoxia (hypoxic pulmonary vasoconstriction; HPV), lung pathology, and fetal to neonatal transition, emphasising pharmacological interventions as viable therapeutic options.

6-Amino-3-Methyl-4-(2-nitrophenyl)-1,4-Dihydropyrano[2,3-c]Pyrazole-5-Carbonitrile Shows Antihypertensive and Vasorelaxant Action via Calcium Channel Blockade.

Several 4H-pyran derivatives were designed and synthesized previously as vasorelaxant agents for potential antihypertensive drugs. In this context, the objective of the present investigation was to determine the functional mechanism of vasorelaxant action of 6-amino-3-methyl-4-(2-nitrophenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (1: ) and its in vivo antihypertensive effect. Thus, compound 1: showed significant vasorelaxant action on isolated aorta rat rings pre-contracted with serotonin or noradrenaline, and the effect was not endothelium-dependent. Compound 1: induced a significant relaxant effect when aortic rings were contracted with KCl (80 mM), indicating that the main mechanism of action is related to L-type calcium channel blockade. Last was corroborated since compound 1: induced a significant concentration-dependent lowering of contraction provoked by cumulative CaCl2 adding. Moreover, compound 1: was capable to block the contraction induced by FPL 64176, a specific L-type calcium channel agonist, in a concentration-dependent manner. On the other hand, docking studies revealed that compound 1: interacts on two possible sites of the L-type calcium channel and it had better affinity energy (-7.80+/-0.00 kcal/mol on the best poses) than nifedipine (-6.86+/-0.14 kcal/mol). Finally, compound 1: (50 mg/kg) showed significant antihypertensive activity, lowering the systolic and diastolic blood pressure on spontaneously hypertensive rats (SHR) without modifying heart rate.

In Vitro Model for Ischemic Stroke: Functional Analysis of Vascular Smooth Muscle Cells.

The Neurovascular Unit (NVU) is formed by vascular and neural cells controlling the cerebral hyperaemia. All the components are anatomically and functionally linked to each other, resulting in a highly efficient regulation of the cerebral blood flow, which, when interrupted, can lead to stroke. An ischemic stroke (IS) is the most common type of stroke with high rates of morbidity, mortality and disability. Therefore, it is of extreme importance to protect the functional and structural integrity of the NVU in patients with IS, understanding the mechanisms involved and how it affects each component of the NVU. Thus, the aim of this work is to analyse how the vascular smooth muscle cells from the rat middle cerebral artery function/react after an ischemic event. To mimic this event, primary cortical cultures were challenged to oxygen and glucose deprivation (OGD) for 4h and 6h, and the smooth muscle cells (SMCs) contractility was analysed after exposure to different media previously conditioned by the cortical cultures upon reperfusion. The results show a dual effect on the SMCs response to the vasorelaxant agent, only for cells exposed to the reperfusion media conditioned by neuron-glia cultures challenged by OGD, leading to increased relaxation of the SMCs for OGD 4h, whereas for OGD 6h the effect is reversed leading to contraction of the SMCs. These differences demonstrate that the astrocytes mediate the vasoactive response of vascular smooth muscle by releasing factors into the reperfusion medium, and the hypoxia time is fundamental for a beneficial/harmful response by the vascular smooth muscle.

Discovery of trans-3,4,4′-trihydroxystilbene as new lead vasorelaxant agent for antihypertensive drug development

AimsThe structure-vasorelaxant activity relationships (SARs) assessment in previous study has found that trans-3,4,4′-trihydroxystilbene (344OH) could potentially act as a vasorelaxing agent with demonstration of over 2-fold maximal relaxation (Rmax) compared to its analogue, resveratrol. The present study focuses on the mechanism of actions and pathways employed by 344OH and compared to its analogue to further speculate the SAR of stilbenoids towards vasorelaxation. Materials and methodsThe 344OH employed in present study was synthesized based on the protocol in previous study. The vascular responses towards the cumulative addition of 344OH were evaluated using in vitro rat aortic rings assays. Key findingsThe pEC50 and Rmax values were found to be 4.33 ± 0.05 and 106 ± 3.99%, respectively. Results showed that the vasorelaxation of 344OH were predominated by G-protein-coupled muscarinic- (M3) and β2-adrenergic receptors, followed by PGI2/AC/cAMP- and NO/sGC/cGMP-dependent pathways. It was also identified that 344OH employed voltage-activated- (Kv), calcium-activated- (Kca) and inwardly-rectifying (Kir) potassium channels and act as an antagonist for both VOCC and IP3R while regulating the action potential in the vasculature. SignificanceThe different position of hydroxyl substituent located in A-ring of the stilbenoid backbone in 344OH compared to resveratrol resulted in a significant difference in mechanistic actions that lead to 344OH's fast-acting and less time-dependent vasorelaxation behaviour. This has substantially increased the potential of 344OH to be developed as an effective antihypertensive drug in future. Present findings further strengthen our inferences where the SARs study approach should be carried out as the mainstream methodology in future drug development research.

SYNTHESIS, IN SILICO CHARACTERIZATION AND EX VIVO EVALUATION OF THE NOVEL ORGANIC NITRATE NDIBP AS A POTENTIAL VASORELAXANT AGENT

Objective: This study aimed to describe the synthesis and biological/pharmacokinetic potential of the 1,3-diisobutoxypropan-2-yl nitrate (NDIBP) using in silico and ex vivo approaches.
 Methods: The compound was characterized by Fourier-transform infrared spectroscopy and 1H and 13C- nuclear magnetic resonance spectra. NDIBP biological activity spectrum was obtained by Prediction of Activity Spectra for Substances (PASS). The pharmacological effect was validated in ex vivo studies using mesenteric artery. Drug-like properties and Absorption Distribution Metabolism Excretion and Toxicity (ADMET) studies were carried out by pkCSM (Predicting Small-Molecule Pharmacokinetic Properties Using Graph-Based Signatures) software.
 Results: PASS prediction indicated NDIBP as nitric oxide (NO) donor with vasodilator effect. Ex vivo studies validated PASS analysis and showed the NDIBP vasorelaxant activity in mesenteric arteries. Physicochemical parameters and ADMET prediction suggested that NDIBP is a drug-like molecule with a good theoretical oral bioavailability, good absorption in the gastrointestinal tract, and a low distribution in the tissues.
 Conclusion: All the data indicated that NDIBP possesses biological activities and drug-like properties to be considered as a vasorelaxant agent and a good candidate for further investigation in the treatment of arterial hypertension and drug development studies.

Synthesis and characterization of new pyrazole-tetrazole derivatives as new vasorelaxant agents.

The synthesis of new functionalized tetrazole-pyrazole compounds is reported. They were fully characterized by spectroscopy and spectrometry methods. The vasorelaxant potency of these molecules was also investigated. All compounds showed a good vasorelaxant activity but the Compound 6 "ethyl 1-((2-(3-bromopropyl)-2H-tetrazol-5-yl)methyl)-5-methyl-1H-pyrazole-3-carboxylate" seems to have the highest effect, which reached 70% at 10-4 M concentration. This effect was partially endothelium-dependent; also, the vasorelaxant pattern of this compound was quite similar to that of the verapamil.

Antihypertensive and vasorelaxant effect of leucodin and achillin isolated from Achillea millefolium through calcium channel blockade and NO production: In vivo, functional ex vivo and in silico studies

Ethnopharmacological relevanceAchillea millefolium L. (Asteraceae), known as yarrow (milenrama), is a plant used in Mexican traditional medicine for the treatment of hypertension, diabetes, and related diseases. AimTo determine the vasorelaxant and antihypertensive effect of A. millefollium and to isolate the main bioactive antihypertensive agents. Materials and methodsOrganic (hexane, dichloromethane and methanol) and hydro-alcohol (Ethanol-H2O: 70:30) extracts obtained from flowers, leaves and stems were evaluated on isolated aorta rat rings with and without endothelium to determine their vasorelaxant effect. Hexane extract from flowers (HEAmF) was studied to evaluate its antihypertensive effect on spontaneously hypertensive rats (SHR). From HEAmF, bioactive compounds were obtained by bio-guided phytochemical separation through chromatography. ResultsOrganic extracts showed the best vasorelaxant activity. Hexane extract from flowers was the most potent and efficient ex vivo vasorelaxant agent, showing significant decrease of systolic and diastolic blood pressure in SHR (p < 0.05). Phytochemical separation of HEAmF yielded two epimeric sesquiterpene lactones: leucodin (1) and achillin (2), the major components of the extract. Both 1 and 2 showed similar vasorelaxant action ex vivo (p < 0.05), and their effects where modified by L-NAME (10 μM, nitric oxide synthase inhibitor), by ODQ (1 μM, soluble guanylyl cyclase inhibitor), and also relaxed the contraction induced by KCl (80 mM). Finally, 1 and 2 intragastric administration (50 mg/kg) decreased systolic and diastolic blood pressure in SHR. ConclusionsAchillea millefolium showed antihypertensive and vasorelaxant effects, due mainly to leucodin and achillin (epimers). Both compounds showed antihypertensive activity by vasorelaxation putatively by endothelium-dependent NO release and cGMP increase, as well as by calcium channels blockade.

Cellular S-denitrosylases: Potential role and interplay of Thioredoxin, TRP14, and Glutaredoxin systems in thiol-dependent protein denitrosylation.

Nitric Oxide is a very well known gaseous second messenger molecule and vasorelaxant agent involved in a variety of signaling in the body such as neurotransmission, ion channel modulation, and inflammation modulation. However, it's reversible covalent attachment to thiol groups of cysteine residues under nitrosative stress leading to aberrant protein S-nitrosylation (PSNO) has been reported in several pathological conditions in the body stemming from neurodegenerative diseases, cancer, cardiovascular system, and immune system disorders. In the cell, PSNOs are partly unstable and transit to a more stable disulfide state serving as an intermediate step towards disulfide formation thus eliciting the biological response. Scientists have identified several cellular thiol-dependent disulfide reductases that have the intrinsic capability to reverse the modification by reducing the stable disulfides formed in PSNOs and thereby rescue S-nitrosylation-induced altered proteins. The physiological roles of these major cellular ubiquitous S-denitrosylases and their probable implementations have not been fully explored. Gaining knowledge from current research and development this review provides a deeper insight into understanding the interplay and role of the major ubiquitous S-denitrosylases in maintaining cellular redox homeostasis. This review umbrellas the mechanism of Thioredoxin, TRP14, and Glutaredoxin systems and highlights their substrates specificities at different cellular conditions, physiological roles, and importance in diseased conditions that would allow researchers to investigate effective therapeutic interventions for nitrosative stress-related diseases and disorders.

NO-Releasing Nanoparticles Ameliorate Detrusor Overactivity in Transgenic Sickle Cell Mice via Restored NO/ROCK Signaling.

Sickle cell disease (SCD) is associated with overactive bladder (OAB). Detrusor overactivity, a component of OAB, is present in an SCD mouse, but the molecular mechanisms for this condition are not well-defined. We hypothesize that nitric oxide (NO)/ ras homolog gene family (Rho) A/Rho-associated kinase (ROCK) dysregulation is a mechanism for detrusor overactivity and that NO-releasing nanoparticles (NO-nps), a novel NO delivery system, may serve to treat this condition. Male adult SCD transgenic, combined endothelial NO synthases (eNOSs) and neuronal NOS (nNOS) gene-deficient (dNOS-/-), and wild-type (WT) mice were used. Empty nanoparticle or NO-np was injected into the bladder, followed by cystometric studies. The expression levels of phosphorylated eNOS (Ser-1177), protein kinase B (Akt) (Ser-473), nNOS (Ser-1412), and myosin phosphatase target subunit 1 (MYPT1) (Thr-696) were assessed in the bladder. SCD and dNOS-/- mice had a greater (P < 0.05) number of voiding and nonvoiding contractions compared with WT mice, and they were normalized by NO-np treatment. eNOS (Ser-1177) and AKT (Ser-473) phosphorylation were decreased (P < 0.05) in the bladder of SCD compared with WT mice and reversed by NO-np. Phosphorylated MYPT1, a marker of the RhoA/ROCK pathway, was increased (P < 0.05) in the bladder of SCD mice compared with WT and reversed by NO-np. nNOS phosphorylation on positive (Ser-1412) regulatory site was decreased (P < 0.05) in the bladder of SCD mice compared with WT and was not affected by NO-np. NO-nps did not affect any of the measured parameters in WT mice. In conclusion, dysregulation of NO and RhoA/ROCK pathways is associated with detrusor overactivity in SCD mice; NO-np reverses these molecular derangements in the bladder and decreases detrusor overactivity. SIGNIFICANCE STATEMENT: Voiding abnormalities commonly affect patients with sickle cell disease (SCD) but are problematic to treat. Clarification of the science for this condition in an animal model of SCD may lead to improved interventions for it. Our findings suggest that novel topical delivery of a vasorelaxant agent nitric oxide into the bladder of these mice corrects overactive bladder by improving deranged bladder physiology regulatory signaling.

Effect of the double bond conjugation on the vascular physiology and nitric oxide production of isomers of eicosapentaenoic and docosahexaenoic acids prepared from shark oil.

A collection of evidence suggests that conjugation of double bonds of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids, omega-3 polyunsaturated fatty acids (n-3 PUFAs), increases their anticarcinogenic activity; however, the effect of such conjugation on vascular tone activity remains unknown. We propose that the mixture of conjugated PUFAs exerts higher vasorelaxation activity than the corresponding mixture of nonconjugated PUFAs. The vascular response to different concentrations of conjugated and nonconjugated isomers of EPA and DHA, among other fatty acids (FAs) naturally present in shark oil, and the role of nitric oxide (NO) as a vasorelaxant agent were investigated. Both conjugated EPA (CEPA) and conjugated DHA (CDHA) were prepared by alkaline isomerization of all PUFAs contained in shark oil. Different concentrations of conjugated and nonconjugated PUFAs were placed in contact with precontracted aortic rings of Wistar rats to assess their effect on vascular tone. All tested samples exerted a vasorelaxant effect. Compared to nonconjugated PUFAs, conjugated isomers exhibited an increase in the dilatation of the aortic rings (P<0.001) in a dose-dependent manner (P<0.001). In addition, nonconjugated PUFAs produced nitric oxide (NO) in a dose-dependent manner, while conjugated PUFAs did not, suggesting that their dilatation mechanism is not totally dependent on NO.

Extract Stem Bark of Hymenaea Rubriflora D: A New Perspective of Vasorelaxant Agent

In this study, was investigated the action of the hydroalcoholic extract of the stem bark of Hymenaea rubriflora Ducke (HR-HAc) on the vascular reactivity of rats in vitro and administered in vivo. Cumulative doses of HR-HAc promoted dose-dependent relaxation aortic rings of Wistar rats with functional endothelium, which was inhibited in the presence of L-NAME. After, animals (n=5) were treated with 25, 50 and 100 mg / kg or saline for four weeks for determination of reactivity to acetylcholine, nitroprusside and phenylephrine. Was observed increased acetylcholine relaxing potency at all doses, with a greater effect on G50 (pD2 = 7.8 ± 0.1, Emax = 95.6 ± 1.1) and a decreased contractile potency to phenylephrine in G25 (pD2 = 6.9 ± 0.06, Emax = 61.5 ± 6.0%) and G50 (pD2 = 6.6 ± 0.06, Emax = 71.0 ± 8.5%) when compared to GC in the presence and absence of endothelium (pD2 = 6.4 ± 0.1, 6.4 ± 0.1 and 6.9 ± 0.1, respectively). Cumulative doses of nitroprusside resulted in increased relaxing potency in all supplemented groups and maintained Emax at 100%. Concludes that HR-HAc has vasorelaxant capacity and endothelium-dependent contractile inhibitor, either applied directly to aortic rings or after treatment with in vivo supplementation, which places this extract as a potential antihypertensive agent for future studies.

English

Hypertension is associated with endothelial dysfunction characterized by decreased vasorelaxation. Our research group recently demonstrated that hydroalcoholic extract of Syzygium cumini leaves (HESc) reduces the blood pressure in spontaneously hypertensive rats (SHR). This study evaluated the ability of HESc and chloroform fraction (CF) in promoting vasorelaxation on resistance arteries rings. Endothelium-deprived superior mesenteric artery rings were suspended in organ baths containing warm perfusion medium that was continuously bubbled with carbogen and then the vasorelaxant ability of HESc and CF were assayed. The cumulative additions of HESc (0.1 to 10 mg/mL) caused a concentration-dependent relaxant response, in precontracted preparations by NE or KCl. CF (0.1 to 1.0 mg/mL) exhibited remarkable vasorelaxant activity in preparations endothelium-denuded pre-contracted with NE, in a concentration-dependent manner. The pretreatment of TEA did not decrease significantly in relaxation. The incubation of CF (0.25 and 0.5 mg/ml) reduced in a concentration-dependent way, the Emax induced by NE in mesenteric artery, however, did not altered the pD2 of the NE. Additionally, CF promoted concentration-dependent manner, maximal effect inhibition and also led to a significant rightward shift in the concentration-response curve for Ca2+ in endothelium-denuded rings. This finding indicates that S. cumini acts as a vasorelaxant agent and interfere with the responsiveness of vascular smooth muscle cell, probably acting on the regulation of intracellular Ca2+ levels through voltage-operated calcium channels. &nbsp; Key words: S. cumini, calcium channels, vasorelaxant, medicinal plant, antihypertensive.