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Sample records for contractile endothelin etb

  1. Enhanced expression of contractile endothelin ET(B) receptors in rat coronary artery after organ culture

    DEFF Research Database (Denmark)

    Johnsson, E.; Maddahi, A.; Wackenfors, A.

    2008-01-01

    . In cardiovascular disease and in organ culture in vitro, endothelin ET(B) receptors are up-regulated on smooth muscle cells. The objectives of the present study were to characterise the endothelin receptor-induced vasoconstriction and quantify the endothelin receptor mRNA levels and immunoreactivity in fresh...... and cultured rat coronary arteries. We demonstrate that endothelin-1 induces strong and equal concentration-dependent contractions in fresh and cultured segments from the left anterior descending coronary artery. Sarafotoxin 6c, an endothelin ET(B) receptor agonist, had negligible effect in fresh arteries...... but produced significant vasoconstriction after organ culture. The endothelin ET(B) receptor mRNA level and the receptor protein immunoreactivity were increased, whereas the level of endothelin ET(A) receptor mRNA was down-regulated but not its receptor protein immunoreactivity after organ culture...

  2. Upregulation of endothelin ETB receptor-mediated vasoconstriction in rat coronary artery after organ culture

    DEFF Research Database (Denmark)

    Eskesen, Karen; Edvinsson, Lars

    2006-01-01

    The aim of this study was to examine if endothelin ET(B) receptor-mediated contraction occurred in isolated segments of rat coronary arteries during organ culture. Presence of contractile endothelin ET(B) receptors was studied by measuring the change in isometric tension in rings of left anterior......(+)-solution was not modified after 1 day in culture medium. The experiments indicate that organ culture of rat coronary arteries upregulate endothelin ET(B) receptor-mediated contraction by inducing synthesis of new protein....... descending coronary arteries isolated from hearts of rats as response to application of the selective endothelin ET(B) receptor agonist, Sarafotoxin 6c and endothelin-1. In segments cultured 1 day in serum free Dulbecco's Modified Eagle's Medium, Sarafotoxin 6c induced a concentration dependent contraction...

  3. LPS from Porphyromonas gingivalis increases the sensitivity of contractile response mediated by endothelin-B (ET(B)) receptors in cultured endothelium-intact rat coronary arteries

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    Ghorbani, Bahareh; Holmstrup, Palle; Edvinsson, Lars

    2010-01-01

    The purpose of our study was to examine if lipopolysaccharide (LPS) from Porphyromonas gingivalis (P.g.) modifies the vasomotor responses to Endothelin-1 (ET-1) and Sarafotoxin 6c (S6c) in rat coronary arteries. The arteries were studied directly or following organ culture for 24h in absence...

  4. Imaging evidence for endothelin ETA/ETB receptor heterodimers in isolated rat mesenteric resistance arteries

    DEFF Research Database (Denmark)

    Kapsokalyvas, Dimitrios; Schiffers, Paul M H; Maij, Nathan

    2014-01-01

    AIMS: In engineered cells, endothelin ETA and ETB receptors can heterodimerize. We tested whether this can also be observed in native tissue. MAIN METHODS: Rat mesenteric resistance arteries (rMRA) were maintained in organ culture for 24h to upregulate ETB-mediated contractions in addition to the...

  5. Vascular endothelin ET(B) receptor-mediated contraction requires phosphorylation of ERK1/2 proteins

    DEFF Research Database (Denmark)

    Luo, Guogang; Jamali, Roya; Cao, Yong-Xiao

    2006-01-01

    In cardiovascular diseases, endothelin type B (ET(B)) receptors in arterial smooth muscle cells are upregulated. The present study revealed that organ culture of rat mesenteric artery segments enhanced endothelin ET(B) receptor-mediated contraction paralleled with increase in the receptor mRNA an...

  6. Endothelin-1 activation of ETB receptors leads to a reduced cellular proliferative rate and an increased cellular footprint

    International Nuclear Information System (INIS)

    Wilson, Jamie L.; Taylor, Linda; Polgar, Peter

    2012-01-01

    Endothelin-1 (ET-1) is a vasoactive peptide which signals through two G-protein coupled receptors, endothelin receptor A (ETA) and B (ETB). We determined that ET-1 activation of its ETB receptor in stably cDNA transfected CHO cells leads to a 55% reduction in cell number by end-point cell counting and a 35% decrease in cell growth by a real-time cell-substrate impedance-based assay after 24 h of cell growth. When CHO ETB cells were synchronized in the late G1 cell cycle phase, ET-1 delayed their S phase progression compared to control by 30% as determined by [ 3 H]-thymidine incorporation. On the other hand, no such delay was observed during late G2/M to G1 transit when cells were treated with ET-1 after release from mitotic arrest. Using the cell-substrate impedance-based assay, we observed that ET-1 induces opposing morphological changes in CHO ETA and CHO ETB cells with ETB causing an increase in the cell footprint and ETA a decrease. Likewise, in pulmonary artery smooth muscle cells, which express both ETA and ETB receptors, ET-1 induces an ETA-dependent contraction and an ETB dependent dilation. These results are shedding light on a possible beneficial role for ETB in diseases involving ET-1 dysfunction such as pulmonary hypertension. -- Highlights: ► ET- hinders cell proliferation in CHO cells transfected with ETB. ► ET-1 also decreases the rate of DNA synthesis in CHO ETB cells. ► JNK and PI3K appear to be involved in this reduction of DNA synthesis. ► ETB activation in CHO ETB cells and hSMCs leads to dilatory morphological changes. ► In CHO ETA and hSMCs, ETA activation leads to constrictive morphological changes.

  7. Endothelin-1 activation of ETB receptors leads to a reduced cellular proliferative rate and an increased cellular footprint

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Jamie L.; Taylor, Linda; Polgar, Peter, E-mail: peterp@bu.edu

    2012-06-10

    Endothelin-1 (ET-1) is a vasoactive peptide which signals through two G-protein coupled receptors, endothelin receptor A (ETA) and B (ETB). We determined that ET-1 activation of its ETB receptor in stably cDNA transfected CHO cells leads to a 55% reduction in cell number by end-point cell counting and a 35% decrease in cell growth by a real-time cell-substrate impedance-based assay after 24 h of cell growth. When CHO ETB cells were synchronized in the late G1 cell cycle phase, ET-1 delayed their S phase progression compared to control by 30% as determined by [{sup 3}H]-thymidine incorporation. On the other hand, no such delay was observed during late G2/M to G1 transit when cells were treated with ET-1 after release from mitotic arrest. Using the cell-substrate impedance-based assay, we observed that ET-1 induces opposing morphological changes in CHO ETA and CHO ETB cells with ETB causing an increase in the cell footprint and ETA a decrease. Likewise, in pulmonary artery smooth muscle cells, which express both ETA and ETB receptors, ET-1 induces an ETA-dependent contraction and an ETB dependent dilation. These results are shedding light on a possible beneficial role for ETB in diseases involving ET-1 dysfunction such as pulmonary hypertension. -- Highlights: Black-Right-Pointing-Pointer ET- hinders cell proliferation in CHO cells transfected with ETB. Black-Right-Pointing-Pointer ET-1 also decreases the rate of DNA synthesis in CHO ETB cells. Black-Right-Pointing-Pointer JNK and PI3K appear to be involved in this reduction of DNA synthesis. Black-Right-Pointing-Pointer ETB activation in CHO ETB cells and hSMCs leads to dilatory morphological changes. Black-Right-Pointing-Pointer In CHO ETA and hSMCs, ETA activation leads to constrictive morphological changes.

  8. Structural determinants for selective recognition of peptide ligands for endothelin receptor subtypes ETA and ETB.

    Science.gov (United States)

    Lättig, Jens; Oksche, Alexander; Beyermann, Michael; Rosenthal, Walter; Krause, Gerd

    2009-07-01

    The molecular basis for recognition of peptide ligands endothelin-1, -2 and -3 in endothelin receptors is poorly understood. Especially the origin of ligand selectivity for ET(A) or ET(B) is not clearly resolved. We derived sequence-structure-function relationships of peptides and receptors from mutational data and homology modeling. Our major findings are the dissection of peptide ligands into four epitopes and the delineation of four complementary structural portions on receptor side explaining ligand recognition in both endothelin receptor subtypes. In addition, structural determinants for ligand selectivity could be described. As a result, we could improve the selectivity of BQ3020 about 10-fold by a single amino acid substitution, validating our hypothesis for ligand selectivity caused by different entrances to the receptors' transmembrane binding sites. A narrow tunnel shape in ET(A) is restrictive for a selected group of peptide ligands' N-termini, whereas a broad funnel-shaped entrance in ET(B) accepts a variety of different shapes and properties of ligands.

  9. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice.

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    Michinaga, Shotaro; Nagase, Marina; Matsuyama, Emi; Yamanaka, Daisuke; Seno, Naoki; Fuka, Mayu; Yamamoto, Yui; Koyama, Yutaka

    2014-01-01

    Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs) are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice). Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV) administration of BQ788 (ETB antagonist), IRL-2500 (ETB antagonist), or FR139317 (ETA antagonist) prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.

  10. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice.

    Directory of Open Access Journals (Sweden)

    Shotaro Michinaga

    Full Text Available Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice. Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV administration of BQ788 (ETB antagonist, IRL-2500 (ETB antagonist, or FR139317 (ETA antagonist prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.

  11. Celecoxib offsets the negative renal influences of cyclosporine via modulation of the TGF-β1/IL-2/COX-2/endothelin ET(B) receptor cascade.

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    El-Gowelli, Hanan M; Helmy, Maged W; Ali, Rabab M; El-Mas, Mahmoud M

    2014-03-01

    Endothelin (ET) signaling provokes nephrotoxicity induced by the immunosuppressant drug cyclosporine A (CSA). We tested the hypotheses that (i): celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, counterbalances renal derangements caused by CSA in rats and (ii) the COX-2/endothelin ET(B) receptor signaling mediates the CSA-celecoxib interaction. Ten-day treatment with CSA (20 mg/kg/day) significantly increased biochemical indices of renal function (serum urea, creatinine), inflammation (interleukin-2, IL-2) and fibrosis (transforming growth factor-β₁, TGF-β₁). Histologically, CSA caused renal tubular atrophy along with interstitial fibrosis. These detrimental renal effects of CSA were largely reduced in rats treated concurrently with celecoxib (10 mg/kg/day). We also report that cortical glomerular and medullary tubular protein expressions of COX-2 and ET(B) receptors were reduced by CSA and restored to near-control values in rats treated simultaneously with celecoxib. The importance of ET(B) receptors in renal control and in the CSA-celecoxib interaction was further verified by the findings (i) most of the adverse biochemical, inflammatory, and histopathological profiles of CSA were replicated in rats treated with the endothelin ETB receptor antagonist BQ788 (0.1 mg/kg/day, 10 days), and (ii) the BQ788 effects, like those of CSA, were alleviated in rats treated concurrently with celecoxib. Together, the data suggest that the facilitation of the interplay between the TGF-β1/IL-2/COX-2 pathway and the endothelin ET(B) receptors constitutes the cellular mechanism by which celecoxib ameliorates the nephrotoxic manifestations of CSA in rats. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Effects of endothelin, calcium channel blockade and EDRF inhibition on the contractility of human uteroplacental arteries.

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    Fried, G; Liu, Y A

    1994-08-01

    In order to examine the possibility that endothelin might be important in the regulation of placental blood flow, human uteroplacental vessels were superfused in vitro to study the contractile effect of endothelin as compared with a known strong contractor of placental blood vessels, serotonin (5-HT). The contractile responses were compared in the presence and absence of calcium channel blocking agents, as well as in the presence of L-NMA, an inhibitor of EDRF/nitric oxide. Endothelin (ET, 10(-10)-10(-6) M) and 5-HT (10(-8)-10(-4) M) induced contractions in the vessels. Maximal contractions in the presence of endothelin were elicited at 10(-7) M, whereas 5-HT elicited maximal contractions at 10(-5) M. At 10(-7) M, ET was more potent than 5-HT. The calcium-channel blocking agents nifedipine, diltiazem and NiCl2 relaxed the vessels by 5-15% from baseline. The contractile response to ET in the presence of nifedipine or diltiazem was reduced by 55 and 67%, respectively. The response of 5-HT in the presence of nifedipine was reduced by 58%. The contractile response to 5-HT as well as ET in the presence of both nifedipine and NiCl2 was not significantly lower than in the presence of nifedipine only. The EDRF-inhibiting agent L-NMA caused a small contractile response at concentrations of 10(-6)-10(-5) M. ET as well as 5-HT added after pretreatment with L-NMA produced a larger contractile response than ET or 5-HT alone. The results show that ET has a strong contractile effect on placental blood vessels at concentrations likely to occur during labor and delivery. The mechanism whereby ET as well as 5-HT contracts placental vessel smooth muscle appears to partly involve nifedipine- and diltiazem-sensitive calcium channels, but almost half of the response depends on mobilization of calcium through other means.

  13. The endothelin ET(B) receptor agonist [125I]BQ-3020 binds predominantly to nerves in the bovine retractor penis muscle and penile artery.

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    Parkkisenniemi, U M; Palkama, A; Virtanen, I; Klinge, E

    2000-11-01

    Preliminary pharmacological experiments have suggested that in the bovine retractor penis muscle there are relaxation-mediating endothelin ET(B) receptors, at least part of which are located on the inhibitory nitrergic nerves. The present work was undertaken to test this hypothesis by means of receptor autoradiography and additional pharmacological experiments. In the retractor penis muscle and the penile artery, specific binding of the ETB receptor-selective agonist [125I]BQ-3020 took place predominantly to nerve trunks and minor nerve branches. The situation was the same in the dorsal metatarsal artery, that was included as a reference because of its different innervation. Throughout the nerves the silver grains were evenly distributed over the nuclei of Schwann cells and the spaces between them. In the retractor penis there was also a small amount of specific binding to smooth muscle. No specific endothelial binding was observed in any of the tissues examined. The pharmacological studies confirmed that the relaxation of the retractor penis muscle induced by the ET(B) receptor-selective agonist, sarafotoxin S6c, is susceptible to tetrodotoxin as well as to inhibition of nitric oxide synthase. The relaxation was also characterized by inconsistency, weakness and tachyphylaxis. The electrical field stimulation-induced submaximal relaxation of the retractor penis was unaffected by stimulation or blockade of ET(B) receptors. The autoradiography suggests that in all the three bovine tissues studied there are ET(B) receptors located on nerves independently of the type of efferent nerve. The pharmacological experiments do not support the concept that in the bovine retractor penis muscle neuronal ET(B) receptors exert important immediate effects on the functioning of the penile erection-mediating nitrergic nerves.

  14. Expression profile of endothelin receptors (ETA and ETB) and microRNAs-155 and -199 in the corpus cavernosum of rats submitted to chronic alcoholism and diabetes mellitus.

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    Gonçalves, F Z; Lizarte Neto, F S; Novais, P C; Gattas, D; Lourenço, L G; de Carvalho, C A M; Tirapelli, D P C; Molina, C A F; Tirapelli, L F; Tucci, S

    2018-03-01

    Recent evidence shows that chronic ethanol consumption increases endothelin (ET)-1 induced sustained contraction of trabecular smooth muscle cells of the corpora cavernosa in corpus cavernosum of rats by a mechanism that involves increased expression of ETA and ETB receptors. Our goal was to evaluate the effects of alcohol and diabetes and their relationship to miRNA-155, miRNA-199 and endothelin receptors in the corpus cavernosum and blood of rats submitted to the experimental model of diabetes mellitus and chronic alcoholism. Forty-eight male Wistar rats were divided into four groups: control (C), alcoholic (A), diabetic (D), and alcoholic-diabetic (AD). Samples of the corpus cavernosum were prepared to study the protein expression of endothelin receptors by immunohistochemistry and expression of miRNAs-155 and -199 in serum and the cavernous tissue. Immunostaining for endothelin receptors was markedly higher in the A, D, and AD groups than in the C group. Moreover, a significant hypoexpression of the miRNA-199 in the corpus cavernosum tissue from the AD group was observed, compared to the C group. When analyzing the microRNA profile in blood, a significant hypoexpression of miRNA-155 in the AD group was observed compared to the C group. The miRNA-199 analysis demonstrated significant hypoexpression in D and AD groups compared to the C group. Our findings in corpus cavernosum showed downregulated miRNA-155 and miRNA-199 levels associated with upregulated protein expression and unaltered mRNA expression of ET receptors suggesting decreased ET receptor turnover, which can contribute to erectile dysfunction in diabetic rats exposed to high alcohol levels.

  15. Expression profile of endothelin receptors (ETA and ETB and microRNAs-155 and -199 in the corpus cavernosum of rats submitted to chronic alcoholism and diabetes mellitus

    Directory of Open Access Journals (Sweden)

    F.Z. Gonçalves

    2018-03-01

    Full Text Available Recent evidence shows that chronic ethanol consumption increases endothelin (ET-1 induced sustained contraction of trabecular smooth muscle cells of the corpora cavernosa in corpus cavernosum of rats by a mechanism that involves increased expression of ETA and ETB receptors. Our goal was to evaluate the effects of alcohol and diabetes and their relationship to miRNA-155, miRNA-199 and endothelin receptors in the corpus cavernosum and blood of rats submitted to the experimental model of diabetes mellitus and chronic alcoholism. Forty-eight male Wistar rats were divided into four groups: control (C, alcoholic (A, diabetic (D, and alcoholic-diabetic (AD. Samples of the corpus cavernosum were prepared to study the protein expression of endothelin receptors by immunohistochemistry and expression of miRNAs-155 and -199 in serum and the cavernous tissue. Immunostaining for endothelin receptors was markedly higher in the A, D, and AD groups than in the C group. Moreover, a significant hypoexpression of the miRNA-199 in the corpus cavernosum tissue from the AD group was observed, compared to the C group. When analyzing the microRNA profile in blood, a significant hypoexpression of miRNA-155 in the AD group was observed compared to the C group. The miRNA-199 analysis demonstrated significant hypoexpression in D and AD groups compared to the C group. Our findings in corpus cavernosum showed downregulated miRNA-155 and miRNA-199 levels associated with upregulated protein expression and unaltered mRNA expression of ET receptors suggesting decreased ET receptor turnover, which can contribute to erectile dysfunction in diabetic rats exposed to high alcohol levels.

  16. Affinity and selectivity of PD156707, a novel nonpeptide endothelin antagonist, for human ET(A) and ET(B) receptors.

    Science.gov (United States)

    Maguire, J J; Kuc, R E; Davenport, A P

    1997-02-01

    We have determined the affinity and selectivity of a new nonpeptide antagonist PD156707 (sodium 2-benzo(1,3ioxol-5-yl-4-(4-methoxy-pheny l)-4-oxo-3-(3,4,5-trime tho xybenzyl)-but-2-enoate) for human endothelin (ET)(A) and ET(B) receptors. In human coronary artery and saphenous vein the affinity of the ET(A) receptor for PD156707 was 0.15 +/- 0.06 nM and 0.5 +/- 0.13 nM, respectively. Competition experiments in human left ventricle and kidney revealed that PD156707 had 1,000- to 15,000-fold selectivity for the ET(A) receptor over the ET(B) receptor. This selectivity was confirmed autoradiographically. In human coronary artery, mammary artery and saphenous vein PD156707 (3-300 nM) potently antagonized the vasoconstrictor responses to ET-1. The pA2 values estimated from the Gaddum-Schild equation were 8.07 +/- 0.09, 8.45 +/- 0.11 and 8.70 +/- 0.13, respectively. The concentration-response curves to ET-1 were shifted to the right in parallel fashion, without reduction of the maximum response. However, the regression lines fitted to the resulting Schild data deviated significantly from one. PD156707 appeared to be a more effective antagonist at lower concentrations than at the higher ones. It is possible that PD156707, a sodium salt, was reverting to a less soluble form which results in underestimation of its potency. These data show that PD156707 is a potent and selective antagonist at human ET(A) receptors and will be useful in clarifying the role of the endothelin peptides in human cardiovascular disease.

  17. Permanent Distal Occlusion of Middle Cerebral Artery in Rat Causes Local Increased ETB, 5-HT1B and AT1 Receptor-Mediated Contractility Downstream of Occlusion

    DEFF Research Database (Denmark)

    Rasmussen, Marianne N P; Hornbak, Malene; Larsen, Stine S

    2013-01-01

    Background/Aims: In response to experimental stroke, a characteristic functional and expressional upregulation of contractile G-protein-coupled receptors has been uncovered in the affected cerebral vasculature; however, the mechanism initiating this phenomenon remains unknown. Methods: Using...... a model of permanent distal occlusion of rat middle cerebral arteries, we investigated whether there was a regional difference in receptor-mediated contractility of segments located upstream and downstream of the occlusion site. The contractile response to endothelin, angiotensin and 5-hydroxytryptamine...... receptor stimulation was studied by sensitive wire myograph. Results: Only downstream segments exhibited an augmented contractile response to stimulation with each of the three ligands, with the response towards sarafotoxin 6c being especially augmented compared to sham, upstream and contralateral controls...

  18. Protein kinase C inhibition prevents upregulation of vascular ET(B) and 5-HT(1B) receptors and reverses cerebral blood flow reduction after subarachnoid haemorrhage in rats

    DEFF Research Database (Denmark)

    Beg, Saema S; Hansen-Schwartz, Jacob A; Vikman, Petter J

    2007-01-01

    with Western blot; only PKCdelta and PKCalpha subtypes were increased after SAH RO-31-7549 treatment abolished this. At 2 days after the SAH basilar and middle cerebral arteries were harvested and the contractile response to endothelin-1 (ET-1; ET(A) and ET(B) receptor agonist) and 5-carboxamidotryptamine (5......-CT; 5-HT(1) receptor agonist) were investigated with a myograph. The contractile responses to ET-1 and 5-CT were increased (Poperated rats. In parallel, the ET(B) and 5-HT(1B) receptor mRNA and protein expression were significantly elevated after SAH, as analysed...

  19. Lipid-soluble smoke particles upregulate vascular smooth muscle ETB receptors via activation of mitogen-activating protein kinases and NF-kappaB pathways

    DEFF Research Database (Denmark)

    Xu, C.B.; Zheng, J.P.; Zhang, W.

    2008-01-01

    Cigarette smoke is a strong risk factor for cardiovascular disease. However, the underlying molecular mechanisms that lead to cigarette smoke-associated cardiovascular disease remain elusive. With functional and molecular methods, we demonstrate for the first time that lipid-soluble cigarette smoke...... particles (dimethylsulfoxide-soluble cigarette smoke particles; DSP) increased the expression of endothelin type B (ET(B)) receptors in arterial smooth muscle cells. The increased ET(B) receptors in arterial smooth muscle cells was documented as enhanced contractility (sensitive myograph technique...

  20. Endothelin-1 and endothelin-2 initiate and maintain contractile responses by different mechanisms in rat mesenteric and cerebral arteries

    DEFF Research Database (Denmark)

    Compeer, M. G.; Janssen, G. M. J.; De Mey, J. G. R.

    2013-01-01

    , but relaxed ET-1-induced contractions in MRA. A PLC inhibitor prevented contractile responses to ET-1 and ET-2 in MRA and BA, and relaxed ET-1- and ET-2-induced responses in MRA and ET-1 effects in BA. A Rho-kinase inhibitor did not modify sensitivity, maximum and maintenance of responses to both peptides...... in both arteries but relaxed ET-2, but not ET-1, effects in MRA and ET-1 effects in BA. Conclusions and ImplicationsPLC played a key role in arterial contractile responses to ETs, but ET-1 and ET-2 initiated and maintained vasoconstriction through different mechanisms, and these differed between MRA...

  1. Expression of ET(A) and ET(B) receptor mRNA in human cerebral arteries

    DEFF Research Database (Denmark)

    Hansen-Schwartz, J; Szok, D; Edvinsson, L

    2002-01-01

    The vascular effects of endothelins (ET) are in mammals mediated via two receptor subtypes, endothelin A (ET(A), mainly constrictive) and endothelin B (ET(B), mainly dilating) receptors. We have examined the presence of ET(A) and ET(B) receptor mRNA using the reverse transcription polymerase chai...

  2. Endothelin type B (ETB) receptors: friend or foe in the pathogenesis of pre-eclampsia and future cardiovascular disease (CVD) risk?

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    Mirabito Colafella, Katrina M

    2018-01-16

    In a recent issue of Clinical Science, Stanhewicz et al. investigated persistent microvascular dysfunction in women up to 16 months postpartum. The authors found sensitivity to the pressor effects of endothelin-1 (ET-1) was enhanced when compared with women who had a normotensive pregnancy. Importantly, the authors demonstrated that this effect was mediated via the endothelin type B (ET B ) receptors. Therefore, the present study highlights the possibility that alterations in the localization of the ET B receptor contributes to the pathogenesis of pre-eclampsia and future cardiovascular disease (CVD) risk. Currently, there is great interest in the role of the endothelin system in pre-eclampsia. Targetting the endothelin system, potentially by modulating upstream pathways to prevent ET B receptor dysfunction, may improve health outcomes for women and their offspring during pre-eclampsia and later life. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  3. Upregulation of contractile endothelin type B receptors by lipid-soluble cigarette smoking particles in rat cerebral arteries via activation of MAPK

    International Nuclear Information System (INIS)

    Sandhu, Hardip; Xu, Cang Bao; Edvinsson, Lars

    2010-01-01

    Cigarette smoke exposure increases the risk of stroke. However, the underlying molecular mechanisms are poorly understood. Endothelin system plays key roles in the pathogenesis of stroke. The present study was designed to examine if lipid-soluble (dimethyl sulfoxide-soluble) cigarette smoke particles (DSP) induces upregulation of contractile endothelin type B (ET B ) receptors in rat cerebral arteries and if activation of mitogen activated protein kinase (MAPK) and nuclear factor-kappaB (NF-κB) mediate the upregulation of contractile endothelin receptors in the cerebral arteries. Rat middle cerebral arteries were isolated and organ cultured in serum free medium for 24 h in the presence of DSP with or without specific inhibitors: MEK specific (U0126), p38 specific (SB202190), JNK specific (SP600125), NF-κB specific (BMS-345541) or (IMD-0354), transcription inhibitor (actinomycin D), or translation blocker (cycloheximide). Contractile responses to the ET B receptor agonist sarafotoxin 6c were investigated by a sensitive myograph. The expression of the ET B receptors were studied at mRNA and protein levels using quantitative real time PCR and immunohistochemistry, respectively. Results show that organ culture per se induced transcriptional upregulation of contractile ET B receptors in the cerebral vascular smooth muscle cells. This upregulation was further increased at the translational level by addition of DSP to the organ culture, but this increase was not seen by addition of nicotine or water-soluble cigarette smoke particles to the organ culture. The increased upregulation of contractile ET B receptors by DSP was abrogated by U0126, SP600125, actinomycin D, and cycloheximide, suggesting that the underlying molecular mechanisms involved in this process include activation of MEK and JNK MAPK-mediated transcription and translation of new contractile ET B receptors. Thus, the MAPK-mediated upregulation of contractile ET B receptors in cerebral arteries might be a

  4. Contractile effects and binding properties of endothelins/sarafotoxins in the guinea pig ileum.

    Science.gov (United States)

    Wollberg, Z; Bdolah, A; Galron, R; Sokolovsky, M; Kochva, E

    1991-05-30

    Seven of the eight known isopeptides of the endothelin/sarafotoxin (ET/SRTX) family were tested on the isolated guinea pig ileum and found to cause a concentration-dependent increase in basal tone. The rate or the amplitude of the spontaneous rhythmic contractions of the ileal smooth muscle were essentially not affected by any of the peptides. The maximum contraction elicited by vasoactive intestinal contractor (VIC) was slightly stronger than that induced by endothelin-1 (ET-1) or sarafotoxin-b (SRTX-b), and significantly stronger than the maximal contractions elicited by sarafotoxin-a (SRTX-a), sarafotoxin-c (SRTX-c), or endothelin-3 (ET-3). Sarafotoxin-d (SRTX-d) caused, essentially, no contraction but a rather marked relaxation. The potencies of the various peptides to induce the increase in tension, in terms of EC50 values (cumulative effective concentrations that induce half-maximum response), ranged between 6 and 95 nM depending on the peptide. VIC, ET-1, SRTX-b and SRTX-a had similar potencies and were significantly more potent than SRTX-c and ET-3. A high concentration of SRTX-b elicited no additional response when applied to the organ bath after one of the other peptides had shown a maximal effect. Binding experiments with ileal membranes revealed similar binding properties for the various peptides. Competition with iodinated SRTX-b showed no meaningful differences between the various peptides. It is concluded that all the ET/SRTX peptides compete for the same receptor subtype in the ileum. In terms of efficacy, VIC can be considered as a full agonist of this receptor, SRTX-d is probably an antagonist, while all the other peptides behave as partial agonists.

  5. Increased expression of endothelin ET(B) and angiotensin AT(1) receptors in peripheral resistance arteries of patients with suspected acute coronary syndrome

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Ekelund, Ulf; Edvinsson, Lars

    2009-01-01

    of arterial vasoconstrictor endothelin (ET) and angiotensin (AT) receptors. Our aim was to investigate if the arterial expressions of these receptors are changed in patients with suspected but ruled out acute coronary syndrome (ACS). Small subcutaneous arteries (diameter of 100 microm) were surgically removed...... in the regulation of coronary tone and in the development of atherosclerosis, and may be related to increased cardiovascular risk....

  6. Activation of either the ETA or the ETB receptors is involved in the development of electrographic seizures following intrahippocampal infusion of the endothelin-1 in immature rats

    Czech Academy of Sciences Publication Activity Database

    Tsenov, Grygoriy; Vondráková, Kateřina; Otáhal, Jakub; Burchfiel, J.; Kubová, Hana

    2015-01-01

    Roč. 265, Mar 2015 (2015), s. 40-47 ISSN 0014-4886 R&D Projects: GA ČR(CZ) GPP304/11/P386; GA ČR(CZ) GBP304/12/G069; GA ČR(CZ) GA14-20613S Institutional support: RVO:67985823 Keywords : focal ischemia * endothelin-1 * cerebral blood flow * oxygen saturation * seizures * hippocampus * immature rat * ET receptors Subject RIV: FH - Neurology Impact factor: 4.657, year: 2015

  7. Endothelin receptors and activity differ in human, dog, and rabbit lung.

    Science.gov (United States)

    McKay, K O; Armour, C L; Black, J L

    1996-01-01

    In this study, we have examined dog and rabbit airways as potential models for human airways in regard to the activity of endothelin. The receptors involved in the response to endothelin-1 (ET-1) in airway tissue from human, rabbit, and dog lung were investigated, as was the mechanism responsible for the contraction to ET-1 in tissue from the three species. By using specific endothelin receptor agonists and antagonists, we have demonstrated that ETB receptors predominate in rabbit and human airways and ETA receptors in dog airways. The contraction to ET-1 is not dependent on cyclooxygenase products of arachidonic acid, as indomethacin had no effect on the response to ET-1. Extracellular calcium influx via voltage-dependent channels is necessary for contraction to ET-1 in rabbit and dog airways. These results are in contrast to our previously reported results in human airways, in which neither removal of extracellular calcium nor verapamil affected the ET-1 response. The sustained phase of the contraction to ET-1 in all three species may be mediated in part by activation of protein kinase C (PKC), as the inhibitor staurosporine significantly altered the time course of the response to endothelin. We therefore conclude that in rabbit airways ET-1 activates ETB receptors, triggers the influx of extracellular calcium through voltage-dependent channels, and induces a contractile response that is, in part, dependent upon stimulation of PKC. The same mechanism is triggered in dog bronchus; however, the receptors involved in this species are of the ETA type. Finally, in human airways, the contractile response to ET-1, while independent of extracellular calcium influx, is dependent upon PKC activation after binding of the peptide to ETB receptors.

  8. Stimuli of sensory-motor nerves terminate arterial contractile effects of endothelin-1 by CGRP and dissociation of ET-1/ET(A)-receptor complexes

    DEFF Research Database (Denmark)

    Meens, Merlijn J P M T; Compeer, Matthijs G; Hackeng, Tilman M

    2010-01-01

    of the antagonists and (ii) can be selectively dissociated by an endogenous counterbalancing mechanism. METHODOLOGY/PRINCIPAL FINDINGS: In isolated rat mesenteric resistance arteries, ET(A)-antagonists, endothelium-derived relaxing factors and synthetic vasodilators transiently reduced contractile effects of ET-1......BACKGROUND: Endothelin-1 (ET-1), a long-acting paracrine mediator, is implicated in cardiovascular diseases but clinical trials with ET-receptor antagonists were not successful in some areas. We tested whether the quasi-irreversible receptor-binding of ET-1 (i) limits reversing effects...... but did not prevent persistent effects of the peptide. Stimuli of peri-vascular vasodilator sensory-motor nerves such as capsaicin not only reduced but also terminated long-lasting effects of ET-1. This was prevented by CGRP-receptor antagonists and was mimicked by exogenous calcitonin gene...

  9. Respiratory syncytial virus infection in sheep bronchial explants is associated with enhanced ETB receptor-mediate contractile functional and autoradiographic studies

    International Nuclear Information System (INIS)

    Fernandes, L.B.; D'Aprile, A.C.; Betts, R.J.; Goldie, R.G.

    2001-01-01

    Full text: Respiratory syncytial virus (RSV) is an important precipitant of asthma in children. The impact of RSV infection on endothelin (ET) receptor density and function in airways is unknown. In the present study, sheep bronchial rings were maintained as explants in culture for up to 48 h. During this time, both the structural integrity of the epithelium and carbachol responsiveness were preserved. Bronchial rings in culture were exposed to non-infected culture medium or to RSV (1/50 TCID 50 ) for 0, 24 and 48 h which caused marked damage to and loss of the epithelium. RSV infection did not significantly alter responsiveness to ET-1 at either 24 (Control EC 40 = 102 nM, 95% confidence limits, 76-138 nM vs RSV EC 40 = 66 nM, 95% confidence limits, 48-91 nM, n=5-6, P>0.05) or 48 h (Control EC 40 35 nM, 95% confidence limits, 19-66 nM vs RSV EC 40 = 55 nM, 95% confidence limits, 32-93 nM, n=8, P>0.05). As seen previously (Goldie et al., 1994), sarafotoxin S6c (StxS6c, ET B -selective) did not cause contraction in non-infected sheep bronchial explants. In contrast, StxS6c (300 nM) increased tone by 8±3% carbachol Emax (n=6-8) in explants exposed to RSV for 24 or 48 h. Light microscopic autoradiography was used to determine the relative distribution of ET A and ET B receptors using [ 125 I]-ET-1, BQ-123 (ET A -selective) and StxS6c. Sheep airway smooth muscle contains a homogeneous population of ET A receptors (Goldie et al., 1994). Since StxS6c caused significant contraction in RSV-infected bronchial explants, it was surprising that autoradiographic techniques failed to detect airway smooth muscle ET B receptors in these preparations. It is likely that ET B receptors fell below the level of detection of autoradiography. The significant StxS6c-induced contraction of sheep bronchi suggests the novel expression of ET B receptors triggered by RSV which might be relevant to RSV-associated asthma. Copyright (2001) Australasian Society of Clinical and Experimental

  10. Endothelin-1 and endothelin-3 regulate endothelin receptor expression in rat coronary arteries

    DEFF Research Database (Denmark)

    Skovsted, Gry Freja; Kilic, Semsi; Edvinsson, Lars

    2015-01-01

    In ischaemic hearts, endothelin (ET) levels are increased, and vasoconstrictor responses to ET-1 are greatly enhanced. We previously reported that ETB receptors are up-regulated in the smooth muscle layer of coronary arteries after myocardial ischaemia-reperfusion and that the MEK-ERK1/2 signalli...

  11. Reduced Mechanical Stretch Induces Enhanced Endothelin B Receptor-mediated Contractility via Activation of Focal Adhesion Kinase and Extra Cellular-regulated Kinase 1/2 in Cerebral Arteries from Rat

    DEFF Research Database (Denmark)

    Spray, Stine; Rasmussen, Marianne N P; Skovsted, Gry F

    2016-01-01

    that rapid and sustained reduction in wall tension/stretch is a possible trigger mechanism for this vascular remodelling. Isolated rat middle cerebral artery (MCA) segments were incubated in a wire-myograph with or without mechanical stretch, prior to assessment of their contractile response to the selective...... expression to SMC expression and 2) an increased calcium sensitivity of the SMCs due to an increased expression of the calcium channel transient receptor potential canonical 1. Collectively, our results present a possible mechanism linking lack of vessel wall stretch/tension to changes in ETB receptor...

  12. Stimuli of sensory-motor nerves terminate arterial contractile effects of endothelin-1 by CGRP and dissociation of ET-1/ET(A-receptor complexes.

    Directory of Open Access Journals (Sweden)

    Merlijn J P M T Meens

    Full Text Available BACKGROUND: Endothelin-1 (ET-1, a long-acting paracrine mediator, is implicated in cardiovascular diseases but clinical trials with ET-receptor antagonists were not successful in some areas. We tested whether the quasi-irreversible receptor-binding of ET-1 (i limits reversing effects of the antagonists and (ii can be selectively dissociated by an endogenous counterbalancing mechanism. METHODOLOGY/PRINCIPAL FINDINGS: In isolated rat mesenteric resistance arteries, ET(A-antagonists, endothelium-derived relaxing factors and synthetic vasodilators transiently reduced contractile effects of ET-1 but did not prevent persistent effects of the peptide. Stimuli of peri-vascular vasodilator sensory-motor nerves such as capsaicin not only reduced but also terminated long-lasting effects of ET-1. This was prevented by CGRP-receptor antagonists and was mimicked by exogenous calcitonin gene-related peptide (CGRP. Using 2-photon laser scanning microscopy in vital intact arteries, capsaicin and CGRP, but not ET(A-antagonism, were observed to promote dissociation of pre-existing ET-1/ET(A-receptor complexes. CONCLUSIONS: Irreversible binding and activation of ET(A-receptors by ET-1 (i occur at an antagonist-insensitive site of the receptor and (ii are selectively terminated by endogenously released CGRP. Hence, natural stimuli of sensory-motor nerves that stimulate release of endogenous CGRP can be considered for therapy of diseases involving ET-1.

  13. Stimuli of Sensory-Motor Nerves Terminate Arterial Contractile Effects of Endothelin-1 by CGRP and Dissociation of ET-1/ETA-Receptor Complexes

    Science.gov (United States)

    Meens, Merlijn J. P. M. T.; Compeer, Matthijs G.; Hackeng, Tilman M.; van Zandvoort, Marc A.; Janssen, Ben J. A.; De Mey, Jo G. R.

    2010-01-01

    Background Endothelin-1 (ET-1), a long-acting paracrine mediator, is implicated in cardiovascular diseases but clinical trials with ET-receptor antagonists were not successful in some areas. We tested whether the quasi-irreversible receptor-binding of ET-1 (i) limits reversing effects of the antagonists and (ii) can be selectively dissociated by an endogenous counterbalancing mechanism. Methodology/Principal findings In isolated rat mesenteric resistance arteries, ETA-antagonists, endothelium-derived relaxing factors and synthetic vasodilators transiently reduced contractile effects of ET-1 but did not prevent persistent effects of the peptide. Stimuli of peri-vascular vasodilator sensory-motor nerves such as capsaicin not only reduced but also terminated long-lasting effects of ET-1. This was prevented by CGRP-receptor antagonists and was mimicked by exogenous calcitonin gene-related peptide (CGRP). Using 2-photon laser scanning microscopy in vital intact arteries, capsaicin and CGRP, but not ETA-antagonism, were observed to promote dissociation of pre-existing ET-1/ETA-receptor complexes. Conclusions Irreversible binding and activation of ETA-receptors by ET-1 (i) occur at an antagonist-insensitive site of the receptor and (ii) are selectively terminated by endogenously released CGRP. Hence, natural stimuli of sensory-motor nerves that stimulate release of endogenous CGRP can be considered for therapy of diseases involving ET-1. PMID:20532232

  14. Low density lipoprotein induces upregulation of vasoconstrictive endothelin type B receptor expression

    DEFF Research Database (Denmark)

    Xu, Cang-Bao; Zheng, Jian-Pu; Zhang, Wei

    2014-01-01

    Vasoconstrictive endothelin type B (ET(B)) receptors promote vasospasm and ischemic cerebro- and cardiovascular diseases. The present study was designed to examine if low density lipoprotein (LDL) induces upregulation of vasoconstrictive ET(B) receptor expression and if extracellular signal...

  15. NF-kappaB signaling mediates vascular smooth muscle endothelin type B receptor expression in resistance arteries

    DEFF Research Database (Denmark)

    Zheng, Jian-Pu; Zhang, Yaping; Edvinsson, Lars

    2010-01-01

    Vascular smooth muscle cells (SMC) endothelin type B (ET(B)) receptor upregulation results in strong vasoconstriction and reduction of local blood flow. We hypothesizes that the underlying molecular mechanisms involve transcriptional factor nuclear factor-kappaB (NF-kappaB) pathway. ET(B) recepto...

  16. Vascular reactivity of mesenteric arteries and veins to endothelin-1 in a murine model of high blood pressure.

    Science.gov (United States)

    Pérez-Rivera, Alex A; Fink, Gregory D; Galligan, James J

    2005-06-01

    We characterized vascular reactivity to endothelin-1 (ET-1) in mesenteric vessels from DOCA-salt hypertensive and SHAM control mice and assessed the effect that endothelial-derived vasodilators have on ET-1-induced vasoconstriction. Changes in the diameter of unpressurized small mesenteric arteries and veins (100- to 300-microm outside diameter) were measured in vitro using computer-assisted video microscopy. Veins were more sensitive than arteries to the contractile effects of ET-1. There was a decrease in arterial maximal responses (E(max)) compared to veins, this effect was larger in DOCA-salt arteries. The selective ET(B) receptor agonist, sarafotoxin 6c (S6c), contracted DOCA-salt and SHAM veins but did not contract arteries. The ET(B) receptor antagonist, BQ-788 (100 nM), but not the ET(A) receptor antagonist, BQ-610 (100 nM), blocked S6c responses. BQ-610 partially inhibited responses to ET-1 in mesenteric veins from DOCA-salt and SHAM mice while BQ-788 did not affect responses to ET-1. Co-administration of both antagonists inhibited responses to ET-1 to a greater extent than BQ-610 alone suggesting a possible functional interaction between ET(A) and ET(B) receptors. Responses to ET-1 in mesenteric arteries were completely inhibited by BQ-610 while BQ-788 did not affect arterial responses. Nitric oxide synthase inhibition potentiated ET-1 responses in veins from SHAM but not DOCA-salt mice. There was a prominent role for ET-mediated nitric oxide release in DOCA-salt but not SHAM arteries. In summary, these studies showed a differential regulation of ET-1 contractile mechanisms between murine mesenteric arteries and veins.

  17. Evaporation characteristics of ETBE-blended gasoline

    International Nuclear Information System (INIS)

    Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

    2015-01-01

    Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

  18. Evaporation characteristics of ETBE-blended gasoline

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Katsuhiro, E-mail: okamoto@nrips.go.jp [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan); Hiramatsu, Muneyuki [Yamanashi Prefectural Police H.Q., 312-4 Kubonakajima, Isawa-cho, Usui, Yamanashi 406-0036 (Japan); Hino, Tomonori; Otake, Takuma [Metropolitan Police Department, 2-1-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8929 (Japan); Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi [National Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba 277-0882 (Japan)

    2015-04-28

    Highlights: • We chose 8-component hydrocarbon mixture as a model gasoline, and defined the molar mass of gasoline. • We proposed an evaporation model assuming a 2-component mixture of gasoline and ETBE. • We predicted the change in the vapor pressure of ETBE-blended gasoline by evaporation. • The vapor pressures were measured and compared as a means of verifying the model. • We presented the method for predicting flash points of the ETBE-blended gasoline. - Abstract: To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were

  19. Endothelin Regulates Porphyromonas gingivalis-Induced Production of Inflammatory Cytokines.

    Directory of Open Access Journals (Sweden)

    Ga-Yeon Son

    Full Text Available Periodontitis is a very common oral inflammatory disease that results in the destruction of supporting connective and osseous tissues of the teeth. Although the exact etiology is still unclear, Gram-negative bacteria, especially Porphyromonas gingivalis in subgingival pockets are thought to be one of the major etiologic agents of periodontitis. Endothelin (ET is a family of three 21-amino acid peptides, ET-1, -2, and -3, that activate G protein-coupled receptors, ETA and ETB. Endothelin is involved in the occurrence and progression of various inflammatory diseases. Previous reports have shown that ET-1 and its receptors, ETA and ETB are expressed in the periodontal tissues and, that ET-1 levels in gingival crevicular fluid are increased in periodontitis patients. Moreover, P. gingivalis infection has been shown to induce the production of ET-1 along with other inflammatory cytokines. Despite these studies, however, the functional significance of endothelin in periodontitis is still largely unknown. In this study, we explored the cellular and molecular mechanisms of ET-1 action in periodontitis using human gingival epithelial cells (HGECs. ET-1 and ETA, but not ETB, were abundantly expressed in HGECs. Stimulation of HGECs with P. gingivalis or P. gingivalis lipopolysaccharide increased the expression of ET-1 and ETA suggesting the activation of the endothelin signaling pathway. Production of inflammatory cytokines, IL-1β, TNFα, and IL-6, was significantly enhanced by exogenous ET-1 treatment, and this effect depended on the mitogen-activated protein kinases via intracellular Ca2+ increase, which resulted from the activation of the phospholipase C/inositol 1,4,5-trisphosphate pathway. The inhibition of the endothelin receptor-mediated signaling pathway with the dual receptor inhibitor, bosentan, partially ameliorated alveolar bone loss and immune cell infiltration. These results suggest that endothelin plays an important role in P. gingivalis

  20. Functional ET(A)-ET(B) Receptor Cross-talk in Basilar Artery In Situ From ET(B) Receptor Deficient Rats.

    Science.gov (United States)

    Yoon, SeongHun; Gariepy, Cheryl E; Yanagisawa, Masashi; Zuccarello, Mario; Rapoport, Robert M

    2016-03-01

    The role of endothelin (ET)(A)-ET(B) receptor cross-talk in limiting the ET(A) receptor antagonist inhibition of ET-1 constriction is revealed by the partial or complete dependency of the ET(A) receptor antagonist inhibition on functional removal of the ET(B) receptor. Although functional removal of the ET(B) receptor is generally accomplished with ET(B) receptor antagonist, a novel approach using rats containing a naturally occurring deletion mutation in the ET(B) receptor [rescued "spotting lethal" (sl) rats; ET(B)(sl/sl)] demonstrated increased ET(A) receptor antagonist inhibition of ET-1 constriction in vena cava. We investigated whether this deletion mutation was also sufficient to remove the ET(B) receptor dependency of the ET(A) receptor antagonist inhibition of ET-1 constriction in the basilar artery. Consistent with previous reports, ET-1 plasma levels were elevated in ET(B)(sl/sl) as compared with ET(B)(+/+) rats. ET(B) receptor antagonist failed to relax the ET-1 constricted basilar artery from ET(B)(+/+) and ET(B)(sl/sl) rats. Relaxation to combined ET(A) and ET(B) receptor antagonist was greater than relaxation to ET(A) receptor antagonist in the basilar artery from ET(B)(+/+) and, unexpectedly, ET(B)(sl/sl) rats. These findings confirm the presence of ET(A)-ET(B) receptor cross-talk in the basilar artery. We speculate that mutant ET(B) receptor expression produced by alternative splicing may be sufficient to allow cross-talk.

  1. Evaporation characteristics of ETBE-blended gasoline.

    Science.gov (United States)

    Okamoto, Katsuhiro; Hiramatsu, Muneyuki; Hino, Tomonori; Otake, Takuma; Okamoto, Takashi; Miyamoto, Hiroki; Honma, Masakatsu; Watanabe, Norimichi

    2015-04-28

    To reduce greenhouse gas emissions, which contribute to global warming, production of gasoline blended with ethyl tert-buthyl ether (ETBE) is increasing annually. The flash point of ETBE is higher than that of gasoline, and blending ETBE into gasoline will change the flash point and the vapor pressure. Therefore, it is expected that the fire hazard caused by ETBE-blended gasoline would differ from that caused by normal gasoline. The aim of this study was to acquire the knowledge required for estimating the fire hazard of ETBE-blended gasoline. Supposing that ETBE-blended gasoline was a two-component mixture of gasoline and ETBE, we developed a prediction model that describes the vapor pressure and flash point of ETBE-blended gasoline in an arbitrary ETBE blending ratio. We chose 8-component hydrocarbon mixture as a model gasoline, and defined the relation between molar mass of gasoline and mass loss fraction. We measured the changes in the vapor pressure and flash point of gasoline by blending ETBE and evaporation, and compared the predicted values with the measured values in order to verify the prediction model. The calculated values of vapor pressures and flash points corresponded well to the measured values. Thus, we confirmed that the change in the evaporation characteristics of ETBE-blended gasoline by evaporation could be predicted by the proposed model. Furthermore, the vapor pressure constants of ETBE-blended gasoline were obtained by the model, and then the distillation curves were developed. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Role of ERK/MAPK in endothelin receptor signaling in human aortic smooth muscle cells

    DEFF Research Database (Denmark)

    Chen, Qing-wen; Edvinsson, Lars; Xu, Cang-Bao

    2009-01-01

    muscle cells (VSMCs) through activation of endothelin type A (ETA) and type B (ETB) receptors. The extracellular signal-regulated kinase 1 and 2 (ERK1/2) mitogen-activated protein kinases (MAPK) are involved in ET-1-induced VSMC contraction and proliferation. This study was designed to investigat...

  3. Protein kinase mediated upregulation of endothelin A, endothelin B and 5-hydroxytryptamine 1B/1D receptors during organ culture in rat basilar artery

    DEFF Research Database (Denmark)

    Hansen-Schwartz, Jacob; Svensson, Carl-Lennart; Xu, Cang-Bao

    2002-01-01

    with ET-1 (unspecific ET(A) and ET(B) agonist), S6c (specific ET(B) agonist) and 5-CT (5-HT(1) agonist). Levels of mRNA coding for the ET(A), ET(B), 5-HT(1B) and 5-HT(1D) receptors were analysed using real-time RT-PCR. 3. Classical PKC's are critically involved in the appearance of the ET(B) receptor; co....... 2. The effect of inhibiting protein kinases during organ culture with staurosporine (unspecific protein kinase inhibitor), RO 31-7549 (specific inhibitor of classical PKC's) and H 89 (specific inhibitor of PKA) was examined using in vitro pharmacological examination of cultured vessel segments......-culture with RO 31-7549 abolished the contractile response (6.9 +/- 1.8%) and reduced the ET(B) receptor mRNA by 44 +/- 4% as compared to the cultured control. Correlation between decreased ET(B) receptor mRNA and abolished contractile function indicates upstream involvement of PKC. 4. Inhibition of PKA generally...

  4. Endothelin B receptor blockade attenuates pulmonary vasodilation in oxygen-ventilated fetal lambs.

    Science.gov (United States)

    Ivy, D Dunbar; Lee, Dong-Seok; Rairigh, Robyn L; Parker, Thomas A; Abman, Steven H

    2004-01-01

    Endothelin-1 (ET-1) contributes to the regulation of pulmonary vascular tone in the normal ovine fetus and in models of perinatal pulmonary hypertension. In the fetal lamb lung, the effects of ET-1 depend on the balance of at least two endothelin receptor subtypes: ETA and ETB. ETA receptors are located on smooth muscle cells and mediate vasoconstriction and smooth muscle proliferation. Stimulation of endothelial ETB receptors causes vasodilation through release of nitric oxide and also functions to remove ET-1 from the circulation. However, whether activation of ETB receptors contributes to the fall in pulmonary vascular tone at birth is unknown. To determine the role of acute ETB receptor blockade in pulmonary vasodilation in response to birth-related stimuli, we studied the hemodynamic effects of selective ETB receptor blockade with BQ-788 during mechanical ventilation with low (<10%) and high FiO2 (100%) in near-term fetal sheep. Intrapulmonary infusion of BQ-788 did not change left pulmonary artery (LPA) blood flow and pulmonary vascular resistance (PVR) at baseline. In comparison with controls, BQ-788 treatment attenuated the rise in LPA flow with low and high FiO2 ventilation (p <0.001 vs. control for each FiO2 concentration). PVR progressively decreased during mechanical ventilation with low and high FiO2 in both groups, but PVR remained higher after BQ-788 treatment throughout the study period (p <0.001). We conclude that selective ETB receptor blockade attenuates pulmonary vasodilation at birth. We speculate that ETB receptor stimulation contributes to pulmonary vasodilation at birth in the ovine fetus.

  5. The heart as an extravascular target of endothelin-1 in ...

    Science.gov (United States)

    Exposure to particulate matter air pollution has been causally linked to cardiovascular disease in humans. Several broad and overlapping hypotheses describing the biological mechanisms by which particulate matter exposure leads to cardiovascular disease and cardiac dysfunction have been explored, though linkage with specific factors or genes remains limited. Given evidence pointing to autocrine/paracrine signaling systems as modulators of cardiac dysfunction, the present review highlights the emerging role of endothelins as mediators of cardiac dysfunction following particulate matter exposure. Endothelin-1 is a small multifunctional protein expressed in the pulmonary and cardiovascular system, known for its ability to constrict blood vessels. Although endothelin-1 can also directly and indirectly (via secondary signaling events) modulate cardiac contractility, heart rate, and rhythm, research on the role of endothelins in the context of air pollution has tended to focus on the vascular effects. The plausibility of endothelin as a mechanism underlying particulate matter-induced cardiac dysfunction is further supported by the therapeutic utility of certain endothelin receptor antagonists. Extravascular effects of endothelin on the heart could better explain one mechanism by which particulate matter exposure may lead to cardiac dysfunction. We propose and support the novel hypothesis that autocrine/paracrine signaling systems, such as endothelins, mediate cardiac

  6. Endothelin B receptors contribute to retinal ganglion cell loss in a rat model of glaucoma.

    Directory of Open Access Journals (Sweden)

    Alena Z Minton

    Full Text Available Glaucoma is an optic neuropathy, commonly associated with elevated intraocular pressure (IOP characterized by optic nerve degeneration, cupping of the optic disc, and loss of retinal ganglion cells which could lead to loss of vision. Endothelin-1 (ET-1 is a 21-amino acid vasoactive peptide that plays a key role in the pathogenesis of glaucoma; however, the receptors mediating these effects have not been defined. In the current study, endothelin B (ET(B receptor expression was assessed in vivo, in the Morrison's ocular hypertension model of glaucoma in rats. Elevation of IOP in Brown Norway rats produced increased expression of ET(B receptors in the retina, mainly in retinal ganglion cells (RGCs, nerve fiber layer (NFL, and also in the inner plexiform layer (IPL and inner nuclear layer (INL. To determine the role of ET(B receptors in neurodegeneration, Wistar-Kyoto wild type (WT and ET(B receptor-deficient (KO rats were subjected to retrograde labeling with Fluoro-Gold (FG, following which IOP was elevated in one eye while the contralateral eye served as control. IOP elevation for 4 weeks in WT rats caused an appreciable loss of RGCs, which was significantly attenuated in KO rats. In addition, degenerative changes in the optic nerve were greatly reduced in KO rats compared to those in WT rats. Taken together, elevated intraocular pressure mediated increase in ET(B receptor expression and its activation may contribute to a decrease in RGC survival as seen in glaucoma. These findings raise the possibility of using endothelin receptor antagonists as neuroprotective agents for the treatment of glaucoma.

  7. Discovery of Dual ETA/ETB Receptor Antagonists from Traditional Chinese Herbs through in Silico and in Vitro Screening

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2016-03-01

    Full Text Available Endothelin-1 receptors (ETAR and ETBR act as a pivotal regulator in the biological effects of ET-1 and represent a potential drug target for the treatment of multiple cardiovascular diseases. The purpose of the study is to discover dual ETA/ETB receptor antagonists from traditional Chinese herbs. Ligand- and structure-based virtual screening was performed to screen an in-house database of traditional Chinese herbs, followed by a series of in vitro bioassay evaluation. Aristolochic acid A (AAA was first confirmed to be a dual ETA/ETB receptor antagonist based intracellular calcium influx assay and impedance-based assay. Dose-response curves showed that AAA can block both ETAR and ETBR with IC50 of 7.91 and 7.40 μM, respectively. Target specificity and cytotoxicity bioassay proved that AAA is a selective dual ETA/ETB receptor antagonist and has no significant cytotoxicity on HEK293/ETAR and HEK293/ETBR cells within 24 h. It is a feasible and effective approach to discover bioactive compounds from traditional Chinese herbs using in silico screening combined with in vitro bioassay evaluation. The structural characteristic of AAA for its activity was especially interpreted, which could provide valuable reference for the further structural modification of AAA.

  8. The endothelin system has a significant role in the pathogenesis and progression of Mycobacterium tuberculosis infection.

    Science.gov (United States)

    Correa, Andre F; Bailão, Alexandre M; Bastos, Izabela M D; Orme, Ian M; Soares, Célia M A; Kipnis, Andre; Santana, Jaime M; Junqueira-Kipnis, Ana Paula

    2014-12-01

    Tuberculosis (TB) remains a major global health problem, and although multiple studies have addressed the relationship between Mycobacterium tuberculosis and the host on an immunological level, few studies have addressed the impact of host physiological responses. Proteases produced by bacteria have been associated with important alterations in the host tissues, and a limited number of these enzymes have been characterized in mycobacterial species. M. tuberculosis produces a protease called Zmp1, which appears to be associated with virulence and has a putative action as an endothelin-converting enzyme. Endothelins are a family of vasoactive peptides, of which 3 distinct isoforms exist, and endothelin 1 (ET-1) is the most abundant and the best-characterized isoform. The aim of this work was to characterize the Zmp1 protease and evaluate its role in pathogenicity. Here, we have shown that M. tuberculosis produces and secretes an enzyme with ET-1 cleavage activity. These data demonstrate a possible role of Zmp1 for mycobacterium-host interactions and highlights its potential as a drug target. Moreover, the results suggest that endothelin pathways have a role in the pathogenesis of M. tuberculosis infections, and ETA or ETB receptor signaling can modulate the host response to the infection. We hypothesize that a balance between Zmp1 control of ET-1 levels and ETA/ETB signaling can allow M. tuberculosis adaptation and survival in the lung tissues. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. Effects of age and caloric restriction in the vascular response of renal arteries to endothelin-1 in rats.

    Science.gov (United States)

    Amor, Sara; García-Villalón, Angel Luis; Rubio, Carmen; Carrascosa, Jose Ma; Monge, Luis; Fernández, Nuria; Martín-Carro, Beatriz; Granado, Miriam

    2017-02-01

    Cardiovascular alterations are the most prevalent cause of impaired physiological function in aged individuals with kidney being one the most affected organs. Aging-induced alterations in renal circulation are associated with a decrease in endothelium-derived relaxing factors such as nitric oxide (NO) and with an increase in contracting factors such as endothelin-1(ET-1). As caloric restriction (CR) exerts beneficial effects preventing some of the aging-induced alterations in cardiovascular system, the aim of this study was to analyze the effects of age and caloric restriction in the vascular response of renal arteries to ET-1 in aged rats. Vascular function was studied in renal arteries from 3-month-old Wistar rats fed ad libitum (3m) and in renal arteries from 8-and 24-month-old Wistar rats fed ad libitum (8m and 24m), or subjected to 20% caloric restriction during their three last months of life (8m-CR and 24m-CR). The contractile response to ET-1 was increased in renal arteries from 8m and 24m compared to 3m rats. ET-1-induced contraction was mediated by ET-A receptors in all experimental groups and also by ET-B receptors in 24m rats. Caloric restriction attenuated the increased contraction to ET-1 in renal arteries from 8m but not from 24m rats possibly through NO release proceeding from ET-B endothelial receptors. In 24m rats, CR did not attenuate the aging-increased response of renal arteries to ET-1, but it prevented the aging-induced increase in iNOS mRNA levels and the aging-induced decrease in eNOS mRNA levels in arterial tissue. In conclusion, aging is associated with an increased response to ET-1 in renal arteries that is prevented by CR in 8m but not in 24m rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Bioremediation treatment of MTBE and ETBE in contaminated soils

    Directory of Open Access Journals (Sweden)

    Alissara Reungsang

    2006-07-01

    Full Text Available Three Methyl Tertiary Butyl Ether (MTBE degradative consortia were isolated from gasoline-contaminated soil namely: mKMS, mKGS1 and mKGS2. These consortia were tested for the ability to degrade Ethyl Tertiary Butyl Ether (ETBE at the concentration of 100 mg/L and to degrade a mixture of MTBE and ETBE in the Nutrient Broth (NB media at the concentration of 50 mg/L each. The results showed that mKGS1 was the best degraders in which 74% of MTBE, 25% of ETBE and 16% of MTBE and 23% of ETBE in the mixture were degraded, within 30 days. mKGS1 was then further used in the bioaugmentation and biostimulation experiments. Degradation of MTBE increased from 34% to 61% after 70 days when mKGS1 was amended in soil mixed with the combination of MTBE and ETBE (at 50 mg/L each. However, mKGS1 did not significantly help the ETBE degradation when it was amended in soil (biostimulation technique. One percent glucose significantly stimulated the degradation of MTBE by the indigenous microorganisms. The presence of mKGS1 and an addition of 1% glucose as extra carbon source improved the degradation of MTBE, from 42 to 51%, suggesting mKGS1 played an important role in the degradation of MTBE.

  11. 25 Years of endothelin research

    DEFF Research Database (Denmark)

    Emoto, Noriaki; Vignon-Zellweger, Nicolas; Lopes, Rhéure Alves Moreira

    2014-01-01

    In the past three decades, endothelin and endothelin receptor antagonists have received great scientific and clinical interest, leading to the publication of more than 27,000 scientific articles since its discovery. The Thirteenth International Conference on Endothelin (ET-13) was held on Septemb...

  12. Endothelin in human brain and pituitary gland: Presence of immunoreactive endothelin, endothelin messenger ribonucleic acid, and endothelin receptors

    International Nuclear Information System (INIS)

    Takahashi, K.; Ghatei, M.A.; Jones, P.M.; Murphy, J.K.; Lam, H.C.; O'Halloran, D.J.; Bloom, S.R.

    1991-01-01

    The presence of immunoreactive (IR) endothelin, endothelin mRNA, and endothelin receptors in human brain and pituitary gland has been studied by RIA, Northern blot hybridization, and receptor assay. IR endothelin was detected in all five brain regions examined (cerebral cortex, cerebellum, brain stem, basal ganglia, and hypothalamus) (6-10 fmol/g wet wt) and spinal cord (22 +/- 6 fmol/g wet wt, n = 7, mean +/- SEM). Higher concentrations of IR endothelin were found in the pituitary gland (147 +/- 30 fmol/g wet wt). Fast protein liquid chromatographic analysis of the IR endothelin in pituitary gland showed a large IR peak in the position of endothelin-3 and a smaller peak in the position of endothelin-1, whereas IR endothelin in the hypothalamus and brain stem was mainly endothelin-1. Endothelin messenger RNA was detected by Northern blot hybridization in the pituitary but not in hypothalamus. The receptor assay showed that 125I-endothelin-1 binding sites were present in large numbers in all five brain regions but were much less abundant in the pituitary gland. Binding capacity and dissociation constant were 5052 +/- 740 fmol/mg protein and 0.045 +/- 0.007 nM in brain stem and 963 +/- 181 fmol/mg protein and 0.034 +/- 0.009 nM in hypothalamus. In the pituitary gland, there were two classes of binding sites for endothelin with dissociation constants of 0.059 +/- 0.002 nM (binding capacity = 418 +/- 63 fmol/mg protein) and 0.652 +/- 0.103 nM (binding capacity = 1717 +/- 200 fmol/mg protein). Endothelin-1, -2 and -3 were almost equipotent in displacing the binding (IC50 approximately 0.04 nM). These findings are in accord with the possibility that endothelin acts as a neurotransmitter, neuromodulator or neurohormone in man

  13. Endothelin-1 and antiangiogenesis

    NARCIS (Netherlands)

    S. Lankhorst (Stephanie); A.H.J. Danser (Jan); A.H. van den Meiracker (Anton)

    2016-01-01

    textabstractAntiangiogenesis, targeting vascular endothelial growth factor (VEGF), has become a well-established treatment for patients with cancer. This treatment is associated with nitric oxide (NO) suppression and a dose-dependent activation of the endothelin system, resulting in

  14. Vascular mechanism of action of endothelin-1: Effect of Ca2+ antagonists

    International Nuclear Information System (INIS)

    Chabrier, P.E.; Auguet, M.; Roubert, P.; Lonchampt, M.O.; Gillard, V.; Guillon, J.M.; Delaflotte, S.; Braquet, P.

    1989-01-01

    The vasoconstrictive properties of the endothelium-derived peptide, endothelin-1 (ET-1), were investigated on rat isolated aorta and on cultured rat aortic smooth muscle cells. In rat isolated aorta, endothelin-1 induced a slow and sustained contraction in a Ca2+-free medium; after calcium readmission, an additional sustained contraction was elicited. In vascular smooth muscle cells, endothelin-1 provoked a dose-dependent Ca2+ influx that was not inhibited by calcium entry blockers (nifedipine, D 600, or diltiazem). In these cells, [ 125 I]-endothelin-1 bound to a specific, saturable, and high affinity recognition site (Kd about 10(-9) M and Bmax = 52 +/- 2 fmol/10(6) cells). The binding was not reversible and not affected by calcium antagonists. These data do not support the hypothesis that endothelin-1 acts as an endogenous agonist of the voltage-dependent Ca2+ channels. The action of endothelin-1 can be separated into two components: one dependent on Ca2+ influx but insensitive to calcium antagonists and another independent of extracellular Ca2+. The irreversible binding of endothelin-1 may reflect an internalization of the ligand inside the cell membrane, leading to multiple contractile events

  15. A feed-forward regulation of endothelin receptors by c-Jun in human non-pigmented ciliary epithelial cells and retinal ganglion cells.

    Directory of Open Access Journals (Sweden)

    Junming Wang

    Full Text Available c-Jun, c-Jun N-terminal kinase(JNK and endothelin B (ETB receptor have been shown to contribute to the pathogenesis of glaucoma. Previously, we reported that an increase of c-Jun and CCAAT/enhancer binding protein β (C/EBPβ immunohistostaining is associated with upregulation of the ETB receptor within the ganglion cell layer of rats with elevated intraocular pressure (IOP. In addition, both transcription factors regulate the expression of the ETB receptor in human non-pigmented ciliary epithelial cells (HNPE. The current study addressed the mechanisms by which ET-1 produced upregulation of ET receptors in primary rat retinal ganglion cells (RGCs and HNPE cells. Treatment of ET-1 and ET-3 increased the immunocytochemical staining of c-Jun and C/EBPβ in primary rat RGCs and co-localization of both transcription factors was observed. A marked increase in DNA binding activity of AP-1 and C/EBPβ as well as elevated protein levels of c-Jun and c-Jun-N-terminal kinase (JNK were detected following ET-1 treatment in HNPE cells. Overexpression of ETA or ETB receptor promoted the upregulation of c-Jun and also elevated its promoter activity. In addition, upregulation of C/EBPβ augmented DNA binding and mRNA expression of c-Jun, and furthermore, the interaction of c-Jun and C/EBPβ was confirmed using co-immunoprecipitation. Apoptosis of HNPE cells was identified following ET-1 treatment, and overexpression of the ETA or ETB receptor produced enhanced apoptosis. ET-1 mediated upregulation of c-Jun and C/EBPβ and their interaction may represent a novel mechanism contributing to the regulation of endothelin receptor expression. Reciprocally, c-Jun was also found to regulate the ET receptors and C/EBPβ appeared to play a regulatory role in promoting expression of c-Jun. Taken together, the data suggests that ET-1 triggers the upregulation of c-Jun through both ETA and ETB receptors, and conversely c-Jun also upregulates endothelin receptor expression

  16. Endothelin-like action of Pausinystalia yohimbe aqueous extract on vascular and renal regional hemodynamics in Sprague Dawley rats.

    Science.gov (United States)

    Ajayi, A A; Newaz, M; Hercule, H; Saleh, M; Bode, C O; Oyekan, A O

    2003-12-01

    The bark of the African tree Pausinystalia yohimbe has been used as a food additive with aphrodisiac and penile erection enhancing properties. The effect of an aqueous extract of P. yohimbe (CCD-X) on renal circulation was assessed in order to test the hypothesis that it possesses additional effects on nitric oxide production and/or endothelin-1 (ET-1)-like actions. In vivo studies with CCD-X in Sprague Dawley rats demonstrated a dose-dependent (1-1000 ng/kg) increase in mean blood pressure (p < 0.001) and an increase in medullary blood flow (MBF) (p < 0.001). Both the pressor action and renal medullary vasodilation were blocked by endothelinA (ETA) receptor antagonist BMS182874 and endothelinB (ETB) receptor antagonist BQ788 in combination. L-Nomega-nitro-l-arginine methyl ester (L-NAME; 10 mg/kg) also inhibited the increase in MBF induced by CCD-X. In vitro studies in isolated perfused kidney and in pressurized renal microvessels confirmed the dose-dependent vasoconstrictor action of this extract. ETA receptor antagonist BQ610 and ETB receptor antagonist BQ788 separately and significantly attenuated the renal vasoconstrictor actions of the extract (p < 0.001 ANOVA). These preliminary observations indicate that, in addition to the alpha-adrenergic antagonist actions that characterize yohimbine, CCD-X possesses endothelin-like actions and affects nitric oxide (NO) production in renal circulation. These findings suggest a strong possibility of post-receptor cross-talk between alpha2-adrenoceptors and endothelin, as well as a direct effect of alpha2-adrenoceptors on renal NO production. (c) 2003 Prous Science

  17. Increased expression of vascular endothelin type B and angiotensin type 1 receptors in patients with ischemic heart disease

    DEFF Research Database (Denmark)

    Dimitrijevic, Ivan; Edvinsson, Lars; Chen, Qingwen

    2009-01-01

    expression in subcutaneous arteries from patients with different degrees of ischemic heart disease. METHODS: Subcutaneous arteries were obtained, by biopsy from the abdomen, from patients undergoing coronary artery bypass graft (CABG) surgery because of ischemic heart disease (n = 15), patients with angina...... pectoris without established myocardial infarction (n = 15) and matched cardiovascular healthy controls (n = 15). Endothelin type A (ETA) and type B (ETB), and angiotensin type 1 (AT1) and type 2 (AT2) receptors expression and function were examined using immunohistochemistry, Western blot and in vitro...

  18. Endothelin receptor a blockade is an ineffective treatment for adriamycin nephropathy.

    Directory of Open Access Journals (Sweden)

    Roderick J Tan

    Full Text Available Endothelin is a vasoconstricting peptide that plays a key role in vascular homeostasis, exerting its biologic effects via two receptors, the endothelin receptor A (ETA and endothelin receptor B (ETB. Activation of ETA and ETB has opposing actions, in which hyperactive ETA is generally vasoconstrictive and pathologic. Selective ETA blockade has been shown to be beneficial in renal injuries such as diabetic nephropathy and can improve proteinuria. Atrasentan is a selective pharmacologic ETA blocker that preferentially inhibits ETA activation. In this study, we evaluated the efficacy of ETA blockade by atrasentan in ameliorating proteinuria and kidney injury in murine adriamycin nephropathy, a model of human focal segmental glomerulosclerosis. We found that ETA expression was unaltered during the course of adriamycin nephropathy. Whether initiated prior to injury in a prevention protocol (5 mg/kg/day, i.p. or after injury onset in a therapeutic protocol (7 mg/kg or 20 mg/kg three times a week, i.p., atrasentan did not significantly affect the initiation and progression of adriamycin-induced albuminuria (as measured by urinary albumin-to-creatinine ratios. Indices of glomerular damage were also not improved in atrasentan-treated groups, in either the prevention or therapeutic protocols. Atrasentan also failed to improve kidney function as determined by serum creatinine, histologic damage, and mRNA expression of numerous fibrosis-related genes such as collagen-I and TGF-β1. Therefore, we conclude that selective blockade of ETA by atrasentan has no effect on preventing or ameliorating proteinuria and kidney injury in adriamycin nephropathy.

  19. Endothelin receptor antagonists influence cardiovascular morphology in uremic rats.

    Science.gov (United States)

    Nabokov, A V; Amann, K; Wessels, S; Münter, K; Wagner, J; Ritz, E

    1999-02-01

    In is generally held that renal failure results in blood pressure (BP)-independent structural changes of the myocardium and the vasculature. The contribution, if any, of endothelin (ET) to these changes has been unknown. We morphometrically studied random samples of the left ventricle myocardium and small intramyocardial arteries in subtotally (5/6) nephrectomized (SNx) male Sprague-Dawley rats treated with either the selective ETA receptor antagonist BMS182874 (30 mg/kg/day) or the nonselective ETA/ETB receptor antagonist Ro46-2005 (30 mg/kg/day) in comparison with either sham-operated rats, untreated SNx, or SNx rats treated with the angiotensin-converting enzyme inhibitor trandolapril (0.1 mg/kg/day). Eight weeks later, systolic BP was lower in trandolapril-treated SNx compared with untreated SNx animals. No decrease in BP was seen following either ET receptor antagonist at the dose used. A significantly increased volume density of the myocardial interstitium was found in untreated SNx rats as compared with sham-operated controls. Such interstitial expansion was prevented by trandolapril and either ET receptor antagonist. SNx caused a substantial increase in the wall thickness of small intramyocardial arteries. The increase was prevented by trandolapril or BMS182874 treatment. The arteriolar wall:lumen ratio was significantly lower in all treated groups when compared with untreated SNx. In contrast, only trandolapril, but not the ET receptor antagonists, attenuated thickening of the aortic media in SNx animals. The ETA-selective and ETA/ETB-nonselective receptor antagonists appear to prevent development of myocardial fibrosis and structural changes of small intramyocardial arteries in experimental chronic renal failure. This effect is independent of systemic BP.

  20. Retrofit of an MTBE-unit to ETBE

    Energy Technology Data Exchange (ETDEWEB)

    Rix, A.; Peters, U. [Degussa GmbH, Marl (Germany)

    2007-07-01

    New European policies on renewable fuels have created substantial market pressure to increase the share of bio-fuels. For blending in gasoline, ETBE formed by etherification of isobutene with bio-ethanol is an interesting alternative to direct blending of bio-ethanol. Since the physical properties of methanol and ethanol - and consequently MTBE and ETBE - are quite similar, MTBE-plants can be retrofitted for ETBE-production. Experience from a retrofit-project at Marl is presented. In an integrated C4-plant, isobutene removal is one the most important tasks of the etherification unit to purify the raffinate 2 stream for butene-1 production. Compared to MTBE, reaction rate and equilibrium constant are lower and suitable means of maintaining isobutene conversion on former levels must be found. Furthermore, the extraction of excess alcohol and its recovery by distillation is more difficult. The ethanol-water azeotrope formed on top of the alcohol recovery column has to undergo a further drying process. Alternatives for ethanol drying have been evaluated and performance data for a membrane process is presented. (orig.)

  1. Evolution of endothelin receptors in vertebrates.

    Science.gov (United States)

    Braasch, Ingo; Schartl, Manfred

    2014-12-01

    Endothelin receptors are G protein coupled receptors (GPCRs) of the β-group of rhodopsin receptors that bind to endothelin ligands, which are 21 amino acid long peptides derived from longer prepro-endothelin precursors. The most basal Ednr-like GPCR is found outside vertebrates in the cephalochordate amphioxus, but endothelin ligands are only present among vertebrates, including the lineages of jawless vertebrates (lampreys and hagfishes), cartilaginous vertebrates (sharks, rays, and chimaeras), and bony vertebrates (ray-finned fishes and lobe-finned vertebrates including tetrapods). A bona fide endothelin system is thus a vertebrate-specific innovation with important roles for regulating the cardiovascular system, renal and pulmonary processes, as well as for the development of the vertebrate-specific neural crest cell population and its derivatives. Expectedly, dysregulation of endothelin receptors and the endothelin system leads to a multitude of human diseases. Despite the importance of different types of endothelin receptors for vertebrate development and physiology, current knowledge on endothelin ligand-receptor interactions, on the expression of endothelin receptors and their ligands, and on the functional roles of the endothelin system for embryonic development and in adult vertebrates is very much biased towards amniote vertebrates. Recent analyses from a variety of vertebrate lineages, however, have shown that the endothelin system in lineages such as teleost fish and lampreys is more diverse and is divergent from the mammalian endothelin system. This diversity is mainly based on differential evolution of numerous endothelin system components among vertebrate lineages generated by two rounds of whole genome duplication (three in teleosts) during vertebrate evolution. Here we review current understanding of the evolutionary history of the endothelin receptor family in vertebrates supplemented with surveys on the endothelin receptor gene complement of

  2. Cooperation of endothelin-1 signaling with melanosomes plays a role in developing and/or maintaining human skin hyperpigmentation

    Directory of Open Access Journals (Sweden)

    Daiki Murase

    2015-10-01

    Full Text Available Skin hyperpigmentation is characterized by increased melanin synthesis and deposition that can cause significant psychosocial and psychological distress. Although several cytokine-receptor signaling cascades contribute to the formation of ultraviolet B-induced cutaneous hyperpigmentation, their possible involvement in other types of skin hyperpigmentation has never been clearly addressed. Since our continuous studies using skin specimens from more than 30 subjects with ethnic skin diversity emphasized a consistent augmentation in the expression of endothelin-1 (ET-1 and its receptor (Endothelin B receptor, ET-B in hyperpigmented lesions, including senile lentigos (SLs, the precise function of ET-1 signaling was investigated in the present study. In line with previous studies, ET-1 significantly induced melanogenesis followed by increases in melanosome transport in melanocytes and in its transfer to keratinocytes while inhibition of ET-B function substantially depressed melanogenic ability in tissue-cultured SLs. Additionally, in agreement with a previous report that the formation of autophagosomes rather than melanosomes is stimulated according to starvation or defective melanosome production, ET-1 was found to remarkably augment the expression of components necessary for early melanosome formation, indicating its counteraction against autophagy-targeting melanosome degradation in melanocytes. Despite the lack of substantial impact of ET-1 on keratinocyte melanogenic functions, the expression of ET-1 was enhanced following melanosome uptake by keratinocytes. Taken together, our data suggest that ET-1 plays a substantial role in the development and/or maintenance of skin hyperpigmentation in reciprocal cooperation with increased melanosome incorporation.

  3. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (External Review Draft)

    Science.gov (United States)

    The IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) was released for external peer review in June 2017. EPA’s Science Advisory Board’s (SAB) Chemical Assessment Advisory Committee (CAAC) will conduct a peer review of the scientific basis supporting the ETB...

  4. Role of ERK/MAPK in endothelin receptor signaling in human aortic smooth muscle cells

    DEFF Research Database (Denmark)

    Chen, Qing-wen; Edvinsson, Lars; Xu, Cang-Bao

    2009-01-01

    muscle cells (VSMCs) through activation of endothelin type A (ETA) and type B (ETB) receptors. The extracellular signal-regulated kinase 1 and 2 (ERK1/2) mitogen-activated protein kinases (MAPK) are involved in ET-1-induced VSMC contraction and proliferation. This study was designed to investigate...... agonist, Sarafotoxin 6c (S6c) caused a time-dependent ERK1/2 activation with a maximal effect by less than 20% of the ET-1-induced activation of ERK1/2. Increase in bosentan concentration up to 10 microM further inhibited ET-1-induced activation of ERK1/2 and had a stronger inhibitory effect than BQ123...

  5. Involvement of endothelin and ET(A) endothelin receptor in mechanical allodynia in mice given orthotopic melanoma inoculation.

    Science.gov (United States)

    Fujita, Masahide; Andoh, Tsugunobu; Saiki, Ikuo; Kuraishi, Yasushi

    2008-02-01

    We investigated whether endothelin (ET) would be involved in skin cancer pain in mice. Orthotopic inoculation of B16-BL6 melanoma cells into the plantar region of the hind paw produced marked mechanical allodynia in C57BL/6 mice. Intraplantar injections of the ET(A)-receptor antagonist BQ-123 (0.3 - 3 nmol/site), but not the ET(B)-receptor antagonist BQ-788 (1 and 3 nmol/site), inhibited mechanical allodynia in mice with grown melanoma. In naive mice, an intraplantar injection of tumor extract (1 and 3 mg/site), which was prepared from the grown melanoma in the paw, produced mechanical allodynia, which was inhibited by BQ-123 and BQ-788 at doses of 3 and 10 nmol/site. An intraplantar injection of ET-1 (1 and 10 pmol/site) elicited licking behavior, which was increased in the melanoma-bearing hind paw. BQ-123 (3 and 10 nmol/site) inhibited licking induced by ET-1 (10 pmol/site). The level of mRNA of ET(A), but not ET(B), receptor, was significantly increased in the dorsal root ganglia on the inoculated side. Cultured B16-BL6 cells contained ET, and the melanoma mass increased the concentration of ET as it grew bigger. These results suggest that ET-1 and ET(A) receptor are at least partly involved in the induction of pain induced by melanoma cell inoculation.

  6. Pancreatic acini possess endothelin receptors whose internalization is regulated by PLC-activating agents.

    Science.gov (United States)

    Hildebrand, P; Mrozinski, J E; Mantey, S A; Patto, R J; Jensen, R T

    1993-05-01

    Endothelin-1 (ET-1) and ET-3 mRNA have been found in the pancreas. We investigated the ability of ET-1, ET-2, and ET-3 to interact with and alter dispersed rat pancreatic acinar cell function. Radiolabeled ETs bound in a time- and temperature-dependent fashion, which was specific and saturable. Analysis demonstrated two classes of receptors, one class (ETA receptor) had a high affinity for ET-1 but a low affinity for ET-3, and the other class (ETB receptor) had equally high affinities for ET-1 and ET-3. No specific receptor for ET-2 was identified. Pancreatic secretagogues that activate phospholipase C (PLC) inhibited binding of 125I-labeled ET-1 (125I-ET-1) or 125I-ET-3, whereas agents that act through adenosine 3',5'-cyclic monophosphate (cAMP) did not. A23187 had no effect on 125I-ET-1 or 125I-ET-3 binding, whereas the phorbol ester 12-O-tetradecanoylphorbol 13-acetate reduced binding. The effect of cholecystokinin octapeptide (CCK-8) was mediated through its own receptor. Stripping of surface bound ligand studies demonstrated that both 125I-labeled ET-1 and 125I-labeled ET-3 were rapidly internalized. CCK-8 decreased the internalization but did not change the amount of surface bound ligand. Endothelins neither stimulate nor alter changes in enzyme secretion, intracellular calcium, cAMP, or [3H]inositol trisphosphate (IP3). This study demonstrates the presence of ETA and ETB receptors on rat pancreatic acini; occupation of both receptors resulted in rapid internalization, which is regulated by PLC-activating secretagogues. Occupation of either ET receptor did not alter intracellular calcium, cAMP, IP3, or stimulate amylase release.

  7. Fractalkine depresses cardiomyocyte contractility.

    Directory of Open Access Journals (Sweden)

    David Taube

    Full Text Available Our laboratory reported that male mice with cardiomyocyte-selective knockout of the prostaglandin E2 EP4 receptor sub-type (EP4 KO exhibit reduced cardiac function. Gene array on left ventricles (LV showed increased fractalkine, a chemokine implicated in heart failure. We therefore hypothesized that fractalkine is regulated by PGE2 and contributes to depressed contractility via alterations in intracellular calcium.Fractalkine was measured in LV of 28-32 week old male EP4 KO and wild type controls (WT by ELISA and the effect of PGE2 on fractalkine secretion was measured in cultured neonatal cardiomyocytes and fibroblasts. The effect of fractalkine on contractility and intracellular calcium was determined in Fura-2 AM-loaded, electrical field-paced cardiomyocytes. Cardiomyocytes (AVM from male C57Bl/6 mice were treated with fractalkine and responses measured under basal conditions and after isoproterenol (Iso stimulation.LV fractalkine was increased in EP4 KO mice but surprisingly, PGE2 regulated fractalkine secretion only in fibroblasts. Fractalkine treatment of AVM decreased both the speed of contraction and relaxation under basal conditions and after Iso stimulation. Despite reducing contractility after Iso stimulation, fractalkine increased the Ca(2+ transient amplitude but decreased phosphorylation of cardiac troponin I, suggesting direct effects on the contractile machinery.Fractalkine depresses myocyte contractility by mechanisms downstream of intracellular calcium.

  8. Endothelin-1 and endothelin-3 in cirrhosis: relations to systemic and splanchnic haemodynamics

    DEFF Research Database (Denmark)

    Møller, S; Gülberg, V; Gerbes, A L

    1995-01-01

    correlated with the hepatic venous pressure gradient (r = 0.61, p blood pressure (r = -0.31, p blood volume (-0.36, p ... haemodynamics. METHODS: Endothelin-1 and endothelin-3 were measured in samples from a hepatic vein and the femoral artery in 42 patients with cirrhosis, eight hypertensive controls and 10 normotensive controls. RESULTS: Hepatic venous endothelin-1 was significantly higher in the patients with cirrhosis, mean 21.......002). The same pattern was found in arterial endothelin-3. Hepatic venous endothelin-3 correlated significantly with central and arterial blood volume (r = 0.56, p

  9. Endothelins in chronic liver disease

    DEFF Research Database (Denmark)

    Møller, Søren; Henriksen, Jens Henrik

    1996-01-01

    This review describes recent progress in the accumulation of knowledge about the endothelins (ETs), a family of vasoactive 21-amino acid polypeptides, in chronic liver disease. Particular prominence is given to the dynamics of ET-1 and ET-3 and their possible relation to the disturbed circulation...... renal failure. Studies on liver biopsies have revealed synthesis of ET-1 in hepatic endothelial and other cells, and recent investigations have identified the hepatosplanchnic system as a major source of ET-1 and ET-3 spillover into the circulation, with a direct relation to portal venous hypertension...

  10. Development of occlusive neointimal lesions in distal pulmonary arteries of endothelin B receptor-deficient rats: a new model of severe pulmonary arterial hypertension.

    Science.gov (United States)

    Ivy, D Dunbar; McMurtry, Ivan F; Colvin, Kelley; Imamura, Masatoshi; Oka, Masahiko; Lee, Dong-Seok; Gebb, Sarah; Jones, Peter Lloyd

    2005-06-07

    Human pulmonary arterial hypertension (PAH) is characterized by proliferation of vascular smooth muscle and, in its more severe form, by the development of occlusive neointimal lesions. However, few animal models of pulmonary neointimal proliferation exist, thereby limiting a complete understanding of the pathobiology of PAH. Recent studies of the endothelin (ET) system demonstrate that deficiency of the ET(B) receptor predisposes adult rats to acute and chronic hypoxic PAH, yet these animals fail to develop neointimal lesions. Herein, we determined and thereafter showed that exposure of ET(B) receptor-deficient rats to the endothelial toxin monocrotaline (MCT) leads to the development of neointimal lesions that share hallmarks of human PAH. The pulmonary hemodynamic and morphometric effects of 60 mg/kg MCT in control (MCT(+/+)) and ET(B) receptor-deficient (MCT(sl/sl)) rats at 6 weeks of age were assessed. MCT(sl/sl) rats developed more severe PAH, characterized by elevated pulmonary artery pressure, diminished cardiac output, and right ventricular hypertrophy. In MCT(sl/sl) rats, morphometric evaluation revealed the presence of neointimal lesions within small distal pulmonary arteries, increased medial wall thickness, and decreased arterial-to-alveolar ratio. In keeping with this, barium angiography revealed diminished distal pulmonary vasculature of MCT(sl/sl) rat lungs. Cells within neointimal lesions expressed smooth muscle and endothelial cell markers. Moreover, cells within neointimal lesions exhibited increased levels of proliferation and were located in a tissue microenvironment enriched with vascular endothelial growth factor, tenascin-C, and activated matrix metalloproteinase-9, factors already implicated in human PAH. Finally, assessment of steady state mRNA showed that whereas expression of ET(B) receptors was decreased in MCT(sl/sl) rat lungs, ET(A) receptor expression increased. Deficiency of the ET(B) receptor markedly accelerates the progression of

  11. Development of Occlusive Neointimal Lesions in Distal Pulmonary Arteries of Endothelin B Receptor–Deficient Rats: A New Model of Severe Pulmonary Arterial Hypertension

    Science.gov (United States)

    Ivy, D. Dunbar; McMurtry, Ivan F.; Colvin, Kelley; Imamura, Masatoshi; Oka, Masahiko; Lee, Dong-Seok; Gebb, Sarah; Jones, Peter Lloyd

    2007-01-01

    Background Human pulmonary arterial hypertension (PAH) is characterized by proliferation of vascular smooth muscle and, in its more severe form, by the development of occlusive neointimal lesions. However, few animal models of pulmonary neointimal proliferation exist, thereby limiting a complete understanding of the pathobiology of PAH. Recent studies of the endothelin (ET) system demonstrate that deficiency of the ETB receptor predisposes adult rats to acute and chronic hypoxic PAH, yet these animals fail to develop neointimal lesions. Herein, we determined and thereafter showed that exposure of ETB receptor–deficient rats to the endothelial toxin monocrotaline (MCT) leads to the development of neointimal lesions that share hallmarks of human PAH. Methods and Results The pulmonary hemodynamic and morphometric effects of 60 mg/kg MCT in control (MCT+/+) and ETB receptor–deficient (MCTsl/sl) rats at 6 weeks of age were assessed. MCTsl/sl rats developed more severe PAH, characterized by elevated pulmonary artery pressure, diminished cardiac output, and right ventricular hypertrophy. In MCTsl/sl rats, morphometric evaluation revealed the presence of neointimal lesions within small distal pulmonary arteries, increased medial wall thickness, and decreased arterial-to-alveolar ratio. In keeping with this, barium angiography revealed diminished distal pulmonary vasculature of MCTsl/sl rat lungs. Cells within neointimal lesions expressed smooth muscle and endothelial cell markers. Moreover, cells within neointimal lesions exhibited increased levels of proliferation and were located in a tissue microenvironment enriched with vascular endothelial growth factor, tenascin-C, and activated matrix metalloproteinase-9, factors already implicated in human PAH. Finally, assessment of steady state mRNA showed that whereas expression of ETB receptors was decreased in MCTsl/sl rat lungs, ETA receptor expression increased. Conclusions Deficiency of the ETB receptor markedly

  12. Polymorphisms of the endothelin-A and -B receptor genes in relation to blood pressure and myocardial infarction: the Etude Cas-Témoins sur l'Infarctus du Myocarde (ECTIM) Study.

    Science.gov (United States)

    Nicaud, V; Poirier, O; Behague, I; Herrmann, S M; Mallet, C; Troesch, A; Bouyer, J; Evans, A; Luc, G; Ruidavets, J B; Arveiler, D; Bingham, A; Tiret, L; Cambien, F

    1999-03-01

    Endothelin-1 is a potent vasoconstrictor that has also mitogenic properties, stimulating the synthesis and secretion of several vasoactive molecules. There is much evidence to suggest that endothelin-1 might be involved in the pathogenesis of hypertension, atherosclerosis, and ischemic heart disease. Endothelin-1 exerts its effects through at least two receptors, ET(A) and ET(B), which are encoded by different genes and have separate tissue distributions and biologic properties. The objective of this study was to identify polymorphisms of the ET(A) and ET(B) receptor genes and to study their association with myocardial infarction (MI) and blood pressure. The coding regions and 1.3 kb upstream of the ET(A) and ET(B) receptor genes were explored by polymerase chain reaction/single strand conformation polymorphism. Six polymorphisms were found in the ET(A) receptor gene and three in the ET(B) receptor gene. Most of these polymorphisms were frequent. Associations between the detected polymorphisms, blood pressure, and MI were examined in the ECTIM study, a multicenter study comparing 652 patients having survived an MI and 773 controls from Belfast (Northern Ireland) and France. Alleles at the different polymorphic sites were similarly distributed in patients with MI and controls. Allele frequencies were similar in both countries, except for the ET(A)/-231 G allele, which appeared more frequently in France than in Belfast (P < .01). The mean systolic and diastolic blood pressure levels did not significantly differ between genotypes. However, a C/T substitution located in the nontranslated part of exon 8 of the ET(A) receptor gene (ET(A)/EX8nt1363) was associated with pulse pressure (P < .005). These results do not support an involvement of the endothelin receptor genes in a predisposition to MI or the determination of blood pressure levels, but suggest that a polymorphism of the ET(A) receptor gene might influence the pulse pressure. This result will have to be

  13. Study of an aquifer contaminated by ethyl tert-butyl ether (ETBE): Site characterization and on-site bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle-Guichard, Francoise, E-mail: francoise.fayolle@ifpen.fr [IFP Energies nouvelles, 1 et 4 avenue de Bois-Preau, 92852 Rueil-Malmaison (France); Durand, Jonathan [Institut EGID Bordeaux 3, 1 Allee Daguin 33607 Pessac Cedex (France); SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); Cheucle, Mathilde [SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); Rosell, Monica [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Michelland, Rory Julien [Universite de Lyon, F-69622 Lyon (France); Universite Lyon 1, Villeurbanne (France); CNRS, UMR5557, Ecologie Microbienne (France); Tracol, Jean-Philippe [SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); Le Roux, Francoise [IFP Energies nouvelles, 1 et 4 avenue de Bois-Preau, 92852 Rueil-Malmaison (France); Grundman, Genevieve [Universite de Lyon, F-69622 Lyon (France); Universite Lyon 1, Villeurbanne (France); CNRS, UMR5557, Ecologie Microbienne (France); Atteia, Olivier [Institut EGID Bordeaux 3, 1 Allee Daguin 33607 Pessac Cedex (France); Richnow, Hans H. [Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig (Germany); Dumestre, Alain [SERPOL, 2 chemin du Genie, BP 80, 69633 Venissieux Cedex (France); and others

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer Ethyl tert-butyl ether (ETBE) (>300 mg L{sup -1}) found in a groundwater (gas-station). Black-Right-Pointing-Pointer No significant carbon or hydrogen isotopic fractionation of ETBE along the plume. Black-Right-Pointing-Pointer MC-IFP culture degraded ETBE (0.91 mg L{sup -1} h{sup -1}) and BTEX (0.64 mg L{sup -1} h{sup -1}). Black-Right-Pointing-Pointer A pilot plant (2 m{sup 3}) inoculated with MC-IFP degraded ETBE in groundwater (15 Degree-Sign C). Black-Right-Pointing-Pointer ethB gene (ETBE biodegradation) amplified during bioaugmentation (5 Multiplication-Sign 10{sup 6}ethB gene copies L{sup -1}). - Abstract: Ethyl tert-butyl ether (ETBE) was detected at high concentration (300 mg L{sup -1}) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L{sup -1} h{sup -1} and BTEX: 0.64 and 0.82 mg L{sup -1} h{sup -1}, respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L{sup -1}). An on-site pilot plant (2 m{sup 3}) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant

  14. Study of an aquifer contaminated by ethyl tert-butyl ether (ETBE): Site characterization and on-site bioremediation

    International Nuclear Information System (INIS)

    Fayolle-Guichard, Françoise; Durand, Jonathan; Cheucle, Mathilde; Rosell, Mònica; Michelland, Rory Julien; Tracol, Jean-Philippe; Le Roux, Françoise; Grundman, Geneviève; Atteia, Olivier; Richnow, Hans H.; Dumestre, Alain

    2012-01-01

    Highlights: ► Ethyl tert-butyl ether (ETBE) (>300 mg L −1 ) found in a groundwater (gas-station). ► No significant carbon or hydrogen isotopic fractionation of ETBE along the plume. ► MC-IFP culture degraded ETBE (0.91 mg L −1 h −1 ) and BTEX (0.64 mg L −1 h −1 ). ► A pilot plant (2 m 3 ) inoculated with MC-IFP degraded ETBE in groundwater (15 °C). ► ethB gene (ETBE biodegradation) amplified during bioaugmentation (5 × 10 6 ethB gene copies L −1 ). - Abstract: Ethyl tert-butyl ether (ETBE) was detected at high concentration (300 mg L −1 ) in the groundwater below a gas-station. No significant carbon neither hydrogen isotopic fractionation of ETBE was detected along the plume. ETBE and BTEX biodegradation capacities of the indigenous microflora Pz1-ETBE and of a culture (MC-IFP) composed of Rhodococcus wratislaviensis IFP 2016, Rhodococcus aetherivorans IFP 2017 and Aquincola tertiaricarbonis IFP 2003 showed that ETBE and BTEX degradation rates were in the same range (ETBE: 0.91 and 0.83 mg L −1 h −1 and BTEX: 0.64 and 0.82 mg L −1 h −1 , respectively) but tert-butanol (TBA) accumulated transiently at a high level using Pz1-ETBE (74 mg L −1 ). An on-site pilot plant (2 m 3 ) filled with polluted groundwater and inoculated by MC-IFP, successfully degraded four successive additions of ETBE and gasoline. However, an insignificant ETBE isotopic fractionation was also accompanying this decrease which suggested the involvement of low fractionating-strains using EthB enzymes, but required of additional proofs. The ethB gene encoding a cytochrome P450 involved in ETBE biodegradation (present in R. aetherivorans IFP 2017) was monitored by quantitative real-time polymerase chain reaction (q-PCR) on DNA extracted from water sampled in the pilot plant which yield up to 5 × 10 6 copies of ethB gene per L −1 .

  15. Regulatory mechanism of endothelin receptor B in the cerebral arteries after focal cerebral ischemia

    DEFF Research Database (Denmark)

    Grell, Anne-Sofie; Thigarajah, Rushani; Edvinsson, Lars

    2014-01-01

    BACKGROUND AND PURPOSE: Increased expression of endothelin receptor type B (ETBR), a vasoactive receptor, has recently been implied in the reduced cerebral blood flow and exacerbated neuronal damage after ischemia-reperfusion (I/R). The study explores the regulatory mechanisms of ETBR to identify...... drug targets to restore normal cerebral artery contractile function as part of successful neuroprotective therapy. METHODS: We have employed in vitro methods on human and rat cerebral arteries to study the regulatory mechanisms and the efficacy of target selective inhibitor, Mithramycin A (Mit...... the ETBR mRNA and protein levels. It also significantly reduced the ETBR mediated cerebrovascular contractility. Detailed analysis indicated that ERK1/2 mediated phosphorylation of Sp1 might be essential for ETBR transcription. CONCLUSION: Transcription factor Sp1 regulates the ETBR mediated...

  16. Thermodynamic characterization of bio-fuels: Excess functions for binary mixtures containing ETBE and hydrocarbons

    International Nuclear Information System (INIS)

    Segovia, Jose J.; Villamanan, Rosa M.; Martin, M. Carmen; Chamorro, Cesar R.; Villamanan, Miguel A.

    2010-01-01

    European energy policy is promoting the use of bio-fuels for transportation. Bioethers and bioalcohols are used as blending agents for enhancing the octane number. They make gasoline work harder, help the engine last longer and reduce air pollution. They also cause changes in the fuel properties. Development of renewable fuels needs both knowledge of new thermodynamic data and improvement of clean energy technologies. In this context, the use of ethanol of vegetable origin in its manufacture process, increases the interest of ETBE or bio-ETBE as an oxygenated additive. A complete study of the behaviour of ETBE + hydrocarbons mixtures is presented. Some experimental data concerning vapor-liquid equilibria and heats of mixing were determined in our laboratory. All the techniques have a high accuracy. The data were reduced by well-known models, such as NRTL and used to model the thermodynamic properties.

  17. Temperature influence on mixing properties of {ethyl tert-butyl ether (ETBE) + gasoline additives}

    International Nuclear Information System (INIS)

    Gonzalez-Olmos, R.; Iglesias, M.

    2007-01-01

    The densities and ultrasonic velocity of {ethyl tert-butyl ether (ETBE) + (benzene, toluene, ethylbenzene, isooctane, tert-butyl alcohol, and ethanol)} over the temperature range (288.15 to 323.15) K and atmospheric pressure, have been measured over the whole concentration range. The experimental excess volumes and deviation of isentropic compressibilities data have been analysed in terms of different theoretical models. The gathered data improve open literature related to gasoline additives, and help to understand the ETBE volumetric and acoustic trend into different chemical environment

  18. Endothelins in chronic liver disease

    DEFF Research Database (Denmark)

    Møller, S; Henriksen, Jens Henrik Sahl

    1996-01-01

    renal failure. Studies on liver biopsies have revealed synthesis of ET-1 in hepatic endothelial and other cells, and recent investigations have identified the hepatosplanchnic system as a major source of ET-1 and ET-3 spillover into the circulation, with a direct relation to portal venous hypertension......This review describes recent progress in the accumulation of knowledge about the endothelins (ETs), a family of vasoactive 21-amino acid polypeptides, in chronic liver disease. Particular prominence is given to the dynamics of ET-1 and ET-3 and their possible relation to the disturbed circulation....... In addition, marked associations with disturbance of systemic haemodynamics and with abnormal distribution of blood volume have been reported. Although the pathophysiological importance of the ET system in chronic liver disease is not completely understood, similarities to other vasopressive...

  19. Airborne fine particulate matter induces an upregulation of endothelin receptors on rat bronchi

    International Nuclear Information System (INIS)

    Wang, Rong; Xiao, Xue; Cao, Lei; Shen, Zhen-xing; Lei, Ying; Cao, Yong-xiao

    2016-01-01

    Airborne fine particulate matter (PM2.5) is a risk factor for respiratory diseases. However, little is known about the effects of PM2.5 on bronchi. The present study investigated the effect of airborne PM2.5 on rat bronchi and the underlying mechanisms. Isolated rat bronchial segments were cultured for 24 h. Endothelin (ET) receptor-mediated contractile responses were recorded using a wire myograph. The mRNA and protein expression levels of ET receptors were studied using quantitative real-time PCR, Western blotting, and immunohistochemistry. The results demonstrated that ET A and ET B receptor agonists induced remarkable contractile responses on fresh and cultured bronchial segments. PM2.5 (1.0 or 3.0 μg/ml) significantly enhanced ET A and ET B receptor-mediated contractile responses in bronchi with a markedly increased maximal contraction compared to the DMSO or fresh groups. PM2.5 increased the mRNA and protein expression levels of ET A and ET B receptors. U0126 (a MEK1/2 inhibitor) and SB203580 (a p38 inhibitor) significantly suppressed PM2.5-induced increases in ET B receptor-mediated contractile responses, mRNA and protein levels. SP600125 (a JNK inhibitor) and SB203580 significantly abrogated the PM2.5-induced enhancement of ET A receptor-mediated contraction and receptor expression. In conclusion, PM2.5 upregulates ET receptors in bronchi. ET B receptor upregulation is associated with MEK1/2 and p38 pathways, and the upregulation of ET A receptor is involved in JNK and p38 pathways. - Highlights: • Airborne PM2.5 induces bronchial hyperreactivity mediated with endothelin ET B and ET A receptors in rats. • PM2.5 increases mRNA and protein expressions of endothelin ET B and ET A receptors in bronchi. • The upregulation of ET B receptor is associated with MEK1/2 and p38 pathways. • The upregulation of ET A receptor is involved in JNK and p38 pathways. • The research provides novel understanding for PM2.5-associated respiratory diseases.

  20. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (Preliminary Assessment Materials)

    Science.gov (United States)

    In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for ETBE to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in ...

  1. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (Public Comment Draft)

    Science.gov (United States)

    In September 2016, the U.S. Environmental Protection Agency's (USEPA) released the draft Integrated Risk Information System (IRIS) Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE). Consistent with the 2013 IRIS Enhancements, draft IRIS assessments are released prior to e...

  2. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (External Review Draft, 2009)

    Science.gov (United States)

    EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of ethyl tertiary butyl ether (ETBE) that when finalized will appear on the Integrated Risk Information System (IRIS) database.

  3. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (Interagency Science Consultation Draft)

    Science.gov (United States)

    In September 2016, EPA released the draft IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) for public comment and discussion. The draft assessment was reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent ...

  4. Endothelin-1 Regulation of Exercise-Induced Changes in Flow: Dynamic Regulation of Vascular Tone

    Directory of Open Access Journals (Sweden)

    Robert M. Rapoport

    2017-10-01

    Full Text Available Although endothelin (ET-1 is a highly potent vasoconstrictor with considerable efficacy in numerous vascular beds, the role of endogenous ET-1 in the regulation of vascular tone remains unclear. The perspective that ET-1 plays little role in the on-going regulation of vascular tone at least under physiologic conditions is supported by findings that potential ET-1 constriction is minimized by the release of the vasodilator and ET-1 synthesis inhibitor, nitric oxide (NO. Indeed, ET-1 release and constriction is self-limited by ET-1-induced, endothelial ETB receptor-mediated release of NO. Moreover, even if the balance between ET-1 and NO were reversed as the result of lowered NO activity, as occurs in a number of pathophysiologies associated with endothelial dysfunction, the well-known resistance of ET-1 constriction to reversal (as determined with exogenous ET-1 precludes ET-1 in the dynamic, i.e., moment-to-moment, regulation of vascular tone. On the other hand, and as presently reviewed, findings of ET-1-dependent modulation of organ blood flow with exercise under physiologic conditions demonstrate the dynamic regulation of vascular tone by ET-1. We speculate that this regulation is mediated at least in part through changes in ET-1 synthesis/release caused by pulsatile flow-induced shear stress and NO.

  5. Cerebrovascular endothelin receptor upregulation in cerebral ischemia

    DEFF Research Database (Denmark)

    Edvinsson, Lars

    2009-01-01

    Stroke is a serious neurological disease and the third leading cause of death in the western world. In roughly 15 % of the cases, the cause is due to an intracranial haemorrhage, and the remaining 85 % represent ischemic strokes. Ischemic stroke is caused by the occlusion of a cerebral artery...... either by an embolus or by local thrombosis. Several studies have shown an involvement of the endothelin system in ischemic stroke. This review aims to examine the alterations of vascular endothelin receptor expression in ischemic stroke. Furthermore, studies of the intracellular signalling pathways...... leading to the enhanced expression of vascular endothelin receptors show that both protein kinase C (PKC) and mitogen activating protein kinase (MAPK) play important roles. The results from this work provide new perspectives on the pathophysiology of ischemic stroke, and give a possible explanation...

  6. Endothelin-1 in systemic sclerosis

    Directory of Open Access Journals (Sweden)

    C. Pizzorni

    2011-09-01

    Full Text Available We evaluated endothelin-1 (ET-1 plasma levels in patients affected by primary Raynaud’s phenomenon (PRP, as well as in patients with systemic sclerosis (SSc and secondary Raynaud’s phenomenon (SRP. Furthermore, ET-1 levels were investigated in SSc patients with different patterns of peripheral microvascular damage, as evaluated by nailfold videocapillaroscopy (NVC. Methods: 23 PRP patients, 67 SSc patients according to ACR criteria, and 23 healthy subjects were enrolled. SSc microvascular involvement was classified in three different patterns (Early, Active, and Late by NVC, as previously described. Results: ET-1 was found significantly higher in both PRP and SRP, when compared with controls (median ±IQR: 3.3±2.8, 2.7±2.2, 2.0±2.2, respectively (p=0.05. No statistically significant difference of ET-1 levels was observed between PRP and SRP patients. ET-1 was found higher in patients with Late NVC pattern, when compared with both Active and Early NVC patterns (median±IQR: 3.4±2.5, 2.4±2.2, 2.5±2.1, respectively, but without statistical significance. Patients with Late NVC pattern showed significantly higher ET-1 plasma levels than controls (p=0.03. No correlation was found between ET-1 levels and disease duration in both groups, as well as between ET-1 levels and age of patients. Conclusions: These data support previous studies, reporting increased ET-1 plasma levels in both PRP and SRP patients. Interestingly, patients with the Late NVC pattern of microangiopathy showed higher ET-1 plasma levels than controls. The high levels of ET-1 detected in the Late NVC pattern of microangiopathy might be related to the larger fibrotic involvement typical of the advanced stages of disease.

  7. Vascular endothelial cells mediate mechanical stimulation-induced enhancement of endothelin hyperalgesia via activation of P2X2/3 receptors on nociceptors.

    Science.gov (United States)

    Joseph, Elizabeth K; Green, Paul G; Bogen, Oliver; Alvarez, Pedro; Levine, Jon D

    2013-02-13

    Endothelin-1 (ET-1) is unique among a broad range of hyperalgesic agents in that it induces hyperalgesia in rats that is markedly enhanced by repeated mechanical stimulation at the site of administration. Antagonists to the ET-1 receptors, ET(A) and ET(B), attenuated both initial as well as stimulation-induced enhancement of hyperalgesia (SIEH) by endothelin. However, administering antisense oligodeoxynucleotide to attenuate ET(A) receptor expression on nociceptors attenuated ET-1 hyperalgesia but had no effect on SIEH, suggesting that this is mediated via a non-neuronal cell. Because vascular endothelial cells are both stretch sensitive and express ET(A) and ET(B) receptors, we tested the hypothesis that SIEH is dependent on endothelial cells by impairing vascular endothelial function with octoxynol-9 administration; this procedure eliminated SIEH without attenuating ET-1 hyperalgesia. A role for protein kinase Cε (PKCε), a second messenger implicated in the induction and maintenance of chronic pain, was explored. Intrathecal antisense for PKCε did not inhibit either ET-1 hyperalgesia or SIEH, suggesting no role for neuronal PKCε; however, administration of a PKCε inhibitor at the site of testing selectively attenuated SIEH. Compatible with endothelial cells releasing ATP in response to mechanical stimulation, P2X(2/3) receptor antagonists eliminated SIEH. The endothelium also appears to contribute to hyperalgesia in two ergonomic pain models (eccentric exercise and hindlimb vibration) and in a model of endometriosis. We propose that SIEH is produced by an effect of ET-1 on vascular endothelial cells, sensitizing its release of ATP in response to mechanical stimulation; ATP in turn acts at the nociceptor P2X(2/3) receptor.

  8. Endothelin-1 and endothelin-3 in cirrhosis: relations to systemic and splanchnic haemodynamics

    DEFF Research Database (Denmark)

    Møller, Søren; Gülberg, V; Henriksen, Jens Henrik

    1995-01-01

    correlated with the hepatic venous pressure gradient (r = 0.61, p r = 0.35, p r = -0.31, p r = -0.41, p r = -0.56, p ... correlated to the cardiac output in the group with cirrhosis (r = 0.35, p ....002). The same pattern was found in arterial endothelin-3. Hepatic venous endothelin-3 correlated significantly with central and arterial blood volume (r = 0.56, p

  9. Modulation of rhodopsin gene expression and signaling mechanisms evoked by endothelins in goldfish and murine pigment cell lines

    Directory of Open Access Journals (Sweden)

    G.J.D. Lopes

    2010-09-01

    Full Text Available Endothelins (ETs and sarafotoxins (SRTXs belong to a family of vasoconstrictor peptides, which regulate pigment migration and/or production in vertebrate pigment cells. The teleost Carassius auratus erythrophoroma cell line, GEM-81, and Mus musculus B16 melanocytes express rhodopsin, as well as the ET receptors, ETB and ETA, respectively. Both cell lines are photoresponsive, and respond to light with a decreased proliferation rate. For B16, the doubling time of cells kept in 14-h light (14L:10-h darkness (10D was higher compared to 10L:14D, or to DD. The doubling time of cells kept in 10L:14D was also higher compared to DD. Using real-time PCR, we demonstrated that SRTX S6c (12-h treatment, 100 pM and 1 nM; 24-h treatment, 1 nM and ET-1 (12-h treatment, 10 and 100 pM; 24- and 48-h treatments, 100 pM increased rhodopsin mRNA levels in GEM-81 and B16 cells, respectively. This modulation involves protein kinase C (PKC and the mitogen-activated protein kinase cascade in GEM-81 cells, and phospholipase C, Ca2+, calmodulin, a Ca2+/calmodulin-dependent kinase, and PKC in B16 cells. Cells were kept under constant darkness throughout the gene expression experiments. These results show that rhodopsin mRNA levels can be modulated by SRTXs/ETs in vertebrate pigment cells. It is possible that SRTX S6c binding to the ETB receptors in GEM-81 cells, and ET-1 binding to ETA receptors in B16 melanocytes, although activating diverse intracellular signaling mechanisms, mobilize transcription factors such as c-Fos, c-Jun, c-Myc, and neural retina leucine zipper protein. These activated transcription factors may be involved in the positive regulation of rhodopsin mRNA levels in these cell lines.

  10. Structural comparison of contractile nanomachines

    Directory of Open Access Journals (Sweden)

    Sebastian Kube

    2015-05-01

    Full Text Available Contractile molecular machines are a common feature among bacteriophages and prokaryotes. Due to their stability and the large size, contractile-tailed bacteriophages are traditionally investigated by electron microscopic methods. Complemented by crystallographic studies, a molecular model of contraction for the T4 phage was developed. Lately, also related contractile structures like the Photorhabdus virulence cassette-like particles, the R-Type pyocins and the contractile tubule of the bacterial Type VI secretion system have been analyzed by cryo electron microscopy. Photorhabdus virulence cassette particles and R-Type pyocins are toxin complexes reminiscent of bacteriophage tails that are secreted by bacteria to kill their insect host or competing bacteria. In contrast, the Type VI secretion system is an intracellular apparatus for injection of effector proteins into bacterial and eukaryotic cells. Although it shares homology with other contractile systems, the Type VI secretion system is additionally equipped with a recycling function, which makes it suitable for multiple rounds of action. Starting from the 3D reconstructions, we compare these molecular machines structurally and functionally to their viral counterparts and summarize the current knowledge on their respective mode of action.

  11. Elevated endothelin-1 (ET-1) levels may contribute to hypoadiponectinemia in childhood obesity.

    Science.gov (United States)

    Nacci, Carmela; Leo, Valentina; De Benedictis, Leonarda; Carratù, Maria Rosaria; Bartolomeo, Nicola; Altomare, Maria; Giordano, Paola; Faienza, Maria Felicia; Montagnani, Monica

    2013-04-01

    Pediatric obesity is associated with endothelial dysfunction and hypoadiponectinemia, but the relationship between these two conditions remains to be fully clarified. Whether enhanced release of endothelin-1 (ET-1) may directly impair adiponectin (Ad) production in obese children is not known. The aim of the study was to explore whether and how high circulating levels of ET-1 may contribute to impair Ad production, release, and vascular activity. Sixty children were included into obese (Ob; n = 30), overweight (OW; n = 11), and lean (n = 19) groups. Total and high-molecular-weight Ad, ET-1, vascular cell adhesion molecule-1, and von Willebrand factor levels were measured in serum samples. Adipocytes were stimulated with exogenous ET-1 or with sera from lean, OW, and Ob, and Ad production and release measured in the absence or in the presence of ETA (BQ-123) and ETB (BQ-788) receptor blockers, p42/44 MAPK inhibitor PD-98059, or c-Jun NH2-terminal protein kinase inhibitor SP-600125. Vasodilation to Ad was evaluated in rat isolated arteries in the absence or in the presence of BQ-123/788. Total and high-molecular-weight Ad was significantly decreased and ET-1 levels significantly increased in OW (P ET-1. Exposure of adipocytes to exogenous ET-1 or serum from OW and Ob significantly decreased Ad mRNA and protein levels (P ET-1 on Ad was reverted by BQ-123/788 or PD-98059 but not SP-600125. Ad-mediated vasodilation was further increased in arteries pretreated with BQ-123/788. ET-1-mediated inhibition of Ad synthesis via p42/44 MAPK signaling may provide a possible explanation for hypoadiponectinemia in pediatric obesity and contribute to the development of cardiovascular complications.

  12. Genetic interactions between neurofibromin and endothelin receptor B in mice.

    Directory of Open Access Journals (Sweden)

    Mugdha Deo

    Full Text Available When mutations in two different genes produce the same mutant phenotype, it suggests that the encoded proteins either interact with each other, or act in parallel to fulfill a similar purpose. Haploinsufficiency of Neurofibromin and over-expression of Endothelin 3 both cause increased numbers of melanocytes to populate the dermis during mouse development, and thus we are interested in how these two signaling pathways might intersect. Neurofibromin is mutated in the human genetic disease, neurofibromatosis type 1, which is characterized by the development of Schwann cell based tumors and skin hyper-pigmentation. Neurofibromin is a GTPase activating protein, while the Endothelin 3 ligand activates Endothelin receptor B, a G protein coupled receptor. In order to study the genetic interactions between endothelin and neurofibromin, we defined the deletion breakpoints of the classical Ednrb piebald lethal allele (Ednrb(s-l and crossed these mice to mice with a loss-of-function mutation in neurofibromin, Dark skin 9 (Dsk9. We found that Neurofibromin haploinsufficiency requires Endothelin receptor B to darken the tail dermis. In contrast, Neurofibromin haploinsufficiency increases the area of the coat that is pigmented in Endothelin receptor B null mice. We also found an oncogenic mutation in the G protein alpha subunit, GNAQ, which couples to Endothelin receptor B, in a uveal melanoma from a patient with neurofibromatosis type 1. Thus, this data suggests that there is a complex relationship between Neurofibromin and Endothelin receptor B.

  13. Melatonin inhibits endothelin-1 and induces endothelial nitric oxide ...

    African Journals Online (AJOL)

    Although, I/R augmented the endothelin-1 (ET-1) gene expression and the level of big endothelin-1 (big ET-1) in liver tissue, melatonin attenuated these increases. Conversely, non-significant decrease in endothelial nitric oxide synthase (eNOS) mRNA expression in I/R group was significantly elevated by melatonin in ...

  14. Increased perfusion pressure enhances the expression of endothelin (ETB) and angiotensin II (AT1, AT2) receptors in rat mesenteric artery smooth muscle cells

    DEFF Research Database (Denmark)

    Lindstedt, Isak; Xu, Cang-Bao; Zhang, Yaping

    2009-01-01

    and luminally perfused in a perfusion chamber. After either exposure to no ("organ culture" (0 mmHg)), normal (85/75 mmHg) or high pressure (160/150 mmHg) at constant flow for 1-17 h, the vessel segments were snap frozen and real-time polymerase chain reaction was performed to quantify the ET- and AT-receptor m...

  15. Off-Axis Driven Current Effects on ETB and ITB Formations based on Bifurcation Concept

    Science.gov (United States)

    Pakdeewanich, J.; Onjun, T.; Chatthong, B.

    2017-09-01

    This research studies plasma performance in fusion Tokamak system by investigating parameters such as plasma pressure in the presence of an edge transport barrier (ETB) and an internal transport barrier (ITB) as the off-axis driven current position is varied. The plasma is modeled based on the bifurcation concept using a suppression function that can result in formation of transport barriers. In this model, thermal and particle transport equations, including both neoclassical and anomalous effects, are solved simultaneously in slab geometry. The neoclassical coefficients are assumed to be constant while the anomalous coefficients depend on gradients of local pressure and density. The suppression function, depending on flow shear and magnetic shear, is assumed to affect only on the anomalous channel. The flow shear can be calculated from the force balance equation, while the magnetic shear is calculated from the given plasma current. It is found that as the position of driven current peak is moved outwards from the plasma center, the central pressure is increased. But at some point it stars to decline, mostly when the driven current peak has reached the outer half of the plasma. The higher pressure value results from the combination of ETB and ITB formations. The drop in central pressure occurs because ITB stats to disappear.

  16. Odour and flavour thresholds of gasoline additives (MTBE, ETBE and TAME) and their occurrence in Dutch drinking water collection areas

    NARCIS (Netherlands)

    van Wezel, A.; Puijker, L.; Vink, C.; Versteegh, A.; de Voogt, P.

    2009-01-01

    The use of ETBE (ethyl-tert-butylether) as gasoline additive has recently grown rapidly. Contamination of aquatic systems is well documented for MTBE (methyl-tert-butylether), but less for other gasoline additives. Due to their mobility they may easily reach drinking water collection areas. Odour

  17. Anaerobic degradation of a mixture of MtBE, EtBE, TBA, and benzene under different redox conditions

    NARCIS (Netherlands)

    Waals, van der Marcelle J.; Pijls, Charles; Sinke, Anja J.C.; Langenhoff, Alette A.M.; Smidt, Hauke; Gerritse, Jan

    2018-01-01

    The increasing use of biobased fuels and fuel additives can potentially change the typical fuel-related contamination in soil and groundwater. Anaerobic biotransformation of the biofuel additive ethyl tert-butyl ether (EtBE), as well as of methyl tert-butyl ether (MtBE), benzene, and tert-butyl

  18. Different endothelin receptor affinities in dog tissues

    International Nuclear Information System (INIS)

    Loeffler, B.M.L.; Loehrer, W.

    1991-01-01

    Endothelin (ET) is a long-lasting potent vasoconstrictor-peptide. Here the authors report different binding affinities of endothelin-1 (ET-1) to ET-receptors of various dog tissues. Crude microsomal fractions were prepared after homogenisation of dog tissues in 50 mM Tris/HCl, 20 mM MnCl2, 1 mM EDTA, pH 7.4 by differential centrifugation. Aliquots of microsomal fractions (70 micrograms of protein) were incubated at 25 degrees C for 180 min in the presence of 20 pM 125I-ET-1 and various concentrations of cold ET-1. Four different ET-1 receptor binding affinities were found: adrenals, cerebrum, liver, heart, skeletal muscle and stomach microsomal membranes contained high affinity binding sites (Kd 50 - 80 pM, Bmax 60 - 250 fmol/mg). In cerebellum and spleen medium affinity ET-1 receptors (Kd 350 pM, Bmax 880 and 1200 fmol/mg respectively) were present. In comparison lung and kidney microsomes contained a low affinity ET-1 receptor (Kd 800 and 880 pM, Bmax 1600 and 350 fmol/mg). Receptors of even lower affinity were present in heart, intestine and liver microsomes with Kd values of 3 - 6 nM

  19. Modulatory effects of taurine on jejunal contractility

    Directory of Open Access Journals (Sweden)

    Q.Y. Yao

    2014-12-01

    Full Text Available Taurine (2-aminoethanesulfonic acid is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

  20. Modulatory effects of taurine on jejunal contractility

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y. [Dalian Medical University, Dalian, Liaoning (China)

    2014-10-14

    Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca{sup 2+} dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism.

  1. Modulatory effects of taurine on jejunal contractility

    International Nuclear Information System (INIS)

    Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y.

    2014-01-01

    Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca 2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism

  2. Modulatory effects of taurine on jejunal contractility

    Science.gov (United States)

    Yao, Q.Y.; Chen, D.P.; Ye, D.M.; Diao, Y.P.; Lin, Y.

    2014-01-01

    Taurine (2-aminoethanesulfonic acid) is widely distributed in animal tissues and has diverse pharmacological effects. However, the role of taurine in modulating smooth muscle contractility is still controversial. We propose that taurine (5-80 mM) can exert bidirectional modulation on the contractility of isolated rat jejunal segments. Different low and high contractile states were induced in isolated jejunal segments of rats to observe the effects of taurine and the associated mechanisms. Taurine induced stimulatory effects on the contractility of isolated rat jejunal segments at 3 different low contractile states, and inhibitory effects at 3 different high contractile states. Bidirectional modulation was not observed in the presence of verapamil or tetrodotoxin, suggesting that taurine-induced bidirectional modulation is Ca2+ dependent and requires the presence of the enteric nervous system. The stimulatory effects of taurine on the contractility of isolated jejunal segments was blocked by atropine but not by diphenhydramine or by cimetidine, suggesting that muscarinic-linked activation was involved in the stimulatory effects when isolated jejunal segments were in a low contractile state. The inhibitory effects of taurine on the contractility of isolated jejunal segments were blocked by propranolol and L-NG-nitroarginine but not by phentolamine, suggesting that adrenergic β receptors and a nitric oxide relaxing mechanism were involved when isolated jejunal segments were in high contractile states. No bidirectional effects of taurine on myosin phosphorylation were observed. The contractile states of jejunal segments determine taurine-induced stimulatory or inhibitory effects, which are associated with muscarinic receptors and adrenergic β receptors, and a nitric oxide associated relaxing mechanism. PMID:25387674

  3. Smooth Muscle Endothelin B Receptors Regulate Blood Pressure but Not Vascular Function or Neointimal Remodeling.

    Science.gov (United States)

    Miller, Eileen; Czopek, Alicja; Duthie, Karolina M; Kirkby, Nicholas S; van de Putte, Elisabeth E Fransen; Christen, Sibylle; Kimmitt, Robert A; Moorhouse, Rebecca; Castellan, Raphael F P; Kotelevtsev, Yuri V; Kuc, Rhoda E; Davenport, Anthony P; Dhaun, Neeraj; Webb, David J; Hadoke, Patrick W F

    2017-02-01

    The role of smooth muscle endothelin B (ET B ) receptors in regulating vascular function, blood pressure (BP), and neointimal remodeling has not been established. Selective knockout mice were generated to address the hypothesis that loss of smooth muscle ET B receptors would reduce BP, alter vascular contractility, and inhibit neointimal remodeling. ET B receptors were selectively deleted from smooth muscle by crossing floxed ET B mice with those expressing cre-recombinase controlled by the transgelin promoter. Functional consequences of ET B deletion were assessed using myography. BP was measured by telemetry, and neointimal lesion formation induced by femoral artery injury. Lesion size and composition (day 28) were analyzed using optical projection tomography, histology, and immunohistochemistry. Selective deletion of ET B was confirmed by genotyping, autoradiography, polymerase chain reaction, and immunohistochemistry. ET B -mediated contraction was reduced in trachea, but abolished from mesenteric veins, of knockout mice. Induction of ET B -mediated contraction in mesenteric arteries was also abolished in these mice. Femoral artery function was unaltered, and baseline BP modestly elevated in smooth muscle ET B knockout compared with controls (+4.2±0.2 mm Hg; P<0.0001), but salt-induced and ET B blockade-mediated hypertension were unaltered. Circulating endothelin-1 was not altered in knockout mice. ET B -mediated contraction was not induced in femoral arteries by incubation in culture medium or lesion formation, and lesion size was not altered in smooth muscle ET B knockout mice. In the absence of other pathology, ET B receptors in vascular smooth muscle make a small but significant contribution to ET B -dependent regulation of BP. These ET B receptors have no effect on vascular contraction or neointimal remodeling. © 2016 The Authors.

  4. Compensatory Hypertrophy of Skeletal Muscle: Contractile Characteristics

    Science.gov (United States)

    Ianuzzo, C. D.; Chen, V.

    1977-01-01

    Describes an experiment using rats that demonstrates contractile characteristics of normal and hypertrophied muscle. Compensatory hypertrophy of the plantaris muscle is induced by surgical removal of the synergistic gastrocnemium muscle. Includes methods for determination of contractile properties of normal and hypertrophied muscle and…

  5. Anaerobic degradation of a mixture of MtBE, EtBE, TBA, and benzene under different redox conditions.

    Science.gov (United States)

    van der Waals, Marcelle J; Pijls, Charles; Sinke, Anja J C; Langenhoff, Alette A M; Smidt, Hauke; Gerritse, Jan

    2018-04-01

    The increasing use of biobased fuels and fuel additives can potentially change the typical fuel-related contamination in soil and groundwater. Anaerobic biotransformation of the biofuel additive ethyl tert-butyl ether (EtBE), as well as of methyl tert-butyl ether (MtBE), benzene, and tert-butyl alcohol (TBA, a possible oxygenate metabolite), was studied at an industrially contaminated site and in the laboratory. Analysis of groundwater samples indicated that in the field MtBE was degraded, yielding TBA as major product. In batch microcosms, MtBE was degraded under different conditions: unamended control, with medium without added electron acceptors, or with ferrihydrite or sulfate (with or without medium) as electron acceptor, respectively. Degradation of EtBE was not observed under any of these conditions tested. TBA was partially depleted in parallel with MtBE. Results of microcosm experiments with MtBE substrate analogues, i.e., syringate, vanillate, or ferulate, were in line with the hypothesis that the observed TBA degradation is a cometabolic process. Microcosms with ferulate, syringate, isopropanol, or diethyl ether showed EtBE depletion up to 86.5% of the initial concentration after 83 days. Benzene was degraded in the unamended controls, with medium without added electron acceptors and with ferrihydrite, sulfate, or chlorate as electron acceptor, respectively. In the presence of nitrate, benzene was only degraded after addition of an anaerobic benzene-degrading community. Nitrate and chlorate hindered MtBE, EtBE, and TBA degradation.

  6. Overexpression of endothelin B receptor in glioblastoma: a prognostic marker and therapeutic target?

    KAUST Repository

    Vasaikar, Suhas; Tsipras, Giorgos; Landá zuri, Natalia; Costa, Helena; Wilhelmi, Vanessa; Scicluna, Patrick; Cui, Huanhuan L.; Mohammad, Abdul-Aleem; Davoudi, Belghis; Shang, Mingmei; Ananthaseshan, Sharan; Strå å t, Klas; Stragliotto, Giuseppe; Rahbar, Afsar; Wong, Kum Thong; Tegner, Jesper; Yaiw, Koon-Chu; Sö derberg-Naucler, Cecilia

    2018-01-01

    of endothelin B receptor (ETBR) has been demonstrated in gliomas, we aimed to test whether ETBR is a useful prognostic marker in GBM and examine if the clinically available endothelin receptor antagonists (ERA) could be useful in the disease treatment

  7. Intraportal nicotine infusion in rats decreases hepatic blood flow through endothelin-1 and both endothelin A and endothelin B receptors

    International Nuclear Information System (INIS)

    Hashimoto, Takashi; Yoneda, Masashi; Shimada, Tadahito; Kurosawa, Mieko; Terano, Akira

    2004-01-01

    Smoking has been demonstrated to aggravate liver injury. Nicotine, a major pharmacological component of tobacco smoke, affects a multitude of functions. Smoking and nicotine induce synthesis of endothelin (ET)-1. The effect of intraportal infusion of nicotine on hepatic circulation and an involvement of ET-1 and ET receptor in the action of nicotine were investigated in rats. Nicotine (0-100 μg/kg/h) was infused into the portal vein of urethane-anesthetized rats, and changes of hepatic blood flow were evaluated. Intraportal infusion of nicotine dose-dependently decreased hepatic blood flow and increased portal pressure without any alteration of heart rate or arterial blood pressure. This action of intraportal nicotine was completely abolished by pretreatment of ET-1 antibody. Either BQ485 (ET A receptor antagonist) or BQ788 (ET B receptor antagonist) partially reversed the effect of nicotine, and combination of BQ788 and BQ485 completely abolished it. These findings suggest that nicotine inhibits hepatic circulation through ET-1, and ET A and ET B receptor

  8. Alternatively Activated (M2) Macrophage Phenotype Is Inducible by Endothelin-1 in Cultured Human Macrophages.

    Science.gov (United States)

    Soldano, Stefano; Pizzorni, Carmen; Paolino, Sabrina; Trombetta, Amelia Chiara; Montagna, Paola; Brizzolara, Renata; Ruaro, Barbara; Sulli, Alberto; Cutolo, Maurizio

    2016-01-01

    Alternatively activated (M2) macrophages are phenotypically characterized by the expression of specific markers, mainly macrophage scavenger receptors (CD204 and CD163) and mannose receptor-1 (CD206), and participate in the fibrotic process by over-producing pro-fibrotic molecules, such as transforming growth factor-beta1 (TGFbeta1) and metalloproteinase (MMP)-9. Endothelin-1 (ET-1) is implicated in the fibrotic process, exerting its pro-fibrotic effects through the interaction with its receptors (ETA and ETB). The study investigated the possible role of ET-1 in inducing the transition from cultured human macrophages into M2 cells. Cultured human monocytes (THP-1 cell line) were activated into macrophages (M0 macrophages) with phorbol myristate acetate and subsequently maintained in growth medium (M0-controls) or treated with either ET-1 (100nM) or interleukin-4 (IL-4, 10ng/mL, M2 inducer) for 72 hours. Similarly, primary cultures of human peripheral blood monocyte (PBM)-derived macrophages obtained from healthy subjects, were maintained in growth medium (untreated cells) or treated with ET-1 or IL-4 for 6 days. Both M0 and PBM-derived macrophages were pre-treated with ET receptor antagonist (ETA/BRA, bosentan 10-5M) for 1 hour before ET-1 stimulation. Protein and gene expression of CD204, CD206, CD163, TGFbeta1 were analysed by immunocytochemistry, Western blotting and quantitative real time polymerase chain reaction (qRT-PCR). Gene expression of interleukin(IL)-10 and macrophage derived chemokine (CCL-22) was evaluated by qRT-PCR. MMP-9 production was investigated by gel zymography. ET-1 significantly increased the expression of M2 phenotype markers CD204, CD206, CD163, IL-10 and CCL-22, and the production of MMP-9 in both cultures of M0 and PBM-derived macrophages compared to M0-controls and untreated cells. In cultured PBM-derived macrophages, ET-1 increased TGFbeta1 protein and gene expression compared to untreated cells. The ET-1-mediated effects were

  9. Characterization of endothelin receptors on a human neuroblastoma cell line: evidence for the ETA subtype.

    Science.gov (United States)

    Wilkes, L C; Boarder, M R

    1991-11-01

    1. Specific binding sites for synthetic endothelin (ET) isoforms were studied on intact cells of the SK-N-MC cell line, derived from a human neuroblastoma. 2. [125I]-ET-1 (2.5 x 10(-11) M) specifically bound to a single class of binding sites on these cells (Hill coefficient of 1.06 +/- 0.04, n = 3) with an apparent Kd of 1.4 +/- 0.3 x 10(-9) M and a Bmax of 3.1 +/- 1.0 pmol mg-1 protein. [125I]-ET-3 (2.5 x 10(-11) M), did not specifically bind to SK-N-MC cells. 3. The binding of [125I]-ET-1 was competitively inhibited by other ET isoforms, the order of potency being ET-1 greater than sarafotoxin S6b greater than ET-3. 4. Association of 1 nM [125I]-ET-1 at 37 degrees C reached apparent equilibrium at 60-80 min, with half-maximal binding being achieved at 12 min. 5. Dissociation was measured after both 10 min and 60 min of association with 64% and 30% respectively of specifically bound [125I]-ET-1 dissociating. The actual amounts of [125I]-ET-1 dissociated were similar in both cases. 6. Incubation of [125I]-ET-3 with SK-N-MC cells at 37 degrees C for 60 min did not result in significant degradation of this peptide. However, [125I]-ET-1 was broken down by incubation with SK-N-MC cells, the pattern of degradation of dissociable [125I]-ET-1 (and that found in the supernatant) being different from that of non-dissociable [125I]-ET-1. 7. ET-1 concentration-dependently induced an increase in total inositol phosphate accumulation in subconfluent (but not in confluent) cultures of SK-N-MC cells (EC50 = 6.43 +/- 1.9 x 1010M). ET-3 was without effect. 8. These results show that ET-1 specifically binds to SK-N-MC cells with the characteristics of an ETA receptor. Our earlier finding that adrenal chromaffin cells express an ETB receptor indicates the existence of multiple ET receptor types on neuronal cells.

  10. Plasma concentrations of endothelin in patients with abnormal vascular reactivity

    International Nuclear Information System (INIS)

    Predel, H.G.; Meyer-Lehnert, H.; Baecker, A.; Stelkens, H.; Kramer, H.J.

    1990-01-01

    We measured circulating concentrations of endothelin in healthy subjects and in patients with abnormal vascular reactivity. Endothelin concentrations were determined by radioimmunoassay after extraction of plasma using Sep-Pak C-18 cartridges in healthy subjects, in patients with diabetes mellitus type I, in patients with mild to moderate essential hypertension and in non-dialyzed patients with stable chronic renal failure. Plasma concentrations were similar in healthy controls, in diabetics and in hypertensive patients averaging 5.0±0.6 pg/ml, 4.7±0.2 pg/ml and 6.5±1.0 pg/ml, respectively. In contrast, plasma concentrations of endothelin were markedly elevated in patients with chronic renal failure averaging 16.6±2.9 pg/ml. No correlations were observed between serum creatinine concentrations ranging from 124 to 850 μmol/l or blood pressure and plasma concentrations of endothelin. Bicycle ergometric exercise in six healthy subjects and an acute modest i.v. saline load of 1,000 ml of 0.45% NaCl administered within 60 min in six patients with mild essential hypertension did not affect plasma concentrations of endothelin

  11. Co-inhibition of Angiotensin II Receptor and Endothelin-1 Attenuates Renal Injury in Unilateral Ureteral Obstructed Mice

    Directory of Open Access Journals (Sweden)

    Yoon-Kyung Chang

    2016-07-01

    Full Text Available Background/Aims: Both endothelin-1 (ET-1 and the renin-angiotensin system (RAS may play important roles in renal fibrosis in the obstructed kidney. However, there have been few clear demonstrations of a relationship between their activation and additive or synergistic roles in renal fibrosis. We investigated the protective roles and relationship between renal RAS and ET-1 in unilateral ureteral obstruction (UUO mice. Methods: 8-week-old male C57BL/6 mice were divided into seven groups: sham, bosentan+sham, valsartan+sham, vehicle+UUO, bosentan+UUO, valsartan+UUO, and valsartan+bosentan+UUO. Valsartan and bosentan were administered orally using an NG tube (valsartan 10 mg/kg/day, bosentan 100 mg/kg/day for 8 days, after which the molecular and structural kidney parameters were evaluated. Bosentan treatment elevated plasma renin activity, renal renin, and AT1R expression in UUO mice. Results: Although valsartan decreased plasma ET-1 in these mice, it did not affect ET(A or ET(B in their kidneys. Co-treatment with valsartan and bosentan decreased ET-1 in these mice compared to the single treatments. Bosentan, but not valsartan, elevated eNOS expression in their kidneys. Co-treatment with valsartan and bosentan reduced TGF-β, α-SMA, and collagen IV expression, and the Masson's trichrome stained area in their kidneys. Conclusions: Bosentan and valsartan acted complementarily, and co-treatment with both drugs had an additive protective effect against renal fibrosis.

  12. Chronic high-sodium diet increases aortic wall endothelin-1 expression in a blood pressure-independent fashion in rats.

    Science.gov (United States)

    Tsai, Yu-Hwai; Ohkita, Mamoru; Gariepy, Cheryl E

    2006-06-01

    Vascular endothelin (ET)-1 is upregulated in several forms of salt-induced hypertension. It is unclear to what extent these effects are primary or secondary to endothelial damage. We hypothesized that a high-sodium diet (HNa) increases vascular ET-1 production independent of arterial blood pressure changes. We investigated the effect of chronic HNa with and without ET(A) blockade on circulating and aortic ET-1 protein levels as well as aortic expression of ET-1 and ET(A) messenger RNA (mRNA) in inbred Wistar-Kyoto (WKY) and congenic ET(B)-deficient rats. Comparing WKY rats fed a low-sodium diet (LNa) with those fed HNa for 3 weeks, aortic wall ET-1 protein is significantly increased in response to HNa (331 +/- 43 pg/g tissue for LNa vs. 557 +/- 34 pg/gm tissue for HNa). HNa also increased aortic wall ET-1 mRNA levels by 40%, as determined by quantitative reverse transcriptase polymerase chain reaction. We then compared rats chronically treated with the ET(A)-selective antagonist, ABT-627, while receiving either LNa or HNa. There were no differences in arterial blood pressure (mean arterial pressure 89 +/- 1 mm Hg for WKY on LNa; 90 +/- 3 for WKY on HNa; 91 +/- 2 for ET(B)-deficient/ABT-627-treated on HNa) or heart rate. However, aortic wall ET-1 protein levels were 4-fold higher in the HNa group. Further, HNa increased aortic wall ET-1 mRNA (approximately 1.5- to 3-fold) and ET(A) mRNA (approximately 2- to 7-fold), independent of activation of ET(B). Therefore, the expression of ET-1 mRNA by the aortic wall is increased in response to chronic high dietary sodium in WKY rats in the absence of changes in arterial blood pressure.

  13. Development and application of a rat PBPK model to elucidate kidney and liver effects induced by ETBE and tert-butanol

    International Nuclear Information System (INIS)

    Salazar, Keith D.; Brinkerhoff, Christopher J.; Lee, Janice S.; Chiu, Weihsueh A.

    2015-01-01

    Subchronic and chronic studies in rats of the gasoline oxygenates ethyl tert-butyl ether (ETBE) and tert-butanol (TBA) report similar noncancer kidney and liver effects but differing results with respect to kidney and liver tumors. Because TBA is a major metabolite of ETBE, it is possible that TBA is the active toxic moiety in all these studies, with reported differences due simply to differences in the internal dose. To test this hypothesis, a physiologically-based pharmacokinetic (PBPK) model was developed for ETBE and TBA to calculate internal dosimetrics of TBA following either TBA or ETBE exposure. This model, based on earlier PBPK models of methyl tert-butyl ether (MTBE), was used to evaluate whether kidney and liver effects are consistent across routes of exposure, as well as between ETBE and TBA studies, on the basis of estimated internal dose. The results demonstrate that noncancer kidney effects, including kidney weight changes, urothelial hyperplasia, and chronic progressive nephropathy (CPN), yielded consistent dose–response relationships across routes of exposure and across ETBE and TBA studies using TBA blood concentration as the dose metric. Relative liver weights were also consistent across studies on the basis of TBA metabolism, which is proportional to TBA liver concentrations. However, kidney and liver tumors were not consistent using any dose metric. These results support the hypothesis that TBA mediates the noncancer kidney and liver effects following ETBE administration; however, additional factors besides internal dose are necessary to explain the induction of liver and kidney tumors. - Highlights: • We model two metabolically-related fuel oxygenates to address toxicity data gaps. • Kidney and liver effects are compared on an internal dose basis. • Noncancer kidney effects are consistent using TBA blood concentration. • Liver weight changes are consistent using TBA metabolic rate. • Kidney and liver tumors are not consistent using

  14. Development and application of a rat PBPK model to elucidate kidney and liver effects induced by ETBE and tert-butanol

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, Keith D., E-mail: Salazar.keith@epa.gov [Toxicity Pathways Branch, IRIS Division, NCEA, ORD, US EPA, Washington, DC 20460 (United States); Brinkerhoff, Christopher J., E-mail: Brinkerhoff.Chris@epa.gov [Risk Assessment Division, OPPT, OCSPP, US EPA, Washington, DC 20460 (United States); Lee, Janice S., E-mail: Lee.JaniceS@epa.gov [Toxicity Pathways Branch, IRIS Division, NCEA, ORD, US EPA, Washington, DC 20460 (United States); Chiu, Weihsueh A., E-mail: wchiu@cvm.tamu.edu [Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A& M University, College Station, TX 77843 (United States)

    2015-11-01

    Subchronic and chronic studies in rats of the gasoline oxygenates ethyl tert-butyl ether (ETBE) and tert-butanol (TBA) report similar noncancer kidney and liver effects but differing results with respect to kidney and liver tumors. Because TBA is a major metabolite of ETBE, it is possible that TBA is the active toxic moiety in all these studies, with reported differences due simply to differences in the internal dose. To test this hypothesis, a physiologically-based pharmacokinetic (PBPK) model was developed for ETBE and TBA to calculate internal dosimetrics of TBA following either TBA or ETBE exposure. This model, based on earlier PBPK models of methyl tert-butyl ether (MTBE), was used to evaluate whether kidney and liver effects are consistent across routes of exposure, as well as between ETBE and TBA studies, on the basis of estimated internal dose. The results demonstrate that noncancer kidney effects, including kidney weight changes, urothelial hyperplasia, and chronic progressive nephropathy (CPN), yielded consistent dose–response relationships across routes of exposure and across ETBE and TBA studies using TBA blood concentration as the dose metric. Relative liver weights were also consistent across studies on the basis of TBA metabolism, which is proportional to TBA liver concentrations. However, kidney and liver tumors were not consistent using any dose metric. These results support the hypothesis that TBA mediates the noncancer kidney and liver effects following ETBE administration; however, additional factors besides internal dose are necessary to explain the induction of liver and kidney tumors. - Highlights: • We model two metabolically-related fuel oxygenates to address toxicity data gaps. • Kidney and liver effects are compared on an internal dose basis. • Noncancer kidney effects are consistent using TBA blood concentration. • Liver weight changes are consistent using TBA metabolic rate. • Kidney and liver tumors are not consistent using

  15. Different pressor and bronchoconstrictor properties of human big-endothelin-1, 2 (1-38) and 3 in ketamine/xylazine-anaesthetized guinea-pigs.

    OpenAIRE

    Gratton, J P; Rae, G A; Claing, A; Télémaque, S; D'Orléans-Juste, P

    1995-01-01

    1. In the present study, the precursors of endothelin-1, endothelin-2 and endothelin-3 were tested for their pressor and bronchoconstrictor properties in the anaesthetized guinea-pig. In addition, the effects of big-endothelin-1 and endothelin-1 were assessed under urethane or ketamine/xylazine anaesthesia. 2. When compared to ketamine/xylazine, urethane markedly depressed the pressor and bronchoconstrictor properties of endothelin-1 and big-endothelin-1. 3. Under ketamine/xylazine anaesthesi...

  16. Physical activity opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes plasma endothelin-1 levels in individuals with essential hypertension

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Hellsten, Ylva

    2013-01-01

    performed lifelong physical activity had similar plasma and muscle endothelin-1 levels as the young controls and had higher ET(A) receptor levels. CONCLUSION: Our findings suggest that aerobic exercise training opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes......AIMS: Endothelin-1 has potent constrictor and proliferative activity in vascular smooth muscle, and essential hypertension and aging are associated with increased endothelin-1-mediated vasoconstrictor tone. The aim of this study was to investigate the effect of physical activity, hypertension...... and age on endothelin-1 levels in plasma and skeletal muscle and endothelin receptors in skeletal muscle in human subjects. METHODS: In study 1, normotensive (46 ± 1 years, n = 11) and hypertensive (47 ± 1 years, n = 10) subjects were studied before and after 8 weeks of aerobic exercise training. In study...

  17. Investigation of role of plasma endothelin in diabetes mellitus patients complicated with angiocardiopathy

    International Nuclear Information System (INIS)

    Cong Jingbo; Wang Zhihua; Niu Aijun

    2001-01-01

    Objective: To study the role of plasma endothelin in diabetes mellitus (DM) patients complicated with angiocardiopathy. Methods: Plasma endothelin levels were determined by radioimmunoassay in 34 diabetics, 27 diabetics complicated with angiocardiopathy and in 30 controls. Results: Plasma endothelin levels in both diabetic groups were significantly higher than those in normal subjects (p < 0.01); plasma endothelin levels in DM patients complicated with angiocardiopathy were significantly higher than those in patients with diabetes only (p < 0.01). Conclusion: Plasma endothelin was of important role in the pathogenesis of DM complicated with angiocardiopathy and could be used as an early and sensitive marker

  18. Endothelin, a peptide inhibitor of Na(+)-K(+)-ATPase in intact renaltubular epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Zeidel, M.L.; Brady, H.R.; Kone, B.C.; Gullans, S.R. (Brigham and Women' s Hospital, Boston, MA (USA))

    1989-12-01

    Endothelin, a potent vasoconstrictor released by vascular endothelial cells, can induce natriuresis in vivo. These studies examined the regulation of Na+ transport by endothelin in suspensions of rabbit proximal tubule (PT) and inner medullary collecting duct (IMCD) cells. Endothelin reduced oxygen consumption (QO2) by 18 +/- 1% in IMCD cells but did not alter QO2 in PT cells. In IMCD cells, endothelin inhibited QO2 half maximally at approximately 5 x 10(-12) M. Several lines of evidence indicate that endothelin reduces QO2 by inhibiting the Na(+)-K(+)-ATPase. (1) Endothelin gave no further inhibition of QO2 after ouabain and blunted the stimulatory effect of amphotericin B on QO2 (+29 +/- 4% in absence of endothelin, 0 +/- 5% in presence of endothelin; n = 6 preparations, P less than 0.001). (2) Endothelin inhibited ouabain-sensitive 86Rb+ uptake by 46.6 +/- 8.6% at 10 s and by 35.4 +/- 5.3% at 30 s without altering uptake at (60 min. 3) Addition of endothelin to IMCD cells induced a net K+ efflux with an initial rate of 32.2 +/- 4.8 nmol.min-1.mg protein-1, consistent with inhibition of the Na(+)-K(+)-ATPase. In contrast to the response observed in intact cells, in permeabilized IMCD cells endothelin did not inhibit ouabain-sensitive ATPase. Several observations indicated that prostaglandin E2 (PGE2) mediates endothelin inhibition of Na(+)-K(+)-ATPase activity. (1) The response to endothelin was blocked by ibuprofen in assays of QO2, net K+ flux, and 86Rb+ uptake. (2) Endothelin and PGE2 gave equivalent, nonadditive inhibition of ouabain-sensitive 86Rb+ uptake.

  19. Endothelin, a peptide inhibitor of Na(+)-K(+)-ATPase in intact renaltubular epithelial cells

    International Nuclear Information System (INIS)

    Zeidel, M.L.; Brady, H.R.; Kone, B.C.; Gullans, S.R.

    1989-01-01

    Endothelin, a potent vasoconstrictor released by vascular endothelial cells, can induce natriuresis in vivo. These studies examined the regulation of Na+ transport by endothelin in suspensions of rabbit proximal tubule (PT) and inner medullary collecting duct (IMCD) cells. Endothelin reduced oxygen consumption (QO2) by 18 +/- 1% in IMCD cells but did not alter QO2 in PT cells. In IMCD cells, endothelin inhibited QO2 half maximally at approximately 5 x 10(-12) M. Several lines of evidence indicate that endothelin reduces QO2 by inhibiting the Na(+)-K(+)-ATPase. (1) Endothelin gave no further inhibition of QO2 after ouabain and blunted the stimulatory effect of amphotericin B on QO2 (+29 +/- 4% in absence of endothelin, 0 +/- 5% in presence of endothelin; n = 6 preparations, P less than 0.001). (2) Endothelin inhibited ouabain-sensitive 86Rb+ uptake by 46.6 +/- 8.6% at 10 s and by 35.4 +/- 5.3% at 30 s without altering uptake at (60 min. 3) Addition of endothelin to IMCD cells induced a net K+ efflux with an initial rate of 32.2 +/- 4.8 nmol.min-1.mg protein-1, consistent with inhibition of the Na(+)-K(+)-ATPase. In contrast to the response observed in intact cells, in permeabilized IMCD cells endothelin did not inhibit ouabain-sensitive ATPase. Several observations indicated that prostaglandin E2 (PGE2) mediates endothelin inhibition of Na(+)-K(+)-ATPase activity. (1) The response to endothelin was blocked by ibuprofen in assays of QO2, net K+ flux, and 86Rb+ uptake. (2) Endothelin and PGE2 gave equivalent, nonadditive inhibition of ouabain-sensitive 86Rb+ uptake

  20. Iontophoresis of endothelin receptor antagonists in rats and men.

    Directory of Open Access Journals (Sweden)

    Matthieu Roustit

    Full Text Available The treatment of scleroderma-related digital ulcers is challenging. The oral endothelin receptor antagonist (ERA bosentan has been approved but it may induce liver toxicity. The objective of this study was to test whether ERAs bosentan and sitaxentan could be locally delivered using iontophoresis.Cathodal and anodal iontophoresis of bosentan and sitaxentan were performed on anaesthetized rat hindquarters without and during endothelin-1 infusion. Skin blood flow was quantified using laser-Doppler imaging and cutaneous tolerability was assessed. Iontophoresis of sitaxentan (20 min, 20 or 100 µA was subsequently performed on the forearm skin of healthy men (n = 5.In rats neither bosentan nor sitaxentan increased skin blood flux compared to NaCl. When simultaneously infusing endothelin-1, cathodal iontophoresis of sitaxentan increased skin blood flux compared to NaCl (AUC(0-20 were 44032.2 ± 12277 and 14957.5 ± 23818.8 %BL.s, respectively; P = 0.01. In humans, sitaxentan did not significantly increase skin blood flux as compared to NaCl. Iontophoresis of ERAs was well tolerated both in animals and humans.This study shows that cathodal iontophoresis of sitaxentan but not bosentan partially reverses endothelin-induced skin vasoconstriction in rats, suggesting that sitaxentan diffuses into the dermis. However, sitaxentan does not influence basal skin microvascular tone in rats or in humans.

  1. Evaluation of Homocysteine, Lipoprotein(a) and Endothelin as ...

    African Journals Online (AJOL)

    Indians have been reported to have high prevalence rates of coronary artery disease (CAD) even in the absence of traditional risk factors. The objective of this study was to assess the role of endothelin, lipoprotein(a), homocysteine and lipid profile as markers of CAD in Indian population. It was a hospital based ...

  2. Blockade of Endothelin-1 Receptor Type B Ameliorates Glucose Intolerance and Insulin Resistance in a Mouse Model of Obstructive Sleep Apnea

    Directory of Open Access Journals (Sweden)

    Jan Polak

    2018-05-01

    Full Text Available Obstructive sleep apnea (OSA is associated with insulin resistance (IR and glucose intolerance. Elevated endothelin-1 (ET-1 levels have been observed in OSA patients and in mice exposed to intermittent hypoxia (IH. We examined whether pharmacological blockade of type A and type B ET-1 receptors (ETA and ETB would ameliorate glucose intolerance and IR in mice exposed to IH. Subcutaneously implanted pumps delivered BQ-123 (ETA antagonist; 200 nmol/kg/day, BQ-788 (ETB antagonist; 200 nmol/kg/day or vehicle (saline or propyleneglycol [PG] for 14 days in C57BL6/J mice (10/group. During treatment, mice were exposed to IH (decreasing the FiO2 from 20.9% to 6%, 60/h or intermittent air (IA. After IH or IA exposure, insulin (0.5 IU/kg or glucose (1 mg/kg was injected intraperitoneally and plasma glucose determined after injection and area under glucose curve (AUC was calculated. Fourteen-day IH increased fasting glucose levels (122 ± 7 vs. 157 ± 8 mg/dL, PG: 118 ± 6 vs. 139 ± 8; both p < 0.05 and impaired glucose tolerance (AUCglucose: 19,249 ± 1105 vs. 29,124 ± 1444, PG AUCglucose: 18,066 ± 947 vs. 25,135 ± 797; both p < 0.05 in vehicle-treated animals. IH-induced impairments in glucose tolerance were partially ameliorated with BQ-788 treatment (AUCglucose: 21,969 ± 662; p < 0.05. Fourteen-day IH also induced IR (AUCglucose: 7185 ± 401 vs. 8699 ± 401; p < 0.05. Treatment with BQ-788 decreased IR under IA (AUCglucose: 5281 ± 401, p < 0.05 and reduced worsening of IR with IH (AUCglucose: 7302 ± 401, p < 0.05. There was no effect of BQ-123 on IH-induced impairments in glucose tolerance or IR. Our results suggest that ET-1 plays a role in IH-induced impairments in glucose homeostasis.

  3. Physical activity opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes plasma endothelin-1 levels in individuals with essential hypertension.

    Science.gov (United States)

    Nyberg, M; Mortensen, S P; Hellsten, Y

    2013-03-01

    Endothelin-1 has potent constrictor and proliferative activity in vascular smooth muscle, and essential hypertension and aging are associated with increased endothelin-1-mediated vasoconstrictor tone. The aim of this study was to investigate the effect of physical activity, hypertension and age on endothelin-1 levels in plasma and skeletal muscle and endothelin receptors in skeletal muscle in human subjects. In study 1, normotensive (46 ± 1 years, n = 11) and hypertensive (47 ± 1 years, n = 10) subjects were studied before and after 8 weeks of aerobic exercise training. In study 2, young (23 ± 1 years, n = 8), older lifelong sedentary (66 ± 2 years, n = 8) and older lifelong endurance-trained (62 ± 2 years, n = 8) subjects were studied in a cross-sectional design. Skeletal muscle and plasma endothelin-1 levels were increased with age and plasma endothelin-1 levels were higher in hypertensive than normotensive individuals. Eight weeks of exercise training normalized plasma endothelin-1 levels in the hypertensive subjects and increased the protein expression of the ET(A) receptor in skeletal muscle of normotensive subjects. Similarly, individuals that had performed lifelong physical activity had similar plasma and muscle endothelin-1 levels as the young controls and had higher ET(A) receptor levels. Our findings suggest that aerobic exercise training opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes plasma endothelin-1 levels in individuals with essential hypertension. This effect may explain some of the beneficial effects of training on the cardiovascular system in older and hypertensive subjects. © 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.

  4. The observation on plasma endothelin levels in patients with graves' disease

    International Nuclear Information System (INIS)

    Hao Xiaojun; Liu Changshan; Yang Lianrong; Zhang Qiliang; Wang Honggang; Liu Xudong

    2002-01-01

    Observing the plasma endothelin levels in patients with Graves' disease to probe its clinical significance, plasma endothelin levels were measured in 55 cases of Graves' disease before and after treatment respectively, and these were compared with that of 23 health subjects. Results: plasma endothelin levels in patients with Graves' disease significantly increase, compared with heath subjects (150.4 +- 29.31 ng/L vs 42.80 +- 7.58 ng/L, P < 0.01); post-treatment endothelin levels apparently decrease (97.61 +- 15.99 ng/L vs 150.4 +- 29.31 ng/L, P < 0.01). Plasma endothelin levels in patients with Graves' disease significantly increase, and after treatment the endothelin levels decrease following decreasing of thyroid hormone level and high hemodynamics

  5. The insulinotropic effect of endothelin-1 is mediated by glucagon release from the islet alpha cells

    DEFF Research Database (Denmark)

    Brock, B; Gregersen, S; Kristensen, K

    1999-01-01

    AIMS/HYPOTHESIS: The circulating concentrations of endothelin-1 (ET-1), a peptide derived from endothelium, are increased in hypertension and diabetes. Endothelin-1 has recently been shown to be an insulinotropic agent. The mechanism of action of endothelin-1 on the endocrine pancreas has not yet...... been clarified. METHODS: We investigated the action of endothelin-1 on the insulin secretion, the binding of (125)I-ET-1 to beta cells as well as its effects on purified beta and non-beta cells from normal rats. The expression of endothelin receptors in alpha- and beta-cell lines and in normal rat...... from purified beta cells. Endothelin-1-(100 nmol/l) increased, however, both insulin and glucagon secretion from a mixture of purified beta and non-beta cells indicating that alpha cells seem to have a key role for the action of ET-1 on insulin secretion. CONCLUSION/INTERPRETATION: The insulinotropic...

  6. Alteration in contractile G-protein coupled receptor expression by moist snuff and nicotine in rat cerebral arteries

    DEFF Research Database (Denmark)

    Sandhu, Hardip; Xu, Cang-Bao; Edvinsson, Lars

    2011-01-01

    The cardiovascular risk for users of use of Swedish snus/American snuff (moist tobacco) has been debated for a long time. The present study was designed to examine the effects of water- or lipid-soluble (DMSO-soluble) snus and nicotine, the most important substance in tobacco, on the expression...... kinases (MAPK). However, the effects of moist tobacco on the expression of GPCR are less studied. Rat middle cerebral arteries were isolated and organ cultured in serum-free medium for 24h in the presence of water-soluble snus (WSS), DMSO-soluble snus (DSS), or nicotine. The dose of snus and nicotine...... was kept at plasma level of snus users (25ng nicotine/ml). A high dose (250ng nicotine/ml) was also included due to the previous results showing alteration in the GPCR expression by nicotine at this concentration. Contractile responses to the ET(B) receptor agonist sarafotoxin 6c, 5-HT(1B) receptor agonist...

  7. NITRIC OXIDE AND ENDOTHELIN-1 IN CHILDREN WITH DIGESTIVE DISORDERS

    Directory of Open Access Journals (Sweden)

    I. V. Panova

    2012-01-01

    Full Text Available The important part in the group of biological compounds, participating in the regulation of the functions of the gastro-intestinal tract, is assigned to endothelial factors because of their impact on the majority of physiological and pathophysiological processes of the digestive system. The article provides information about physiological role of nitric oxide and endothelin-1 and presents a review of scientific data on the participation of nitric oxide and endothelin-1 in the pathogenesis of many digestive system diseases, emphasizing chronic inflammatory disorders of the upper gastrointestinal tract. The authors accentuate the importance of endothelium endocrine function research in children with esophagogastroduodenal disorders at the beginning of puberty, which is the critical period of ontogenesis.

  8. Actomyosin contractility rotates the cell nucleus.

    Science.gov (United States)

    Kumar, Abhishek; Maitra, Ananyo; Sumit, Madhuresh; Ramaswamy, Sriram; Shivashankar, G V

    2014-01-21

    The cell nucleus functions amidst active cytoskeletal filaments, but its response to their contractile stresses is largely unexplored. We study the dynamics of the nuclei of single fibroblasts, with cell migration suppressed by plating onto micro-fabricated patterns. We find the nucleus undergoes noisy but coherent rotational motion. We account for this observation through a hydrodynamic approach, treating the nucleus as a highly viscous inclusion residing in a less viscous fluid of orientable filaments endowed with active stresses. Lowering actin contractility selectively by introducing blebbistatin at low concentrations drastically reduced the speed and coherence of the angular motion of the nucleus. Time-lapse imaging of actin revealed a correlated hydrodynamic flow around the nucleus, with profile and magnitude consistent with the results of our theoretical approach. Coherent intracellular flows and consequent nuclear rotation thus appear to be an intrinsic property of cells.

  9. Spontaneous actin dynamics in contractile rings

    Science.gov (United States)

    Kruse, Karsten; Wollrab, Viktoria; Thiagarajan, Raghavan; Wald, Anne; Riveline, Daniel

    Networks of polymerizing actin filaments are known to be capable to self-organize into a variety of structures. For example, spontaneous actin polymerization waves have been observed in living cells in a number of circumstances, notably, in crawling neutrophils and slime molds. During later stages of cell division, they can also spontaneously form a contractile ring that will eventually cleave the cell into two daughter cells. We present a framework for describing networks of polymerizing actin filaments, where assembly is regulated by various proteins. It can also include the effects of molecular motors. We show that the molecular processes driven by these proteins can generate various structures that have been observed in contractile rings of fission yeast and mammalian cells. We discuss a possible functional role of each of these patterns. The work was supported by Agence Nationale de la Recherche, France, (ANR-10-LABX-0030-INRT) and by Deutsche Forschungsgemeinschaft through SFB1027.

  10. Modulation by endothelin-1 of spontaneous activity and membrane currents of atrioventricular node myocytes from the rabbit heart.

    Directory of Open Access Journals (Sweden)

    Stéphanie C Choisy

    Full Text Available The atrioventricular node (AVN is a key component of the cardiac pacemaker-conduction system. Although it is known that receptors for the peptide hormone endothelin-1 (ET-1 are expressed in the AVN, there is very little information available on the modulatory effects of ET-1 on AVN electrophysiology. This study characterises for the first time acute modulatory effects of ET-1 on AVN cellular electrophysiology.Electrophysiological experiments were conducted in which recordings were made from rabbit isolated AVN cells at 35-37°C using the whole-cell patch clamp recording technique.Application of ET-1 (10 nM to spontaneously active AVN cells led rapidly (within ~13 s to membrane potential hyperpolarisation and cessation of spontaneous action potentials (APs. This effect was prevented by pre-application of the ET(A receptor inhibitor BQ-123 (1 µM and was not mimicked by the ET(B receptor agonist IRL-1620 (300 nM. In whole-cell voltage-clamp experiments, ET-1 partially inhibited L-type calcium current (I(Ca,L and rapid delayed rectifier K(+ current (I(Kr, whilst it transiently activated the hyperpolarisation-activated current (I(f at voltages negative to the pacemaking range, and activated an inwardly rectifying current that was inhibited by both tertiapin-Q (300 nM and Ba(2+ ions (2 mM; each of these effects was sensitive to ET(A receptor inhibition. In cells exposed to tertiapin-Q, ET-1 application did not produce membrane potential hyperpolarisation or immediate cessation of spontaneous activity; instead, there was a progressive decline in AP amplitude and depolarisation of maximum diastolic potential.Acutely applied ET-1 exerts a direct modulatory effect on AVN cell electrophysiology. The dominant effect of ET-1 in this study was activation of a tertiapin-Q sensitive inwardly rectifying K(+ current via ET(A receptors, which led rapidly to cell quiescence.

  11. L-arginine does not prevent the renal effects of endothelin in humans

    NARCIS (Netherlands)

    Bijlsma, J. A.; Rabelink, A. J.; Kaasjager, K. A.; Koomans, H. A.

    1995-01-01

    The infusion of endothelin to obtain plasma levels as present in sodium-retaining conditions such as heart failure and hepatorenal syndrome has been shown to cause sodium retention and renal vasoconstriction. Whether these renal effects of endothelin could be modulated by the stimulation of nitric

  12. Endothelin-1 is associated with fibrosis in proliferative diabetic retinopathy membranes.

    Science.gov (United States)

    Chang, William; Lajko, Michelle; Fawzi, Amani A

    2018-01-01

    To characterize the relationship between endothelin-1 and fibrosis in epiretinal membranes in proliferative diabetic retinopathy and explore the role of endothelial-mesenchymal transition in these membranes. Membranes were obtained from eyes undergoing pars plana vitrectomy for complicated proliferative diabetic retinopathy or idiopathic epiretinal membrane. Through standard immunohistochemical techniques, we labeled membranes to explore the distribution of endothelin-1 and endothelin receptor B, comparing proliferative diabetic retinopathy and idiopathic epiretinal membranes. In addition, membranes were also labeled with markers for fibroblasts, endothelial, and glial cells and studied with confocal laser scanning microscopy. The intensity of endothelin-1 labeling was quantified using standard image analysis software. Fourteen membranes were included in the analysis, nine from eyes with proliferative diabetic retinopathy and five idiopathic membranes. Flatmount diabetic membranes showed co-localization of endothelin-1 with S100A4 and CD31. Immunohistochemistry and quantitative analysis of cross-sectional membranes showed significantly higher endothelin-1 labeling in proliferative diabetic retinopathy membranes compared to idiopathic membranes (pmembranes showed more elements staining positive for S100A4 compared to idiopathic membranes. Epiretinal membrane formation in proliferative diabetic retinopathy involves higher tissue levels of endothelin-1 and fibroblastic activity. Furthermore, endothelin-1, endothelial and fibroblastic staining appear to be correlated, suggestive of endothelial-to-mesenchymal transition in proliferative diabetic retinopathy.

  13. In depth pharmacological characterization of endothelin B receptors in the rat middle cerebral artery

    DEFF Research Database (Denmark)

    Szok, D; Hansen-Schwartz, J; Edvinsson, L

    2001-01-01

    Whereas the endothelin A receptor is generally believed to mediate vasoconstriction; the endothelin B receptor seems elusive; both dilative and constrictive responses have been reported. Using the in vitro arteriograph, a method allowing compartmentalized study of vessel segments, segments of rat...

  14. Cell stiffness, contractile stress and the role of extracellular matrix

    International Nuclear Information System (INIS)

    An, Steven S.; Kim, Jina; Ahn, Kwangmi; Trepat, Xavier; Drake, Kenneth J.; Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne; Fredberg, Jeffrey J.; Biswal, Shyam

    2009-01-01

    Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses.

  15. Cell stiffness, contractile stress and the role of extracellular matrix

    Energy Technology Data Exchange (ETDEWEB)

    An, Steven S., E-mail: san@jhsph.edu [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Kim, Jina [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Ahn, Kwangmi [Division of Biostatistics, Penn State College of Medicine, Hershey, PA 17033 (United States); Trepat, Xavier [CIBER, Enfermedades Respiratorias, 07110 Bunyola (Spain); Drake, Kenneth J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Fredberg, Jeffrey J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Biswal, Shyam [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205 (United States)

    2009-05-15

    Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses.

  16. Cadmium translocation by contractile roots differs from that in regular, non-contractile roots.

    Science.gov (United States)

    Lux, Alexander; Lackovič, Andrej; Van Staden, Johannes; Lišková, Desana; Kohanová, Jana; Martinka, Michal

    2015-06-01

    Contractile roots are known and studied mainly in connection with the process of shrinkage of their basal parts, which acts to pull the shoot of the plant deeper into the ground. Previous studies have shown that the specific structure of these roots results in more intensive water uptake at the base, which is in contrast to regular root types. The purpose of this study was to find out whether the basal parts of contractile roots are also more active in translocation of cadmium to the shoot. Plants of the South African ornamental species Tritonia gladiolaris were cultivated in vitro for 2 months, at which point they possessed well-developed contractile roots. They were then transferred to Petri dishes with horizontally separated compartments of agar containing 50 µmol Cd(NO3)2 in the region of the root base or the root apex. Seedlings of 4-d-old maize (Zea mays) plants, which do not possess contractile roots, were also transferred to similar Petri dishes. The concentrations of Cd in the leaves of the plants were compared after 10 d of cultivation. Anatomical analyses of Tritonia roots were performed using appropriately stained freehand cross-sections. The process of contraction required specific anatomical adaptation of the root base in Tritonia, with less lignified and less suberized tissues in comparison with the subapical part of the root. These unusual developmental characteristics were accompanied by more intensive translocation of Cd ions from the basal part of contractile roots to the leaves than from the apical-subapical root parts. The opposite effects were seen in the non-contractile roots of maize, with higher uptake and transport by the apical parts of the root and lower uptake and transport by the basal part. The specific characteristics of contractile roots may have a significant impact on the uptake of ions, including toxic metals from the soil surface layers. This may be important for plant nutrition, for example in the uptake of nutrients from

  17. A sensitive radioimmunoassay measuring endothelin-like immunoreactivity in human plasma: comparison of levels in patients with essential hypertension and normotensive control subjects

    International Nuclear Information System (INIS)

    Davenport, A.P.; Ashby, M.J.; Easton, Patricia

    1990-01-01

    A radioimmunoassay was developed to measure endothelin-like immunoreactivity in human plasma using antibody raised against endothelin-1 which also cross-reacts with big endothelin-1 and endothelin-2 but not endothelin-3. The sensitivity was 1 fmol/tube with inter- and intra-assay coefficients of variation of 13% and 9%, respectively. Cross-reactivity with endothelin-3 and non-endothelin peptides was less than 1%. Endothelin-like immunoreactivity was present in plasma of hypertensive patients (n = 25) at 5.7±0.5 pmol/1 (mean±SEM), not significantly different from that of age-matched control subjects (5.1±0.5 pmol/1). At these levels, endothelin-1 is unlikely to function as a circulating hormone. In the normotensive group, the concentration of endothelin-like immunoreactivity in plasma was positively correlated with mean arterial blood pressure, but in hypertensive patients it showed significant negative correlation. (author)

  18. Contractility Dispersion in Long QT Syndrome

    Directory of Open Access Journals (Sweden)

    MH Nikoo

    2009-09-01

    Full Text Available Background: Previous studies, using M mode echocardiography, provided unexpected evidence of a mechanical alteration in patients with long QT syndrome. The aim of this study was to evaluate entire left ventricular (LV wall motion characteristics in patients with long QT syndrome using tissue Doppler imaging. Methods: We enrolled 17 patients with congenital long QT syndrome [11 female and 6 male], aged 21 to 45 years. 10 subjects without cardiac disease were also selected as a control group. Two-dimensional tissue Doppler imaging (TDI recording of the LV was obtained from the basal and mid-segments from apical four-chamber, two-chamber, and long-axis views. ‘Myocardial Contraction Duration’ [MCD] was defined as the time from start of R wave on ECG to end of S wave on TDI. MCD was measured in the six LV wall positions: septal, anteroseptal, lateral, inferior, posterior and anterior positions.Results: LV contractility dispersion was significantly greater in long QT syndrome patients compared to control group [0.051 ± 0.011 vs. 0.016 ± 0.06; P < 0.001]. Conclusion: Our study evaluated left ventricular dispersion of contractility duration in patients with long QT syndrome. This mechanical dispersion may be a reflection of the inhomogeneity of repolarisation in the long QT syndrome.

  19. High endothelin-converting enzyme-1 expression independently predicts poor survival of patients with esophageal squamous cell carcinoma.

    Science.gov (United States)

    Wu, Ching-Fang; Lee, Ching-Tai; Kuo, Yao-Hung; Chen, Tzu-Haw; Chang, Chi-Yang; Chang, I-Wei; Wang, Wen-Lun

    2017-09-01

    Patients with esophageal squamous cell carcinoma have poor survival and high recurrence rate, thus an effective prognostic biomarker is needed. Endothelin-converting enzyme-1 is responsible for biosynthesis of endothelin-1, which promotes growth and invasion of human cancers. The role of endothelin-converting enzyme-1 in esophageal squamous cell carcinoma is still unknown. Therefore, this study investigated the significance of endothelin-converting enzyme-1 expression in esophageal squamous cell carcinoma clinically. We enrolled patients with esophageal squamous cell carcinoma who provided pretreated tumor tissues. Tumor endothelin-converting enzyme-1 expression was evaluated by immunohistochemistry and was defined as either low or high expression. Then we evaluated whether tumor endothelin-converting enzyme-1 expression had any association with clinicopathological findings or predicted survival of patients with esophageal squamous cell carcinoma. Overall, 54 of 99 patients with esophageal squamous cell carcinoma had high tumor endothelin-converting enzyme-1 expression, which was significantly associated with lymph node metastasis ( p = 0.04). In addition, tumor endothelin-converting enzyme-1 expression independently predicted survival of patients with esophageal squamous cell carcinoma, and the 5-year survival was poorer in patients with high tumor endothelin-converting enzyme-1 expression ( p = 0.016). Among patients with locally advanced and potentially resectable esophageal squamous cell carcinoma (stage II and III), 5-year survival was poorer with high tumor endothelin-converting enzyme-1 expression ( p = 0.003). High tumor endothelin-converting enzyme-1 expression also significantly predicted poorer survival of patients in this population. In patients with esophageal squamous cell carcinoma, high tumor endothelin-converting enzyme-1 expression might indicate high tumor invasive property. Therefore, tumor endothelin-converting enzyme-1 expression

  20. Contractile injection systems of bacteriophages and related systems

    DEFF Research Database (Denmark)

    Taylor, Nicholas M I; van Raaij, Mark J; Leiman, Petr G

    2018-01-01

    Contractile tail bacteriophages, or myobacteriophages, use a sophisticated biomolecular structure to inject their genome into the bacterial host cell. This structure consists of a contractile sheath enveloping a rigid tube that is sharpened by a spike-shaped protein complex at its tip. The spike ...

  1. Relationship between insulin resistance and plasma endothelin in hypertension patients

    International Nuclear Information System (INIS)

    Duan Yongqiang; Wang Zuobing; Yu Hui; Cao Wei; Wang Jing; Li Xiaoqin

    2011-01-01

    To explore the relationship between plasma endothelin and hypertension insulin resistance, and the improvement of insulin resistance in hypertension patients treated with captopril and l-amlodipine, 25 patients with primary hypertension and impaired glucose tolerance were selected and treated by captopril and l-amlodipine. Systolic pressure, diastolic pressure, fasting blood glucose, insulin and insulin antibody were measured before and after treatment and compared with healthy controls. The results showed that the plasma ET-1 level in hypertension group was significantly higher than that of healthy controls (P<0.01), and he plasma ET-1 level was positively correlated with FPG, FINS, Anti-INS, HOMA-IR. The systolic pressure, diastolic pressure, fasting blood glucose, insulin, insulin antibody and insulin resistance index in hypertension patients were decreased significantly after treatment (P<0.05). There is a good correlation between endothelin and insulin resistance index in hypertension patients. Captopril and l-amlodipine had obvious improvement effect on insulin resistance in hypertension patients. (authors)

  2. Targeted activation of endothelin-1 exacerbates hypoxia-induced pulmonary hypertension

    International Nuclear Information System (INIS)

    Satwiko, Muhammad Gahan; Ikeda, Koji; Nakayama, Kazuhiko; Yagi, Keiko; Hocher, Berthold; Hirata, Ken-ichi; Emoto, Noriaki

    2015-01-01

    Pulmonary arterial hypertension (PAH) is a fatal disease that eventually results in right heart failure and death. Current pharmacologic therapies for PAH are limited, and there are no drugs that could completely cure PAH. Enhanced activity of endothelin system has been implicated in PAH severity and endothelin receptor antagonists have been used clinically to treat PAH. However, there is limited experimental evidence on the direct role of enhanced endothelin system activity in PAH. Here, we investigated the correlation between endothelin-1 (ET-1) and PAH using ET-1 transgenic (ETTG) mice. Exposure to chronic hypoxia increased right ventricular pressure and pulmonary arterial wall thickness in ETTG mice compared to those in wild type mice. Of note, ETTG mice exhibited modest but significant increase in right ventricular pressure and vessel wall thickness relative to wild type mice even under normoxic conditions. To induce severe PAH, we administered SU5416, a vascular endothelial growth factor receptor inhibitor, combined with exposure to chronic hypoxia. Treatment with SU5416 modestly aggravated hypoxia-induced pulmonary hypertension, right ventricular hypertrophy, and pulmonary arterial vessel wall thickening in ETTG mice in association with increased interleukin-6 expression in blood vessels. However, there was no sign of obliterative endothelial cell proliferation and plexiform lesion formation in the lungs. These results demonstrated that enhanced endothelin system activity could be a causative factor in the development of PAH and provided rationale for the inhibition of endothelin system to treat PAH. - Highlights: • Role of endothelin-1 in pulmonary arterial hypertension (PAH) was investigated. • The endothelin-1 transgenic (ETTG) and wild type (WT) mice were analyzed. • ETTG mice spontaneously developed PAH under normoxia conditions. • SU5416 further aggravated PAH in ETTG mice. • Enhanced endothelin system activity could be a causative factor in

  3. Targeted activation of endothelin-1 exacerbates hypoxia-induced pulmonary hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Satwiko, Muhammad Gahan [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Ikeda, Koji [Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe (Japan); Nakayama, Kazuhiko [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Yagi, Keiko [Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe (Japan); Hocher, Berthold [Institute for Nutritional Science, University of Potsdam, Potsdam (Germany); Hirata, Ken-ichi [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Emoto, Noriaki, E-mail: emoto@med.kobe-u.ac.jp [Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe (Japan); Department of Clinical Pharmacy, Kobe Pharmaceutical University, Kobe (Japan)

    2015-09-25

    Pulmonary arterial hypertension (PAH) is a fatal disease that eventually results in right heart failure and death. Current pharmacologic therapies for PAH are limited, and there are no drugs that could completely cure PAH. Enhanced activity of endothelin system has been implicated in PAH severity and endothelin receptor antagonists have been used clinically to treat PAH. However, there is limited experimental evidence on the direct role of enhanced endothelin system activity in PAH. Here, we investigated the correlation between endothelin-1 (ET-1) and PAH using ET-1 transgenic (ETTG) mice. Exposure to chronic hypoxia increased right ventricular pressure and pulmonary arterial wall thickness in ETTG mice compared to those in wild type mice. Of note, ETTG mice exhibited modest but significant increase in right ventricular pressure and vessel wall thickness relative to wild type mice even under normoxic conditions. To induce severe PAH, we administered SU5416, a vascular endothelial growth factor receptor inhibitor, combined with exposure to chronic hypoxia. Treatment with SU5416 modestly aggravated hypoxia-induced pulmonary hypertension, right ventricular hypertrophy, and pulmonary arterial vessel wall thickening in ETTG mice in association with increased interleukin-6 expression in blood vessels. However, there was no sign of obliterative endothelial cell proliferation and plexiform lesion formation in the lungs. These results demonstrated that enhanced endothelin system activity could be a causative factor in the development of PAH and provided rationale for the inhibition of endothelin system to treat PAH. - Highlights: • Role of endothelin-1 in pulmonary arterial hypertension (PAH) was investigated. • The endothelin-1 transgenic (ETTG) and wild type (WT) mice were analyzed. • ETTG mice spontaneously developed PAH under normoxia conditions. • SU5416 further aggravated PAH in ETTG mice. • Enhanced endothelin system activity could be a causative factor in

  4. Genome sequence of Haloplasma contractile, an unusual contractile bacterium from a deep-sea anoxic brine lake.

    KAUST Repository

    Antunes, Andre; Alam, Intikhab; El Dorry, Hamza; Siam, Rania; Robertson, Anthony J.; Bajic, Vladimir B.; Stingl, Ulrich

    2011-01-01

    We present the draft genome of Haloplasma contractile, isolated from a deep-sea brine and representing a new order between Firmicutes and Mollicutes. Its complex morphology with contractile protrusions might be strongly influenced by the presence of seven MreB/Mbl homologs, which appears to be the highest copy number ever reported.

  5. Genome sequence of Haloplasma contractile, an unusual contractile bacterium from a deep-sea anoxic brine lake.

    KAUST Repository

    Antunes, Andre

    2011-09-01

    We present the draft genome of Haloplasma contractile, isolated from a deep-sea brine and representing a new order between Firmicutes and Mollicutes. Its complex morphology with contractile protrusions might be strongly influenced by the presence of seven MreB/Mbl homologs, which appears to be the highest copy number ever reported.

  6. The mechanism of action of endothelin-1 as compared with other agonists in vascular smooth muscle

    International Nuclear Information System (INIS)

    Wallnoefer, A.W.; Weir, S.; Rueegg, U.C.; Cauvin, C.

    1989-01-01

    The effects of endothelin-1 (ET-1) on tension and membrane potential in rat isolated mesenteric resistance vessels (MRVs) and on 45Ca influx, 45Ca efflux, inositol-1,4,5-triphosphate (IP3) production, and cytoplasmic Ca2+ concentration ([Ca2+]1) in cultured aortic smooth muscle cells were compared with those of other agonists. ET-1 induced contractions of the MRVs, which were slow in onset, but reached a similar maximum amplitude (at 10 nM ET-1) as that seen with norepinephrine (NE, 10 microM) or [arg8]vasopressin (AVP, 0.1 microM). The EC50 for ET-1 was 1.3 +/- 0.1 nM. Removal of extracellular Ca2+ reduced ET-1-induced contractions to 11 +/- 3% of those in Ca2+-containing medium. With NE, the same procedure reduced contractions to 47 +/- 7% of those in Ca2+-containing medium, while with AVP, the reduction was similar in magnitude to that induced by ET-1 (11 +/- 5% of those in Ca2+-containing medium). Relaxation of ET-1-induced and NE-induced contractions by diltiazem was not complete (maximal at 58 +/- 6% with 10 microM diltiazem after 6 nM ET-1, and at 70 +/- 3% after 0.1 microM NE), in contrast to that of 80 mM K+-induced contractions, which were potently (IC50 = 0.2 microM) and completely reversed (100% relaxation at 10 microM diltiazem). ET-1 (6 nM) caused a small but significant depolarization of the MRVs (approximately 7 mV), the magnitude of which was only about one-third of that induced by equieffective contractile concentrations of NE and AVP. The voltage-sensitive Ca2+ channel agonist Bay K 8644 (1 microM), in contrast to ET-1, NE, and AVP, produced a small contraction (30 +/- 2% of the maximum response to NE), but no further depolarization when added in the presence of 15 mM K+ (which elicited approximately 12 mV depolarization but no contraction)

  7. Considerations for Contractile Electroactive Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Lenore Rasmussen, David Schramm, Paul Rasmussen, Kevin Mullaly, Ras Labs, LLC, Intelligent Materials for Prosthetics & Automation, Lewis D. Meixler, Daniel Pearlman and Alice Kirk

    2011-05-23

    Ras Labs produces contractile electroactive polymer (EAP) based materials and actuators that bend, swell, ripple, and contract (new development) with low electric input. In addition, Ras Labs produces EAP materials that quickly contract and expand, repeatedly, by reversing the polarity of the electric input, which can be cycled. This phenomenon was explored using molecular modeling, followed by experimentation. Applied voltage step functions were also investigated. High voltage steps followed by low voltage steps produced a larger contraction followed by a smaller contraction. Actuator control by simply adjusting the electric input is extremely useful for biomimetic applications. Muscles are able to partially contract. If muscles could only completely contract, nobody could hold an egg, for example, without breaking it. A combination of high and low voltage step functions could produce gross motor function and fine manipulation within the same actuator unit. Plasma treated electrodes with various geometries were investigated as a means of providing for more durable actuation.

  8. User experience analysis of e-TB Manager, a nationwide electronic tuberculosis recording and reporting system in Ukraine

    Directory of Open Access Journals (Sweden)

    Niranjan Konduri

    2017-05-01

    Full Text Available Ukraine has successfully implemented e-TB Manager nationwide as its mandatory national tuberculosis registry after first introducing it in 2009. Our objective was to perform an end-of-programme evaluation after formal handover of the registry administration to Ukraine's Centre for Disease Control in 2015. We conducted a nationwide, cross-sectional, anonymous, 18-point user experience survey, and stratified the registry's transaction statistics to demonstrate usability. Contrary to initial implementation experience, older users (aged >50 years, often with limited or no computer proficiency prior to using the registry, had significantly better user experience scores for at least six of the 12 measures compared to younger users (aged 18–29 years. Using the registry for >3 years was associated with significantly higher scores for having capacity, adequacy of training received and satisfaction with the registry. Of the 5.9 million transactions over a 4-year period, nine out of 24 oblasts (regions and Kiev city accounted for 62.5% of all transactions, and corresponded to 59% of Ukraine's tuberculosis burden. There were 437 unique active users in 486 rayons (districts of Ukraine, demonstrating extensive reach. Our key findings complement the World Health Organization and European Respiratory Society's agenda for action on digital health to help implement the End TB Strategy.

  9. Role of endothelin receptor activation in secondary pulmonary hypertension in awake swine after myocardial infarction

    NARCIS (Netherlands)

    B. Houweling (Birgit); D. Merkus (Daphne); O. Sorop (Oana); F. Boomsma (Frans); D.J.G.M. Duncker (Dirk)

    2006-01-01

    textabstractWe previously observed that pulmonary hypertension secondary to myocardial infarction (MI) in swine is characterized by elevated plasma endothelin (ET) levels and pulmonary vascular resistance (PVR). Consequently, we tested the hypothesis that an increased ET-mediated vasoconstrictor

  10. Insulin decreases atherosclerosis by inducing endothelin receptor B expression

    DEFF Research Database (Denmark)

    Park, Kyoungmin; Mima, Akira; Li, Qian

    2016-01-01

    Endothelial cell (EC) insulin resistance and dysfunction, caused by diabetes, accelerates atherosclerosis. It is unknown whether specifically enhancing EC-targeted insulin action can decrease atherosclerosis in diabetes. Accordingly, overexpressing insulin receptor substrate-1 (IRS1...... induction of NO action, which increases endothelin receptor B (EDNRB) expression and intracellular [Ca(2+)]. Using the mice with knockin mutation of eNOS, which had Ser1176 mutated to alanine (AKI), deleting the only known mechanism for insulin to activate eNOS/NO pathway, we observed that IRS1...... overexpression in the endothelia of Aki/ApoE(-/-) mice significantly decreased atherosclerosis. Interestingly, endothelial EDNRB expression was selectively reduced in intima of arteries from diabetic patients and rodents. However, endothelial EDNRB expression was upregulated by insulin via P13K/Akt pathway...

  11. Specific receptor for endothelin in cultured rat cardiocytes

    International Nuclear Information System (INIS)

    Hirata, Y.; Fukuda, Y.; Yoshimi, H.; Emori, T.; Shichiri, M.; Marumo, F.

    1989-01-01

    Specific binding sites for the endothelium-derived vasoconstrictor endothelin (ET) and its effect on cytosolic free Ca2+ concentrations [( Ca2+]i) were studied in a primary culture of cardiocytes from neonatal rats. Binding studies using 125 I-labeled-porcine ET as a radioligand revealed the presence of a single class of high-affinity binding sites for ET in cardiocytes with an apparent Kd of 6-9 x 10(-10) M and a Bmax of 50,000-80,000 sites/cell. Neither various vasoconstrictors nor Ca2+-channel blockers affected the binding. Pretreatment with ET substantially reduced the total number of ET receptors without changing their affinity. ET dose-dependently increased [Ca2+]i in fura-2-loaded cardiocytes. These data indicate that cardiocytes have specific ET receptors that are controlled by a down-regulation mechanism, and that ET induces a receptor-mediated increase in [Ca2+]i in cardiocytes

  12. Neurobiology of opioid withdrawal: Role of the endothelin system.

    Science.gov (United States)

    Bhalla, Shaifali; Andurkar, Shridhar V; Gulati, Anil

    2016-08-15

    Morphine and oxycodone are potent opioid analgesics most commonly used for the management of moderate to severe acute and chronic pain. Their clinical utility is limited by undesired side effects like analgesic tolerance, dependence, and withdrawal. We have previously demonstrated that endothelin-A (ETA) receptor antagonists potentiate opioid analgesia and eliminate analgesic tolerance. Mechanistically, G proteins and regulatory proteins such as β-arrestins have shown to play an important role in mediating opioid tolerance, dependence, and withdrawal. Recently, the involvement of central ET mechanisms in opioid withdrawal was investigated. ETA receptor antagonist was shown to block majority of the signs and symptoms associated with opioid withdrawal. This review focuses on ET as one of the potential novel strategies to manage the challenge of opioid withdrawal. An overview of additional players in this process (G proteins and β-arrestin2), and the possible therapeutic implications of these findings are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Genetic fuzzy system predicting contractile reactivity patterns of small arteries

    DEFF Research Database (Denmark)

    Tang, J; Sheykhzade, Majid; Clausen, B F

    2014-01-01

    strategies. Results show that optimized fuzzy systems (OFSs) predict contractile reactivity of arteries accurately. In addition, OFSs identified significant differences that were undetectable using conventional analysis in the responses of arteries between groups. We concluded that OFSs may be used...

  14. Regional gastrointestinal contractility parameters using the wireless motility capsule

    DEFF Research Database (Denmark)

    Farmer, A D; Wegeberg, A-M L; Brock, B

    2018-01-01

    BACKGROUND: The wireless motility capsule concurrently measures temperature, pH and pressure as it traverses the gastrointestinal tract. AIMS: To describe normative values for motility/contractility parameters across age, gender and testing centres. METHODS: Healthy participants underwent...

  15. Considerations for Contractile Electroactive Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Lenore; Erickson, Carl J.; Meixler, Lewis D.; Ascione, George; Gentile, Charles A.; Tilson, Carl; Bernasek, Stephen L.; Abelev, Esta

    2010-02-19

    Ras Labs produces electroactive polymer (EAP) based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life-like motion. The mechanism of contraction is not well understood. Radionuclide-labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode-EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing, and mechanical testing were conducted to test metal surfaces and metal-polymer interfaces. The nitrogen plasma treatment of titanium produced a strong metal-polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal-polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface.

  16. Operative contractility: a functional concept of the inotropic state.

    Science.gov (United States)

    Curiel, Roberto; Perez-Gonzalez, Juan; Torres, Edwar; Landaeta, Ruben; Cerrolaza, Miguel

    2005-10-01

    1. Initial unsuccessful attempts to evaluate ventricular function in terms of the 'heart as a pump' led to focusing on the 'heart as a muscle' and to the concept of myocardial contractility. However, no clinically ideal index exists to assess the contractile state. The aim of the present study was to develop a mathematical model to assess cardiac contractility. 2. A tri-axial system was conceived for preload (PL), afterload (AL) and contractility, where stroke volume (SV) was represented as the volume of the tetrahedron. Based on this model, 'operative' contractility ('OperCon') was calculated from the readily measured values of PL, AL and SV. The model was tested retrospectively under a variety of different experimental and clinical conditions, in 71 studies in humans and 29 studies in dogs. A prospective echocardiographic study was performed in 143 consecutive subjects to evaluate the ability of the model to assess contractility when SV and PL were measured volumetrically (mL) or dimensionally (cm). 3. With inotropic interventions, OperCon changes were comparable to those of ejection fraction (EF), velocity of shortening (Vcf) and dP/dt-max. Only with positive inotropic interventions did elastance (Ees) show significantly larger changes. With load manipulations, OperCon showed significantly smaller changes than EF and Ees and comparable changes to Vcf and dP/dt-max. Values of OperCon were similar when AL was represented by systolic blood pressure or wall stress and when volumetric or dimensional values were used. 4. Operative contractility is a reliable, simple and versatile method to assess cardiac contractility.

  17. Design of ET(B) receptor agonists: NMR spectroscopic and conformational studies of ET7-21[Leu7, Aib11, Cys(Acm)15].

    Science.gov (United States)

    Hewage, Chandralal M; Jiang, Lu; Parkinson, John A; Ramage, Robert; Sadler, Ian H

    2002-03-01

    In a previous report we have shown that the endothelin-B receptor-selective linear endothelin peptide, ET-1[Cys (Acm)1,15, Ala3, Leu7, Aib11], folds into an alpha-helical conformation in a methanol-d3/water co-solvent [Hewage et al. (1998) FEBS Lett., 425, 234-238]. To study the requirements for the structure-activity relationships, truncated analogues of this peptide were subjected to further studies. Here we report the solution conformation of ET7-21[Leu7, Aib11, Cys(Acm)15], in a methanol-d3/water co-solvent at pH 3.6, by NMR spectroscopic and molecular modelling studies. Further truncation of this short peptide results in it displaying poor agonist activity. The modelled structure shows that the peptide folds into an alpha-helical conformation between residues Lys9-His16, whereas the C-terminus prefers no fixed conformation. This truncated linear endothelin analogue is pivotal for designing endothelin-B receptor agonists.

  18. Elevated plasma endothelin-1 and pulmonary arterial pressure in children exposed to air pollution.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J; Reed, William

    2007-08-01

    Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O(3) that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. We conducted a study of 81 children, 7.9 +/- 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O(3) levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 mum in aerodynamic diameter (PM(2.5)) before endothelin-1 measurement (p = 0.03). Chronic exposure of children to PM(2.5) is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure.

  19. Elevated Plasma Endothelin-1 and Pulmonary Arterial Pressure in Children Exposed to Air Pollution

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Vincent, Renaud; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Henríquez-Roldán, Carlos; Barragán-Mejía, Gerardo; Garrido-García, Luis; Camacho-Reyes, Laura; Valencia-Salazar, Gildardo; Paredes, Rogelio; Romero, Lina; Osnaya, Hector; Villarreal-Calderón, Rafael; Torres-Jardón, Ricardo; Hazucha, Milan J.; Reed, William

    2007-01-01

    Background Controlled exposures of animals and humans to particulate matter (PM) or ozone air pollution cause an increase in plasma levels of endothelin-1, a potent vasoconstrictor that regulates pulmonary arterial pressure. Objectives The primary objective of this field study was to determine whether Mexico City children, who are chronically exposed to levels of PM and O3 that exceed the United States air quality standards, have elevated plasma endothelin-1 levels and pulmonary arterial pressures. Methods We conducted a study of 81 children, 7.9 ± 1.3 years of age, lifelong residents of either northeast (n = 19) or southwest (n = 40) Mexico City or Polotitlán (n = 22), a control city with PM and O3 levels below the U.S. air quality standards. Clinical histories, physical examinations, and complete blood counts were done. Plasma endothelin-1 concentrations were determined by immunoassay, and pulmonary arterial pressures were measured by Doppler echocardiography. Results Mexico City children had higher plasma endothelin-1 concentrations compared with controls (p < 0.001). Mean pulmonary arterial pressure was elevated in children from both northeast (p < 0.001) and southwest (p < 0.05) Mexico City compared with controls. Endothelin-1 levels in Mexico City children were positively correlated with daily outdoor hours (p = 0.012), and 7-day cumulative levels of PM air pollution < 2.5 μm in aerodynamic diameter (PM2.5) before endothelin-1 measurement (p = 0.03). Conclusions Chronic exposure of children to PM2.5 is associated with increased levels of circulating endothelin-1 and elevated mean pulmonary arterial pressure. PMID:17687455

  20. Enhanced expression of Gqα and PLC-β1 proteins contributes to vascular smooth muscle cell hypertrophy in SHR: role of endogenous angiotensin II and endothelin-1.

    Science.gov (United States)

    Atef, Mohammed Emehdi; Anand-Srivastava, Madhu B

    2014-07-01

    Vascular Gqα signaling has been shown to contribute to cardiac hypertrophy. In addition, angiotensin II (ANG II) was shown to induce vascular smooth muscle cell (VSMC) hypertrophy through Gqα signaling; however, the studies on the role of Gqα and PLC-β1 proteins in VSMC hypertrophy in animal model are lacking. The present study was therefore undertaken to examine the role of Gqα/PLC-β1 proteins and the signaling pathways in VSMC hypertrophy using spontaneously hypertensive rats (SHR). VSMC from 16-wk-old SHR and not from 12-wk-old SHR exhibited enhanced levels of Gqα/PLC-β1 proteins compared with age-matched Wistar-Kyoto (WKY) rats as determined by Western blotting. However, protein synthesis as determined by [(3)H]leucine incorporation was significantly enhanced in VSMC from both 12- and 16-wk-old SHR compared with VSMC from age-matched WKY rats. Furthermore, the knockdown of Gqα/PLC-β1 in VSMC from 16-wk-old SHR by antisense and small interfering RNA resulted in attenuation of protein synthesis. In addition, the enhanced expression of Gqα/PLC-β1 proteins, enhanced phosphorylation of ERK1/2, and enhanced protein synthesis in VSMC from SHR were attenuated by the ANG II AT1 and endothelin-1 (ET-1) ETA receptor antagonists losartan and BQ123, respectively, but not by the ETB receptor antagonist BQ788. In addition, PD98059 decreased the enhanced expression of Gqα/PLC-β1 and protein synthesis in VSMC from SHR. These results suggest that the enhanced levels of endogenous ANG II and ET-1 through the activation of AT1 and ETA receptors, respectively, and MAP kinase signaling, enhanced the expression of Gqα/PLC-β1 proteins in VSMC from 16-wk-old SHR and result in VSMC hypertrophy. Copyright © 2014 the American Physiological Society.

  1. Endothelin receptor antagonism in single ventricle physiology with fontan palliation: A systematic review and meta-analysis

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    Gwendolyn Derk

    2015-04-01

    Conclusions: Bosentan was found to be a safe and well tolerated endothelin receptor antagonist in Fontan patients over 3–6 months of therapy. Bosentan use was associated with improved functional capacity. Future studies with larger sample size and longer duration are warranted to examine the long-term safety and efficacy of endothelin blockade in Fontan physiology.

  2. Endothelin-1 and -3 plasma concentrations in patients with cirrhosis: role of splanchnic and renal passage and liver function

    DEFF Research Database (Denmark)

    Gerbes, A L; Møller, S; Gülberg, V

    1995-01-01

    of splanchnic and renal passage and of liver function on plasma concentrations of endothelin-1 (ET-1) and endothelin-3 (ET-3) in patients with cirrhosis compared with controls. Eighteen patients with cirrhosis and 8 normotensive controls of similar age were investigated. Arterial and venous plasma samples were...

  3. Endothelin-1 is a Risk Factor for Pathogenesis of Hypertension

    International Nuclear Information System (INIS)

    Abdelhalim, Mohamed Anwar K.

    2007-01-01

    The purpose of this present study was to investigate the effects of endothelin-1 (ET-1) on the systemic blood pressure, microvascular blood flow velocity and diameter of arterioles and venules of the rat mesentery in vivo. For this purpose, the mesentery was arranged for in situ intravital microscopic observation under transillumination, and cumulative injections of ET-1(30-2000 p mole/kg) were infused intravenously through a catheter inserted into the right jugular vein. Infusion of low doses of ET-1(30-125 pmole/kg) induced a slight increase in the systemic blood pressure, a dose-dependent increase in blood flow velocity of arterioles (20-30 micron m) and venules (30-50 micron m). Diameters of arterioles and venules exhibited no significant change as compared with the control data. On the contrary, the infusion of high doses of ET-1 (250-2000 pmole/kg) induced a long-lasting pressor effect, a dose-dependent decrease in the blood flow velocity of arterioles and venules. Microvascular diameter exhibited a vasoconstrictive effect more prominent in arterioles than in venules. These findings suggest that vasoconstriction produced by ET-1 in rat mesenteric microcirculation may be the causal factor for its potent pressor effect in rats. Moreover, ET-1 may be involved in the regulation of the blood flow velocity distribution of rat mesenteric microcirculation. Finally, ET-1 may be considered as one of the more important risk factors which contribute to the pathogenesis of hypertension. (author)

  4. Endothelin-1 and Exercise Intensity in Sedentary Adolescents with Obesity

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    Brooke E. Starkoff

    2015-01-01

    Full Text Available Inactivity combined with obesity during adolescence increases the risk of future cardiovascular disease. The study purpose was to compare the influence of differing intensities of exercise on endothelial function in sedentary adolescents with obesity. Participants were randomized to one of two groups in a 6-week exercise intervention: moderate intensity (MOD or high intensity interval exercise (HIIE. Endothelial function was assessed pre- and post-intervention via fasted serum levels of endothelin-1 (ET-1. Pre-measures of ET-1 concentrations were elevated at baseline. No significant differences in ET-1 were found between or within exercise groups. However, in the HIIE group, ET-1 was inversely associated with percentages of age predicted maximal heart rate achieved during the intervention (p=0.035, r=-0.567. The exercise interventions did not positively change ET-1 levels, yet participants who exercised at higher intensities in the HIIE group experienced greater decreases in ET-1. Keywords: childhood obesity, endothelial function, high intensity interval exercise

  5. Calcium-responsive contractility during fertilization in sea urchin eggs.

    Science.gov (United States)

    Stack, Christianna; Lucero, Amy J; Shuster, Charles B

    2006-04-01

    Fertilization triggers a reorganization of oocyte cytoskeleton, and in sea urchins, there is a dramatic increase in cortical F-actin. However, the role that myosin II plays during fertilization remains largely unexplored. Myosin II is localized to the cortical cytoskeleton both before and after fertilization and to examine myosin II contractility in living cells, Lytechinus pictus eggs were observed by time-lapse microscopy. Upon sperm binding, a cell surface deflection traversed the egg that was followed by and dependent on the calcium wave. The calcium-dependence of surface contractility could be reproduced in unfertilized eggs, where mobilization of intracellular calcium in unfertilized eggs under compression resulted in a marked contractile response. Lastly, inhibition of myosin II delayed absorption of the fertilization cone, suggesting that myosin II not only responds to the same signals that activate eggs but also participates in the remodeling of the cortical actomyosin cytoskeleton during the first zygotic cell cycle. (c) 2006 Wiley-Liss, Inc.

  6. The inhibition of the potassium channel TASK-1 in rat cardiac muscle by endothelin-1 is mediated by phospholipase C.

    Science.gov (United States)

    Schiekel, Julia; Lindner, Moritz; Hetzel, Andrea; Wemhöner, Konstantin; Renigunta, Vijay; Schlichthörl, Günter; Decher, Niels; Oliver, Dominik; Daut, Jürgen

    2013-01-01

    The two-pore-domain potassium channel TASK-1 is robustly inhibited by the activation of receptors coupled to the Gα(q) subgroup of G-proteins, but the signal transduction pathway is still unclear. We have studied the mechanisms by which endothelin receptors inhibit the current carried by TASK-1 channels (I(TASK)) in cardiomyocytes. Patch-clamp measurements were carried out in isolated rat cardiomyocytes. I(TASK) was identified by extracellular acidification to pH 6.0 and by the application of the TASK-1 blockers A293 and A1899. Endothelin-1 completely inhibited I(TASK) with an EC(50) of Application of 20 nM endothelin-1 caused a significant increase in action potential duration under control conditions; this was significantly reduced after pre-incubation of the cardiomyocytes with 200 nM A1899. The inhibition of I(TASK) by endothelin-1 was not affected by inhibitors of protein kinase C or rho kinase, but was strongly reduced by U73122, an inhibitor of phospholipase C (PLC). The ability of endothelin-1 to activate PLC-mediated signalling pathways was examined in mammalian cells transfected with TASK-1 and the endothelin-A receptor using patch-clamp measurements and total internal reflection microscopy. U73122 prevented the inhibition of I(TASK) by endothelin-1 and blocked PLC-mediated signalling, as verified with a fluorescent probe for phosphatidylinositol-(4,5)-bisphosphate hydrolysis. Our results show that I(TASK) in rat cardiomyocytes is controlled by endothelin-1 and suggest that the inhibition of TASK-1 via endothelin receptors is mediated by the activation of PLC. The prolongation of the action potential observed with 20 nM endothelin-1 was mainly due to the inhibition of I(TASK).

  7. The Association of Endothelin-1 Signaling with Bone Alkaline Phosphatase Expression and Protumorigenic Activities in Canine Osteosarcoma.

    Science.gov (United States)

    Neumann, Z L; Pondenis, H C; Masyr, A; Byrum, M L; Wycislo, K L; Fan, T M

    2015-01-01

    Canine osteosarcoma (OS) is an aggressive sarcoma characterized by pathologic skeletal resorption and pulmonary metastases. A number of negative prognostic factors, including bone alkaline phosphatase, have been identified in dogs with OS, but the underlying biologic factors responsible for such observations have not been thoroughly investigated. Endothelin-1-mediated signaling is active during bone repair, and is responsible for osteoblast migration, survival, proliferation, and bone alkaline phosphatase expression. The endothelin-1 signaling axis is active in canine OS cells, and this pathway is utilized by malignant osteoblasts for promoting cellular migration, survival, proliferation, and bone alkaline phosphatase activities. 45 dogs with appendicular OS. The expressions of endothelin-1 and endothelin A receptor were studied in OS cell lines and in samples from spontaneously occurring tumors. Activities mediated by endothelin-1 signaling were investigated by characterizing responses in 3 OS cell lines. In 45 dogs with OS, bone alkaline phosphatase concentrations were correlated with primary tumor osteoproductivity. Canine OS cells express endothelin-1 and endothelin A receptor, and this signaling axis mediates OS migration, survival, proliferation, and bone alkaline phosphatase activities. In OS-bearing dogs, circulating bone alkaline phosphatase activities were positively correlated with primary tumor relative bone mineral densities. Canine OS cells express endothelin-1 and functional endothelin A receptors, with the potential for a protumorigenic signaling loop. Increases in bone alkaline phosphatase activity are associated with osteoblastic OS lesions, and might be an epiphenomenon of active endothelin-1 signaling or excessive osteoproduction within the localized bone microenvironment. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  8. Blood pressure and the contractility of a human leg muscle.

    Science.gov (United States)

    Luu, Billy L; Fitzpatrick, Richard C

    2013-11-01

    These studies investigate the relationships between perfusion pressure, force output and pressor responses for the contracting human tibialis anterior muscle. Eight healthy adults were studied. Changing the height of tibialis anterior relative to the heart was used to control local perfusion pressure. Electrically stimulated tetanic force output was highly sensitive to physiological variations in perfusion pressure showing a proportionate change in force output of 6.5% per 10 mmHg. This perfusion-dependent change in contractility begins within seconds and is reversible with a 53 s time constant, demonstrating a steady-state equilibrium between contractility and perfusion pressure. These stimulated contractions did not produce significant cardiovascular responses, indicating that the muscle pressor response does not play a major role in cardiovascular regulation at these workloads. Voluntary contractions at forces that would require constant motor drive if perfusion pressure had remained constant generated a central pressor response when perfusion pressure was lowered. This is consistent with a larger cortical drive being required to compensate for the lost contractility with lower perfusion pressure. The relationship between contractility and perfusion for this large postural muscle was not different from that of a small hand muscle (adductor pollicis) and it responded similarly to passive peripheral and active central changes in arterial pressure, but extended over a wider operating range of pressures. If we consider that, in a goal-oriented motor task, muscle contractility determines central motor output and the central pressor response, these results indicate that muscle would fatigue twice as fast without a pressor response. From its extent, timing and reversibility we propose a testable hypothesis that this change in contractility arises through contraction- and perfusion-dependent changes in interstitial K(+) concentration.

  9. Comparison of contractile and extensile pneumatic artificial muscles

    Science.gov (United States)

    Pillsbury, Thomas E.; Wereley, Norman M.; Guan, Qinghua

    2017-09-01

    Pneumatic artificial muscles (PAMs) are used in robotic and prosthetic applications due to their high power to weight ratio, controllable compliance, and simple design. Contractile PAMs are typically used in traditional hard robotics in place of heavy electric motors. As the field of soft robotics grows, extensile PAMs are beginning to have increased usage. This work experimentally tests, models, and compares contractile and extensile PAMs to demonstrate the advantages and disadvantages of each type of PAM and applications for which they are best suited.

  10. Effect of cadmium on myocardial contractility and calcium fluxes

    International Nuclear Information System (INIS)

    Pilati, C.F.

    1979-01-01

    The effect of cadmium on myocardial mechanical performance and calcium fluxes was studied in kitten isometric papillary muscles and in isovolumic Langendorff-perfused rabbit hearts. Therefore, it is concluded that cadmium-induced decreases in contractility are not primarily the result of cadmium interference with ATP metabolic processes. Furthermore, these results imply that cadmium causes no structural alterations of the contractile proteins. These data suggest that cadmium may be competing with the calcium needed for excitation-contraction coupling. During experiments using radioisotopic calcium, a statistically significant cellular influx of calcium was observed following the onset of 100 μM Cd ++ perfusion of isolated, Langendorff-prepared rabbit hearts

  11. Endothelin receptor antagonist and airway dysfunction in pulmonary arterial hypertension

    Directory of Open Access Journals (Sweden)

    Borst Mathias M

    2009-12-01

    Full Text Available Abstract Background In idiopathic pulmonary arterial hypertension (IPAH, peripheral airway obstruction is frequent. This is partially attributed to the mediator dysbalance, particularly an excess of endothelin-1 (ET-1, to increased pulmonary vascular and airway tonus and to local inflammation. Bosentan (ET-1 receptor antagonist improves pulmonary hemodynamics, exercise limitation, and disease severity in IPAH. We hypothesized that bosentan might affect airway obstruction. Methods In 32 IPAH-patients (19 female, WHO functional class II (n = 10, III (n = 22; (data presented as mean ± standard deviation pulmonary vascular resistance (11 ± 5 Wood units, lung function, 6 minute walk test (6-MWT; 364 ± 363.7 (range 179.0-627.0 m, systolic pulmonary artery pressure, sPAP, 79 ± 19 mmHg, and NT-proBNP serum levels (1427 ± 2162.7 (range 59.3-10342.0 ng/L were measured at baseline, after 3 and 12 months of oral bosentan (125 mg twice per day. Results and Discussion At baseline, maximal expiratory flow at 50 and 25% vital capacity were reduced to 65 ± 25 and 45 ± 24% predicted. Total lung capacity was 95.6 ± 12.5% predicted and residual volume was 109 ± 21.4% predicted. During 3 and 12 months of treatment, 6-MWT increased by 32 ± 19 and 53 ± 69 m, respectively; p Conclusion This study gives first evidence in IPAH, that during long-term bosentan, improvement of hemodynamics, functional parameters or serum biomarker occur independently from persisting peripheral airway obstruction.

  12. Endothelin mechanisms in altered thyroid states in the rat.

    Science.gov (United States)

    Rebello, S; Thompson, E B; Gulati, A

    1993-06-11

    Endothelin (ET) and its receptor characteristics were studied in hyper- and hypo-thyroid states in the rats. Hyperthyroidism was induced by daily administration of thyroxine (0.1 mg/kg i.p.) for 8 weeks, while hypothyrodism was induced by daily administration of methimazole (10 mg/kg i.p.) for 8 weeks. The chronic administration of thyroxine to rats decreased their rate of gain of body weight, increased serum T3 and T4 concentration, blood pressure and heart rate. The chronic administration of methimazole decreased the rate of gain of body weight, serum T3 and T4 concentration, blood pressure and heart rate as compared to vehicle-treated control. Plasma ET-1 levels were found to be similar in control and methimazole-treated rats, while the levels were found to be significantly (P < 0.002) increased in thyroxine-treated rats as compared to control rats. Binding studies showed that [125I]ET-1 bound to a single, high affinity binding site in the cerebral cortex, hypothalamus and pituitary. The density (Bmax) and the affinity (Kd) of [125I]ET-1 binding in the cerebral cortex and hypothalamus were found to be similar in control, methimazole- and thyroxine-treated rats. The pituitary of thyroxine-treated rats showed a decrease in the binding (34.3% decrease in the density) of [125I]ET-1 as compared to control rats. No difference was observed in the binding of [125I]ET-1 to pituitary membranes from control and methimazole-treated rats. Competition studies showed that the IC50 and Ki values of ET-3 for [125]ET-1 binding were about 8 to 11 times higher than ET-1 in cerebral cortex, hypothalamus and pituitary.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Male-female differences in upregulation of vasoconstrictor responses in human cerebral arteries.

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    Hilda Ahnstedt

    Full Text Available BACKGROUND AND PURPOSE: Male-female differences may significantly impact stroke prevention and treatment in men and women, however underlying mechanisms for sexual dimorphism in stroke are not understood. We previously found in males that cerebral ischemia upregulates contractile receptors in cerebral arteries, which is associated with lower blood flow. The present study investigates if cerebral arteries from men and women differ in cerebrovascular receptor upregulation. EXPERIMENTAL APPROACH: Freshly obtained human cerebral arteries were placed in organ culture, an established model for studying receptor upregulation. 5-hydroxtryptamine type 1B (5-HT1B, angiotensin II type 1 (AT1 and endothelin-1 type A and B (ETA and ETB receptors were evaluated using wire myograph for contractile responses, real-time PCR for mRNA and immunohistochemistry for receptor expression. KEY RESULTS: Vascular sensitivity to angiotensin II and endothelin-1 was markedly lower in cultured cerebral arteries from women as compared to men. ETB receptor-mediated contraction occurred in male but not female arteries. Interestingly, there were similar upregulation in mRNA and expression of 5-HT1B, AT1, and ETB receptors and in local expression of Ang II after organ culture. CONCLUSIONS AND IMPLICATIONS: In spite of receptor upregulation after organ culture in both sexes, cerebral arteries from women were significantly less responsive to vasoconstrictors angiotensin II and endothelin-1 as compared to arteries from men. This suggests receptor coupling and/or signal transduction mechanisms involved in cerebrovascular contractility may be suppressed in females. This is the first study to demonstrate sex differences in the vascular function of human brain arteries.

  14. Inhalation of Budesonide/Formoterol Increases Diaphragm Muscle Contractility

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    Chiyohiko Shindoh

    2012-01-01

    Conclusions: BUD/FORM inhalation has an inotropic effect on diaphragm muscle, protects diaphragm muscle deterioration after endotoxin injection, and inhibits NO production. Increments in muscle contractility with BUD/FORM inhalation are induced through a synergistic effect of an anti-inflammatory agent and 02-agonist.

  15. Clinical Relationship between Steatocholecystitis and Gallbladder Contractility Measured by Cholescintigraphy

    Directory of Open Access Journals (Sweden)

    Chang Seok Bang

    2015-01-01

    Full Text Available Objective. Contractility of gallbladder is known to be decreased in fatty gallbladder diseases. However, clinical estimation data about this relationship is still lacking. The aim of this study was to investigate the association between steatocholecystitis and contractility of gallbladder. Methods. Patients with cholecystitis (steatocholecystitis versus nonsteatocholecystitis who underwent cholescintigraphy before cholecystectomy were retrospectively evaluated in a single teaching hospital of Korea. The association of steatocholecystitis with contractility of gallbladder, measured by preoperative cholescintigraphy, was assessed by univariable and multivariable analysis. Results. A total of 432 patients were finally enrolled (steatocholecystitis versus nonsteatocholecystitis; 75 versus 357, calculous versus acalculous cholecystitis; 316 versus 116. In the multivariable analysis, age (OR: 0.94, 95% CI: 0.90–0.99, P=0.01 and total serum cholesterol (OR: 1.02, 95% CI: 1.01–1.04, P=0.04 were related to steatocholecystitis in patients with acalculous cholecystitis. Only age (OR: 0.97, 95% CI: 0.94–0.99, P=0.004 was significantly related to steatocholecystitis in patients with calculous cholecystitis. However, ejection fraction of gallbladder reflecting contractility measured by cholescintigraphy was not related to steatocholecystitis irrespective of presence of gallbladder stone in patients with cholecystitis. Conclusion. Ejection fraction of gallbladder measured by cholescintigraphy cannot be used for the detection or confirmation of steatocholecystitis.

  16. Myocardial contractile function in survived neonatal piglets after cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Popov Aron-Frederik

    2010-11-01

    Full Text Available Abstract Background Hemodynamic function may be depressed in the early postoperative stages after cardiac surgery. The aim of this study was the analysis of the myocardial contractility in neonates after cardiopulmonary bypass (CPB and mild hypothermia. Methods Three indices of left ventricular myocardial contractile function (dP/dt, (dP/dt/P, and wall thickening were studied up to 6 hours after CPB in neonatal piglets (CPB group; n = 4. The contractility data were analysed and then compared to the data of newborn piglets who also underwent median thoracotomy and instrumentation for the same time intervals but without CPB (non-CPB group; n = 3. Results Left ventricular dP/dtmax and (dP/dtmax/P remained stable in CPB group, while dP/dtmax decreased in non-CPB group 5 hours postoperatively (1761 ± 205 mmHg/s at baseline vs. 1170 ± 205 mmHg/s after 5 h; p max and (dP/dtmax/P there were no statistically significant differences between the two groups. Comparably, although myocardial thickening decreased in the non-CPB group the differences between the two groups were not statistically significant. Conclusions The myocardial contractile function in survived neonatal piglets remained stable 6 hours after cardiopulmonary bypass and mild hypothermia probably due to regional hypercontractility.

  17. Stalk-length-dependence of the contractility of Vorticella convallaria

    Science.gov (United States)

    Gul Chung, Eun; Ryu, Sangjin

    2017-12-01

    Vorticella convallaria is a sessile protozoan of which the spasmoneme contracts on a millisecond timescale. Because this contraction is induced and powered by the binding of calcium ions (Ca2+), the spasmoneme showcases Ca2+-powered cellular motility. Because the isometric tension of V. convallaria increases linearly with its stalk length, it is hypothesized that the contractility of V. convallaria during unhindered contraction depends on the stalk length. In this study, the contractile force and energetics of V. convallaria cells of different stalk lengths were evaluated using a fluid dynamic drag model which accounts for the unsteadiness and finite Reynolds number of the water flow caused by contracting V. convallaria and the wall effect of the no-slip substrate. It was found that the contraction displacement, peak contraction speed, peak contractile force, total mechanical work, and peak power depended on the stalk length. The observed stalk-length-dependencies were simulated using a damped spring model, and the model estimated that the average spring constant of the contracting stalk was 1.34 nN µm-1. These observed length-dependencies of Vorticella’s key contractility parameters reflect the biophysical mechanism of the spasmonemal contraction, and thus they should be considered in developing a theoretical model of the Vorticella spasmoneme.

  18. Endothelin receptor mediated Ca(2+) signaling in coronary arteries after experimentally induced ischemia/reperfusion injury in rat

    DEFF Research Database (Denmark)

    Kristiansen, Sarah Brøgger; Haanes, Kristian A.; Sheykhzade, Majid

    2017-01-01

    a phenotypical shift, which includes increased evoked ETB induced contraction in the smooth muscle cell, and also a higher basal tone development which both are dependent on Ca(2+) influx through VGCCs. This is combined with alterations in the ETA calcium handling, which has a stronger dependence on Ca(2...

  19. Endothelin-1 Regulation of exercise-induced changes in flow: Dynamic regulation of vascular tone

    NARCIS (Netherlands)

    Rapoport, R.M. (Robert M.); D. Merkus (Daphne)

    2017-01-01

    textabstractAlthough endothelin (ET)-1 is a highly potent vasoconstrictor with considerable efficacy in numerous vascular beds, the role of endogenous ET-1 in the regulation of vascular tone remains unclear. The perspective that ET-1 plays little role in the on-going regulation of vascular tone at

  20. NO and prostanoids blunt endothelin-mediated coronary vasoconstrictor influence in exercising swine

    NARCIS (Netherlands)

    D. Merkus (Daphne); O. Sorop (Oana); B. Houweling (Birgit); F. Boomsma (Frans); A.H. van den Meiracker (Anton); D.J.G.M. Duncker (Dirk)

    2006-01-01

    textabstractWithdrawal of the endothelin (ET)-mediated vasoconstrictor influence contributes to metabolic coronary vasodilation during exercise. Because production of nitric oxide (NO) and prostanoids increases with increasing shear stress and because NO and prostanoids are able to modify the

  1. Neurosensory changes in a human model of endothelin-1 induced pain: a behavioral study

    NARCIS (Netherlands)

    Hans, Guy; Deseure, Kristof; Robert, Dominique; de Hert, Stefan

    2007-01-01

    Although pain is a frequent feature in patients with cancer, its etiology is still poorly understood. In recent years, endothelin-1 (ET-1) has become a major target molecule in the etiology of cancer pain. In this randomised, double-blind study the effects of intradermal injection of ET-1 on

  2. Clinical significance of determination of plasma endothelin (ET) and homocysteine (Hcy) levels in patients with diabetic nephropathy

    International Nuclear Information System (INIS)

    Zhang Aimin; Jin Ying; Zhou Xiu

    2005-01-01

    Objective: To determine the plasma levels of endothelin (ET) and homocysteine (Hcy) in patients with diabetic nephropathy. Methods: Plasma ET (with RIA) and Hcy( with electrochemiluminescence) contents were determined in 32 DM2 patients without nephropathy, 35 DM2 patients with nephropathy and 30 controls. Results: Endothelin and homocysteine levels were significantly higher in patients with diabetic nephropathy than those in patients without nephropathy and controls (P<0.05- 0.01). Conclusion: Endothelin and homocysteine were involved in the pathogenesis of diabetic nephropathy, and determination of which were of diagnostic and prognostic value in clinical practice. (authors)

  3. Murine study of portal hypertension associated endothelin-1 hypo-response.

    Science.gov (United States)

    Theodorakis, Nicholas; Maluccio, Mary; Skill, Nicholas

    2015-04-28

    To investigate endothelin-1 hypo-responsive associated with portal hypertension in order to improve patient treatment outcomes. Wild type, eNOS(-/-) and iNOS(-/-) mice received partial portal vein ligation surgery to induce portal hypertension or sham surgery. Development of portal hypertension was determined by measuring the splenic pulp pressure, abdominal aortic flow and portal systemic shunting. To measure splenic pulp pressure, a microtip pressure transducer was inserted into the spleen pulp. Abdominal aortic flow was measured by placing an ultrasonic Doppler flow probe around the abdominal aorta between the diaphragm and celiac artery. Portal systemic shunting was calculated by injection of fluorescent microspheres in to the splenic vein and determining the percentage accumulation of spheres in liver and pulmonary beds. Endothelin-1 hypo-response was evaluated by measuring the change in abdominal aortic flow in response to endothelin-1 intravenous administration. In addition, thoracic aorta endothelin-1 contraction was measured in 5 mm isolated thoracic aorta rings ex-vivo using an ADI small vessel myograph. In wild type and iNOS(-/-) mice splenic pulp pressure increased from 7.5 ± 1.1 mmHg and 7.2 ± 1 mmHg to 25.4 ± 3.1 mmHg and 22 ± 4 mmHg respectively. In eNOS(-/-) mice splenic pulp pressure was increased after 1 d (P = NS), after which it decreased and by 7 d was not significantly elevated when compared to 7 d sham operated controls (6.9 ± 0.6 mmHg and 7.3 ± 0.8 mmHg respectively, P = 0.3). Abdominal aortic flow was increased by 80% and 73% in 7 d portal vein ligated wild type and iNOS when compared to shams, whereas there was no significant difference in 7 d portal vein ligated eNOS(-/-) mice when compared to shams. Endothelin-1 induced a rapid reduction in abdominal aortic blood flow in wild type, eNOS(-/-) and iNOS(-/-) sham mice (50% ± 8%, 73% ± 9% and 47% ± 9% respectively). Following portal vein ligation endothelin-1 reduction in blood flow

  4. Study of Endothelin-1 and Vascular Endothelial Growth Factor in Patients with Cancer Colon

    International Nuclear Information System (INIS)

    ABDEL-GAWAD, I.A.; HASSANEIN, H.M.R.; BAHGAT, N.A.; ABDEL SATTAR, M.A.; EL-SISSY, A.H.; ALTAWEEL, M.A.; HELAL, A.M.

    2008-01-01

    Purpose: The levels of endothelin-1 and VEGF were evaluated in the sera of newly diagnosed patients with cancer colon and were compared with the routinely used tumor markers; CEA and CA19.9. Their relations with some prognostic factors of cancer colon were also investigated. Subjects and Methods: The study included 48 patients with cancer colon and 20 apparently healthy volunteers as a control group. Patients were 23 males and 25 females with age range from 18 to 71 years (mean = 47±1.8). Both serum and plasma samples were obtained from patients and controls. Results: Six percent of patients had grade 1 tumors, 77% had grade 2 and 17% had grade 3 disease. As regard to the stage, 52% of patients were stage II, 35.5% were stage III, while 12.5% were stage IV. Liver metastasis was present in 12.5%, while 35% showed lymph node metastasis. The VEGF, endothelin-1, CA 19.9 and CEA were significantly higher in the cancer colon patients than in control groups (p-value <0.001, 0.006, <0.001 and <0.001; respectively). Plasma level of endothelin-1 and serum level of VEGF showed significantly higher levels in advanced stages of the disease (p value <0 .001) and in presence of liver metastasis (p value <0.001 and 0.002 respectively), while VEGF showed significant result when compared with the grade (p value=0.032). In this study, when comparing the levels of plasma endothelin-1 and serum VEGF between the metastatic, non-metastatic liver patients of the cancer colon group and the control group, the comparison was statistically significant for both markers (p<0.001). Endothelin-1 and VEGF showed significant positive correlation (r=0.77 and p-value <0.0001). Serum VEGF and CA 19.9 showed good sensitivities which were not different (97.9% and 87.5%; respectively), while there was no significant difference between VEGF, CA 19.9 and CEA with respect to specificities (100%, 90% and 100% respectively). Conclusion: Both endothelin-1 and VEGF may be used for early detection of liver

  5. The emerging role of endothelin-1 in the pathogenesis of pre-eclampsia.

    Science.gov (United States)

    Saleh, Langeza; Verdonk, Koen; Visser, Willy; van den Meiracker, Anton H; Danser, A H Jan

    2016-10-01

    Pre-eclampsia (PE) is the most frequently encountered medical complication during pregnancy. It is characterized by a rise in systemic vascular resistance with a relatively low cardiac output and hypovolemia, combined with severe proteinuria. Despite the hypovolemia, renin-angiotensin system (RAS) activity is suppressed and aldosterone levels are decreased to the same degree as renin. This suggests that the RAS is not the cause of the hypertension in PE, but rather that its suppression is the consequence of the rise in blood pressure. Abnormal placentation early in pregnancy is widely assumed to be an important initial event in the onset of PE. Eventually, this results in the release of anti-angiogenic factors [in particular, soluble Fms-like tyrosine kinase-1 (sFlt-1)] and cytokines, leading to generalized vascular dysfunction. Elevated sFlt-1 levels bind and inactivate vascular endothelial growth factor (VEGF). Of interest, VEGF inhibition with drugs like sunitinib, applied in cancer patients, results in a PE-like syndrome, characterized by hypertension, proteinuria and renal toxicity. Both in cancer patients treated with sunitinib and in pregnant women with PE, significant rises in endothelin-1 occur. Multiple regression analysis revealed that endothelin-1 is an independent determinant of the hypertension and proteinuria in PE, and additionally a renin suppressor. Moreover, studies in animal models representative of PE, have shown that endothelin receptor blockers prevent the development of this disease. Similarly, endothelin receptor blockers are protective during sunitinib treatment. Taken together, activation of the endothelin system emerges as an important pathway causing the clinical manifestations of PE. This paper critically addresses this concept, taking into consideration both clinical and preclinical data, and simultaneously discusses the therapeutic consequences of this observation. © The Author(s), 2016.

  6. Protein kinase Cα deletion causes hypotension and decreased vascular contractility.

    Science.gov (United States)

    Wynne, Brandi M; McCarthy, Cameron G; Szasz, Theodora; Molina, Patrick A; Chapman, Arlene B; Webb, R Clinton; Klein, Janet D; Hoover, Robert S

    2018-03-01

    Protein kinase Cα (PKCα) is a critical regulator of multiple cell signaling pathways including gene transcription, posttranslation modifications and activation/inhibition of many signaling kinases. In regards to the control of blood pressure, PKCα causes increased vascular smooth muscle contractility, while reducing cardiac contractility. In addition, PKCα has been shown to modulate nephron ion transport. However, the role of PKCα in modulating mean arterial pressure (MAP) has not been investigated. In this study, we used a whole animal PKCα knock out (PKC KO) to test the hypothesis that global PKCα deficiency would reduce MAP, by a reduction in vascular contractility. Radiotelemetry measurements of ambulatory blood pressure (day/night) were obtained for 18 h/day during both normal chow and high-salt (4%) diet feedings. PKCα mice had a reduced MAP, as compared with control, which was not normalized with high-salt diet (14 days). Metabolic cage studies were performed to determine urinary sodium excretion. PKC KO mice had a significantly lower diastolic, systolic and MAP as compared with control. No significant differences in urinary sodium excretion were observed between the PKC KO and control mice, whether fed normal chow or high-salt diet. Western blot analysis showed a compensatory increase in renal sodium chloride cotransporter expression. Both aorta and mesenteric vessels were removed for vascular reactivity studies. Aorta and mesenteric arteries from PKC KO mice had a reduced receptor-independent relaxation response, as compared with vessels from control. Vessels from PKC KO mice exhibited a decrease in maximal contraction, compared with controls. Together, these data suggest that global deletion of PKCα results in reduced MAP due to decreased vascular contractility.

  7. Ginsenoside Rb1 Attenuates Agonist-Induced Contractile Response via Inhibition of Store-Operated Calcium Entry in Pulmonary Arteries of Normal and Pulmonary Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Rui-Xing Wang

    2015-03-01

    Full Text Available Background: Pulmonary hypertension (PH is characterized by sustained vasoconstriction, enhanced vasoreactivity and vascular remodeling, which leads to right heart failure and death. Despite several treatments are available, many forms of PH are still incurable. Ginsenoside Rb1, a principle active ingredient of Panax ginseng, exhibits multiple pharmacological effects on cardiovascular system, and suppresses monocrotaline (MCT-induced right heart hypertrophy. However, its effect on the pulmonary vascular functions related to PH is unknown. Methods: We examined the vasorelaxing effects of ginsenoside Rb1 on endothelin-1 (ET-1 induced contraction of pulmonary arteries (PAs and store-operated Ca2+ entry (SOCE in pulmonary arterial smooth muscle cells (PASMCs from chronic hypoxia (CH and MCT-induced PH. Results: Ginsenoside Rb1 elicited concentration-dependent relaxation of ET-1-induced PA contraction. The vasorelaxing effect was unaffected by nifedipine, but abolished by the SOCE blocker Gd3+. Ginsenoside Rb1 suppressed cyclopiazonic acid (CPA-induced PA contraction, and CPA-activated cation entry and Ca2+ transient in PASMCs. ET-1 and CPA-induced contraction, and CPA-activated cation entry and Ca2+ transients were enhanced in PA and PASMCs of CH and MCT-treated rats; the enhanced responses were abolished by ginsenoside Rb1. Conclusion: Ginsenoside Rb1 attenuates ET-1-induced contractile response via inhibition of SOCE, and it can effectively antagonize the enhanced pulmonary vasoreactivity in PH.

  8. Recently active contractile deformation in the forearc of southern Peru

    Science.gov (United States)

    Hall, S. R.; Farber, D.; Audin, L.; Finkel, R. C.

    2010-12-01

    In the Precordillera and Western Cordillera of southern Peru (14°-18°S), vast pediment surfaces have been abandoned through drainage diversion and river incision, with the major drainages carving deep canyons. Within this region, we have identified range-sub-parallel contractile structures that accommodate significant distributed crustal deformation. Young geomorphic features document both the presence and youthfulness of these contractile structures. Here, we determine exposure ages on geomorphic features such as pediment surfaces and fluvial terraces using in situ produced cosmogenic radionuclides, in conjunction with field and remote mapping. This chronologic data reveals that ancient surfaces have been preserved as a result of very low erosion rates. We measure this rate to be chronology and geomorphic mapping, we calculate a Pleistocene river incision rate of ~0.3mm/yr determined from data collected along exoreic rivers. This rate is consistent with longer-term incision rates measured in other localities along this margin. We suggest that, in this region of southern Peru, the steep western wedge of the Andean margin supports the high topography of the Altiplano through a combination of uplift along steeply dipping contractile west-vergent structures and isostatic responses to the focused removal of large amounts of crustal material through canyon incision. Further, that these range sub-parallel structures are related at depth to a thrust system that plays a role in not only the maintenance of the Andean margin, but potentially in its formation as well.

  9. Effects of hypoxia and hypercapnia on geniohyoid contractility and endurance.

    Science.gov (United States)

    Salmone, R J; Van Lunteren, E

    1991-08-01

    Sleep apnea and other respiratory diseases produce hypoxemia and hypercapnia, factors that adversely affect skeletal muscle performance. To examine the effects of these chemical alterations on force production by an upper airway dilator muscle, the contractile and endurance characteristics of the geniohyoid muscle were examined in situ during severe hypoxia (arterial PO2 less than 40 Torr), mild hypoxia (PO2 45-65 Torr), and hypercapnia (PCO2 55-80 Torr) and compared with hyperoxic-normocapnic conditions in anesthetized cats. Muscles were studied at optimal length, and contractile force was assessed in response to supramaximal electrical stimulation of the hypoglossal nerve (n = 7 cats) or geniohyoid muscle (n = 2 cats). There were no significant changes in the twitch kinetics or force-frequency curve of the geniohyoid muscle during hypoxia or hypercapnia. However, the endurance of the geniohyoid, as reflected in the fatigue index (ratio of force at 2 min to initial force in response to 40-Hz stimulation at a duty cycle 0.33), was significantly reduced by severe hypoxia but not by hypercapnia or mild hypoxia. In addition, the downward shift in the force-frequency curve after the repetitive stimulation protocol was greater during hypoxia than hyperoxia, especially at higher frequencies. In conclusion, the ability of the geniohyoid muscle to maintain force output during high levels of activation is adversely affected by severe hypoxia but not mild hypoxia or hypercapnia. However, none of these chemical perturbations affected muscle contractility acutely.

  10. Intrahippocampal Injection of Endothelin-1: A New Model of Ischemia-induced Seizures in Immature Rats

    Czech Academy of Sciences Publication Activity Database

    Tsenov, Grygoriy; Máttéffyová, Adéla; Mareš, Pavel; Otáhal, Jakub; Kubová, Hana

    2007-01-01

    Roč. 48, Suppl.5 (2007), s. 7-13 ISSN 0013-9580 R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA305/06/0713; GA ČR(CZ) GD305/03/H148 Institutional research plan: CEZ:AV0Z50110509 Keywords : endothelin-1 * epileptic seizures * immature rats Subject RIV: ED - Physiology Impact factor: 3.569, year: 2007

  11. Effect of endothelin-1 on the excitability of rat cortical and hippocampal slices in vitro

    Czech Academy of Sciences Publication Activity Database

    Konopková, Renata; Világi, I.; Borbély, S.; Kubová, Hana; Otáhal, Jakub

    2012-01-01

    Roč. 61, č. 2 (2012), s. 215-219 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LC554; GA AV ČR(CZ) 1QS501210509; GA ČR(CZ) GD305/08/H037 Institutional research plan: CEZ:AV0Z50110509 Keywords : Endothelin-1 * excitability * hippocampus * somatosensory cortex * rat * epileptogenesis Subject RIV: FH - Neurology Impact factor: 1.531, year: 2012

  12. Binding sites for endothelin-1 in rat tissues: An autoradiographic study

    International Nuclear Information System (INIS)

    Koseki, C.; Imai, M.; Hirata, Y.; Yanagisawa, M.; Masaki, T.

    1989-01-01

    By tissue autoradiography in the rat, we demonstrated that receptors for endothelin-1 (ET-1) were distributed not only in the cardiovascular system but also in the noncardiovascular organs including the brain, lung, intestine, etc. In the brain, the receptors were mainly found in the basal ganglia and brainstem, in which nuclei are known to be cardiovascular regulatory sites. In addition to its direct vasoconstricting action, ET-1 may exert neural cardiovascular control as a neuropeptide

  13. Protective effect of estrogen in endothelin-induced middle cerebral artery occlusion in female rats

    OpenAIRE

    Glendenning, Michele L.; Lovekamp-Swan, Tara; Schreihofer, Derek A.

    2008-01-01

    Estrogen is a powerful endogenous and exogenous neuroprotective agent in animal models of brain injury, including focal cerebral ischemia. Although this protection has been demonstrated in several different treatment and injury paradigms, it has not been demonstrated in focal cerebral ischemia induced by intraparenchymal endothelin-1 injection, a model with many advantages over other models of experimental focal ischemia. Reproductively mature female Sprague-Dawley rats were ovariectomized an...

  14. Culture of human intestinal epithelial cell using the dissociating enzyme thermolysin and endothelin-3

    Directory of Open Access Journals (Sweden)

    Z. Liu

    2010-05-01

    Full Text Available Epithelium, a highly dynamic system, plays a key role in the homeostasis of the intestine. However, thus far a human intestinal epithelial cell line has not been established in many countries. Fetal tissue was selected to generate viable cell cultures for its sterile condition, effective generation, and differentiated character. The purpose of the present study was to culture human intestinal epithelial cells by a relatively simple method. Thermolysin was added to improve the yield of epithelial cells, while endothelin-3 was added to stimulate their growth. By adding endothelin-3, the achievement ratio (viable cell cultures/total cultures was enhanced to 60% of a total of 10 cultures (initiated from 8 distinct fetal small intestines, allowing the generation of viable epithelial cell cultures. Western blot, real-time PCR and immunofluorescent staining showed that cytokeratins 8, 18 and mouse intestinal mucosa-1/39 had high expression levels in human intestinal epithelial cells. Differentiated markers such as sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV also showed high expression levels in human intestinal epithelial cells. Differentiated human intestinal epithelial cells, with the expression of surface markers (cytokeratins 8, 18 and mouse intestinal mucosa-1/39 and secretion of cytokines (sucrase-isomaltase, aminopeptidase N and dipeptidylpeptidase IV, may be cultured by the thermolysin and endothelin-3 method and maintained for at least 20 passages. This is relatively simple, requiring no sophisticated techniques or instruments, and may have a number of varied applications.

  15. Comparison of plasma endothelin levels between osteoporotic, osteopenic and normal subjects

    Directory of Open Access Journals (Sweden)

    Biçimoğlu Ali

    2005-09-01

    Full Text Available Abstract Background It has been demonstrated that endothelins (ET have significant roles in bone remodeling, metabolism and physiopathology of several bone diseases. We aimed to investigate if there was any difference between the plasma ET levels of osteoporotic patients and normals. Methods 86 patients (70 women and 16 men with a mean age of 62.6 (ranges: 51–90 years were included in this study. Patients were divided into groups of osteoporosis, osteopenia and normal regarding reported T scores of DEXA evaluation according to the suggestions of World Health Organization. According to these criteria 19, 43 and 24 were normal, osteopenic and osteoporotic respectively. Then total plasma level of ET was measured in all patients with monoclonal antibody based sandwich immunoassay (EIA method. One-way analysis of variance test was used to compare endothelin values between normals, osteopenics and osteoporotics. Results Endothelin total plasma level in patients was a mean of 98.36 ± 63.96, 100.92 ± 47.2 and 99.56 ± 56.6 pg/ml in osteoporotic, osteopenic and normal groups respectively. The difference between groups was not significant (p > 0.05. Conclusion No significant differences in plasma ET levels among three groups of study participants could be detected in this study.

  16. Venous plasma levels of endothelin-1 are not altered immediately after nitroglycerin infusion in healthy subjects

    DEFF Research Database (Denmark)

    Thomsen, L L; Iversen, Helle Klingenberg; Emmeluth, C

    1995-01-01

    before and immediately (5-30 s) after 80 min infusion of NTG (glyceryl trinitrate) or saline in 12 healthy subjects. On two different days separated by at least 1 week, NTG in four different doses, 0.015, 0.25, 1.0, and 2.0 micrograms. kg-1. min-1, or placebo (isotonic saline) was infused successively...... for 20 min each dose. During the infusion blood pressure and heart rate were measured. NTG infusion significantly decreased systolic blood pressure from 112.4 to 103.4 mmHg and pulse pressure from 39.3 to 29.5 mmHg. Heart rate increased from 62.7 to 73.1 beats. min-1. No changes in endothelin-1 plasma...... levels were induced by NTG infusion (2.4 pg.ml-1 before NTG vs. 2.7 pg.ml-1 after NTG) and placebo infusion also did not affect plasma endothelin-1. It is concluded that venous plasma levels of endothelin-1 are not altered immediately after NTG infusion....

  17. Resolving the role of actoymyosin contractility in cell microrheology.

    Directory of Open Access Journals (Sweden)

    Christopher M Hale

    2009-09-01

    Full Text Available Einstein's original description of Brownian motion established a direct relationship between thermally-excited random forces and the transport properties of a submicron particle in a viscous liquid. Recent work based on reconstituted actin filament networks suggests that nonthermal forces driven by the motor protein myosin II can induce large non-equilibrium fluctuations that dominate the motion of particles in cytoskeletal networks. Here, using high-resolution particle tracking, we find that thermal forces, not myosin-induced fluctuating forces, drive the motion of submicron particles embedded in the cytoskeleton of living cells. These results resolve the roles of myosin II and contractile actomyosin structures in the motion of nanoparticles lodged in the cytoplasm, reveal the biphasic mechanical architecture of adherent cells-stiff contractile stress fibers interdigitating in a network at the cell cortex and a soft actin meshwork in the body of the cell, validate the method of particle tracking-microrheology, and reconcile seemingly disparate atomic force microscopy (AFM and particle-tracking microrheology measurements of living cells.

  18. Atomic Structure of Type VI Contractile Sheath from Pseudomonas aeruginosa.

    Science.gov (United States)

    Salih, Osman; He, Shaoda; Planamente, Sara; Stach, Lasse; MacDonald, James T; Manoli, Eleni; Scheres, Sjors H W; Filloux, Alain; Freemont, Paul S

    2018-02-06

    Pseudomonas aeruginosa has three type VI secretion systems (T6SSs), H1-, H2-, and H3-T6SS, each belonging to a distinct group. The two T6SS components, TssB/VipA and TssC/VipB, assemble to form tubules that conserve structural/functional homology with tail sheaths of contractile bacteriophages and pyocins. Here, we used cryoelectron microscopy to solve the structure of the H1-T6SS P. aeruginosa TssB1C1 sheath at 3.3 Å resolution. Our structure allowed us to resolve some features of the T6SS sheath that were not resolved in the Vibrio cholerae VipAB and Francisella tularensis IglAB structures. Comparison with sheath structures from other contractile machines, including T4 phage and R-type pyocins, provides a better understanding of how these systems have conserved similar functions/mechanisms despite evolution. We used the P. aeruginosa R2 pyocin as a structural template to build an atomic model of the TssB1C1 sheath in its extended conformation, allowing us to propose a coiled-spring-like mechanism for T6SS sheath contraction. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  19. Effect of serotonin on small intestinal contractility in healthy volunteers

    DEFF Research Database (Denmark)

    Hansen, M.B.; Arif, F.; Gregersen, H.

    2008-01-01

    The physiological significance of serotonin released into the intestinal lumen for the regulation of motility is unknown in humans. The aim of this study was to evaluate the effect of serotonin infused into the lumen of the gastric antrum, duodenum or the jejunum, on antro-duodeno-jejunal contrac......The physiological significance of serotonin released into the intestinal lumen for the regulation of motility is unknown in humans. The aim of this study was to evaluate the effect of serotonin infused into the lumen of the gastric antrum, duodenum or the jejunum, on antro......-duodeno-jejunal contractility in healthy human volunteers. Manometric recordings were obtained and the effects of either a standard meal, continuous intravenous infusion of serotonin (20 nmol/kg/min) or intraluminal bolus infusions of graded doses of serotonin (2.5, 25 or 250 nmol) were compared. In addition, platelet......-depleted plasma levels of serotonin, blood pressure, heart rate and electrocardiogram were evaluated. All subjects showed similar results. Intravenous serotonin increased migrating motor complex phase In frequency 3-fold and migrating velocity 2-fold. Intraluminal infusion of serotonin did not change contractile...

  20. Plasma endothelin-1 and tumor necrosis factor-alpha concentrations in pregnant and cyclic rats after low-dose endotoxin infusion

    NARCIS (Netherlands)

    Faas, MM; Bakker, WW; Valkhof, N; Baller, JFW; Schuiling, GA

    Plasma endothelin-1 and tumor necrosis factor-alpha were determined in pregnant and cyclic rats after infusion of either endotoxin (1.0 mu g/kg of body weight) or saline solution. After endotoxin, but not after saline solution, administration there was a transient endothelin-1 response in pregnant

  1. Contractility of the guinea pig bladder measured in situ and in vitro

    NARCIS (Netherlands)

    J.M. Groen (Jan); R. van Mastrigt (Ron); J.L.H.R. Bosch (Ruud)

    1994-01-01

    textabstractTo study the relative importance of neurogenic factors in detrusor contractility and to relate a total bladder in vitro contractility model to a previously described bladder wall strip model, active intravesical pressure values were compared in situ and in vitro in eight male guinea

  2. Free radicals in hypoxic rat diaphragm contractility: no role for xanthine oxidase.

    NARCIS (Netherlands)

    Heunks, L.M.A.; Machiels, H.A.; Abreu, R.A. de; Zhu, X.; Heijden, E. van der; Dekhuijzen, P.N.R.

    2001-01-01

    Recent evidence indicates that hypoxia enhances the generation of oxidants. Little is known about the role of free radicals in contractility of the rat diaphragm during hypoxia. We hypothesized that antioxidants improve contractility of the hypoxic rat diaphragm and that xanthine oxidase (XO) is an

  3. Effects of ageing on single muscle fibre contractile function following short-term immobilisation

    DEFF Research Database (Denmark)

    Hvid, Lars G; Ørtenblad, Niels; Aagaard, Per

    2011-01-01

    Very little attention has been given to the combined effect of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...

  4. Transient impairments in single muscle fibre contractile function after prolonged cycling in elite endurance athletes

    DEFF Research Database (Denmark)

    Hvid, L G; Gejl, Kasper Degn; Bech, R D

    2013-01-01

    Prolonged muscle activity impairs whole-muscle performance and function. However, little is known about the effects of prolonged muscle activity on the contractile function of human single muscle fibres. The purpose of this study was to investigate the effects of prolonged exercise and subsequent...... recovery on the contractile function of single muscle fibres obtained from elite athletes....

  5. Detecting cardiac contractile activity in the early mouse embryo using multiple modalities

    Directory of Open Access Journals (Sweden)

    Chiann-mun eChen

    2015-01-01

    Full Text Available The heart is one of the first organs to develop during mammalian embryogenesis. In the mouse, it starts to form shortly after gastrulation, and is derived primarily from embryonic mesoderm. The embryonic heart is unique in having to perform a mechanical contractile function while undergoing complex morphogenetic remodelling. Approaches to imaging the morphogenesis and contractile activity of the developing heart are important in understanding not only how this remodelling is controlled but also the origin of congenital heart defects. Here, we describe approaches for visualising contractile activity in the developing mouse embryo, using brightfield time lapse microscopy and confocal microscopy of calcium transients. We describe an algorithm for enhancing this image data and quantifying contractile activity from it. Finally we describe how atomic force microscopy can be used to record contractile activity prior to it being microscopically visible.

  6. Lactate, endothelin, and central venous oxygen saturation as predictors of mortality in patients with Tetralogy of Fallot

    Directory of Open Access Journals (Sweden)

    Poonam Malhotra Kapoor

    2016-01-01

    Full Text Available Background: Lactate and central venous oxygen saturation (ScVO2 are well known biomarkers for adequacy of tissue oxygenation. Endothelin, an inflammatory marker has been associated with patient′s nutritional status and degree of cyanosis. The aim of this study was to explore the hypothesis that lactate, ScVO2 and endothelin before induction may be predictive of mortality in pediatric cardiac surgery. Methods: We conducted a prospective observational study of 150 pediatric (6 months to 12 years patients who were posted for intracardiac repair for tetralogy of fallot and measured lactate, ScVO2 and endothelin before induction (T1, 20 minutes after protamine administration (T2 and 24 hours after admission to ICU (T3. Results: Preinduction lactate and endothelin levels were found to predict mortality in patients of tetralogy of fallot with an odds ratio of 6.020 (95% CI 2.111-17.168 and 1.292(95% CI 1.091-1.531 respectively. In the ROC curve analysis for lactate at T1, the AUC was 0.713 (95% CI 0.526-0.899 P = 0.019. At the cutoff value of 1.750mmol/lt, the sensitivity and specificity for the prediction of mortality was 63.6% and 65.5%, respectively. For endothelin at T1, the AUC was 0.699 (95% CI 0.516-0.883, P = 0.028 and the cutoff value was ≤2.50 (sensitivity, 63.6%; specificity, 58.3 %. ScVO2 (odds ratio 0.85 at all three time intervals, suggested that improving ScVO2 can lead to 15% reduction in mortality. Conclusions: Lactate, ScVO2 and endothelin all showed association with mortality with lactate having the maximum prediction. Lactate was found to be an independent, reliable and cost-effective measure of prediction of mortality in patients with tetralogy of fallot.

  7. G-231A and G+70C polymorphisms of endothelin receptor type-A gene could affect the psoriasis area and severity index score and endothelin 1 levels

    Directory of Open Access Journals (Sweden)

    Gökhan Okan

    2015-01-01

    Full Text Available Background: The etiopathogenesis of psoriasis has not been clearly elucidated although the role of chronic inflammation, imbalance between pro- and anti-inflammatory cytokines, and many immunological events have been established. Endothelin 1 (EDN1 and endothelin receptor type-A (EDNRA are implicated in the inflammatory process. The relationships between EDN1 and EDNRA polymorphisms with several diseases have been found. Aims and Objectives: This study examined the possible association of EDN1 (G5665T and T-1370G and EDNRA (G-231A and G + 70C single nucleotide polymorphisms (SNPs with the occurence of psoriasis, and evaluated the relationship between genotypes and clinical/laboratory manifestation of psoriasis. Materials and Methods: We analyzed genotype and allele distributions of the above-mentioned polymorphisms in 151 patients with psoriasis and 152 healthy controls by real-time PCR combined with melting curve analysis. Results: We did not find significant differences in the genotype and allele distributions of EDN1 T-1370G, EDNRA G-231A, and EDNRA G+70C polymorphisms between patients with psoriasis and healthy controls. Psoriasis area and severity index (PASI score of EDNRA -231 polymorphic A allele carrying subjects (AA and AA + AG was higher than that of wild homozygotes (P = 0.044 and P = 0.027, respectively. In addition, EDN1 levels in EDNRA+70 polymorphic C allele carriers (CC + CG were elevated when compared with GG genotype; however, the difference was at borderline significance (P = 0.05. Conclusion: Although there were no associations between studied polymorphisms and psoriasis susceptibility, the PASI score and EDN1 levels seem to be affected by EDNRA G-231A and G + 70C polymorphisms.

  8. Plasma Endothelin-1 Levels in Preterm Neonatal Infants with Acute Respiratory Failure

    Directory of Open Access Journals (Sweden)

    D. V. Dmitriyev

    2008-01-01

    Full Text Available Increased pulmonary vascular resistance in preterm infants is associated with acute respiratory failure (ARF and at the same time endothelin-1 (E-1 plays an important role in neonatal pulmonary vascular responsiveness. Methods. Endothelin-1 levels were measured in two blood samples in 12 preterm infants with ARF and in 12 controls (at 32.2±1.3 and 29.8±1.2 weeks of gestation, respectively by enzyme immunoassay. For this, the first and second blood samples were taken at 18 to 40 hours after birth. Results. The plasma level of E-1 in the first sample did not differ between the neonates of both groups. In the second sample, significantly higher E-1 concentrations were observed in the newborns with ARF than in the controls. In the first sample, E-1 concentration were higher than in the second one in both groups (p<0.001. There was a significant positive correlation between the second E-1 sample and the SNAPPE 2 scale rating (r=0.38; p=0.02. The plasma level of E-1 in the first sample did not differ in both groups (11.9 and 12.2 pg/ml, respectively. Conclusion. Neonates with and without ARF had the similar plasma E-1 levels in the first sample, by taking into account the fact that the E-1 levels were higher in ARF than in the controls at 18 to 40 hour after birth. Increased vascular resistance in ARF may be associated with the high level of E-1. Key words: endothe-lin-1, acute respiratory failure.

  9. Plasma Interleukin-8 and Endothelin-1 in Symptomatic and Asymptomatic Children

    International Nuclear Information System (INIS)

    Radwan, Z.; El-Abiad, N.; Soliman, M. S.; Ali, A.I.; Ali, G.S.

    2004-01-01

    This study was designed to evaluate the extent to which IL-8 and endothelin-1 are involved in the development of acute exacerbation of atopic asthma. Two asthmatic groups, each of 20 patients were studied, the asymptomatic group where patients were free of symptoms and the symptomatic group where patients were suffering from acute exacerbation of their asthma. Both of asthmatic groups were subclassified into mild and moderate subgroups, each of 10 patients according to the asthma severity. All subjects were subjected to chest X-ray and peak expiratory flow rate (PEFR) recording for sub-classification of patients, skin prick testing using common allergens (patients only) for the identification of atopic asthmatic patients and laboratory investigations including complete blood count (CBC), absolute eosi-nophil count (AEC), urine and stool exam-ination, total serum 1 gE level, plasma inter-leukin-8 (IL-8) level and plasma endothelin-1 (ET-1) level. The data obtained revealed non-significant differences between the studied groups as regards AEC, while serum total 1 gE of the asthmatic groups showed highly significant elevations in comparison to control group. Also, There were highly significant elevations in plasma endothelin-1 and plasma IL-8 levels of the symptomatic asthmatic subgroups in comparison to control group and asymptomatic asthmatic subgroups in comparison to control group and asymptomatic asthmatic subgroups. In conclusion: although it is clear now that IL-8 and ET-1 are involved in acute exacerbation of atopic asthmatic patients, a causal link between those mediators and development of the exacerbation has not been definitively established. Surely, those mediators, their receptors, synthesis and degradation pathways offer potentially important therapeutic targets

  10. The vascular endothelial growth factor receptor inhibitor sunitinib causes a preeclampsia-like syndrome with activation of the endothelin system

    DEFF Research Database (Denmark)

    Kappers, Mariëtte H W; Smedts, Frank M M; Horn, Thomas

    2011-01-01

    of endothelin 1, decreased nitric oxide (NO) bioavailability, and increased oxidative stress in the development of sunitinib-induced hypertension and renal toxicity. In rats on sunitinib, light and electron microscopic examination revealed marked glomerular endotheliosis, a characteristic histological feature...... be prevented with the endothelin receptor antagonist macitentan (¿BP: 12.3±1.5 mm Hg) and only mildly with Tempol, a superoxide dismutase mimetic (¿BP: 25.9±2.3 mm Hg). Both compounds could not prevent the sunitinib-induced rise in serum creatinine or renal histological abnormalities and had no effect on urine...

  11. The vascular endothelial growth factor receptor inhibitor sunitinib causes a preeclampsia-like syndrome with activation of the endothelin system

    DEFF Research Database (Denmark)

    Kappers, Mariëtte H W; Smedts, Frank M M; Horn, Thomas

    2011-01-01

    of endothelin 1, decreased nitric oxide (NO) bioavailability, and increased oxidative stress in the development of sunitinib-induced hypertension and renal toxicity. In rats on sunitinib, light and electron microscopic examination revealed marked glomerular endotheliosis, a characteristic histological feature...... be prevented with the endothelin receptor antagonist macitentan (ΔBP: 12.3±1.5 mm Hg) and only mildly with Tempol, a superoxide dismutase mimetic (ΔBP: 25.9±2.3 mm Hg). Both compounds could not prevent the sunitinib-induced rise in serum creatinine or renal histological abnormalities and had no effect on urine...

  12. Cardiac contractility, central haemodynamics and blood pressure regulation during semistarvation

    DEFF Research Database (Denmark)

    Stokholm, K H; Breum, L; Astrup, A

    1991-01-01

    pressure (BP) declined. The fall in BP was caused by the reduction in cardiac output as the total peripheral resistance was unchanged. Finally, the decline in total blood volume was not significant. These findings together with a reduction in heart rate indicated that a reduced sympathetic tone via......Eight obese patients were studied before and after 2 weeks of treatment by a very-low-calorie diet (VLCD). Cardiac output and central blood volume (pulmonary blood volume and left atrial volume) were determined by indicator dilution (125I-albumin) and radionuclide angiocardiography (first pass...... and equilibrium technique by [99Tcm]red blood cells). Cardiac output decreased concomitantly with the reduction in oxygen uptake as the calculated systemic arteriovenous difference of oxygen was unaltered. There were no significant decreases in left ventricular contractility indices, i.e. the ejection fraction...

  13. The changes in plasma endothelin after dosing intervention in type 2 diabetes and its clinical significance

    International Nuclear Information System (INIS)

    Yang Xixiu; Sun Jinfeng; Li Lusheng; Wang Shufang; Zhao Xin

    2002-01-01

    To explore the correlation of endothelin (ET), insulin resistance and microvascular complications in type 2 diabetes, the serum concentrations of OGTT, INS, C-P and plasma ET were measured by radioimmunoassay in 30 normal subjects and 82 patients with type 2 diabetes. ET level had a linear negative correlationship with IAI. The level of ET were significantly greater in group with microangiopathy than in group without microangiopathy (P<0.01). Insulin sensitivity are strongly correlated with vascular endothelial cells. The intervention may play an important role in decreasing insulin resistance of type 2 diabetes, and it is a vascular complications

  14. Endothelin-3 production by human rhabdomyosarcoma: a possible new marker with a paracrine role.

    Science.gov (United States)

    Palladini, Arianna; Astolfi, Annalisa; Croci, Stefania; De Giovanni, Carla; Nicoletti, Giordano; Rosolen, Angelo; Sartori, Francesca; Lollini, Pier-Luigi; Landuzzi, Lorena; Nanni, Patrizia

    2006-03-01

    Several autocrine and paracrine growth factor circuits have been found in human rhabdomyosarcoma cells. In this study we show that endothelin-3 (ET-3), a vasoactive peptide, is produced by human rhabdomyosarcoma cell lines, whereas it is not expressed by human sarcoma cell lines of non-muscle origin. We did not find evidence of a significant autocrine loop; nevertheless ET-3 produced by rhabdomyosarcoma cells can act as a paracrine factor, since it promotes migration of endothelial cells. Moreover ET-3 is present in plasma of mice bearing xenografts of human rhabdomyosarcoma cells, and may be potential new marker of the human rhabdomyosarcoma to be studied further.

  15. Matrix elasticity regulates the optimal cardiac myocyte shape for contractility

    Science.gov (United States)

    McCain, Megan L.; Yuan, Hongyan; Pasqualini, Francesco S.; Campbell, Patrick H.

    2014-01-01

    Concentric hypertrophy is characterized by ventricular wall thickening, fibrosis, and decreased myocyte length-to-width aspect ratio. Ventricular thickening is considered compensatory because it reduces wall stress, but the functional consequences of cell shape remodeling in this pathological setting are unknown. We hypothesized that decreases in myocyte aspect ratio allow myocytes to maximize contractility when the extracellular matrix becomes stiffer due to conditions such as fibrosis. To test this, we engineered neonatal rat ventricular myocytes into rectangles mimicking the 2-D profiles of healthy and hypertrophied myocytes on hydrogels with moderate (13 kPa) and high (90 kPa) elastic moduli. Actin alignment was unaffected by matrix elasticity, but sarcomere content was typically higher on stiff gels. Microtubule polymerization was higher on stiff gels, implying increased intracellular elastic modulus. On moderate gels, myocytes with moderate aspect ratios (∼7:1) generated the most peak systolic work compared with other cell shapes. However, on stiffer gels, low aspect ratios (∼2:1) generated the most peak systolic work. To compare the relative contributions of intracellular vs. extracellular elasticity to contractility, we developed an analytical model and used our experimental data to fit unknown parameters. Our model predicted that matrix elasticity dominates over intracellular elasticity, suggesting that the extracellular matrix may potentially be a more effective therapeutic target than microtubules. Our data and model suggest that myocytes with lower aspect ratios have a functional advantage when the elasticity of the extracellular matrix decreases due to conditions such as fibrosis, highlighting the role of the extracellular matrix in cardiac disease. PMID:24682394

  16. Progesterone Metabolites Produced by Cytochrome P450 3A Modulate Uterine Contractility in a Murine Model

    Science.gov (United States)

    Patil, Avinash S.; Swamy, Geeta K.; Murtha, Amy P.; Heine, R. Phillips; Zheng, Xiaomei; Grotegut, Chad A.

    2015-01-01

    Objective: We seek to characterize the effect of progesterone metabolites on spontaneous and oxytocin-induced uterine contractility. Study Design: Spontaneous contractility was studied in mouse uterine horns after treatment with progesterone, 2α-hydroxyprogesterone, 6β-hydroxyprogesterone (6β-OHP), 16α-hydroxyprogesterone (16α-OHP), or 17-hydroxyprogesterone caproate (17-OHPC) at 10−9 to 10−6 mol/L. Uterine horns were exposed to progestins (10−6 mol/L), followed by increasing concentrations of oxytocin (1-100 nmol/L) to study oxytocin-induced contractility. Contraction parameters were compared for each progestin and matched vehicle control using repeated measures 2-way analysis of variance. In vitro metabolism of progesterone by recombinant cytochrome P450 3A (CYP3A) microsomes (3A5, 3A5, and 3A7) identified major metabolites. Results: Oxytocin-induced contractile frequency was decreased by 16α-OHP (P = .03) and increased by 6β-OHP (P = .05). Progesterone and 17-OHPC decreased oxytocin-induced contractile force (P = .02 and P = .04, respectively) and frequency (P = .02 and P = .03, respectively). Only progesterone decreased spontaneous contractile force (P = .02). Production of 16α-OHP and 6β-OHP metabolites were confirmed in all CYP3A isoforms tested. Conclusion: Progesterone metabolites produced by maternal or fetal CYP3A enzymes influence uterine contractility. PMID:26037300

  17. The Endothelin Type A Receptor as a Potential Therapeutic Target in Preeclampsia.

    Science.gov (United States)

    Bakrania, Bhavisha; Duncan, Jeremy; Warrington, Junie P; Granger, Joey P

    2017-02-28

    Preeclampsia (PE) is a disorder of pregnancy typically characterized by new onset hypertension after gestational week 20 and proteinuria. Although PE is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disease remain unclear and treatment options are limited. However, there is increasing evidence to suggest that endothelin-1 (ET-1) plays a critical role in the pathophysiology of PE. Multiple studies report that ET-1 is increased in PE and some studies report a positive correlation between ET-1 and the severity of symptoms. A number of experimental models of PE are also associated with elevated tissue levels of prepro ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 infusion, Tumor necrosis factor (TNF) -α infusion, and Angiotensin II type 1 receptor autoantibody (AT1-AA) infusion) have proven to be susceptible to Endothelin Type A (ET A ) receptor antagonism. While the results are promising, further work is needed to determine whether ET antagonists could provide an effective therapy for the management of preeclampsia.

  18. Low levels of plasma endothelin-1 in patients with retinitis pigmentosa

    Directory of Open Access Journals (Sweden)

    Hiroshi Ohguro

    2010-06-01

    Full Text Available Hiroshi Ohguro1, Yukihiko Mashima2, Mitsuru Nakazawa31Department of Ophthalmology, Sapporo Medical University School of Medicine, 2Department of Ophthalmology, Keio University School of Medicine, 3Department of Ophthalmology, Hirosaki University School of Medicine, JapanPurpose: The aim of this study was to elucidate the role of endothelin-1 (ET-1 in the pathophysiology of retinitis pigmentosa (RP.Methods: Plasma ET-1 levels and ophthalmic features in 50 RP patients were compared with those in 20 healthy-eye control subjects. Plasma ET-1 concentrations were determined using a commercially available enzyme-linked immunosorbent assay kit.Results: Mean plasma ET-1 levels of RP patients (1.88 ± 0.56 pg/mL were significantly lower than those of control subjects (2.30 ± 0.30 pg/mL, Mann-Whitney’s U test; P < 0.01. However, ET-1 concentrations varied markedly in each patient. Among RP patients, a significant correlation of ET-1 concentrations was not observed in terms of its hereditary forms or other clinical factors.Conclusion: ET-1 may be important in the pathogenesis of RP, and measurement of its plasma concentrations may also contribute to additional insights into the retinal hemodynamics of RP.Keywords: endothelin-1, retinitis pigmentosa, retinal hemodynamics

  19. Down-regulation of endothelin binding sites in rat vascular smooth muscle cells

    International Nuclear Information System (INIS)

    Roubert, P.; Gillard, V.; Plas, P.; Chabrier, P.E.; Braquet, P.

    1990-01-01

    In cultured rat aortic smooth muscle cells, [ 125 I]endothelin (ET-1) bound to an apparent single class of high affinity recognition sites with a dissociation constant of 1.84 +/- 0.29 nmol/L and a maximum binding of 62 +/- 10.5 fmol/10(6) cells. The binding was not affected by calcium antagonists or vasoactive substances, including angiotensin II, arginine vasopressin, atrial natriuretic factor and bradykinin. Exposure of the cells to ET-1 (0.01 nmol/L to 10 nmol/L) resulted in an apparent dose-dependent reduction of the number of endothelin binding sites with no significant modification of its binding affinity. The time course of the down-regulation of ET-1 binding sites showed that this effect was present after 30 min incubation and persisted after 18 h. This indicates that down-regulation of ET-1 binding sites can modulate the activity of ET-1 and suggests a rapid internalization of ET-1 in vascular cells

  20. Subarachnoid hemorrhage enhances endothelin receptor expression and function in rat cerebral arteries

    DEFF Research Database (Denmark)

    Hansen-Schwartz, Jacob; Hoel, Natalie Løvland; Zhou, Mingfang

    2003-01-01

    OBJECTIVE: Inspired by organ culture-induced changes in the vascular endothelin (ET) receptor population, we investigated whether such changes occur in cerebral arteries in a rat subarachnoid hemorrhage (SAH) model. METHODS: SAH was induced with injection of 250 microl of blood into the prechiasm......OBJECTIVE: Inspired by organ culture-induced changes in the vascular endothelin (ET) receptor population, we investigated whether such changes occur in cerebral arteries in a rat subarachnoid hemorrhage (SAH) model. METHODS: SAH was induced with injection of 250 microl of blood...... into the prechiasmatic cistern. After 2 days, the middle cerebral artery, basilar artery, and posterior communicating artery were harvested. Pharmacological studies were performed in vitro, and levels of messenger ribonucleic acid (mRNA) were quantified in real-time reverse transcriptase-polymerase chain reaction assays....... RESULTS: In the middle cerebral artery and basilar artery from rats with induced SAH, enhanced biphasic responses to ET-1 were observed. The -log(50% effective concentration) value for the high-affinity phase was approximately 12, compared with approximately 8.5 for sham-operated animals...

  1. Overexpression of endothelin B receptor in glioblastoma: a prognostic marker and therapeutic target?

    KAUST Repository

    Vasaikar, Suhas

    2018-02-06

    BackgroundGlioblastoma (GBM) is the most common malignant brain tumor with median survival of 12-15 months. Owing to uncertainty in clinical outcome, additional prognostic marker(s) apart from existing markers are needed. Since overexpression of endothelin B receptor (ETBR) has been demonstrated in gliomas, we aimed to test whether ETBR is a useful prognostic marker in GBM and examine if the clinically available endothelin receptor antagonists (ERA) could be useful in the disease treatment.MethodsData from The Cancer Genome Atlas and the Gene Expression Omnibus database were analyzed to assess ETBR expression. For survival analysis, glioblastoma samples from 25 Swedish patients were immunostained for ETBR, and the findings were correlated with clinical history. The druggability of ETBR was assessed by protein-protein interaction network analysis. ERAs were analyzed for toxicity in in vitro assays with GBM and breast cancer cells.ResultsBy bioinformatics analysis, ETBR was found to be upregulated in glioblastoma patients, and its expression levels were correlated with reduced survival. ETBR interacts with key proteins involved in cancer pathogenesis, suggesting it as a druggable target. In vitro viability assays showed that ERAs may hold promise to treat glioblastoma and breast cancer.ConclusionsETBR is overexpressed in glioblastoma and other cancers and may be a prognostic marker in glioblastoma. ERAs may be useful for treating cancer patients.

  2. Protective effect of estrogen in endothelin-induced middle cerebral artery occlusion in female rats.

    Science.gov (United States)

    Glendenning, Michele L; Lovekamp-Swan, Tara; Schreihofer, Derek A

    2008-11-14

    Estrogen is a powerful endogenous and exogenous neuroprotective agent in animal models of brain injury, including focal cerebral ischemia. Although this protection has been demonstrated in several different treatment and injury paradigms, it has not been demonstrated in focal cerebral ischemia induced by intraparenchymal endothelin-1 injection, a model with many advantages over other models of experimental focal ischemia. Reproductively mature female Sprague-Dawley rats were ovariectomized and divided into placebo and estradiol-treated groups. Two weeks later, halothane-anesthetized rats underwent middle cerebral artery (MCA) occlusion by interparenchymal stereotactic injection of the potent vasoconstrictor endothelin 1 (180pmoles/2microl) near the middle cerebral artery. Laser-Doppler flowmetry (LDF) revealed similar reductions in cerebral blood flow in both groups. Animals were behaviorally evaluated before, and 2 days after, stroke induction, and infarct size was evaluated. In agreement with other models, estrogen treatment significantly reduced infarct size evaluated by both TTC and Fluoro-Jade staining and behavioral deficits associated with stroke. Stroke size was significantly correlated with LDF in both groups, suggesting that cranial perfusion measures can enhance success in this model.

  3. The Role of Endothelin System in Renal Structure and Function during the Postnatal Development of the Rat Kidney.

    Science.gov (United States)

    Albertoni Borghese, María F; Ortiz, María C; Balonga, Sabrina; Moreira Szokalo, Rocío; Majowicz, Mónica P

    2016-01-01

    Renal development in rodents, unlike in humans, continues during early postnatal period. We aimed to evaluate whether the pharmacological inhibition of Endothelin system during this period affects renal development, both at structural and functional level in male and female rats. Newborn rats were treated orally from postnatal day 1 to 20 with vehicle or bosentan (Actelion, 20 mg/kg/day), a dual endothelin receptor antagonist (ERA). The animals were divided in 4 groups: control males, control females, ERA males and ERA females. At day 21, we evaluated renal function, determined the glomerular number by a maceration method and by morphometric analysis and evaluated possible structural renal alterations by three methods: 〈alpha〉-Smooth muscle actin (α-SMA) immunohistochemistry, Masson's trichrome and Sirius red staining. The pharmacological inhibition of Endothelin system with a dual ERA during the early postnatal period of the rat did not leads to renal damage in the kidneys of male and female rats. However, ERA administration decreased the number of glomeruli, the juxtamedullary filtration surface area and the glomerular filtration rate and increased the proteinuria. These effects could predispose to hypertension or renal diseases in the adulthood. On the other hand, these effects were more pronounced in male rats, suggesting that there are sex differences that could be greater later in life. These results provide evidence that Endothelin has an important role in rat renal postnatal development. However these results do not imply that the same could happen in humans, since human renal development is complete at birth.

  4. Endothelin-1 Mediates Brain Microvascular Dysfunction Leading to Long-Term Cognitive Impairment in a Model of Experimental Cerebral Malaria.

    Directory of Open Access Journals (Sweden)

    Brandi D Freeman

    2016-03-01

    Full Text Available Plasmodium falciparum infection causes a wide spectrum of diseases, including cerebral malaria, a potentially life-threatening encephalopathy. Vasculopathy is thought to contribute to cerebral malaria pathogenesis. The vasoactive compound endothelin-1, a key participant in many inflammatory processes, likely mediates vascular and cognitive dysfunctions in cerebral malaria. We previously demonstrated that C57BL6 mice infected with P. berghei ANKA, our fatal experimental cerebral malaria model, sustained memory loss. Herein, we demonstrate that an endothelin type A receptor (ETA antagonist prevented experimental cerebral malaria-induced neurocognitive impairments and improved survival. ETA antagonism prevented blood-brain barrier disruption and cerebral vasoconstriction during experimental cerebral malaria, and reduced brain endothelial activation, diminishing brain microvascular congestion. Furthermore, exogenous endothelin-1 administration to P. berghei NK65-infected mice, a model generally regarded as a non-cerebral malaria negative control for P. berghei ANKA infection, led to experimental cerebral malaria-like memory deficits. Our data indicate that endothelin-1 is critical in the development of cerebrovascular and cognitive impairments with experimental cerebral malaria. This vasoactive peptide may thus serve as a potential target for adjunctive therapy in the management of cerebral malaria.

  5. Effect of the dual endothelin receptor antagonist bosentan on untreatable skin ulcers in a patient with diabetes: a case report

    Directory of Open Access Journals (Sweden)

    Brito Suárez Manuel

    2011-04-01

    Full Text Available Abstract Introduction Refractory skin ulcers are a major burden in patients with diabetes. Their pathogenesis is multifactorial, and data increasingly implicate endothelin as a mediator of diabetic macro- and microvasculopathy. Here we describe the first reported case of an endothelin receptor antagonist being used to successfully treat refractory skin ulcers in a patient with diabetes. Case presentation An 85-year-old Caucasian man with a 30-year history of type 2 diabetes developed multiple skin ulcerations, including a right heel ulcer. Despite appropriate treatment, the ulcer showed little improvement and the risk of amputation was high. The patient was treated with the dual endothelin receptor antagonist bosentan. After three weeks of treatment, major improvements were observed, and after 21 weeks, all ulcers had healed. No abnormalities were observed during monitoring of blood pressure, erythrocyte sedimentation rate or serum aminotransferase levels. Conclusion In patients with refractory ulceration associated with diabetes, bosentan may be of real benefit, especially in terms of amputation prevention. This case supports the proposed role for endothelin in the pathogenesis of skin ulceration in diabetes and is suggestive of a potential benefit of bosentan in this patient type. This case report is of interest to diabetologists and dermatologists.

  6. Progestins oppose the effects of estradiol on the endothelin-1 receptor type B in coronary arteries from ovariectomized hyperlipidemic rabbits

    DEFF Research Database (Denmark)

    Pedersen, Susan H; Nielsen, Lars B; Mortensen, Alicja

    2008-01-01

    OBJECTIVE: Progestins may be associated with the adverse cardiovascular outcomes observed with estrogen plus progestogen therapy, but the mechanism is not resolved. In this study we examined the effect of 17beta-estradiol (E2) alone and in combination with two progestins on the endothelin-1 (ET-1...

  7. Up-Regulation of Endothelin Type A Receptor in Human and Rat Radiation Proctitis: Preclinical Therapeutic Approach With Endothelin Receptor Blockade

    International Nuclear Information System (INIS)

    Jullien, Nicolash; Blirando, Karl; Milliat, Fabien; Sabourin, Jean-Christophe; Benderitter, Marc; Francois, Agnes

    2009-01-01

    Purpose: Rectum radiation damage and fibrosis are often associated with radiation therapy of pelvic tumors. The endothelin (ET) system has been implicated in several fibrotic diseases but never studied in the context of gastrointestinal radiation damage. This study assessed modifications in ET type 1 (ET-1), ET type A receptor (ET A ), and ET type B receptor (ET B ) localization and/or expression in irradiated human rectal tissue and in a rat model of delayed colorectal injury. We also evaluated the therapeutic potential of long-term ET receptor blockade. Methods and Materials: Routine histological studies of sections of healthy and radiation-injured human rectum tissue were done; the sections were also immunostained for ET A and ET B receptors. The rat model involved the delivery of 27 Gy in a single dose to the colons and rectums of the animals. The ET-1/ET A /ET B expression and ET A /ET B localization were studied at 10 weeks postexposure. The abilities of bosentan and atrasentan to protect against delayed rectal injury were also investigated. Results: The immunolocalization of ET A and ET B in healthy human rectums was similar to that in rat rectums. However, strong ET A immunostaining was seen in the presence of human radiation proctitis, and increased ET A mRNA levels were seen in the rat following colorectal irradiation. Immunostaining for ET A was also strongly positive in rats in areas of radiation-induced mucosal ulceration, atypia, and fibroproliferation. However, neither bosentan nor atrasentan prevented radiation damage to the rectum when given long term. The only effect seen for atrasentan was an increased number of sclerotic vessel sections in injured tissues. Conclusions: As the result of the overexpression of ET A , radiation exposure deregulates the endothelin system through an 'ET A profile' in the human and rodent rectum. However, therapeutic interventions involving mixed or specific ET A receptor blockade do not prevent radiation damage

  8. Stimulation of phospholipase C in cultured microvascular endothelial cells from human frontal lobe by histamine, endothelin and purinoceptor agonists.

    Science.gov (United States)

    Purkiss, J. R.; West, D.; Wilkes, L. C.; Scott, C.; Yarrow, P.; Wilkinson, G. F.; Boarder, M. R.

    1994-01-01

    1. Cultures of endothelial cells derived from the microvasculature of human frontal lobe have been investigated for phospholipase C (PLC) responses to histamine, endothelins and purinoceptor agonists. 2. Using cells prelabelled with [3H]-inositol and measuring total [3H]-inositol (poly)phosphates, histamine acting at H1 receptors stimulated a substantial response with an EC50 of about 10 microM. 3. Endothelin-1 also gave a clear stimulation of phosphoinositide-specific phospholipase C. Both concentration-response curves and binding curves showed effective responses and binding in the rank order of endothelin-1 > sarafotoxin S6b > endothelin-3, suggesting an ETA receptor. 4. Assay of total [3H]-inositol (poly)phosphates showed no response to the purinoceptor agonists, 2-methylthioadenosine 5'-trisphosphate (2MeSATP), adenosine 5'-O-(3-thiotrisphosphate) (ATP gamma S) or beta,gamma-methylene ATP. Both ATP and UTP gave a small PLC response. 5. Similarly, when formation of [32P]-phosphatidic acid from cells prelabelled with 32Pi was used as an index of both PLC and phospholipase D, a small response to ATP and UTP was seen but there was no response to the other purinoceptor agonists tested. 6. Study by mass assay of stimulation by ATP of inositol (1,4,5) trisphosphate accumulation revealed a transient response in the first few seconds, a decline to basal, followed by a small sustained response. 7. These results show that human brain endothelial cells in culture are responsive to histamine and endothelins in a manner which may regulate brain capillary permeability. Purines exert a lesser influence. PMID:8032588

  9. Enhanced expressions of microvascular smooth muscle receptors after focal cerebral ischemia occur via the MAPK MEK/ERK pathway

    Directory of Open Access Journals (Sweden)

    Edvinsson Lars

    2008-09-01

    Full Text Available Abstract Background MEK1/2 is a serine/threonine protein that phosphorylates extracellular signal-regulated kinase (ERK1/2. Cerebral ischemia results in enhanced expression of cerebrovascular contractile receptors in the middle cerebral artery (MCA leading to the ischemic region. Here we explored the role of the MEK/ERK pathway in receptor expression following ischemic brain injury using the specific MEK1 inhibitor U0126. Methods and result Rats were subjected to a 2-h middle cerebral artery occlusion (MCAO followed by reperfusion for 48-h and the ischemic area was calculated. The expression of phosphorylated ERK1/2 and Elk-1, and of endothelin ETA and ETB, angiotensin AT1, and 5-hydroxytryptamine 5-HT1B receptors were analyzed with immunohistochemistry using confocal microscopy in cerebral arteries, microvessels and in brain tissue. The expression of endothelin ETB receptor was analyzed by quantitative Western blot. We demonstrate that there is an increase in the number of contractile smooth muscle receptors in the MCA and in micro- vessels within the ischemic region. The enhanced expression occurs in the smooth muscle cells as verified by co-localization studies. This receptor upregulation is furthermore associated with enhanced expression of pERK1/2 and of transcription factor pElk-1 in the vascular smooth muscle cells. Blockade of transcription with the MEK1 inhibitor U0126, given at the onset of reperfusion or as late as 6 hours after the insult, reduced transcription (pERK1/2 and pElk-1, the enhanced vascular receptor expression, and attenuated the cerebral infarct and improved neurology score. Conclusion Our results show that MCAO results in upregulation of cerebrovascular ETB, AT1 and 5-HT1B receptors. Blockade of this event with a MEK1 inhibitor as late as 6 h after the insult reduced the enhanced vascular receptor expression and the associated cerebral infarction.

  10. Quantifying esophagogastric junction contractility with a novel HRM topographic metric, the EGJ-Contractile Integral: normative values and preliminary evaluation in PPI non-responders.

    Science.gov (United States)

    Nicodème, F; Pipa-Muniz, M; Khanna, K; Kahrilas, P J; Pandolfino, J E

    2014-03-01

    Despite its obvious pathophysiological relevance, the clinical utility of measures of esophagogastric junction (EGJ) contractility is unsubstantiated. High-resolution manometry (HRM) may improve upon this with its inherent ability to integrate the magnitude of contractility over time and length of the EGJ. This study aimed to develop a novel HRM metric summarizing EGJ contractility and test its ability distinguish among subgroups of proton pump inhibitor non-responders (PPI-NRs). 75 normal controls and 88 PPI-NRs were studied. All underwent HRM. PPI-NRs underwent pH-impedance monitoring on PPI therapy scored in terms of acid exposure, number of reflux events, and reflux-symptom correlation and grouped as meeting all criteria, some criteria, or no criteria of abnormality. Control HRM studies were used to establish normal values for candidate EGJ contractility metrics, which were then compared in their ability to differentiate among PPI-NR subgroups. The EGJ contractile integral (EGJ-CI), a metric integrating contractility across the EGJ for three respiratory cycles, best distinguished the All Criteria PPI-NR subgroup from controls and other PPI-NR subgroups. Normal values (median, [IQR]) for this measure were 39 mmHg-cm [25-55 mmHg-cm]. The correlation between the EGJ-CI and a previously proposed metric, the lower esophageal sphincter-pressure integral, that used a fixed 10 s time frame and an atmospheric as opposed to gastric pressure reference was weak. Among HRM metrics tested, the EGJ-CI was best in distinguishing PPI-NRs meeting all criteria of abnormality on pH-impedance testing. Future prospective studies are required to explore its utility in management of broader groups of gastroesophageal reflux disease patients. © 2013 John Wiley & Sons Ltd.

  11. Adipose-derived stem cells inhibit the contractile myofibroblast in Dupuytren's disease.

    NARCIS (Netherlands)

    Verhoekx, J.S.; Mudera, V.; Walbeehm, E.T.; Hovius, S.E.

    2013-01-01

    BACKGROUND: In an attempt to provide minimally invasive treatment for Dupuytren's disease, percutaneous disruption of the affected tissue followed by lipografting is being tested. Contractile myofibroblasts drive this fibroproliferative disorder, whereas stem cells have recently been implicated in

  12. Considerations for Contractile Electroactive Polymeric Materials and Actuators

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Lenore; Erickson, Carl J.; Meixler, Lewis D.; Ascione, George; Gentile, Charles A.; Tilson, Charles; Bernasek, Stephen L.; Abelev, Esta

    2009-06-16

    Ras Labs produces electroactive polymer (EAP) based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life-like motion. The mechanism of contraction is not well understood. Radionuclide-labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode-EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing, and mechanical testing were conducted to test metal surfaces and metal-polymer interfaces. The nitrogen plasma treatment of titanium produced a strong metal-polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal-polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface.

  13. Mechanism of action of ethanol on heart contractility

    International Nuclear Information System (INIS)

    Oquendo-Muriente, I.; De Mello, W.C.

    1986-01-01

    Ethanol depresses heart contractility. To investigate the mechanism of the negative inotropic action of ethanol, rat ventricular strips were dissected and mounted vertically in a transparent chamber. The preparation was superfused initially with normal oxygenated Tyrode solution (32.5 0 C) and electrically stimulated (1 Hz). After 1 hour of equilibration, contractures were elicited by exposing the muscle strips to high K + (100 mM) solution. Studies on the influence of (Ca 2+ ) 0 on K + contractures showed that the first rapid component of the contracture (58 mg/sec - S.E. +/- 8; n = 8) was greatly dependent upon (Ca 2+ ) 0 while the second slow component (20 mg/sec - S.E. +/- 5; n = 8) was slightly altered. The addition of ethanol (400 mg/100 ml) to high K solution abolished the fast component and reduced the amplitude of the second phase of K contractures. Similar results were obtained with verapamil (10 -5 M). These results, as well as studies on the effect of the drug on 45 Ca fluxes support the view that ethanol decreases the permeability of the heart cell membrane to Ca

  14. Mechanism of action of ethanol on heart contractility

    Energy Technology Data Exchange (ETDEWEB)

    Oquendo-Muriente, I.; De Mello, W.C.

    1986-03-05

    Ethanol depresses heart contractility. To investigate the mechanism of the negative inotropic action of ethanol, rat ventricular strips were dissected and mounted vertically in a transparent chamber. The preparation was superfused initially with normal oxygenated Tyrode solution (32.5/sup 0/C) and electrically stimulated (1 Hz). After 1 hour of equilibration, contractures were elicited by exposing the muscle strips to high K/sup +/ (100 mM) solution. Studies on the influence of (Ca/sup 2 +/)/sub 0/ on K/sup +/ contractures showed that the first rapid component of the contracture (58 mg/sec - S.E. +/- 8; n = 8) was greatly dependent upon (Ca/sup 2 +/)/sub 0/ while the second slow component (20 mg/sec - S.E. +/- 5; n = 8) was slightly altered. The addition of ethanol (400 mg/100 ml) to high K solution abolished the fast component and reduced the amplitude of the second phase of K contractures. Similar results were obtained with verapamil (10/sup -5/ M). These results, as well as studies on the effect of the drug on /sup 45/Ca fluxes support the view that ethanol decreases the permeability of the heart cell membrane to Ca.

  15. Contractile Force of Human Extraocular Muscle: A Theoretical Analysis

    Directory of Open Access Journals (Sweden)

    Hongmei Guo

    2016-01-01

    Full Text Available Aim. The length-contractile force relationships of six human extraocular muscles (EOMs in primary innervations should be determined during eye movement modeling and surgery of clinical EOMs. This study aims to investigate these relationships. Method. The proposal is based on the assumption that six EOMs have similar constitutive relationships, with the eye suspended in the primary position. The constitutive relationships of EOMs are obtained by optimizing from previous experimental data and the theory of mechanical equilibrium using traditional model. Further, simulate the existing experiment of resistance force, and then compare the simulated results with the existing experimental results. Finally, the mechanical constitutive relationships of EOMs are obtained. Results. The results show that the simulated resistance forces from the other four EOMs except for the horizontal recti well agree with previous experimental results. Conclusion. The mechanical constitutive relationships of six EOMs in primary innervations are obtained, and the rationality of the constitutive relationships is verified. Whereafter, the active stress-strain relationships of the six EOMs in the primary innervations are obtained. The research results can improve the eye movement model to predict the surgical amounts of EOMs before EOM surgery more precisely.

  16. Postextrasystolic potentiation and contractile reserve: requirements and restrictions.

    Science.gov (United States)

    Lust, R M; Lutherer, L O; Gardner, M E; Cooper, M W

    1982-12-01

    These studies were conducted to examine the basic characteristics of postextrasystolic potentiation (PESP) and the relationship of loading effects to PESP. Measurements of left ventricular (LV) and aortic pressures, the rate of pressure rise, and echocardiographically determined LV dimensions were made in anesthetized open-chest dogs. The hearts were paced, and timed extrasystoles were introduced that were followed by postextrasystoles (PES). PES's were elicited after an interval equal to either a full compensatory pause or a time when the diastolic properties of the LV could not be distinguished from control (isolength). Potentiation of contraction for the PES's introduced after an isolength pause was dependent on both the heart rate and the extrasystolic interval, whereas the PES's that occurred after a full pause showed no dependence on either of these intervals. PESP elicited during the isolength period was not dependent on either preload and afterload. It is concluded that PESP depends on the combination of heart rate and extrasystolic and postextrasystolic intervals. Further, PESP may be inaccurate in assessing contractile reserve unless the heart rate and extrasystolic interval are known and the PES is introduced after an isolength pause.

  17. Considerations for Contractile Electroactive Polymeric Materials and Actuators

    International Nuclear Information System (INIS)

    Rasmussen, L.; Erickson, Carl J.; Meixler, Lewis D.; Ascione, G.; Gentile, Charles A.; Tilson, C.; Bernasek, Stephen L.; Abelev, E.

    2009-01-01

    Ras Labs produces electroactive polymer (EAP) based materials and actuators that bend, swell, ripple and now contract (new development) with low electric input. This is an important attribute because of the ability of contraction to produce life-like motion. The mechanism of contraction is not well understood. Radionuclide-labeled experiments were conducted to follow the movement of electrolytes and water in these EAPs when activated. Extreme temperature experiments were performed on the contractile EAPs with very favorable results. One of the biggest challenges in developing these actuators, however, is the electrode-EAP interface because of the pronounced movement of the EAP. Plasma treatments of metallic electrodes were investigated in order to improve the attachment of the embedded electrodes to the EAP material. Surface analysis, adhesive testing, and mechanical testing were conducted to test metal surfaces and metal-polymer interfaces. The nitrogen plasma treatment of titanium produced a strong metal-polymer interface; however, oxygen plasma treatment of both stainless steel and titanium produced even stronger metal-polymer interfaces. Plasma treatment of the electrodes allows for the embedded electrodes and the EAP material of the actuator to work and move as a unit, with no detachment, by significantly improving the metal-polymer interface

  18. Cellular Architecture Regulates Collective Calcium Signaling and Cell Contractility.

    Directory of Open Access Journals (Sweden)

    Jian Sun

    2016-05-01

    Full Text Available A key feature of multicellular systems is the ability of cells to function collectively in response to external stimuli. However, the mechanisms of intercellular cell signaling and their functional implications in diverse vascular structures are poorly understood. Using a combination of computational modeling and plasma lithography micropatterning, we investigate the roles of structural arrangement of endothelial cells in collective calcium signaling and cell contractility. Under histamine stimulation, endothelial cells in self-assembled and microengineered networks, but not individual cells and monolayers, exhibit calcium oscillations. Micropatterning, pharmacological inhibition, and computational modeling reveal that the calcium oscillation depends on the number of neighboring cells coupled via gap junctional intercellular communication, providing a mechanistic basis of the architecture-dependent calcium signaling. Furthermore, the calcium oscillation attenuates the histamine-induced cytoskeletal reorganization and cell contraction, resulting in differential cell responses in an architecture-dependent manner. Taken together, our results suggest that endothelial cells can sense and respond to chemical stimuli according to the vascular architecture via collective calcium signaling.

  19. Modeling the dispersion effects of contractile fibers in smooth muscles

    Science.gov (United States)

    Murtada, Sae-Il; Kroon, Martin; Holzapfel, Gerhard A.

    2010-12-01

    Micro-structurally based models for smooth muscle contraction are crucial for a better understanding of pathological conditions such as atherosclerosis, incontinence and asthma. It is meaningful that models consider the underlying mechanical structure and the biochemical activation. Hence, a simple mechanochemical model is proposed that includes the dispersion of the orientation of smooth muscle myofilaments and that is capable to capture available experimental data on smooth muscle contraction. This allows a refined study of the effects of myofilament dispersion on the smooth muscle contraction. A classical biochemical model is used to describe the cross-bridge interactions with the thin filament in smooth muscles in which calcium-dependent myosin phosphorylation is the only regulatory mechanism. A novel mechanical model considers the dispersion of the contractile fiber orientations in smooth muscle cells by means of a strain-energy function in terms of one dispersion parameter. All model parameters have a biophysical meaning and may be estimated through comparisons with experimental data. The contraction of the middle layer of a carotid artery is studied numerically. Using a tube the relationships between the internal pressure and the stretches are investigated as functions of the dispersion parameter, which implies a strong influence of the orientation of smooth muscle myofilaments on the contraction response. It is straightforward to implement this model in a finite element code to better analyze more complex boundary-value problems.

  20. Modifying influence of incorporated 137Cs upon the mechanisms of adrenergic control over contractile myucard function

    International Nuclear Information System (INIS)

    Lobanok, L.M.; Bulanova, K.Ya.; Gerasimovich, N.V.; Sineleva, M.V.; Milyutin, A.A.

    1994-01-01

    Incorporated 137 Cs (absorbed dose of 0.26 Gy) causes decrease of myocard's contractile function and intropic response to β-adrenagonists effect, isoproterenol-stimulated adenylate cyclase activity and β-adrenoreceptors affinity. Adrenergic effects, mediated by α-adrenergic structures on heart contractile function, on the contrary, become stronger, that is due to the increase of the receptors' dencity on sarcolemma surface

  1. Polymorphisms in nitric oxide synthase and endothelin genes among children with obstructive sleep apnea.

    Science.gov (United States)

    Chatsuriyawong, Siriporn; Gozal, David; Kheirandish-Gozal, Leila; Bhattacharjee, Rakesh; Khalyfa, Ahamed A; Wang, Yang; Sukhumsirichart, Wasana; Khalyfa, Abdelnaby

    2013-09-06

    Obstructive sleep apnea (OSA) is associated with adverse and interdependent cognitive and cardiovascular consequences. Increasing evidence suggests that nitric oxide synthase (NOS) and endothelin family (EDN) genes underlie mechanistic aspects of OSA-associated morbidities. We aimed to identify single nucleotide polymorphisms (SNPs) in the NOS family (3 isoforms), and EDN family (3 isoforms) to identify potential associations of these SNPs in children with OSA. A pediatric community cohort (ages 5-10 years) enriched for snoring underwent overnight polysomnographic (NPSG) and a fasting morning blood draw. The diagnostic criteria for OSA were an obstructive apnea-hypopnea Index (AHI) >2/h total sleep time (TST), snoring during the night, and a nadir oxyhemoglobin saturation DNA from peripheral blood was extracted and allelic frequencies were assessed for, NOS1 (209 SNPs), NOS2 (122 SNPs), NOS3 (50 SNPs), EDN1 (43 SNPs), EDN2 (48 SNPs), EDN3 (14 SNPs), endothelin receptor A, EDNRA, (27 SNPs), and endothelin receptor B, EDNRB (23 SNPs) using a custom SNPs array. The relative frequencies of NOS-1,-2, and -3, and EDN-1,-2,-3,-EDNRA, and-EDNRB genotypes were evaluated in 608 subjects [128 with OSA, and 480 without OSA (NOSA)]. Furthermore, subjects with OSA were divided into 2 subgroups: OSA with normal endothelial function (OSA-NEF), and OSA with endothelial dysfunction (OSA-ED). Linkage disequilibrium was analyzed using Haploview version 4.2 software. For NOSA vs. OSA groups, 15 differentially distributed SNPs for NOS1 gene, and 1 SNP for NOS3 emerged, while 4 SNPs for EDN1 and 1 SNP for both EDN2 and EDN3 were identified. However, in the smaller sub-group for whom endothelial function was available, none of the significant SNPs was retained due to lack of statistical power. Differences in the distribution of polymorphisms among NOS and EDN gene families suggest that these SNPs could play a contributory role in the pathophysiology and risk of OSA-induced cardiovascular

  2. Reliability of contractile properties of the knee extensor muscles in individuals with post-polio syndrome.

    Directory of Open Access Journals (Sweden)

    Eric L Voorn

    Full Text Available To assess the reliability of contractile properties of the knee extensor muscles in 23 individuals with post-polio syndrome (PPS and 18 age-matched healthy individuals.Contractile properties of the knee extensors were assessed from repeated electrically evoked contractions on 2 separate days, with the use of a fixed dynamometer. Reliability was determined for fatigue resistance, rate of torque development (MRTD, and early and late relaxation time (RT50 and RT25, using the intraclass correlation coefficient (ICC and standard error of measurement (SEM, expressed as % of the mean.In both groups, reliability for fatigue resistance was good, with high ICCs (>0.90 and small SEM values (PPS: 7.1%, healthy individuals: 7.0%. Reliability for contractile speed indices varied, with the best values found for RT50 (ICCs>0.82, SEM values <2.8%. We found no systematic differences between test and retest occasions, except for RT50 in healthy subjects (p = 0.016.In PPS and healthy individuals, the reliability of fatigue resistance, as obtained from electrically evoked contractions is high. The reliability of contractile speed is only moderate, except for RT50 in PPS, demonstrating high reliability.This was the first study to examine the reliability of electrically evoked contractile properties in individuals with PPS. Our results demonstrate its potential to study mechanisms underlying muscle fatigue in PPS and to evaluate changes in contractile properties over time in response to interventions or from natural course.

  3. Thick filament length and isoform composition determine self-organized contractile units in actomyosin bundles.

    Science.gov (United States)

    Thoresen, Todd; Lenz, Martin; Gardel, Margaret L

    2013-02-05

    Diverse myosin II isoforms regulate contractility of actomyosin bundles in disparate physiological processes by variations in both motor mechanochemistry and the extent to which motors are clustered into thick filaments. Although the role of mechanochemistry is well appreciated, the extent to which thick filament length regulates actomyosin contractility is unknown. Here, we study the contractility of minimal actomyosin bundles formed in vitro by mixtures of F-actin and thick filaments of nonmuscle, smooth, and skeletal muscle myosin isoforms with varied length. Diverse myosin II isoforms guide the self-organization of distinct contractile units within in vitro bundles with shortening rates similar to those of in vivo myofibrils and stress fibers. The tendency to form contractile units increases with the thick filament length, resulting in a bundle shortening rate proportional to the length of constituent myosin thick filament. We develop a model that describes our data, providing a framework in which to understand how diverse myosin II isoforms regulate the contractile behaviors of disordered actomyosin bundles found in muscle and nonmuscle cells. These experiments provide insight into physiological processes that use dynamic regulation of thick filament length, such as smooth muscle contraction. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. A comparative study of contractility of the heart ventricle in some ectothermic vertebrates

    Directory of Open Access Journals (Sweden)

    Sergey Kharin

    2009-07-01

    Full Text Available The purpose of this study was to analyze contractility of the heart ventricle in selected reptilian and amphibian species having the same ventricular excitation pattern. Systolic time intervals and indices of contractility of the heart ventricle were measured in anaesthetized frogs, snakes, and tortoises by use of polycardiography. The electromechanical delay was significantly shorter in tortoises compared with the other two species. The isovolumetric contraction time in frogs was approximately twofold longer than in reptiles. The pre-ejection period was the longest in frogs and the shortest in tortoises, whereas snakes were intermediate. The ejection time was slightly longer in tortoises compared with the other two species. The greatest isovolumetric contraction index and the smallest myocardial tension index corresponded to the frog and tortoise heart ventricle, respectively. The intrasystolic index in tortoises was significantly greater than in frogs, whereas quite similar to that in snakes. The frog ventricle had lower contractility compared with the reptilian one. Although ventricular contractility tended to be lower in snakes compared with tortoises, this difference was not statistically significant. Possible causes for these differences are discussed. We suppose a large variety in ventricular contractility among amphibian and reptilian species having the same ventricular activation pattern. This variety may be conditioned by heart anatomy, intracardiac shunting, lifestyles, and habitats. It can only be hypothesized that on the average, ventricular contractility is higher in reptiles compared with amphibians and in chelonians compared with snakes.

  5. The effects of endothelin-1 on the cardiorespiratory physiology of the freshwater trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias).

    Science.gov (United States)

    Perry, S F; Montpetit, C J; McKendry, J; Desforges, P R; Gilmour, K M; Wood, C M; Olson, K R

    2001-11-01

    The aim of the present study was to evaluate the effects of endothelin-l-elicited cardiovascular events on respiratory gas transfer in the freshwater rainbow trout (Oncorhynchus mykiss) and the marine dogfish (Squalus acanthias). In both species, endothelin-1 (666 pmol kg(-1)) caused a rapid (within 4 min) reduction (ca. 30-50 mmHg) in arterial blood partial pressure of O2. The effects of endothelin-1 on arterial blood partial pressure of CO2 were not synchronised with the changes in O2 partial pressure and the responses were markedly different in trout and dogfish. In trout, arterial CO2 partial pressure was increased transiently by approximately 1.0 mmHg but the onset of the response was delayed and occurred 12 min after endothelin-1 injection. In contrast, CO2 partial pressure remained more-or-less constant in dogfish after injection of endothelin-1 and was increased only slightly (approximately 0.1 mmHg) after 60 min. Pre-treatment of trout with bovine carbonic anhydrase (5 mg ml(-1)) eliminated the increase in CO2 partial pressure that was normally observed after endothelin-1 injection. In both species, endothelin-1 injection caused a decrease in arterial blood pH that mirrored the changes in CO2 partial pressure. Endothelin-1 injection was associated with transient (trout) or persistent (dogfish) hyperventilation as indicated by pronounced increases in breathing frequency and amplitude. In trout, arterial blood pressure remained constant or was decreased slightly and was accompanied by a transient increase in systemic resistance, and a temporary reduction in cardiac output. The decrease in cardiac output was caused solely by a reduction in cardiac frequency; cardiac stroke volume was unaffected. In dogfish, arterial blood pressure was lowered by approximately 10 mmHg at 6-10 min after endothelin-1 injection but then was rapidly restored to pre-injection levels. The decrease in arterial blood pressure reflected an increase in branchial vascular resistance (as

  6. Selective improvement of pulmonary arterial hypertension with a dual ETA/ETB receptors antagonist in the apolipoprotein E-/- model of PAH and atherosclerosis.

    Science.gov (United States)

    Renshall, Lewis; Arnold, Nadine; West, Laura; Braithwaite, Adam; Pickworth, Josephine; Walker, Rachel; Alfaidi, Mabruka; Chamberlain, Janet; Casbolt, Helen; Thompson, A A Roger; Holt, Cathy; Iglarz, Marc; Francis, Sheila; Lawrie, Allan

    2018-01-01

    Idiopathic pulmonary arterial hypertension (IPAH) is increasingly diagnosed in elderly patients who also have an increased risk of co-morbid atherosclerosis. Apolipoprotein E-deficient (ApoE -/- ) mice develop atherosclerosis with severe PAH when fed a high-fat diet (HFD) and have increased levels of endothelin (ET)-1. ET-1 receptor antagonists (ERAs) are used for the treatment of PAH but less is known about whether ERAs are beneficial in atherosclerosis. We therefore examined whether treatment of HFD-ApoE -/- mice with macitentan, a dual ET A /ET B receptor antagonist, would have any effect on both atherosclerosis and PAH. ApoE -/- mice were fed chow or HFD for eight weeks. After four weeks of HFD, mice were randomized to a four-week treatment of macitentan by food (30 mg/kg/day dual ET A /ET B antagonist), or placebo groups. Echocardiography and closed-chest right heart catheterization were used to determine PAH phenotype and serum samples were collected for cytokine analysis. Thoracic aortas were harvested to assess vascular reactivity using wire myography, and histological analyses were performed on the brachiocephalic artery and aortic root to assess atherosclerotic burden. Macitentan treatment of HFD-fed ApoE -/- mice was associated with a beneficial effect on the PAH phenotype and led to an increase in endothelial-dependent relaxation in thoracic aortae. Macitentan treatment was also associated with a significant reduction in interleukin 6 (IL-6) concentration but there was no significant effect on atherosclerotic burden. Dual blockade of ET A /ET B receptors improves endothelial function and improves experimental PAH but had no significant effect on atherosclerosis.

  7. Correlation between plasma endothelin-1 levels and severity of septic liver failure quantified by maximal liver function capacity (LiMAx test. A prospective study.

    Directory of Open Access Journals (Sweden)

    Magnus F Kaffarnik

    Full Text Available To investigate the relationship between the degree of liver dysfunction, quantified by maximal liver function capacity (LiMAx test and endothelin-1, TNF-α and IL-6 in septic surgical patients.28 septic patients (8 female, 20 male, age range 35-80y were prospectively investigated on a surgical intensive care unit. Liver function, defined by LiMAx test, and measurements of plasma levels of endothelin-1, TNF-α and IL-6 were carried out within the first 24 hours after onset of septic symptoms, followed by day 2, 5 and 10. Patients were divided into 2 groups (group A: LiMAx ≥100 μg/kg/h, moderate liver dysfunction; group B: LiMAx <100 μg/kg/h, severe liver dysfunction for analysis and investigated regarding the correlation between endothelin-1 and the severity of liver failure, quantified by LiMAx test.Group B showed significant higher results for endothelin-1 than patients in group A (P = 0.01, d5; 0.02, d10. For TNF-α, group B revealed higher results than group A, with a significant difference on day 10 (P = 0.005. IL-6 showed a non-significant trend to higher results in group B. The Spearman's rank correlation coefficient revealed a significant correlation between LiMAx and endothelin-1 (-0.434; P <0.001, TNF-α (-0.515; P <0.001 and IL-6 (-0.590; P <0.001.Sepsis-related hepatic dysfunction is associated with elevated plasma levels of endothelin-1, TNF-α and IL-6. Low LiMAx results combined with increased endothelin-1 and TNF-α and a favourable correlation between LiMAx and cytokine values support the findings of a crucial role of Endothelin-1 and TNF-α in development of septic liver failure.

  8. Synthesis and in vivo evaluation of a PET radioligand for imaging the endothelin-A receptor

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, William B. [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States)]. E-mail: bmathews@petscan.nm.jhu.edu; Zober, Tamas G. [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States); Ravert, Hayden T. [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States); Scheffel, Ursula [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States); Hilton, John [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States); Sleep, Darryl [Abbott Laboratories, Abbott Park, IL 60064 (United States); Dannals, Robert F. [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States); Szabo, Zsolt [Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD 21287 (United States)

    2006-01-15

    The endothelin-A receptor ligand Atrasentan (ABT-627) was radiolabeled by {sup 11}C-methylaton of the desmethyl precursor in phenolate form. In mice, the highest uptake of [{sup 11}C]ABT-627 was in the liver, kidneys and lungs. No significant binding was observed in mouse brain or heart. PET studies in a baboon, however, showed accumulation in the myocardium and lungs with a tissue/blood equilibrium reached at 40 min postinjection. Between 35 and 75 min, the heart/blood and lung/blood ratios were 1.72 and 1.31, respectively. Pretreatment with a 0.39 mg/kg dose of unlabeled ABT-627 inhibited the uptake of the tracer by 53-54% in both the myocardium and lungs at 65 min.

  9. Clinical significance of plasma atrial natriuretic factor and endothelin detection in hyperthyroidism and hypothyroidism

    International Nuclear Information System (INIS)

    Zhu Yalin; Huo Ying; Pan Yunlong

    2005-01-01

    Plasma at rial natriuretic factor (ANF) and endothelin (ET) were detected by RIA in 58 cases of hyperthyroidism and 47 cases of hypothyroidism. Before the ANF and ET concentration of untreatment hyperthyroid patients was much higher than that of treatment hyperthyroid patients, hypothyroid patients before and after treatment and the normal group (P 3 and FT 4 . Compared with the normal group, ANF concentration in treatment hyperthyroid patients, hypothyroid patients before and after treatment was no significantly different (P>0.05), but that in hypothyroid patients before treatment was significantly decreased compared with hypothyroid patients after treatment (P 0.05), but that in hypothyroid patients before treatment was significantly decreased compared with others (P<0.01 and P<0.05). Detection of ANF and ET level may be have a role in supplementary diagnosis and curative effect observation of hyperthyroidism and hypothyroidism. (authors)

  10. Inverted duplication including Endothelin 3 closely related to dermal hyperpigmentation in Silkie chickens

    Directory of Open Access Journals (Sweden)

    Ming TIAN,Suyun FANG,Yanqiang WANG,Xiaorong GU,Chungang FENG,Rui HAO,Xiaoxiang HU,Ning LI

    2014-06-01

    Full Text Available The dermal hyperpigmentation phenotype in chickens is controlled by the dominant fibromelanosis allele. One of the ten unique characteristics of Silkie chickens is the fibromelanosis phenotype, which is pigmentation in the dermal layer of the skin and connective tissue. In this study, we found a mutation of fibromelanosis, a genomic rearrangement that included an inverted duplication of endothelin3 (EDN3, is responsible. We show that, as a stimulator of melanoblast proliferation, EDN3 expression was increased in silkie embryos and in both skin and muscle throughout adulthood. EDN3 expression led to an increase in expression of the downstream genes EDNRB2 and TYRP2, and was closely relate with the hyperpigmentation phenotype. We examined eight different Chinese chicken breeds showing hyperpigmentation and conclude that this structural genetic variant exists in all fibromelanosis chicken breeds.

  11. Human endothelin subtype A receptor enhancement during tissue culture via de novo transcription

    DEFF Research Database (Denmark)

    Hansen-Schwartz, Jacob; Nordström, Carl-Henrik; Edvinsson, Lars

    2002-01-01

    OBJECTIVE: Endothelin (ET) has, since its discovery, increasingly been considered a key player in the pathophysiological processes of cerebral vasospasm in the course of subarachnoid hemorrhage, although it remains unclear how ET is involved. We present data that indicate an inherent capacity...... of human cerebral arteries to change their sensitivity to ET. METHODS: Human cerebral arteries were obtained from patients undergoing intracranial tumor surgery. The vessels were divided into segments and subjected to organ culture for 48 hours. The vessels were then examined by using in vitro...... pharmacological methods and molecular biological techniques. RESULTS: After organ culture of the cerebral arteries, both the sensitivity to and potency of ET were enhanced (maximal response, 152 +/- 9%; -log (50% effective concentration), 10.3 +/- 0.3), in comparison with data for fresh cerebral arteries...

  12. Synthesis and in vivo evaluation of a PET radioligand for imaging the endothelin-A receptor

    International Nuclear Information System (INIS)

    Mathews, William B.; Zober, Tamas G.; Ravert, Hayden T.; Scheffel, Ursula; Hilton, John; Sleep, Darryl; Dannals, Robert F.; Szabo, Zsolt

    2006-01-01

    The endothelin-A receptor ligand Atrasentan (ABT-627) was radiolabeled by 11 C-methylaton of the desmethyl precursor in phenolate form. In mice, the highest uptake of [ 11 C]ABT-627 was in the liver, kidneys and lungs. No significant binding was observed in mouse brain or heart. PET studies in a baboon, however, showed accumulation in the myocardium and lungs with a tissue/blood equilibrium reached at 40 min postinjection. Between 35 and 75 min, the heart/blood and lung/blood ratios were 1.72 and 1.31, respectively. Pretreatment with a 0.39 mg/kg dose of unlabeled ABT-627 inhibited the uptake of the tracer by 53-54% in both the myocardium and lungs at 65 min

  13. The endothelin antagonist atrasentan lowers residual albuminuria in patients with type 2 diabetic nephropathy

    DEFF Research Database (Denmark)

    de Zeeuw, Dick; Coll, Blai; Andress, Dennis

    2014-01-01

    Despite optimal treatment, including renin-angiotensin system (RAS) inhibitors, patients with type 2 diabetic nephropathy have high cardiorenal morbidity and mortality related to residual albuminuria. We evaluated whether or not atrasentan, a selective endothelin A receptor antagonist, further...... reduces albuminuria when administered concomitantly with maximum tolerated labeled doses of RAS inhibitors. We enrolled 211 patients with type 2 diabetes, urine albumin/creatinine ratios of 300-3500 mg/g, and eGFRs of 30-75 ml/min per 1.73 m(2) in two identically designed, parallel, multinational, double...... parameters returned to pretreatment levels. In conclusion, atrasentan reduced albuminuria and improved BP and lipid spectrum with manageable fluid overload-related adverse events in patients with type 2 diabetic nephropathy receiving RAS inhibitors....

  14. Flavonol-rich dark cocoa significantly decreases plasma endothelin-1 and improves cognition in urban children.

    Science.gov (United States)

    Calderón-Garcidueñas, Lilian; Mora-Tiscareño, Antonieta; Franco-Lira, Maricela; Cross, Janet V; Engle, Randall; Aragón-Flores, Mariana; Gómez-Garza, Gilberto; Jewells, Valerie; Medina-Cortina, Humberto; Solorio, Edelmira; Chao, Chih-Kai; Zhu, Hongtu; Mukherjee, Partha S; Ferreira-Azevedo, Lara; Torres-Jardón, Ricardo; D'Angiulli, Amedeo

    2013-01-01

    Air pollution exposures are linked to systemic inflammation, cardiovascular and respiratory morbidity and mortality, neuroinflammation and neuropathology in young urbanites. In particular, most Mexico City Metropolitan Area (MCMA) children exhibit subtle cognitive deficits, and neuropathology studies show 40% of them exhibiting frontal tau hyperphosphorylation and 51% amyloid-β diffuse plaques (compared to 0% in low pollution control children). We assessed whether a short cocoa intervention can be effective in decreasing plasma endothelin 1 (ET-1) and/or inflammatory mediators in MCMA children. Thirty gram of dark cocoa with 680 mg of total flavonols were given daily for 10.11 ± 3.4 days (range 9-24 days) to 18 children (10.55 years, SD = 1.45; 11F/7M). Key metabolite ratios in frontal white matter and in hippocampus pre and during cocoa intervention were quantified by magnetic resonance spectroscopy. ET-1 significantly decreased after cocoa treatment (p = 0.0002). Fifteen children (83%) showed a marginally significant individual improvement in one or both of the applied simple short memory tasks. Endothelial dysfunction is a key feature of exposure to particulate matter (PM) and decreased endothelin-1 bioavailability is likely useful for brain function in the context of air pollution. Our findings suggest that cocoa interventions may be critical for early implementation of neuroprotection of highly exposed urban children. Multi-domain nutraceutical interventions could limit the risk for endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, cognitive deficits, structural volumetric detrimental brain effects, and the early development of the neuropathological hallmarks of Alzheimer's and Parkinson's diseases.

  15. Big endothelin changes the cellular miRNA environment in TMOb osteoblasts and increases mineralization.

    Science.gov (United States)

    Johnson, Michael G; Kristianto, Jasmin; Yuan, Baozhi; Konicke, Kathryn; Blank, Robert

    2014-08-01

    Endothelin (ET1) promotes the growth of osteoblastic breast and prostate cancer metastases. Conversion of big ET1 to mature ET1, catalyzed primarily by endothelin converting enzyme 1 (ECE1), is necessary for ET1's biological activity. We previously identified the Ece1, locus as a positional candidate gene for a pleiotropic quantitative trait locus affecting femoral size, shape, mineralization, and biomechanical performance. We exposed TMOb osteoblasts continuously to 25 ng/ml big ET1. Cells were grown for 6 days in growth medium and then switched to mineralization medium for an additional 15 days with or without big ET1, by which time the TMOb cells form mineralized nodules. We quantified mineralization by alizarin red staining and analyzed levels of miRNAs known to affect osteogenesis. Micro RNA 126-3p was identified by search as a potential regulator of sclerostin (SOST) translation. TMOb cells exposed to big ET1 showed greater mineralization than control cells. Big ET1 repressed miRNAs targeting transcripts of osteogenic proteins. Big ET1 increased expression of miRNAs that target transcripts of proteins that inhibit osteogenesis. Big ET1 increased expression of 126-3p 121-fold versus control. To begin to assess the effect of big ET1 on SOST production we analyzed both SOST transcription and protein production with and without the presence of big ET1 demonstrating that transcription and translation were uncoupled. Our data show that big ET1 signaling promotes mineralization. Moreover, the results suggest that big ET1's osteogenic effects are potentially mediated through changes in miRNA expression, a previously unrecognized big ET1 osteogenic mechanism.

  16. The Functional Lumen Imaging Probe Detects Esophageal Contractility not Observed with Manometry in Patients with Achalasia

    Science.gov (United States)

    Carlson, Dustin A.; Lin, Zhiyue; Kahrilas, Peter J.; Sternbach, Joel; Donnan, Erica N.; Friesen, Laurel; Listernick, Zoe; Mogni, Benjamin; Pandolfino, John E.

    2015-01-01

    Background & Aims The functional lumen imaging probe (FLIP) could improve characterization of achalasia subtypes by detecting non-occlusive esophageal contractions not observed with standard manometry. We aimed to evaluate for esophageal contractions during volumetric distention in patients with achalasia using FLIP topography. Methods Fifty one treatment-naïve patients with achalasia, defined and sub-classified by high-resolution esophageal pressure topography, and 10 asymptomatic individuals (controls) were evaluated with the FLIP during endoscopy. During stepwise distension, simultaneous intra-bag pressures and 16 channels of cross-sectional areas were measured; data were exported to software that generated FLIP topography plots. Esophageal contractility was identified by noting periods of reduced luminal diameter. Esophageal contractions were further characterized by propagation direction, repetitiveness, and based on whether they were occluding or non-occluding. Results Esophageal contractility was detected in all 10 controls: 8/10 had repetitive, antegrade, contractions and 9/10 had occluding contractions. Contractility was detected in 27% (4/15) of patients with type I achalasia and 65% (18/26, including 9 with occluding contractions) of patients with type II achalasia. Contractility was detected in all 10 patients with type III achalasia; 8 of these patients had a pattern of contractility not observed in controls (repetitive, retrograde contractions). Conclusions Esophageal contractility not observed with manometry can be detected in patients with achalasia using FLIP topography. The presence and patterns of contractility detected with FLIP topography may represent variations in pathophysiology, such as mechanisms of pan-esophageal pressurization in patients with type II achalasia. These findings could have implications for additional sub-classification to supplement prediction of the achalasia disease course. PMID:26278501

  17. Effective prophylaxis of visual and neurological disturbances with an anti-endothelin drug: analysis of 1642 sclerotherapy sessions

    Directory of Open Access Journals (Sweden)

    Alessandro Frullini

    2016-12-01

    Full Text Available In the literature cases of stroke and transient neurological symptoms have been described after sclerotherapy for chronic venous disease The initial interpretation of these phenomena was that of a micro air embolism in association with a patent foramen ovale. This explanation did not always manage to justify all neurological manifestations. Recent theories have demonstrated that in the area of sclerosis, a significant amount of endothelin 1. We carried out a retrospective assessment of sclerotherapy case studies on 540 patients at ten phlebological centres to search for a relationship between the use of aminaftone (a venotropic drug with demonstrated anti-endothelin action and the occurrence of side effects after sclerotherapy was performed. Significant reduction of side effects was observed in sclerotherapy for teleangectasias and in patients with migraine history.

  18. Impact of endothelin blockade on acute exercise-induced changes in blood flow and endothelial function in type 2 diabetes mellitus.

    Science.gov (United States)

    Schreuder, Tim H A; van Lotringen, Jaap H; Hopman, Maria T E; Thijssen, Dick H J

    2014-09-01

    Positive vascular effects of exercise training are mediated by acute increases in blood flow. Type 2 diabetes patients show attenuated exercise-induced increases in blood flow, possibly mediated by the endothelin pathway, preventing an optimal stimulus for vascular adaptation. We examined the impact of endothelin receptor blockade (bosentan) on exercise-induced blood flow in the brachial artery and on pre- and postexercise endothelial function in type 2 diabetes patients (n = 9, 60 ± 7 years old) and control subjects (n = 10, 60 ± 5 years old). Subjects reported twice to the laboratory to perform hand-grip exercise in the presence of endothelin receptor blockade or placebo. We examined brachial artery endothelial function (via flow-mediated dilatation) before and after exercise, as well as blood flow during exercise. Endothelin receptor blockade resulted in a larger increase in blood flow during exercise in type 2 diabetes patients (P = 0.046), but not in control subjects (P = 0.309). Exercise increased shear rate across the exercise protocol, unaffected by endothelin receptor blockade. Exercise did not alter brachial artery diameter in either group, but endothelin receptor blockade resulted in a larger brachial artery diameter in type 2 diabetes patients (P = 0.033). Exercise significantly increased brachial artery flow-mediated dilatation in both groups, unaffected by endothelin receptor blockade. Endothelin receptor blockade increased exercise-induced brachial artery blood flow in type 2 diabetes patients, but not in control subjects. Despite this effect of endothelin receptor blockade on blood flow, we found no impact on baseline or post-exercise endothelial function in type 2 diabetes patients or control subjects, possibly related to normalization of the shear stimulus during exercise. The successful increase in blood flow during exercise in type 2 diabetes patients through endothelin receptor blockade may have beneficial effects in

  19. Relaxing Responses to Hydrogen Peroxide and Nitric Oxide in Human Pericardial Resistance Arteries Stimulated with Endothelin-1

    DEFF Research Database (Denmark)

    Leurgans, Thomas M; Bloksgaard, Maria; Irmukhamedov, Akhmadjon

    2018-01-01

    In human pericardial resistance arteries, effects of the endothelium-dependent vasodilator bradykinin are mediated by NO during contraction induced by K(+) or the TxA2 analogue U46619 and by H2 O2 during contraction by endothelin-1 (ET-1), respectively. We tested the hypotheses that ET-1 reduces...... also acts as an endothelium-dependent vasodilator. This article is protected by copyright. All rights reserved....

  20. Evaluation of Homocysteine, Lipoprotein(a and Endothelin as diagnostic markers of Coronary Artery Disease in Indian population

    Directory of Open Access Journals (Sweden)

    Vandana Saini

    2013-01-01

    Full Text Available Indians have been reported to have high prevalence rates of coronary artery disease (CAD even in the absence of traditional risk factors. The objective of this study was to assess the role of endothelin, lipoprotein(a, homocysteine and lipid profile as markers of CAD in Indian population. It was a hospital based observational case-control study, which included 60 documented patients of CAD, and 50 age and sex matched controls. Routine biochemical parameters were performed. Lipoprotein(a, homocysteine and endothelin levels were estimated by enzyme linked immunosorbent assay. The levels of endothelin (9.78±0.40 pg/ml vs. 7.86±0.31 pg/ml, lipoprotein(a (51.42±1.71 mg/dl vs. 36.26±1.21 mg/dl, homocysteine (21.31±1.22 µmol/L vs. 10.41±0.844 µmol/L and LDL/HDL cholesterol ratio (4.23±0.32 vs. 2.60±0.10 were significantly higher whereas that of HDL (29.82±1.39 mg/dl vs. 40.82±6.24 mg/dl was significantly lower in patients of CAD as compared to the controls (p0.7 for all the markers. Higher levels of homocysteine, endothelin, and lipoprotein(a were independently associated with increased risk of CAD. Thus, they may be helpful in risk assessment in premature cardiovascular disease and in individuals where traditional risk factors are not present.

  1. The role of the biomarker and the genetic polymorphism of endothelin-1 in pulmonary arterial hypertension among Egyptians

    Directory of Open Access Journals (Sweden)

    Emad Ibrahim

    2012-10-01

    Conclusions: In conclusion, our findings suggest a potential link between endothelin-1 level and specific genotypes in the EDN1 gene and susceptibility for PAH with a worse haemodynamic profile. Further investigations are warranted to understand the molecular basis and to confirm the potential clinical importance of these findings on larger cohorts of patients with PAH. This will impact on the management of PAH of Egyptian patients in the near future.

  2. Inhibition of CPU0213, a Dual Endothelin Receptor Antagonist, on Apoptosis via Nox4-Dependent ROS in HK-2 Cells

    Directory of Open Access Journals (Sweden)

    Qing Li

    2016-06-01

    Full Text Available Background/Aims: Our previous studies have indicated that a novel endothelin receptor antagonist CPU0213 effectively normalized renal function in diabetic nephropathy. However, the molecular mechanisms mediating the nephroprotective role of CPU0213 remain unknown. Methods and Results: In the present study, we first detected the role of CPU0213 on apoptosis in human renal tubular epithelial cell (HK-2. It was shown that high glucose significantly increased the protein expression of Bax and decreased Bcl-2 protein in HK-2 cells, which was reversed by CPU0213. The percentage of HK-2 cells that showed Annexin V-FITC binding was markedly suppressed by CPU0213, which confirmed the inhibitory role of CPU0213 on apoptosis. Given the regulation of endothelin (ET system to oxidative stress, we determined the role of redox signaling in the regulation of CPU0213 on apoptosis. It was demonstrated that the production of superoxide (O2-. was substantially attenuated by CPU0213 treatment in HK-2 cells. We further found that CPU0213 dramatically inhibited expression of Nox4 protein, which gene silencing mimicked the role of CPU0213 on the apoptosis under high glucose stimulation. We finally examined the role of CPU0213 on ET-1 receptors and found that high glucose-induced protein expression of endothelin A and B receptors was dramatically inhibited by CPU0213. Conclusion: Taken together, these results suggest that this Nox4-dependenet O2- production is critical for the apoptosis of HK-2 cells in high glucose. Endothelin receptor antagonist CPU0213 has an anti-apoptosis role through Nox4-dependent O2-.production, which address the nephroprotective role of CPU0213 in diabetic nephropathy.

  3. Orphan Nuclear Receptor Nur77 Is a Novel Negative Regulator of Endothelin-1 Expression In Vascular Endothelial Cells

    OpenAIRE

    Qin, Qing; Chen, Ming; Yi, Bing; You, Xiaohua; Yang, Ping; Sun, Jianxin

    2014-01-01

    Endothelin-1 (ET-1) produced by vascular endothelial cells plays essential roles in the regulation of vascular tone and development of cardiovascular diseases. The objective of this study is to identify novel regulators implicated in the regulation of ET-1 expression in vascular endothelial cells (ECs). By using quantitative real-time PCR (qRT-PCR) and Enzyme-linked immunosorbent assay (ELISA), we show that either ectopic expression of orphan nuclear receptor Nur77 or pharmacological activati...

  4. Inflammatory Murine Skin Responses to UV-B Light Are Partially Dependent on Endothelin-1 and Mast Cells

    OpenAIRE

    Metz, Martin; Lammel, Verena; Gibbs, Bernhard F.; Maurer, Marcus

    2006-01-01

    Endothelin (ET-1) has been shown to crucially contribute to UV-induced skin responses such as tanning. To test whether ET-1 is also involved in early cutaneous reactions to UV, we assessed ET-1 skin levels in UV-irradiated mice. In correlation with the levels of UV-induced skin inflammation, ET-1 concentrations increased substantially and continually. Moreover, blocking of ET-1 receptors (ETA) resulted in significantly decreased cutaneous inflammation following UV irradiation. When we assesse...

  5. Correlation of Endothelin-1 Concentration and Angiotensin-Converting Enzyme Activity with the Staging of Liver Fibrosis

    OpenAIRE

    Kardum, Duško; Fabijanić, Damir; Lukić, Anita; Romić, Željko; Petrovečki, Mladen; Bogdanović, Zoran; Jurić, Klara; Urek-Crnčević, Marija; Banić, Marko

    2012-01-01

    Increased serum angiotensin-converting enzyme (SACE) activity and serum concentration of endothelin-1 (ET-1) were found in liver cirrhosis. We investigated a correlation between the different stages of liver fibrosis and SACE activity and serum ET-1 concentration. Seventy patients with pathohistologically established chronic liver disease were divided in three groups according to Ishak criteria for liver fibrosis: minimal fibrosis (Ishak score 0–1, n=20), medium fibrosis (Ishak sc...

  6. 17 alpha-hydroxyprogesterone caproate vehicle, castor oil, enhances the contractile effect of oxytocin in human myometrium in pregnancy.

    Science.gov (United States)

    O'Sullivan, Michael D; Hehir, Mark P; O'Brien, Yvonne M; Morrison, John J

    2010-05-01

    The possibility exists that the vehicle for 17-alpha-hydroxyprogesterone caproate, castor oil, exerts an effect on human uterine contractility. The aim of this study was to evaluate its effects on contractility of myometrial preparations that were obtained during pregnancy. Myometrial strips were suspended under isometric conditions. Contractility was induced with oxytocin. Strips were incubated in castor oil or physiologic salt solution and suspended for a further oxytocin challenge. Contractile integrals were compared between both groups. Strips that were exposed to castor oil demonstrated increased contractile activity that was elicited by oxytocin (mean contractility value, 165.53%+/-17.03%; n=8; P=.004), compared with control strips (mean contractility value, 72.57%+/-7.48%; n=8; P=.003). There was a significant increase in contractile activity of the castor oil-exposed strips, compared with those that were exposed to physiologic salt solution (n=8; Pcastor oil results in enhanced oxytocin-induced contractility. Copyright (c) 2010 Mosby, Inc. All rights reserved.

  7. The role of voltage-gated potassium channels in the regulation of mouse uterine contractility

    Directory of Open Access Journals (Sweden)

    Abel Peter W

    2007-11-01

    Full Text Available Abstract Background Uterine smooth muscle cells exhibit ionic currents that appear to be important in the control of uterine contractility, but how these currents might produce the changes in contractile activity seen in pregnant myometrium has not been established. There are conflicting reports concerning the role of voltage-gated potassium (Kv channels and large-conductance, calcium-activated potassium (BK channels in the regulation of uterine contractility. In this study we provide molecular and functional evidence for a role for Kv channels in the regulation of spontaneous contractile activity in mouse myometrium, and also demonstrate a change in Kv channel regulation of contractility in pregnant mouse myometrium. Methods Functional assays which evaluated the effects of channel blockers and various contractile agonists were accomplished by quantifying contractility of isolated uterine smooth muscle obtained from nonpregnant mice as well as mice at various stages of pregnancy. Expression of Kv channel proteins in isolated uterine smooth muscle was evaluated by Western blots. Results The Kv channel blocker 4-aminopyridine (4-AP caused contractions in nonpregnant mouse myometrium (EC50 = 54 micromolar, maximal effect at 300 micromolar but this effect disappeared in pregnant mice; similarly, the Kv4.2/Kv4.3 blocker phrixotoxin-2 caused contractions in nonpregnant, but not pregnant, myometrium. Contractile responses to 4-AP were not dependent upon nerves, as neither tetrodotoxin nor storage of tissues at room temperature significantly altered these responses, nor were responses dependent upon the presence of the endometrium. Spontaneous contractions and contractions in response to 4-AP did not appear to be mediated by BK, as the BK channel-selective blockers iberiotoxin, verruculogen, or tetraethylammonium failed to affect either spontaneous contractions or 4-AP-elicited responses. A number of different Kv channel alpha subunit proteins were

  8. Impact of Cardiac Contractility during Cerebral Blood Flow in Ischemia

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    Silver, Brian

    2011-05-01

    Full Text Available Objective: In cerebral regions affected by ischemia, intrinsic vascular autoregulation is often lost. Blood flow delivery depends upon cardiac function and may be influenced by neuro-endocrine mediated myocardial suppression. Our objective is to evaluate the relation between ejection fraction (EF and transcranial doppler (TCD peak systolic velocities (PSV in patients with cerebral ischemic events.Methods: We conducted a retrospective cohort study from an existing TCD registry. We evaluated patients admitted within 24 hours of onset of a focal neurological deficit who had an echocardiogram and TCD performed within 72 hours of admission.Results: We identified 58 patients from March to October 2003. Eighty-one percent (n=47 had a hospital discharge diagnosis of ischemic stroke and 18.9% (n=11 had a diagnosis of transient ischemic attack. Fourteen patients had systolic dysfunction (EF50% compared to those with systolic dysfunction (EF<50% was as follows: middle cerebral artery 62.0 + 28.6 cm/s vs. 51.0 + 23.3 cm/s, p=0.11; anterior cerebral artery 52.1 + 21.6 cm/s vs. 45.9 + 22.7 cm/s, p=0.28; internal carotid artery 56.5 + 20.1 cm/s vs. 46.4 + 18.4 cm/s, p=0.04; ophthalmic artery 18.6 + 7.2 cm/s vs. 15.3 + 5.2 cm/s, p=0.11; vertebral artery 34.0 + 13.9 cm/s vs. 31.6 + 15.0 cm/s, p=0.44.Conclusion: Cerebral blood flow in the internal carotid artery territory appears to be higher in cerebral ischemia patients with preserved left ventricular contractility. Our study was unable to differentiate pre-existing cardiac dysfunction from neuro-endocrine mediated myocardial stunning. Future research is necessary to better understand heart-brain interactions in this setting and to further explore the underlying mechanisms and consequences of neuro-endocrine mediated cardiac dysfunction. [West J Emerg Med. 2011;12(2:227-232.

  9. Effect of heat stress on contractility of tissue-engineered artificial skeletal muscle.

    Science.gov (United States)

    Takagi, Shunya; Nakamura, Tomohiro; Fujisato, Toshia

    2018-01-23

    The effects of heat stress on tissue like skeletal muscle have been widely studied. However, the mechanism responsible for the effect of heat stress is still unclear. A useful experimental tissue model is necessary because muscle function in cell culture may differ from native muscle and measuring its contractility is difficult. We previously reported three-dimensional tissue-engineered artificial skeletal muscle (TEM) that can be easily set in a measurement apparatus for quantitative evaluation of contractility. We have now applied TEM to the investigation of heat stress. We analyzed contractility immediately after thermal exposure at 39 °C for 24 or 48 h to evaluate the acute effects and after thermal exposure followed by normal culture to evaluate the aftereffects. Peak twitch contractile force and time-to-peak twitch were used as contractile parameters. Heat stress increased the TCF in the early stage (1 week) after normal culture; the TCF decreased temporarily in the middle to late stages (2-3 weeks). These results suggest that heat stress may affect both myoblast fusion and myotube differentiation in the early stage of TEM culture, but not myotube maturation in the late stage. The TCF increase rate with thermal exposure was significantly higher than that without thermal exposure. Although detailed analysis at the molecular level is necessary for further investigation, our artificial skeletal muscle may be a promising tool for heat stress investigation.

  10. Inhibition of isolated human myometrium contractility by minoxidil and reversal by glibenclamide.

    Science.gov (United States)

    Prabhakaran, S S; Dhanasekar, K R; Thomas, E; Jose, R; Peedicayil, J; Samuel, P

    2010-03-01

    This study investigated the ability of the antihypertensive drug minoxidil to inhibit potassium chloride (KCl)-induced contractility of the isolated human myometrium. Twelve strips of myometrium obtained from 12 patients who underwent hysterectomy were triggered to contract with 55 mM KCl before and after incubation with 3 concentrations (1, 3 and 10 microM) of minoxidil. The percent inhibition by minoxidil on the extent of contraction, and the area under the contractile curve of KCl-induced contraction of the myometrial strips was determined. Furthermore, the effect of 10 microM glibenclamide on the inhibition generated by 3 microM minoxidil on KCl-induced contractility was studied. It was found that minoxidil produced a concentration-dependent inhibition of KCl-induced contractility of the myometrium and that glibenclamide reversed this inhibitory effect. These results suggest that the inhibitory effect of minoxidil on isolated human myometrium contractility may prove useful in clinical conditions requiring relaxation of the myometrium. 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

  11. Slack length reduces the contractile phenotype of the Swine carotid artery.

    Science.gov (United States)

    Rembold, Christopher M; Garvey, Sean M; Tejani, Ankit D

    2013-01-01

    Contraction is the primary function of adult arterial smooth muscle. However, in response to vessel injury or inflammation, arterial smooth muscle is able to phenotypically modulate from the contractile state to several 'synthetic' states characterized by proliferation, migration and/or increased cytokine secretion. We examined the effect of tissue length (L) on the phenotype of intact, isometrically held, initially contractile swine carotid artery tissues. Tissues were studied (1) without prolonged incubation at the optimal length for force generation (1.0 Lo, control), (2) with prolonged incubation for 17 h at 1.0 Lo, or (3) with prolonged incubation at slack length (0.6 Lo) for 16 h and then restoration to 1.0 Lo for 1 h. Prolonged incubation at 1.0 Lo minimally reduced the contractile force without substantially altering the mediators of contraction (crossbridge phosphorylation, shortening velocity or stimulated actin polymerization). Prolonged incubation of tissues at slack length (0.6 Lo), despite return of length to 1.0 Lo, substantially reduced contractile force, reduced crossbridge phosphorylation, nearly abolished crossbridge cycling (shortening velocity) and abolished stimulated actin polymerization. These data suggest that (1) slack length treatment significantly alters the contractile phenotype of arterial tissue, and (2) slack length treatment is a model to study acute phenotypic modulation of intact arterial smooth muscle. Copyright © 2013 S. Karger AG, Basel.

  12. The effects of changes of plasma endothelin level in patients with hypertension after medication of metoprolol tartrate combined with felodipine

    International Nuclear Information System (INIS)

    Tao Zhihu; Pan Quan

    2011-01-01

    Objective: To investigate the clinical efficacy and safety of metoprolol tartrate combined with felodipine sustained-release tablets in treatment of high blood pressure. Methods: Patients were allocated to groups of medication of metoprolol tartrate combined with felodipine (Group A, n=57) and single medication of metoprolol tartrate (Group B, n=60). All patients received daily measurement of blood pressure, heart rate, observation of adverse reactions and detection of the plasma endothelin levels before and after the medication. Results: Compared with Group B after the medication, the therapeutic effect was significant in Group A (P<0.01) and both the plasma endothelin levels and the side effects were much lower(P<0.05, P<0.01, respectively). Conclusion: Metoprolol tartrate combined with sustained release felodipine tablets appears effectively in treatment of hypertension, and the therapeutic effect may be associated with the variation of plasma endothelin levels. In addition, metoprolol in combination sustained release felodipine tablets can counteract the adverse reaction from single dose and is worthy for wide clinical use. (authors)

  13. Role of Dlx6 in regulation of an endothelin-1-dependent, dHAND branchial arch enhancer

    Science.gov (United States)

    Charité, Jeroen; McFadden, David G.; Merlo, Giorgio; Levi, Giovanni; Clouthier, David E.; Yanagisawa, Masashi; Richardson, James A.; Olson, Eric N.

    2001-01-01

    Neural crest cells play a key role in craniofacial development. The endothelin family of secreted polypeptides regulates development of several neural crest sublineages, including the branchial arch neural crest. The basic helix–loop–helix transcription factor dHAND is also required for craniofacial development, and in endothelin-1 (ET-1) mutant embryos, dHAND expression in the branchial arches is down-regulated, implicating it as a transcriptional effector of ET-1 action. To determine the mechanism that links ET-1 signaling to dHAND transcription, we analyzed the dHAND gene for cis-regulatory elements that control transcription in the branchial arches. We describe an evolutionarily conserved dHAND enhancer that requires ET-1 signaling for activity. This enhancer contains four homeodomain binding sites that are required for branchial arch expression. By comparing protein binding to these sites in branchial arch extracts from endothelin receptor A (EdnrA) mutant and wild-type mouse embryos, we identified Dlx6, a member of the Distal-less family of homeodomain proteins, as an ET-1-dependent binding factor. Consistent with this conclusion, Dlx6 was down-regulated in branchial arches from EdnrA mutant mice. These results suggest that Dlx6 acts as an intermediary between ET-1 signaling and dHAND transcription during craniofacial morphogenesis. PMID:11711438

  14. UVB radiation generates sunburn pain and affects skin by activating epidermal TRPV4 ion channels and triggering endothelin-1 signaling.

    Science.gov (United States)

    Moore, Carlene; Cevikbas, Ferda; Pasolli, H Amalia; Chen, Yong; Kong, Wei; Kempkes, Cordula; Parekh, Puja; Lee, Suk Hee; Kontchou, Nelly-Ange; Yeh, Iwei; Ye, Iwei; Jokerst, Nan Marie; Fuchs, Elaine; Steinhoff, Martin; Liedtke, Wolfgang B

    2013-08-20

    At our body surface, the epidermis absorbs UV radiation. UV overexposure leads to sunburn with tissue injury and pain. To understand how, we focus on TRPV4, a nonselective cation channel highly expressed in epithelial skin cells and known to function in sensory transduction, a property shared with other transient receptor potential channels. We show that following UVB exposure mice with induced Trpv4 deletions, specifically in keratinocytes, are less sensitive to noxious thermal and mechanical stimuli than control animals. Exploring the mechanism, we find that epidermal TRPV4 orchestrates UVB-evoked skin tissue damage and increased expression of the proalgesic/algogenic mediator endothelin-1. In culture, UVB causes a direct, TRPV4-dependent Ca(2+) response in keratinocytes. In mice, topical treatment with a TRPV4-selective inhibitor decreases UVB-evoked pain behavior, epidermal tissue damage, and endothelin-1 expression. In humans, sunburn enhances epidermal expression of TRPV4 and endothelin-1, underscoring the potential of keratinocyte-derived TRPV4 as a therapeutic target for UVB-induced sunburn, in particular pain.

  15. Novel nonsense mutation of the endothelin-B receptor gene in a family with Waardenburg-Hirschsprung disease.

    Science.gov (United States)

    Syrris, P; Carter, N D; Patton, M A

    1999-11-05

    Waardenburg syndrome (WS) comprises sensorineural hearing loss, hypopigmentation of skin and hair, and pigmentary disturbances of the irides. Four types of WS have been classified to date; in WS type IV (WS4), patients additionally have colonic aganglionosis (Hirschsprung disease, HSCR). Mutations in the endothelin-3 (EDN3), endothelin-B receptor (EDNRB), and Sox10 genes have been identified as causative for WS type IV. We screened a family with a combined WS-HSCR phenotype for mutations in the EDNRB locus using standard DNA mutation analysis and sequencing techniques. We have identified a novel nonsense mutation at codon 253 (CGA-->TGA, Arg-->STOP). This mutation leads to a premature end of the translation of EDNRB at exon 3, and it is predicted to produce a truncated and nonfunctional endothelin-B receptor. All affected relatives were heterozygous for the Arg(253)-->STOP mutation, whereas it was not observed in over 50 unrelated individuals used as controls. These data confirm the role of EDNRB in the cause of the Waardenburg-Hirschsprung syndrome and demonstrate that in WS-HSCR there is a lack of correlation between phenotype and genotype and a variable expression of disease even within the same family. Copyright 1999 Wiley-Liss, Inc.

  16. Endothelin-1-induced focal cerebral ischemia in the growth hormone/IGF-1 deficient Lewis Dwarf rat.

    Science.gov (United States)

    Yan, Han; Mitschelen, Matthew; Toth, Peter; Ashpole, Nicole M; Farley, Julie A; Hodges, Erik L; Warrington, Junie P; Han, Song; Fung, Kar-Ming; Csiszar, Anna; Ungvari, Zoltan; Sonntag, William E

    2014-11-01

    Aging is a major risk factor for cerebrovascular disease. Growth hormone (GH) and its anabolic mediator, insulin-like growth factor (IGF)-1, decrease with advancing age and this decline has been shown to promote vascular dysfunction. In addition, lower GH/IGF-1 levels are associated with higher stroke mortality in humans. These results suggest that decreased GH/IGF-1 level is an important factor in increased risk of cerebrovascular diseases. This study was designed to assess whether GH/IGF-1-deficiency influences the outcome of cerebral ischemia. We found that endothelin-1-induced middle cerebral artery occlusion resulted in a modest but nonsignificant decrease in cerebral infarct size in GH/IGF-1 deficient dw/dw rats compared with control heterozygous littermates and dw/dw rats with early-life GH treatment. Expression of endothelin receptors and endothelin-1-induced constriction of the middle cerebral arteries were similar in the three experimental groups. Interestingly, dw/dw rats exhibited reduced brain edema and less astrocytic infiltration compared with their heterozygous littermates and this effect was reversed by GH-treatment. Because reactive astrocytes are critical for the regulation of poststroke inflammatory processes, maintenance of the blood-brain barrier and neural repair, further studies are warranted to determine the long-term functional consequences of decreased astrocytic activation in GH/IGF-1 deficient animals after cerebral ischemia. Published by Oxford University Press on behalf of the Gerontological Society of America 2014.

  17. Stretch induced endothelin-1 secretion by adult rat astrocytes involves calcium influx via stretch-activated ion channels (SACs)

    International Nuclear Information System (INIS)

    Ostrow, Lyle W.; Suchyna, Thomas M.; Sachs, Frederick

    2011-01-01

    Highlights: → Endothelin-1 expression by adult rat astrocytes correlates with cell proliferation. → Stretch-induced ET-1 is inhibited by GsMtx-4, a specific inhibitor of Ca 2+ permeant SACs. → The less specific SAC inhibitor streptomycin also inhibits ET-1 secretion. → Stretch-induced ET-1 production depends on a calcium influx. → SAC pharmacology may provide a new class of therapeutic agents for CNS pathology. -- Abstract: The expression of endothelins (ETs) and ET-receptors is often upregulated in brain pathology. ET-1, a potent vasoconstrictor, also inhibits the expression of astrocyte glutamate transporters and is mitogenic for astrocytes, glioma cells, neurons, and brain capillary endothelia. We have previously shown that mechanical stress stimulates ET-1 production by adult rat astrocytes. We now show in adult astrocytes that ET-1 production is driven by calcium influx through stretch-activated ion channels (SACs) and the ET-1 production correlates with cell proliferation. Mechanical stimulation using biaxial stretch ( 2+ threshold. This coupling of mechanical stress to the astrocyte endothelin system through SACs has treatment implications, since all pathology deforms the surrounding parenchyma.

  18. Endothelin role in the orthostatic stress Papel da endotelina no estresse ortostático

    Directory of Open Access Journals (Sweden)

    Marli Cardoso Martins Pinge

    2008-10-01

    Full Text Available Orthostasis adoption causes hemodynamic changes. Hydrostatic opposition to the venous return, venous return reduction and cardiac output decrease act as stimuli and generate compensatory mechanisms. The central nervous system adjusts the autonomic sympathetic and parasympathetic activity. The autonomous nervous system causes a tonic and reflexive influence on the main variables of the cardiovascular system and, together with hormonal components, extends the adaptation capacity in face of postural changes. Any difficulties in this compensatory mechanism that prevents it from functioning properly may result in hypotension response failure, what, on its turn, can lead to cerebral hypoperfusion, hypoxia and loss of consciousness. Blood pressure maintenance at normal levels is important for the internal medium homeosthasis. Baroreflex plays an important role in the cardiovascular control in the short-term in the adaptation of the orthostatic stress, preventing excessive blood pressure alterations. During the orthostatic stress, neuroendocrinal changes also occur as alteration in endothelin plasma levels. Endothelin, a peptide formed by 21 amino acids, shows a powerful vasoconstrictor action. It also demonstrates that its levels in the blood are increased in response to an orthostatic stress. However, although endothelin-1 levels increase in response to an acute postural stress, its role in cardiovascular homeosthasis and its relation in the release of other hormones are still controversial and quite unknown in humans in vivo. A adoção da ortostase promove alterações hemodinâmicas. A oposição hidrostática ao retorno venoso, a redução do retorno venoso e a diminuição do débito cardíaco atua como estímulos e geram mecanismos compensatórios. O sistema nervoso central ajusta a atividade autonômica simpática e parassimpática. O sistema nervoso autônomo influencia tônica e reflexamente as principais variáveis do sistema cardiovascular

  19. Contractile properties are disrupted in Becker muscular dystrophy, but not in limb girdle type 2I.

    Science.gov (United States)

    Løkken, Nicoline; Hedermann, Gitte; Thomsen, Carsten; Vissing, John

    2016-09-01

    We investigated whether a linear relationship between muscle strength and cross-sectional area (CSA) is preserved in calf muscles of patients with Becker muscular dystrophy (BMD, n = 14) and limb-girdle type 2I muscular dystrophy (LGMD2I, n = 11), before and after correcting for muscle fat infiltration. The Dixon magnetic resonance imaging technique was used to quantify fat and calculate a fat-free contractile CSA. Strength was assessed by dynamometry. Muscle strength/CSA relationships were significantly lower in patients versus controls. The strength/contractile-CSA relationship was still severely lowered in BMD, but was almost normalized in LGMD2I. Our findings suggest close to intact contractile properties in LGMD2I, which are severely disrupted in BMD. Ann Neurol 2016;80:466-471. © 2016 American Neurological Association.

  20. Suppression of guinea pig ileum induced contractility by plasma albumin of hibernators

    Science.gov (United States)

    Bruce, David S.; Ambler, Douglas L.; Henschel, Timothy M.; Oeltgen, Peter R.; Nilekani, Sita P.; Amstrup, Steven C.

    1992-01-01

    Previous studies suggest that hibernation may be regulated by internal opioids and that the putative “hibernation induction trigger” (HIT) may itself be an opioid. This study examined the effect of plasma albumin (known to bind HIT) on induced contractility of the guinea pig ileum muscle strip. Morphine (400 nM) depressed contractility and 100 nM naloxone restored it. Ten milligrams of lyophilized plasma albumin fractions from hibernating ground squirrels, woodchucks, black bears, and polar bears produced similar inhibition, with partial reversal by naloxone. Five hundredths mg of d-Ala2-d-Leu5-enkephalin (DADLE) also inhibited contractility and naloxone reversed it. Conclusions are that hibernating individuals of these species contain an HIT substance that is opioid in nature and summer animals do not; an endogenous opioid similar to leu-enkephalin may be the HIT compound or give rise to it.

  1. Mechanobiological induction of long-range contractility by diffusing biomolecules and size scaling in cell assemblies

    Science.gov (United States)

    Dasbiswas, K.; Alster, E.; Safran, S. A.

    2016-06-01

    Mechanobiological studies of cell assemblies have generally focused on cells that are, in principle, identical. Here we predict theoretically the effect on cells in culture of locally introduced biochemical signals that diffuse and locally induce cytoskeletal contractility which is initially small. In steady-state, both the concentration profile of the signaling molecule as well as the contractility profile of the cell assembly are inhomogeneous, with a characteristic length that can be of the order of the system size. The long-range nature of this state originates in the elastic interactions of contractile cells (similar to long-range “macroscopic modes” in non-living elastic inclusions) and the non-linear diffusion of the signaling molecules, here termed mechanogens. We suggest model experiments on cell assemblies on substrates that can test the theory as a prelude to its applicability in embryo development where spatial gradients of morphogens initiate cellular development.

  2. Plasticity of TOM complex assembly in skeletal muscle mitochondria in response to chronic contractile activity.

    Science.gov (United States)

    Joseph, Anna-Maria; Hood, David A

    2012-03-01

    We investigated the assembly of the TOM complex within skeletal muscle under conditions of chronic contractile activity-induced mitochondrial biogenesis. Tom40 import into mitochondria was increased by chronic contractile activity, as was its time-dependent assembly into the TOM complex. These changes coincided with contractile activity-induced augmentations in the expression of key protein import machinery components Tim17, Tim23, and Tom22, as well as the cytosolic chaperone Hsp90. These data indicate the adaptability of the TOM protein import complex and suggest a regulatory role for the assembly of this complex in exercise-induced mitochondrial biogenesis. Copyright © 2011 Elsevier B.V. and Mitochondria Research Society. All rights reserved. All rights reserved.

  3. Effects of minoxidil and nitroprusside on reflex increases in myocardial contractility.

    Science.gov (United States)

    Robie, N W

    1978-01-01

    1 The effects of nitroprusside and minoxidil on increases in myocardial contractility resulting from carotid artery occlusion were investigated in anaesthetized dogs. The results were compared with those produced by intravenous influsion of noradrenaline. 2 Nitroprusside and minoxidil attenuated the pressor responses produced by carotid artery occlusion. 3 Nitroprusside, but not minoxidil, attenuated the maximal myocardial contractility resulting from carotid occlusion. 4 The pressor and contractility responses to noradrenaline infusion were unaffected by either agent. 5 Nitroprusside failed to alter the myocardial responses produced by dimethylphenylpiperazinium. 6 These results, in conjunction with those of other investigators who have demonstrated that nitroprusside does not affect the release of noradrenaline from adrenergic neurons, suggest that nitroprusside may inhibit sympathetic nervous system reflex activity via an afferent and/or central component. PMID:620094

  4. Sex differences and the effects of ovariectomy on the β-adrenergic contractile response

    Science.gov (United States)

    McIntosh, Victoria J.; Chandrasekera, P. Charukeshi

    2011-01-01

    The presence of sex differences in myocardial β-adrenergic responsiveness is controversial, and limited studies have addressed the mechanism underlying these differences. Studies were performed using isolated perfused hearts from male, intact female and ovariectomized female mice to investigate sex differences and the effects of ovarian hormone withdrawal on β-adrenergic receptor function. Female hearts exhibited blunted contractile responses to the β-adrenergic receptor agonist isoproterenol (ISO) compared with males but not ovariectomized females. There were no sex differences in β1-adrenergic receptor gene or protein expression. To investigate the role of adenylyl cyclase, phosphodiesterase, and the cAMP-signaling cascade in generating sex differences in the β-adrenergic contractile response, dose-response studies were performed in isolated perfused male and female hearts using forskolin, 3-isobutyl-1-methylxanthine (IBMX), and 8-(4-chlorophenylthio)adenosine 3′,5′-cyclic monophosphate (CPT-cAMP). Males showed a modestly enhanced contractile response to forskolin at 300 nM and 5 μM compared with females, but there were no sex differences in the response to IBMX or CPT-cAMP. The role of the A1 adenosine receptor (A1AR) in antagonizing the β-adrenergic contractile response was investigated using both the A1AR agonist 2-chloro-N6-cyclopentyl-adenosine and A1AR knockout (KO) mice. Intact females showed an enhanced A1AR anti-adrenergic effect compared with males and ovariectomized females. The β-adrenergic contractile response was potentiated in both male and female A1ARKO hearts, with sex differences no longer present above 1 nM ISO. The β-adrenergic contractile response is greater in male hearts than females, and minor differences in the action of adenylyl cyclase or the A1AR may contribute to these sex differences. PMID:21685268

  5. Clinical Characteristics and Associated Systemic Diseases in Patients With Esophageal "Absent Contractility"-A Clinical Algorithm.

    Science.gov (United States)

    Laique, Sobia; Singh, Tavankit; Dornblaser, David; Gadre, Abhishek; Rangan, Vikram; Fass, Ronnie; Kirby, Donald; Chatterjee, Soumya; Gabbard, Scott

    2018-01-19

    This study was carried out to assess the clinical characteristics and associated systemic diseases seen in patients diagnosed with absent contractility as per the Chicago Classification version 3.0, allowing us to propose a diagnostic algorithm for their etiologic testing. The Chicago Classification version 3.0 has redefined major and minor esophageal motility disorders using high-resolution esophageal manometry. There is a dearth of publications based on research on absent contractility, which historically has been associated with myopathic processes such as systemic sclerosis (SSc). We conducted a retrospective, multicenter study. Data of patients diagnosed with absent contractility were pooled from Cleveland Clinic, Cleveland, OH (January 2006 to July 2016) and Metrohealth Medical Center, Cleveland, OH (July 2014 to July 2016) and included: age, gender, associated medical conditions, surgical history, medications, and specific antibody testing. A total of 207 patients, including 57 male individuals and 150 female individuals, with mean age of 56.1 and 60.0 years, respectively, were included. Disease distribution was as follows: SSc (diffuse or limited cutaneous) 132, overlap syndromes 7, systemic lupus erythematosus17, Sjögren syndrome 4, polymyositis 3, and dermatomyositis 3. Various other etiologies including gastroesophageal reflux disease, postradiation esophagitis, neuromuscular disorders, and surgical complications were seen in the remaining cohort. Most practitioners use the term "absent contractility" interchangeably with "scleroderma esophagus"; however, only 63% of patients with absent contractility had SSc. Overall, 20% had another systemic autoimmune rheumatologic disease and 16% had a nonrheumatologic etiology for absent contractility. Therefore, alternate diagnosis must be sought in these patients. We propose an algorithm for their etiologic evaluation.

  6. Accessory left atrial diverticulae: contractile properties depicted with 64-slice cine-cardiac CT.

    LENUS (Irish Health Repository)

    Killeen, Ronan P

    2012-02-01

    To assess the contractility of accessory left atrial appendages (LAAs) using multiphasic cardiac CT. We retrospectively analyzed the presence, location, size and contractile properties of accessory LAAs using multiphasic cardiac 64-slice CT in 102 consecutive patients (63 males, 39 females, mean age 57). Multiplanar reformats were used to create image planes in axial oblique, sagittal oblique and coronal oblique planes. For all appendages with an orifice diameter >or= 10 mm, axial and sagittal diameters and appendage volumes were recorded in atrial diastole and systole. Regression analysis was performed to assess which imaging appearances best predicted accessory appendage contractility. Twenty-three (23%) patients demonstrated an accessory LAA, all identified along the anterior LA wall. Dimensions for axial oblique (AOD) and sagittal oblique (SOD) diameters and sagittal oblique length (SOL) were 6.3-19, 3.4-20 and 5-21 mm, respectively. All appendages (>or=10 mm) demonstrated significant contraction during atrial systole (greatest diameter reduction was AOD [3.8 mm, 27%]). Significant correlations were noted between AOD-contraction and AOD (R = 0.57, P < 0.05) and SOD-contraction and AOD, SOD and SOL (R = 0.6, P < 0.05). Mean diverticulum volume in atrial diastole was 468.4 +\\/- 493 mm(3) and in systole was 171.2 +\\/- 122 mm(3), indicating a mean change in volume of 297.2 +\\/- 390 mm(3), P < 0.0001. Stepwise multiple regression analysis revealed SOL to be the strongest independent predictor of appendage contractility (R(2) = 0.86, P < 0.0001) followed by SOD (R(2) = 0.91, P < 0.0001). Accessory LAAs show significant contractile properties on cardiac CT. Those accessory LAAs with a large sagittal height or depth should be evaluated for contractile properties, and if present should be examined for ectopic activity during electrophysiological studies.

  7. Endothelin-1 mediates natriuresis but not polyuria during vitamin D-induced acute hypercalcaemia.

    Science.gov (United States)

    Tokonami, Natsuko; Cheval, Lydie; Monnay, Isabelle; Meurice, Guillaume; Loffing, Johannes; Feraille, Eric; Houillier, Pascal

    2017-04-15

    Hypercalcaemia can occur under various pathological conditions, such as primary hyperparathyroidism, malignancy or granulomatosis, and it induces natriuresis and polyuria in various species via an unknown mechanism. A previous study demonstrated that hypercalcaemia induced by vitamin D in rats increased endothelin (ET)-1 expression in the distal nephron, which suggests the involvement of the ET system in hypercalcaemia-induced effects. In the present study, we demonstrate that, during vitamin D-induced hypercalcaemia, the activation of ET system by increased ET-1 is responsible for natriuresis but not for polyuria. Vitamin D-treated hypercalcaemic mice showed a blunted response to amiloride, suggesting that epithelial sodium channel function is inhibited. We have identified an original pathway that specifically mediates the effects of vitamin D-induced hypercalcaemia on sodium handling in the distal nephron without affecting water handling. Acute hypercalcaemia increases urinary sodium and water excretion; however, the underlying molecular mechanism remains unclear. Because vitamin D-induced hypercalcaemia increases the renal expression of endothelin (ET)-1, we hypothesized that ET-1 mediates the effects of hypercalcaemia on renal sodium and water handling. Hypercalcaemia was induced in 8-week-old, parathyroid hormone-supplemented, male mice by oral administration of dihydrotachysterol (DHT) for 3 days. DHT-treated mice became hypercalcaemic and displayed increased urinary water and sodium excretion compared to controls. mRNA levels of ET-1 and the transcription factors CCAAT-enhancer binding protein β and δ were specifically increased in the distal convoluted tubule and downstream segments in DHT-treated mice. To examine the role of the ET system in hypercalcaemia-induced natriuresis and polyuria, mice were treated with the ET-1 receptor antagonist macitentan, with or without DHT. Mice treated with both macitentan and DHT displayed hypercalcaemia and polyuria

  8. Normalization of hemoglobin-based oxygen carrier-201 induced vasoconstriction: targeting nitric oxide and endothelin.

    Science.gov (United States)

    Taverne, Yannick J; de Wijs-Meijler, Daphne; Te Lintel Hekkert, Maaike; Moon-Massat, Paula F; Dubé, Gregory P; Duncker, Dirk J; Merkus, Daphne

    2017-05-01

    Hemoglobin-based oxygen carrier (HBOC)-201 is a cell-free modified hemoglobin solution potentially facilitating oxygen uptake and delivery in cardiovascular disorders and hemorrhagic shock. Clinical use has been hampered by vasoconstriction in the systemic and pulmonary beds. Therefore, we aimed to 1 ) determine the possibility of counteracting HBOC-201-induced pressor effects with either adenosine (ADO) or nitroglycerin (NTG); 2 ) assess the potential roles of nitric oxide (NO) scavenging, reactive oxygen species (ROS), and endothelin (ET) in mediating the observed vasoconstriction; and 3 ) compare these effects in resting and exercising swine. Chronically instrumented swine were studied at rest and during exercise after administration of HBOC-201 alone or in combination with ADO. The role of NO was assessed by supplementation with NTG or administration of the eNOS inhibitor N ω -nitro-l-arginine. Alternative vasoactive pathways were investigated via intravenous administration of the ET A /ET B receptor blocker tezosentan or a mixture of ROS scavengers. The systemic and to a lesser extent the pulmonary pressor effects of HBOC-201 could be counteracted by ADO; however, dosage titration was very important to avoid systemic hypotension. Similarly, supplementation of NO with NTG negated the pressor effects but also required titration of the dose. The pressor response to HBOC-201 was reduced after eNOS inhibition and abolished by simultaneous ET A /ET B receptor blockade, while ROS scavenging had no effect. In conclusion, the pressor response to HBOC-201 is mediated by vasoconstriction due to NO scavenging and production of ET. Further research should explore the effect of longer-acting ET receptor blockers to counteract the side effect of hemoglobin-based oxygen carriers. NEW & NOTEWORTHY Hemoglobin-based oxygen carrier (HBOC)-201 can disrupt hemodynamic homeostasis, mimicking some aspects of endothelial dysfunction, resulting in elevated systemic and pulmonary blood

  9. Validation of an in vitro contractility assay using canine ventricular myocytes

    Energy Technology Data Exchange (ETDEWEB)

    Harmer, A.R., E-mail: alex.harmer@astrazeneca.com; Abi-Gerges, N.; Morton, M.J.; Pullen, G.F.; Valentin, J.P.; Pollard, C.E.

    2012-04-15

    Measurement of cardiac contractility is a logical part of pre-clinical safety assessment in a drug discovery project, particularly if a risk has been identified or is suspected based on the primary- or non-target pharmacology. However, there are limited validated assays available that can be used to screen several compounds in order to identify and eliminate inotropic liability from a chemical series. We have therefore sought to develop an in vitro model with sufficient throughput for this purpose. Dog ventricular myocytes were isolated using a collagenase perfusion technique and placed in a perfused recording chamber on the stage of a microscope at ∼ 36 °C. Myocytes were stimulated to contract at a pacing frequency of 1 Hz and a digital, cell geometry measurement system (IonOptix™) was used to measure sarcomere shortening in single myocytes. After perfusion with vehicle (0.1% DMSO), concentration–effect curves were constructed for each compound in 4–30 myocytes taken from 1 or 2 dog hearts. The validation test-set was 22 negative and 8 positive inotropes, and 21 inactive compounds, as defined by their effect in dog, cynolomolgous monkey or humans. By comparing the outcome of the assay to the known in vivo contractility effects, the assay sensitivity was 81%, specificity was 75%, and accuracy was 78%. With a throughput of 6–8 compounds/week from 1 cell isolation, this assay may be of value to drug discovery projects to screen for direct contractility effects and, if a hazard is identified, help identify inactive compounds. -- Highlights: ► Cardiac contractility is an important physiological function of the heart. ► Assessment of contractility is a logical part of pre-clinical drug safety testing. ► There are limited validated assays that predict effects of compounds on contractility. ► Using dog myocytes, we have developed an in vitro cardiac contractility assay. ► The assay predicted the in vivo contractility with a good level of accuracy.

  10. Spontaneous and α-adrenoceptor-induced contractility in human collecting lymphatic vessels require chloride

    DEFF Research Database (Denmark)

    Mohanakumar, Sheyanth; Majgaard, Jens; Telinius, Niklas

    2018-01-01

    - with the impermeant anion aspartate and inhibition of Cl- transport and channels with the clinical diuretics furosemide and bendroflumethiazide, as well as DIDS and NPPB. The molecular expression of calcium-activated chloride channels was investigated by RT-PCR and proteins localized using immunoreactivity....... Spontaneous and norepinephrine-induced contractility in human lymphatic vessels was highly abrogated after Cl- substitution with aspartate. 100‒300µM DIDS or NPPB inhibited spontaneous contractile behavior. Norepinephrine-stimulated tone was furthermore markedly abrogated by 200µM DIDS. Furosemide lowered...

  11. Sandwich-type enzyme immunoassay for big endothelin-I in plasma: concentrations in healthy human subjects unaffected by sex or posture.

    Science.gov (United States)

    Aubin, P; Le Brun, G; Moldovan, F; Villette, J M; Créminon, C; Dumas, J; Homyrda, L; Soliman, H; Azizi, M; Fiet, J

    1997-01-01

    A sandwich-type enzyme immunoassay has been developed for measuring human big endothelin-1 (big ET-1) in human plasma and supernatant fluids from human cell cultures. Big ET-1 is the precursor of endothelin 1 (ET-1), the most potent vasoconstrictor known. A rabbit antibody raised against the big ET-1 COOH-terminus fragment was used as an immobilized antibody (anti-P16). The Fab' fragment of a monoclonal antibody (1B3) raised against the ET-1 loop fragment was used as the enzyme-labeled antibody, after being coupled to acetylcholinesterase. The lowest detectable value in the assay was 1.2 pg/mL (0.12 pg/well). The assay was highly specific for big ET-1, demonstrating no cross-reactivity with ET-1, big endothelin-2 (big ET-2), and big endothelin-3 (big ET-3). We used this assay to evaluate the effect of two different postural positions (supine and standing) on plasma big ET-1 concentrations in 11 male and 11 female healthy subjects. Data analysis revealed that neither sex nor body position influenced plasma big ET-1 concentrations. This assay should thus permit the detection of possible variations in plasma concentrations of big ET-1 in certain pathologies and, in association with ET-1 assay, make possible in vitro study of endothelin-converting enzyme activity in cell models. Such studies could clarify the physiological and clinical roles of this family of peptides.

  12. 2-Deoxyadenosine triphosphate restores the contractile function of cardiac myofibril from adult dogs with naturally occurring dilated cardiomyopathy

    OpenAIRE

    Cheng, Yuanhua; Hogarth, Kaley A.; O'Sullivan, M. Lynne; Regnier, Michael; Pyle, W. Glen

    2015-01-01

    1) First report to characterize and define the contractile kinetics and defects associated with naturally occurring dilated cardiomyopathy (DCM) in dogs. 2) Novel findings that dATP is able to reverse the contractile defects associated with naturally occurring canine DCM.

  13. Relationship between urine albumin and endothelin in children with anaphylactoid purpura

    International Nuclear Information System (INIS)

    Duan Yongqiang; Chen Nianfa

    2009-01-01

    To study the function of urine albumin and endothelin (ET-1) in the occurrence and progress of ansphylactoid purura (HSP) and anaphylaxis purura nephritis (HSPN) in children, the serum level of ET-1 and urine albumin excretion rate in 29 children with HSP and 21 normal controls was detected by RIA and salicylic acid nephelometry respectively. The results showed that the content of urine albumin in 24 hours in HSP group has no significant difference compared with that of control group (P>0.05) , but the corresponding content in HSPN group has significant difference compared with that of control and HSP group (P<0.01). The serum ET-1 in HSP group has significant difference compared with control group (P<0.05), and the corresponding content in HSPN group has significant difference compared with control group and HSP group (P<0.01, P<0.05). The levels of urine albumin of 24 hours and serum ET-1 in HSPN group after treatment were decreased obviously compared with those before treatment (P<0.01). The content of urine albumin of 24 hours was positively correlated with serum levels of ET-1. The ET-1 participated the formation of HSP and HSPN, and was related to the occurrence and progress of urine albumin. (authors)

  14. The Matrix Metalloproteases and Endothelin-1 in Infection-Associated Preterm Birth

    Directory of Open Access Journals (Sweden)

    Nicole S. Olgun

    2010-01-01

    Full Text Available Preterm birth (PTB is clinically defined as any delivery which occurs before the completion of 37 weeks of gestation, and is currently the most important problem in obstetrics. In the United States, PTB accounts for 12-13% of all live births, and, with the exception of fetuses suffering from anomalies, is the primary cause of perinatal mortality. While the risk factors for PTB are numerous, the single most common cause is intrauterine infection. As there is currently no FDA-approved therapy for infection-associated PTB, understanding the pathogenesis of preterm labor (PTL and delivery should be given high priority. The matrix metalloproteinases (MMPs are a family of enzymes that have been implicated in normal parturition as well as infection-triggered rupture of membranes and preterm birth. Several lines of evidence also suggest a role for endothelin-1 (ET-1 in infection-associated preterm delivery. This paper focuses on the evidence that the MMPs and ET-1 act in the same molecular pathway in preterm birth.

  15. Elevated Serum Tryptase and Endothelin in Patients with ST Segment Elevation Myocardial Infarction: Preliminary Report.

    Science.gov (United States)

    Lewicki, Lukasz; Siebert, Janusz; Marek-Trzonkowska, Natalia; Masiewicz, Emilia; Kolinski, Tomasz; Reiwer-Gostomska, Magdalena; Targonski, Radoslaw; Trzonkowski, Piotr

    2015-01-01

    An inflammatory response plays a crucial role in myocardial damage after an acute myocardial infarction. To measure serum concentrations of several mediators in patients with an acute myocardial infarction (STEMI) and to assess their potential relationship with a risk of coronary instability. The 33 patients with STEMI and 19 healthy volunteers were analyzed. The clinical data were obtained; as well serum concentrations of tryptase, endothelin (ET-1), angiogenin, soluble c-kit, and PDGF were measured. Patients with STEMI had higher serum tryptase and ET-1 than healthy volunteers (2,5 ± 0,4 ng/mL versus 1,1 ± 0,4 ng/mL and 0,7 ± 0,1 ng/mL versus 0,3 ± 0,1 ng/mL, resp.). Subjects with significant lesion in left anterior descending artery (LAD) had lower serum ET-1 compared to those with normal LAD (0,6 ± 0,2 pg/mL versus 0,9 ± 0,4 pg/mL). Patients with three-vessel coronary artery disease (CAD) had higher level of soluble c-kit compared to those with one- or two-vessel CAD: 19,9 ± 24,1 ng/mL versus 5,6 ± 1,9 ng/mL. Elevated serum tryptase and ET-1 may be markers of increased coronary instability; some cytokines may be related to the extension of CAD.

  16. Molecular mechanism of mast cell–mediated innate defense against endothelin and snake venom sarafotoxin

    Science.gov (United States)

    Schneider, Lars A.; Schlenner, Susan M.; Feyerabend, Thorsten B.; Wunderlin, Markus; Rodewald, Hans-Reimer

    2007-01-01

    Mast cells are protective against snake venom sarafotoxins that belong to the endothelin (ET) peptide family. The molecular mechanism underlying this recently recognized innate defense pathway is unknown, but secretory granule proteases have been invoked. To specifically disrupt a single protease function without affecting expression of other proteases, we have generated a mouse mutant selectively lacking mast cell carboxypeptidase A (Mc-cpa) activity. Using this mutant, we have now identified Mc-cpa as the essential protective mast cell enzyme. Mass spectrometry of peptide substrates after cleavage by normal or mutant mast cells showed that removal of a single amino acid, the C-terminal tryptophan, from ET and sarafotoxin by Mc-cpa is the principle molecular mechanism underlying this very rapid mast cell response. Mast cell proteases can also cleave ET and sarafotoxin internally, but such “nicking” is not protective because intramolecular disulfide bridges maintain peptide function. We conclude that mast cells attack ET and sarafotoxin exactly at the structure required for toxicity, and hence sarafotoxins could not “evade” Mc-cpa's substrate specificity without loss of toxicity. PMID:17923505

  17. Clinical value of plasma endothelin levels in children with cardiovascular diseases

    International Nuclear Information System (INIS)

    Chen Nianfa; Duan Yongqiang

    2009-01-01

    To explore the clinical value of plasma endothelin (ET-1) levels in children with cardiovascular diseases, 77 children with heart failure, obesity, hyperlipemia, fatty liver and hypertension were divided into 5 experimental groups and 21 health children with same age and gender as control group. The plasma levels of ET-1 in these children were tested by RIA. The results showed that plasma levels of ET-1 in 5 experimental groups were 112.8 ± 34.1ng/L, 57.8 ± 19.1ng/L,64.5 ± 25.3ng/L, 74.9 ± 28.4ng/L and 60.7 ± 21.6ng/L, respectively. The ET-1 levels in 5 groups were significantly higher than that in control group (P<0.01). The results indicate the higher plasma ET-1 levels in children are related with cardiovascular diseases, and it is useful in the diagnosis of children cardiovascular diseases. (authors)

  18. A complex genomic rearrangement involving the endothelin 3 locus causes dermal hyperpigmentation in the chicken.

    Directory of Open Access Journals (Sweden)

    Ben Dorshorst

    2011-12-01

    Full Text Available Dermal hyperpigmentation or Fibromelanosis (FM is one of the few examples of skin pigmentation phenotypes in the chicken, where most other pigmentation variants influence feather color and patterning. The Silkie chicken is the most widespread and well-studied breed displaying this phenotype. The presence of the dominant FM allele results in extensive pigmentation of the dermal layer of skin and the majority of internal connective tissue. Here we identify the causal mutation of FM as an inverted duplication and junction of two genomic regions separated by more than 400 kb in wild-type individuals. One of these duplicated regions contains endothelin 3 (EDN3, a gene with a known role in promoting melanoblast proliferation. We show that EDN3 expression is increased in the developing Silkie embryo during the time in which melanoblasts are migrating, and elevated levels of expression are maintained in the adult skin tissue. We have examined four different chicken breeds from both Asia and Europe displaying dermal hyperpigmentation and conclude that the same structural variant underlies this phenotype in all chicken breeds. This complex genomic rearrangement causing a specific monogenic trait in the chicken illustrates how novel mutations with major phenotypic effects have been reused during breed formation in domestic animals.

  19. Homocysteine, endothelin-1 and nitric oxide in patients with hypertensive disorders complicating pregnancy.

    Science.gov (United States)

    Zeng, Yachang; Li, Mujun; Chen, Yue; Wang, Sumei

    2015-01-01

    To investigate the change of level of serum homocysteine (Hcy), endothelin-1 (ET-1) and nitric oxide (NO) and clinical significance in patients with HDCP. Two hundred and thirty nine patients with HDCP (137 patients with mild preeclampsia, 102 patients with severe preeclampsia) who were hospitalized between June 2012 and June 2015 and 200 normal pregnancy women in outpatient department were enrolled in our study were divided into HDCP group and control group. Serum Hcy concentration was measured by enzymatic cycling assay. ET-1 concentration was measured by enzyme linked immunosorbent assay. And no concentration was measured by nitrate reductase assay. Serum Hcy and ET-1 in HDCP group were significantly higher as compared to control group (Ppreclampsia group (P<0.05). Level of serum NO in severe preeclampsia group were significantly lower than in mild preeclampsia group (P<0.05). Spearman rank correlation analysis showed that level of serum Hcy and ET-1 was positively correlated with severity of diseases (r=0.689, 0.718, P<0.05). Level of serum NO was negatively correlated with severity of diseases (r=-0.702, P<0.05). Serum Hcy, ET-1 and NO were associated with pathogenesis of HDCP. Comprehensively measurement of them could effectively evaluate the incidence and progress of HDCP.

  20. Facial hyperalgesia due to direct action of endothelin-1 in the trigeminal ganglion of mice.

    Science.gov (United States)

    Gomes, Lenyta Oliveira; Chichorro, Juliana Geremias; Araya, Erika Ivanna; de Oliveira, Jade; Rae, Giles Alexander

    2018-03-23

    This study assessed the ability of endothelin-1 (ET-1) to evoke heat hyperalgesia when injected directly into the trigeminal ganglia (TG) of mice and determined the receptors implicated in this effect. The effects of TG ET A and ET B receptor blockade on alleviation of heat hyperalgesia in a model of trigeminal neuropathic pain induced by infraorbital nerve constriction (CION) were also examined. Naive mice received an intraganglionar (i.g.) injection of ET-1 (0.3-3 pmol) or the selective ET B R agonist sarafotoxin S6c (3-30 pmol), and response latencies to ipsilateral heat stimulation were assessed before the treatment and at 1-h intervals up to 5 h after the treatment. Heat hyperalgesia induced by i.g. ET-1 or CION was assessed after i.g. injections of ET A R and ET B R antagonists (BQ-123 and BQ-788, respectively, each at 0.5 nmol). Intraganglionar ET-1 or sarafotoxin S6c injection induced heat hyperalgesia lasting 4 and 2 h, respectively. Heat hyperalgesia induced by ET-1 was attenuated by i.g. BQ-123 or BQ-788. On day 5 after CION, i.g. BQ-788 injection produced a more robust antihyperalgesic effect compared with BQ-123. ET-1 injection into the TG promotes ET A R/ET B R-mediated facial heat hyperalgesia, and both receptors are clearly implicated in CION-induced hyperalgesia in the murine TG system. © 2018 Royal Pharmaceutical Society.

  1. Characterization of [125I]endothelin-1 binding sites in rat cardiac membrane fragments

    International Nuclear Information System (INIS)

    Gu, X.H.; Casley, D.J.; Nayler, W.G.

    1989-01-01

    Standard binding and displacement techniques were used to identify high-affinity binding sites for [ 125 I]-labeled endothelin-1 (ET-1) in membranes harvested from the hearts of adult female Sprague-Dawley rats. A single population of binding sites was identified, with a KD of 0.20 +/- 0.03 nM at 37 degrees C, and a Bmax of 93.5 +/- 6.4 fmol/mg protein. Bound [ 125 I]ET-1 was displaced by ET-1 (10(-13)-10(-8) M), with a Ki of 0.08 nM. Neither (-)Bay K 8644 (10(-11)-10(-5) M), prenylamine (10(-11)-10(-5) M), (+)-cis-diltiazem (10(-10)-10(-5) M), (-)D888 (10(-10)-10(-5) M), nicardipine (10(-10)-10(-5) M), lidoflazine (10(-11)-10(-5) M), flunarizine (10(-11)-10(-5) M), omega-conotoxin (10(-13)-10(-7) M), nor prazosin (10(-10)-10(-5) M) displaced the bound ligand. Binding occurred in the absence of Ca2+ and was absent in heat-denatured membranes. These results are interpreted to mean that [ 125 I]ET-1 binds to a single class of high-affinity binding sites that differ from those occupied by known regulators of voltage activated L- and N-type Ca2+ channels

  2. Effect of endothelin antagonism on apnea frequency following chronic intermittent hypoxia.

    Science.gov (United States)

    Donovan, Lucas M; Liu, Yuzhen; Weiss, J Woodrow

    2014-04-01

    Chronic hypoxia increases the hypoxic ventilatory response (HVR). Augmented HVR contributes to central apneas seen in heart failure and complex sleep apnea. Endothelin receptor (ETR) antagonism decreases carotid body afferent activity following chronic intermittent hypoxia (CIH). We speculated ETR antagonism would reduce HVR and apneas following CIH. HVR and apneas were measured after exposure to CIH and room air sham (SHAM). ETR blocker Ambrisentan was administered via the chow of CIH-exposed animals from days 1 to 12 of CIH (CIH/AMB). A separate crossover group was exposed to CIH and fed normal chow (placebo) days 1-6, and Ambrisentan days 7-12 (CIH/PLA-AMB). SHAM and CIH/PLA animals were fed placebo days 1-12. The CIH/AMB and CIH/PLA-AMB rats had reduced HVR compared to CIH/PLA, similar HVR compared to sham exposed animals, and reduced apnea frequency compared to CIH/PLA animals. The reduced HVR and post-hypoxic apneas resulting from Ambrisentan administration suggests ETR antagonists may have utility in reducing central apneas following CIH. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Circulating levels of endothelin-1 in a homogenous Gulf Arab population with untreated essential hypertension.

    Science.gov (United States)

    Obineche, Enyioma; Abdulle, Abdishakur M; Bokhari, Awais M; Yasin, Javed Y; Gillett, Michael P T

    2006-01-01

    Racial variations are reported in the natural history of hypertension. For example, hypertension is significantly more prevalent in blacks than whites. Endothelial cells are important regulators of vascular tone and homeostasis, in part through secretions of vasoactive substances including endothelin-1 (ET-1), a small peptide with potent vasopressor actions. In black hypertensives, ET-1 levels are higher than in normotensive blacks and in both hypertensive and normotensive whites. Since ET-1 might play a significant role in the development and severity of hypertension in the indigenous Arab population of the United Arab Emirates, we investigated the circulating levels of ET-1 in this homogenous population. ET-1 levels were measured in plasma samples from 60 untreated hypertensive Arabs and compared with 60 age- and sex-matched normotensive controls. ET-1 levels were significantly higher in hypertensives (mean 10.1 +/- 1 pmol/L) than normotensives (mean 2.2 +/- 0.5 pmol/L). Body mass index (BMI) was slightly higher among the hypertensives. For all subjects these levels significantly (P Arabs as compared with reported levels in white hypertensives and ET-1 could be a risk factor for cardiovascular diseases in this population. The endothelial system might be particularly important with respect to hypertension in this racial group and merits further study.

  4. Endothelin receptor-specific control of endoplasmic reticulum stress and apoptosis in the kidney.

    Science.gov (United States)

    De Miguel, Carmen; Hamrick, William C; Hobbs, Janet L; Pollock, David M; Carmines, Pamela K; Pollock, Jennifer S

    2017-02-23

    Endothelin-1 (ET-1) promotes renal damage during cardiovascular disease; yet, the molecular mechanisms involved remain unknown. Endoplasmic reticulum (ER) stress, triggered by unfolded protein accumulation in the ER, contributes to apoptosis and organ injury. These studies aimed to determine whether the ET-1 system promotes renal ER stress development in response to tunicamycin. ET B deficient (ET B def) or transgenic control (TG-con) rats were used in the presence or absence of ET A receptor antagonism. Tunicamycin treatment similarly increased cortical ER stress markers in both rat genotypes; however, only ET B def rats showed a 14-24 fold increase from baseline for medullary GRP78, sXBP-1, and CHOP. Pre-treatment of TG-con rats with the ET A blocker ABT-627 for 1 week prior to tunicamycin injection significantly reduced the ER stress response in cortex and medulla, and also inhibited renal apoptosis. Pre-treatment with ABT-627 failed to decrease renal ER stress and apoptosis in ET B def rats. In conclusion, the ET-1 system is important for the development of tunicamycin-induced renal ER stress and apoptosis. ET A receptor activation induces renal ER stress genes and apoptosis, while functional activation of the ET B receptor has protective effects. These results highlight targeting the ET A receptor as a therapeutic approach against ER stress-induced kidney injury.

  5. Endothelin receptor antagonist attenuates oxidative stress in a neonatal sepsis piglet model.

    Science.gov (United States)

    Goto, Tatenobu; Hussein, Mohamed Hamed; Kato, Shin; Daoud, Ghada Abdel-Hamid; Kato, Takenori; Sugiura, Takahiro; Kakita, Hiroki; Nobata, Masanori; Kamei, Michi; Mizuno, Haruo; Imai, Masaki; Ito, Tetsuya; Kato, Ineko; Suzuki, Satoshi; Okada, Noriko; Togari, Hajime; Okada, Hidechika

    2012-12-01

    Oxidative stress (oxidant-antioxidant imbalance) plays an important role in the pathophysiology of neonatal sepsis. This study evaluated whether an antisense peptide endothelin receptor antagonist, ETR-P1/fl, could attenuate oxidative stress in a neonatal sepsis model. A total of 18 3-d-old piglets were anesthetized and mechanically ventilated. Six piglets received cecal ligation and perforation (CLP group) for induction of sepsis. Six piglets also received continuous infusion (0.05 mg/kg/h) of ETR-P1/fl 30 min after CLP (ETR-P1/fl group). Six piglets received a sham operation. Serum total hydroperoxide (TH), biological antioxidant potentials (BAPs), oxidative stress index (OSI, calculated as TH/BAP), interleukin (IL)-6, serum glutamic oxaloacetic transaminase (GOT), and creatinine were measured before CLP and at 1, 3, and 6 h after CLP. CLP evoked a state of shock resulting in elevated TH, OSI, and IL-6 levels. ETR-P1/fl administration after CLP resulted in lower serum TH at 1 and 3 h after CLP, OSI at 1 and 3 h after CLP, IL-6 at 1 and 3 h after CLP, and GOT at 3 and 6 h after CLP as compared with the CLP group. ETR-P1/fl treatment significantly attenuated the elevation of serum oxidative stress markers (TH and OSI), IL-6, and GOT in a progressive neonatal sepsis CLP model.

  6. Plasmatic endothelin-1 levels in hyperthyroid patients before and after antithyroid therapy.

    Science.gov (United States)

    Cesareo, R; Tarabuso, A; Di Benedetto, M; Lacerna, F; Reda, G

    2000-03-01

    The Endothelin-1 (ET-1) is a powerful vasoconstrictor peptide produced by endothelial cells in many vascular diseases probably as a response to vessel damage. In hyperthyroidism as in other endocrinological diseases elevated ET-1 plasma levels have been found. The effect of antithyroid therapy on ET-1 plasmatic levels was evaluated by measuring ET-1 plasma levels before and 2 and 6 months after treatment with methimazole in 14 patients affected by hyperthyroidism. The hyperthyroid patients had significantly higher ET-1 levels than the controls (18.85 +/- 5.7 vs 10.9 +/- 2.1 pg/ml), while after treatment no difference was found. The ET-1 plasma levels of hyperthyroid patients correlated closely with the raised thyroid metabolic activity independently of its cause. It is possible that the increased ET-1 levels in hyperthyroid patients are the expression of blood vessel damage caused by high thyroid hormone levels. Moreover the results of this study could suggest that, in future, ET-1 plasmatic levels might be considered as a functional thyroid index in hyperthyroid diseases.

  7. Expression of endothelin-1 gene and protein in human granulosa cells

    Energy Technology Data Exchange (ETDEWEB)

    Magini, A.; Granchi, S.; Susini, T. [Univ. of Florence (Italy)] [and others

    1996-04-01

    Previous studies in animal models indicated an autocrine/paracrine action of endothelin-1 (ET-1) in the ovary. We now report evidence on the presence of ET-1 in human ovary during reproductive life. Immunohistochemical and in situ hybridization studies demonstrated a positive signal into cytoplasm of granulosa cells (GC) of follicles at different growth stages. The concentration of ET-1-like immunoreactivity (ET-1-Li) was also measured by a specific RIA in human follicular fluid (FF). FF samples were obtained from women in an in vitro fertilization program undergoing gonadotropin stimulation (group A; n = 24) or no treatment (group B; n = 7). The mean ({+-}SD) ET-1-LI FF level in group A (4.85 {+-} 2.06 pg/mL) was significantly higher than that in group B (1.29 {+-} 0.43 pg/mL; P < 0.01), whereas the corresponding mean plasma levels were not significantly different and were not correlated to respective FF values. Our results indicate for the first time the presence of ET-1 and its messenger ribonucleic acid in the GC of the human ovary. The higher ET-1-LI levels found in the FF from women undergoing gonadotropin treatment suggest a modulation by gonadotropins and/or ovarian steroids of ET-1 production by GC. 19 refs., 4 figs., 1 tab.

  8. Interlimb Dynamic after Unilateral Focal Lesion of the Cervical Dorsal Corticospinal Tract with Endothelin-1

    Directory of Open Access Journals (Sweden)

    Walther A. Carvalho

    2017-10-01

    Full Text Available Handedness is one of the most recognized lateralized behavior in humans. Usually, it is associated with manual superiority regarding performance proficiency. For instance, more than 90% of the human population is considered more skilled with the right hand, which is controlled by the left hemisphere, than with the left. However, during the performance of bimanual tasks, the two hands usually assume asymmetric roles, with one hand acting on objects while the other provides support, stabilizing the object. Traditionally, the role of the two hands is viewed as fixed. However, several studies support an alternate view with flexible assignments for the two hands depending on the task. The supporting role of the hand depends on a closed loop pathway based on proprioceptive inputs from the periphery. The circuit’s efferent arm courses through the dorsal corticospinal tract (dCST in rodents and terminate on spinal cord interneurons which modulate the excitability of motoneurons in the ventral horn. In the present work, we developed an experimental model of unilateral lesion targeting the cervical dCST with microinjections of the vasoconstrictor endothelin-1 (ET-1 to evaluate the degree of flexibility of forelimb assignment during a food manipulation task. Our results show that just 3 days after unilateral corticospinal tract (CST injury in the cervical region, rats display severe motor impairment of the ipsilateral forepaw together with a remarkable reversal of motor assignment between the forelimbs.

  9. In vitro contractile effects of agents used in the clinical management of postpartum haemorrhage.

    Science.gov (United States)

    Morrison, John J; Crosby, David A; Crankshaw, Denis J

    2016-10-15

    Uterine atony is a major cause of postpartum haemorrhage and maternal mortality. However, the comparative pharmacology of agents used to treat this condition is poorly understood. This study evaluates, using human pregnant myometrium in vitro, a range of contractile parameters for agents used in the clinical treatment of atonic postpartum haemorrhage. The effects of oxytocin, carbetocin, ergometrine, carboprost, syntometrine and misoprostol were investigated in 146 myometrial strips from 19 donors. The potency and maximal response values were obtained, and compared, using both maximal amplitude and mean contractile force as indices of contraction. Single, EC50 concentrations of the agents were administered and both force and contraction peak parameters were compared during a 15-min exposure. Differences were considered significant when Poxytocin and carbetocin being the most potent. The most important difference between the agents was in their ability to increase the mean contractile force, with oxytocin superior to all agents except syntometrine. In single dose experiments, mean contractile force was the parameter that separated the agents. In this respect, oxytocin was not statistically different from carboprost or syntometrine, but was superior to all other agents. These findings support a clear role for oxytocin as the first line agent for treatment of postpartum haemorrhage and raise doubts about the potential clinical usefulness of misoprostol. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Smoothelin-B deficiency results in reduced arterial contractility, hypertension, and cardiac hypertrophy in mice

    NARCIS (Netherlands)

    Rensen, Sander S.; Niessen, Petra M.; van Deursen, Jan M.; Janssen, Ben J.; Heijman, Edwin; Hermeling, Evelien; Meens, Merlijn; Lie, Natascha; Gijbels, Marion J.; Strijkers, Gustav J.; Doevendans, Pieter A.; Hofker, Marten H.; de Mey, Jo G. R.; van Eys, Guillaume J.

    2008-01-01

    Smoothelins are actin-binding proteins that are abundantly expressed in healthy visceral (smoothelin-A) and vascular (smoothelin-B) smooth muscle. Their expression is strongly associated with the contractile phenotype of smooth muscle cells. Analysis of mice lacking both smoothelins (Smtn-A/B(-/-)

  11. Acute hypoxia limits endurance but does not affect muscle contractile properties.

    NARCIS (Netherlands)

    Degens, H.; Sanchez Horneros, J.M.; Hopman, M.T.E.

    2006-01-01

    Acute hypoxia causes skeletal muscle dysfunction in vitro, but little is known about its effect on muscle function in vivo. In 10 healthy male subjects, isometric contractile properties and fatigue resistance of the quadriceps muscle were determined during normoxia and hypoxia using electrically

  12. Effect of a Carbohydrate-Rich Diet on Rat Detrusor Smooth Muscle Contractility: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Mustafa Suat Bolat

    2017-01-01

    Full Text Available Objectives. We aimed to investigate the effect of a carbohydrate-rich diet on detrusor contractility in rats. Materials and Methods. Sprague-Dawley rats were randomized into two groups. The control group received regular food and water. The study group received carbohydrate-rich diet for six weeks. The rats’ detrusor muscle was isolated for pharmacological and histopathological examinations. Results. In the control and study groups, mean body weights were 431.5 ± 27.6 g and 528.0 ± 36.2 g, respectively (p < 0.001. Electrical stimulation of the detrusor strips of the control group resulted in gradual contraction. A decreased contractile response was shown in the study group. Acetylcholine in 10-7-10-3 molar concentration produced a decreased contractile response in the study group, compared to the control group (p < 0.01. The study group showed marked subepithelial and intermuscular fibrosis in the bladder. Conclusion. Carbohydrate-rich diet causes marked subepithelial and extracellular fibrosis and changes in contractility in the detrusor within a six-week period. Changes have higher costs in therapeutic choices and correction of these changes remains difficult. Putting an end to carbohydrate-rich diet would seem to be more cost-effective than dealing with the effects of consuming it in high proportions which should be the national policy worldwide.

  13. Prolonged ischemic heart disease and coronary artery bypass - relation to contractile reserve

    DEFF Research Database (Denmark)

    Kofoed, Klaus F; Bangsgaard, Regitze; Carstensen, Steen

    2002-01-01

    OBJECTIVE: A major effect of coronary artery bypass grafting (CABG) in patients with ischemic heart disease and impaired left ventricular (LV) contractile function is believed to be an improvement in LV function due to recovery of dysfunctional, but viable myocardium. However, recent studies have...

  14. Effect of short-term outlet obstruction on rat bladder nerve density and contractility

    NARCIS (Netherlands)

    Barendrecht, M. M.; Chichester, P.; Michel, M. C.; Levin, R. M.

    2007-01-01

    1 The present study was designed to investigate the relationship between innervation density and contractile responses to field stimulation and exogenous agonists at early time points after induction of bladder outlet obstruction (BOO) in rats. 2 When compared with sham-operated animals, 1, 3 and 7

  15. Contractile responses to ergotamine and dihydroergotamine in the perfused middle cerebral artery of rat

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer; Nilsson, Elisabeth; Edvinsson, Lars

    2007-01-01

    mmHg and luminally perfused. All vessels used attained spontaneous contractile tone (34.9+/-1.8% of resting tone) and responded to luminal adenosine triphosphate (ATP) with dilatation (24.1+/-4.0%), which showed functioning endothelium. Luminally added ergotamine or DHE induced maximal contractions...

  16. Gallbladder contractility and mucus secretion after cholesterol feeding in the prairie dog

    NARCIS (Netherlands)

    Li, Y. F.; Moody, F. G.; Weisbrodt, N. W.; Zalewsky, C. A.; Coelho, J. C.; Senninger, N.; Gouma, D.

    1986-01-01

    The purpose of our study was to evaluate changes in gallbladder contractility and mucus secretion in vitro during the early stages of gallstone formation in prairie dogs. Thirty-two animals were divided into five groups. Control animals were fed a trace cholesterol diet. Experimental animals were

  17. Hydrogen ion changes and contractile behavior in the perfused rat heart

    NARCIS (Netherlands)

    Cingolani, H.E.; Maas, A.H.J.; Zimmerman, A.N.E.; Meijler, F.L.

    1975-01-01

    The effect of acid-base alterations was analyzed using isolated rat hearts perfused at constant coronary perfusion pressure, and stimulated to contract at constant rate. The amount of shortening in the major axis and its derivative were measured to assess myocardial contractility. Both the

  18. The importance of myocardial contractile reserve in predicting response to cardiac resynchronization therapy

    NARCIS (Netherlands)

    Kloosterman, Mariëlle; Damman, Kevin; Van Veldhuisen, Dirk J; Rienstra, Michiel; Maass, Alexander H

    AimTo perform a meta-analysis and systematic review of published data to assess the relationship between contractile reserve and response to cardiac resynchronization therapy (CRT) in patients with heart failure. Methods and resultsWe searched MEDLINE/PubMed and Cochrane for all papers published up

  19. ATP-induced changes in rat skeletal muscle contractility.

    Science.gov (United States)

    Gabdrakhmanov, A I; Khayrullin, A E; Grishin, C H; Ziganshin, A U

    2015-01-01

    considered as typical effects of ATP and other purines on skeletal muscles and could not be extrapolated to all warm-blooded animals. Furthermore the role of ATP and its derivatives in the accumulation of vertebrate muscular effort has not been investigated.It is known that in physiological conditions vertebrates may mobilize only up to a third of the maximum muscle force. Why the two-thirds of muscular strength are not used normally but may be used at stress, remains unknown.It is known that the body's adaptive response to stress is a change in the activity of the endocrine system. The leading role in this is given to catechol amines and glucocorticoids, mobilized in significant quantities in blood under stress.We have found previously that incubation of frog sartorius muscle with hydrocortisone resulted in a decrease of contraction amplitude. However, when hydrocortisone was used in combination with ATP, its inhibitory effect on contractile responses disappeared. It is interesting that hydrocortisone had no effect on the inhibitory effect of adenosine. In the following experiments, assessing the effect of hydrocortisone on rat soleus muscle, it was established that hydrocortisone and purines had similar inhibitory effect. When ATP and hydrocortisone were given together the same oppression occurred. To study the effects of ATP and adenosine on contraction parameters of rat skeletal muscle and assess the impact of the catechol amines on these processes. Contractions of rat soleus muscles were recorded isometrically by mechanical sensor Linton FSG-01 (UK) according to standard procedures. The average of muscle parameters received within 30 seconds (30 responses) was treated as one result. Amplitude and time characteristics of the curve reductions were estimated. During all experiments standard Krebs solution flowed through the bath continuously to which agents were added at necessary concentrations. All experimental animals were maintained and prepared for dissection under

  20. Gene transfer of heterologous G protein-coupled receptors to cardiomyocytes: differential effects on contractility.

    Science.gov (United States)

    Laugwitz, K L; Weig, H J; Moretti, A; Hoffmann, E; Ueblacker, P; Pragst, I; Rosport, K; Schömig, A; Ungerer, M

    2001-04-13

    In heart failure, reduced cardiac contractility is accompanied by blunted cAMP responses to beta-adrenergic stimulation. Parathyroid hormone (PTH)-related peptide and arginine vasopressin are released from the myocardium in response to increased wall stress but do not stimulate contractility or adenylyl cyclase at physiological concentrations. To bypass the defective beta-adrenergic signaling cascade, recombinant P1 PTH/PTH-related peptide receptors (rPTH1-Rs) and V(2) vasopressin receptors (rV(2)-Rs), which are normally not expressed in the myocardium and which are both strongly coupled to adenylyl cyclase, and recombinant beta(2)-adrenergic receptors (rbeta(2)-ARs) were overexpressed in cardiomyocytes by viral gene transfer. The capacity of endogenous hormones to increase contractility via the heterologous, recombinant receptors was compared. Whereas V(2)-Rs are uniquely coupled to Gs, PTH1-Rs and beta(2)-ARs are also coupled to other G proteins. Gene transfer of rPTH1-Rs or rbeta(2)-ARs to adult cardiomyocytes resulted in maximally increased basal contractility, which could not be further stimulated by adding receptor agonists. Agonists at rPTH1-Rs induced increased cAMP formation and phospholipase C activity. In contrast, healthy or failing rV(2)-R-expressing cardiomyocytes showed unaltered basal contractility. Their contractility and cAMP formation increased only at agonist exposure, which did not activate phospholipase C. In summary, we found that gene transfer of PTH1-Rs to cardiomyocytes results in constitutive activity of the transgene, as does that of beta(2)-ARS: In the absence of receptor agonists, rPTH1-Rs and rbeta(2)-ARs increase basal contractility, coupling to 2 G proteins simultaneously. In contrast, rV(2)-Rs are uniquely coupled to Gs and are not constitutively active, retaining their property to be activated exclusively on agonist stimulation. Therefore, gene transfer of V(2)-Rs might be more suited to test the effects of c

  1. Liberación de endotelina-1 por angiotensina ll en miocitos cardíacos aislados Angiotensin II-induced endothelin-1 release in cardiac myocytes

    Directory of Open Access Journals (Sweden)

    María C. Villa-Abrille

    2006-06-01

    Full Text Available Muchos de los efectos de la angiotensina II (Ang II son mediados en realidad por la acción de endotelina (ET endógena liberada y/o producida en respuesta a la Ang II. En este trabajo evaluamos la interacción Ang II/ET-1, sus consecuencias en la contractilidad cardíaca y el papel de las especies reactivas del oxígeno (EROs. Se usaron cardiomiocitos aislados de gato. La Ang II, 1 nM, produjo un efecto inotrópico positivo (EIP de 31.8±3.8% que fue cancelado por inhibición de los receptores AT1, de los receptores de ET, del intercambiador Na+/H+ (NHE, del modo inverso del intercambiador Na+/Ca2+ (NCX o por el secuestro de EROs. La Ang II, 100 nM, produjo un EIP de 70.5±7.6% que fue cancelado por inhibición de los receptores AT1 y bloqueado en parte por inhibición de los receptores de ET, del NHE, del modo inverso del NCX o por el secuestro de EROs. La Ang II, 1 nM, incrementó el ARNm de la preproET-1 lo cual fue anulado por el bloqueo de los receptores AT1. Los resultados permiten concluir que el EIP de la Ang II es debido a la acción de la ET-1 endógena liberada/formada por la Ang II. La ET-1 produce: estimulación del NHE, activación del modo inverso del NCX y un consecuente EIP. Dentro de esta cascada también participarían los EROs.Many of the effects thought to be due to angiotensin II (Ang II are due to the release/formation of endothelin (ET. We tested whether Ang II elicits its positive inotropic effect (PIE by the action of endogenous ET-1 and the role played by the reactive oxygen species (ROS in this mechanism. Experiments were performed in cat isolated ventricular myocytes in which sarcomere shortening (SS was measured to asses contractility after pharmacological interventions and the effect of Ang II on inotropism were analyzed. Ang II 1 nM increased SS by 31.8±3.8% (p<0.05. This PIE was cancelled by AT1 receptor blockade, by ET-1 receptors blockade, by Na+/H+ exchanger (NHE inhibition, by reverse mode Na+/Ca2

  2. PKA catalytic subunit compartmentation regulates contractile and hypertrophic responses to β-adrenergic signaling

    Science.gov (United States)

    Yang, Jason H.; Polanowska-Grabowska, Renata K.; Smith, Jeffrey S.; Shields, Charles W.; Saucerman, Jeffrey J.

    2014-01-01

    β-adrenergic signaling is spatiotemporally heterogeneous in the cardiac myocyte, conferring exquisite control to sympathetic stimulation. Such heterogeneity drives the formation of protein kinase A (PKA) signaling microdomains, which regulate Ca2+ handling and contractility. Here, we test the hypothesis that the nucleus independently comprises a PKA signaling microdomain regulating myocyte hypertrophy. Spatially-targeted FRET reporters for PKA activity identified slower PKA activation and lower isoproterenol sensitivity in the nucleus (t50 = 10.60±0.68 min; EC50 = 89.00 nmol/L) than in the cytosol (t50 = 3.71±0.25 min; EC50 = 1.22 nmol/L). These differences were not explained by cAMP or AKAP-based compartmentation. A computational model of cytosolic and nuclear PKA activity was developed and predicted that differences in nuclear PKA dynamics and magnitude are regulated by slow PKA catalytic subunit diffusion, while differences in isoproterenol sensitivity are regulated by nuclear expression of protein kinase inhibitor (PKI). These were validated by FRET and immunofluorescence. The model also predicted differential phosphorylation of PKA substrates regulating cell contractility and hypertrophy. Ca2+ and cell hypertrophy measurements validated these predictions and identified higher isoproterenol sensitivity for contractile enhancements (EC50 = 1.84 nmol/L) over cell hypertrophy (EC50 = 85.88 nmol/L). Over-expression of spatially targeted PKA catalytic subunit to the cytosol or nucleus enhanced contractile and hypertrophic responses, respectively. We conclude that restricted PKA catalytic subunit diffusion is an important PKA compartmentation mechanism and the nucleus comprises a novel PKA signaling microdomain, insulating hypertrophic from contractile β-adrenergic signaling responses. PMID:24225179

  3. Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

    Energy Technology Data Exchange (ETDEWEB)

    Morton, M.J., E-mail: michael.morton@astrazeneca.com [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Armstrong, D.; Abi Gerges, N. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Bridgland-Taylor, M. [Discovery Sciences, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom); Pollard, C.E.; Bowes, J.; Valentin, J.-P. [Drug Safety and Metabolism, AstraZeneca, Macclesfield, Cheshire SK10 4TG (United Kingdom)

    2014-09-01

    Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility.

  4. Thrombopoietin modulates cardiac contractility in vitro and contributes to myocardial depressing activity of septic shock serum.

    Science.gov (United States)

    Lupia, Enrico; Spatola, Tiziana; Cuccurullo, Alessandra; Bosco, Ornella; Mariano, Filippo; Pucci, Angela; Ramella, Roberta; Alloatti, Giuseppe; Montrucchio, Giuseppe

    2010-09-01

    Thrombopoietin (TPO) is a humoral growth factor that has been shown to increase platelet activation in response to several agonists. Patients with sepsis have increased circulating TPO levels, which may enhance platelet activation, potentially participating to the pathogenesis of multi-organ failure. Aim of this study was to investigate whether TPO affects myocardial contractility and participates to depress cardiac function during sepsis. We showed the expression of the TPO receptor c-Mpl on myocardial cells and tissue by RT-PCR, immunofluorescence and western blotting. We then evaluated the effect of TPO on the contractile function of rat papillary muscle and isolated heart. TPO did not change myocardial contractility in basal conditions, but, when followed by epinephrine (EPI) stimulation, it blunted the enhancement of contractile force induced by EPI both in papillary muscle and isolated heart. An inhibitor of TPO prevented TPO effect on cardiac inotropy. Treatment of papillary muscle with pharmacological inhibitors of phosphatidylinositol 3-kinase, NO synthase, and guanilyl cyclase abolished TPO effect, indicating NO as the final mediator. We finally studied the role of TPO in the negative inotropic effect exerted by human septic shock (HSS) serum and TPO cooperation with TNF-alpha and IL-1beta. Pre-treatment with the TPO inhibitor prevented the decrease in contractile force induced by HSS serum. Moreover, TPO significantly amplified the negative inotropic effect induced by TNF-alpha and IL-1beta in papillary muscle. In conclusion, TPO negatively modulates cardiac inotropy in vitro and contributes to the myocardial depressing activity of septic shock serum.

  5. Retosiban Prevents Stretch-Induced Human Myometrial Contractility and Delays Labor in Cynomolgus Monkeys.

    Science.gov (United States)

    Aye, Irving L M H; Moraitis, Alexandros A; Stanislaus, Dinesh; Charnock-Jones, D Stephen; Smith, Gordon C S

    2018-03-01

    Stretch of the myometrium promotes its contractility and is believed to contribute to the control of parturition at term and to the increased risk of preterm birth in multiple pregnancies. To determine the effects of the putative oxytocin receptor (OTR) inverse agonist retosiban on (1) the contractility of human myometrial explants and (2) labor in nonhuman primates. Human myometrial biopsies were obtained at planned term cesarean, and explants were exposed to stretch in the presence and absence of a range of drugs, including retosiban. The in vivo effects of retosiban were determined in cynomolgus monkeys. Prolonged mechanical stretch promoted myometrial extracellular signal-regulated kinase (ERK)1/2 phosphorylation. Moreover, stretch-induced stimulation of myometrial contractility was prevented by ERK1/2 inhibitors. Retosiban (10 nM) prevented stretch-induced stimulation of myometrial contractility and phosphorylation of ERK1/2. Moreover, the inhibitory effect of retosiban on stretch-induced ERK1/2 phosphorylation was prevented by coincubation with a 100-fold excess of a peptide OTR antagonist, atosiban. Compared with vehicle-treated cynomolgus monkeys, treatment with oral retosiban (100 to 150 days of gestational age) reduced the risk of spontaneous delivery (hazard ratio = 0.07, 95% confidence interval 0.01 to 0.60, P = 0.015). The OTR acts as a uterine mechanosensor, whereby stretch increases myometrial contractility through agonist-free activation of the OTR. Retosiban prevents this through inverse agonism of the OTR and, in vivo, reduced the likelihood of spontaneous labor in nonhuman primates. We hypothesize that retosiban may be an effective preventative treatment of preterm birth in high-risk multiple pregnancies, an area of unmet clinical need.

  6. Dynamic MR cholangiography after fatty meal loading. Cystic contractility and dynamic evaluation of biliary stasis

    International Nuclear Information System (INIS)

    Omata, Takayuki; Saito, Kazuhiro; Kotake, Fumio; Mizokami, Yuji; Matsuoka, Takeshi; Abe, Kimihiko

    2002-01-01

    Dynamic MR cholangiography was conducted on patients with cholelithiasis or choledocholithiasis who had consumed a fatty test meal (Molyork) and the cystic contractility and dynamics of biliary stasis was evaluated. The subjects were 25 with intracystic cholelithiasis, 10 with choledocholithiasis and 10 normal controls. For an imaging sequence, the rapid acquisition with relaxation enhancement (RARE) method was employed and imaging was conducted for 40 min (every 30 s following Molyork administration) without breath-holding. The gallbladder contraction ratio was computed and the contractile ratio for the common bile duct was calculated. To determine the bile flow to the duodenum, the high-intensity signal, indicating the flow from the lower common bile duct, and perfusion of the duodenum were observed in dynamic mode on the monitor with the naked eye and interpreted as positive bile flow. The frequency of this flow was visually monitored. The gallbladder contractile ratio was significantly reduced in patients with cholelithiasis or choledocholithiasis compared with the controls. In a comparison with the normal controls, no sequential changes were noted in the mean contractile ratio of the common bile duct of the patients with cholelithiasis or choledocholithiasis. The mean frequency of bile flow observed for each 40 min period was 13±2.4, 6±2.2, and 4±1.3 times for the controls, those with intracystic cholelithiasis, and those with choledocholithiasis, respectively. Compared with the controls, the latter two patient groups showed evident reductions in the frequency of bile flow to the duodenum (p<0.001). Dynamic MRC combined with Molyork loading makes it possible to compute cystic contractile ratios and perform a dynamic examination of bile flow under non-invasive, near-physiological conditions. (author)

  7. Changes in contractile activation characteristics of rat fast and slow skeletal muscle fibres during regeneration.

    Science.gov (United States)

    Gregorevic, Paul; Plant, David R; Stupka, Nicole; Lynch, Gordon S

    2004-07-15

    Damaged skeletal muscle fibres are replaced with new contractile units via muscle regeneration. Regenerating muscle fibres synthesize functionally distinct isoforms of contractile and regulatory proteins but little is known of their functional properties during the regeneration process. An advantage of utilizing single muscle fibre preparations is that assessment of their function is based on the overall characteristics of the contractile apparatus and regulatory system and as such, these preparations are sensitive in revealing not only coarse, but also subtle functional differences between muscle fibres. We examined the Ca(2+)- and Sr(2+)-activated contractile characteristics of permeabilized fibres from rat fast-twitch (extensor digitorum longus) and slow-twitch (soleus) muscles at 7, 14 and 21 days following myotoxic injury, to test the hypothesis that fibres from regenerating fast and slow muscles have different functional characteristics to fibres from uninjured muscles. Regenerating muscle fibres had approximately 10% of the maximal force producing capacity (P(o)) of control (uninjured) fibres, and an altered sensitivity to Ca(2+) and Sr(2+) at 7 days post-injury. Increased force production and a shift in Ca(2+) sensitivity consistent with fibre maturation were observed during regeneration such that P(o) was restored to 36-45% of that in control fibres by 21 days, and sensitivity to Ca(2+) and Sr(2+) was similar to that of control (uninjured) fibres. The findings support the hypothesis that regenerating muscle fibres have different contractile activation characteristics compared with mature fibres, and that they adopt properties of mature fast- or slow-twitch muscle fibres in a progressive manner as the regeneration process is completed.

  8. Predicting changes in cardiac myocyte contractility during early drug discovery with in vitro assays

    International Nuclear Information System (INIS)

    Morton, M.J.; Armstrong, D.; Abi Gerges, N.; Bridgland-Taylor, M.; Pollard, C.E.; Bowes, J.; Valentin, J.-P.

    2014-01-01

    Cardiovascular-related adverse drug effects are a major concern for the pharmaceutical industry. Activity of an investigational drug at the L-type calcium channel could manifest in a number of ways, including changes in cardiac contractility. The aim of this study was to define which of the two assay technologies – radioligand-binding or automated electrophysiology – was most predictive of contractility effects in an in vitro myocyte contractility assay. The activity of reference and proprietary compounds at the L-type calcium channel was measured by radioligand-binding assays, conventional patch-clamp, automated electrophysiology, and by measurement of contractility in canine isolated cardiac myocytes. Activity in the radioligand-binding assay at the L-type Ca channel phenylalkylamine binding site was most predictive of an inotropic effect in the canine cardiac myocyte assay. The sensitivity was 73%, specificity 83% and predictivity 78%. The radioligand-binding assay may be run at a single test concentration and potency estimated. The least predictive assay was automated electrophysiology which showed a significant bias when compared with other assay formats. Given the importance of the L-type calcium channel, not just in cardiac function, but also in other organ systems, a screening strategy emerges whereby single concentration ligand-binding can be performed early in the discovery process with sufficient predictivity, throughput and turnaround time to influence chemical design and address a significant safety-related liability, at relatively low cost. - Highlights: • The L-type calcium channel is a significant safety liability during drug discovery. • Radioligand-binding to the L-type calcium channel can be measured in vitro. • The assay can be run at a single test concentration as part of a screening cascade. • This measurement is highly predictive of changes in cardiac myocyte contractility

  9. Effect of breed on plasma endothelin-1 concentration, plasma renin activity, and serum cortisol concentration in healthy dogs

    DEFF Research Database (Denmark)

    Höglund, K.; Lequarré, A.-S.; Ljungvall, I.

    2016-01-01

    BACKGROUND: There are breed differences in several blood variables in healthy dogs. OBJECTIVE: Investigate breed variation in plasma endothelin-1 (ET-1) concentration, plasma renin activity, and serum cortisol concentration. ANIMALS: Five-hundred and thirty-one healthy dogs of 9 breeds examined...... at 5 centers (2-4 breeds/center). METHODS: Prospective observational study. Circulating concentrations of ET-1 and cortisol, and renin activity, were measured using commercially available assays. Absence of organ-related or systemic disease was ensured by thorough clinical investigations, including...

  10. Slow receptor dissociation kinetics differentiate macitentan from other endothelin receptor antagonists in pulmonary arterial smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    John Gatfield

    Full Text Available Two endothelin receptor antagonists (ERAs, bosentan and ambrisentan, are currently approved for the treatment of pulmonary arterial hypertension (PAH, a devastating disease involving an activated endothelin system and aberrant contraction and proliferation of pulmonary arterial smooth muscle cells (PASMC. The novel ERA macitentan has recently concluded testing in a Phase III morbidity/mortality clinical trial in PAH patients. Since the association and dissociation rates of G protein-coupled receptor antagonists can influence their pharmacological activity in vivo, we used human PASMC to characterize inhibitory potency and receptor inhibition kinetics of macitentan, ambrisentan and bosentan using calcium release and inositol-1-phosphate (IP(1 assays. In calcium release assays macitentan, ambrisentan and bosentan were highly potent ERAs with K(b values of 0.14 nM, 0.12 nM and 1.1 nM, respectively. Macitentan, but not ambrisentan and bosentan, displayed slow apparent receptor association kinetics as evidenced by increased antagonistic potency upon prolongation of antagonist pre-incubation times. In compound washout experiments, macitentan displayed a significantly lower receptor dissociation rate and longer receptor occupancy half-life (ROt(1/2 compared to bosentan and ambrisentan (ROt(1/2:17 minutes versus 70 seconds and 40 seconds, respectively. Because of its lower dissociation rate macitentan behaved as an insurmountable antagonist in calcium release and IP(1 assays, and unlike bosentan and ambrisentan it blocked endothelin receptor activation across a wide range of endothelin-1 (ET-1 concentrations. However, prolongation of the ET-1 stimulation time beyond ROt(1/2 rendered macitentan a surmountable antagonist, revealing its competitive binding mode. Bosentan and ambrisentan behaved as surmountable antagonists irrespective of the assay duration and they lacked inhibitory activity at high ET-1 concentrations. Thus, macitentan is a competitive

  11. Regular aerobic exercise reduces endothelin-1-mediated vasoconstrictor tone in overweight and obese adults.

    Science.gov (United States)

    Dow, Caitlin A; Stauffer, Brian L; Brunjes, Danielle L; Greiner, Jared J; DeSouza, Christopher A

    2017-09-01

    What is the central question of this study? Does aerobic exercise training reduce endothelin-1 (ET-1)-mediated vasoconstrictor tone in overweight/obese adults? And, if so, does lower ET-1 vasoconstriction underlie the exercise-related enhancement in endothelium-dependent vasodilatation in overweight/obese adults? What is the main finding and its importance? Regular aerobic exercise reduces ET-1-mediated vasoconstrictor tone in previously sedentary overweight/obese adults, independent of weight loss. Decreased ET-1 vasoconstriction is an important mechanism underlying the aerobic exercise-induced improvement in endothelium-dependent vasodilator function in overweight/obese adults. Endothelin-1 (ET-1)-mediated vasoconstrictor tone is elevated in overweight and obese adults, contributing to vasomotor dysfunction and increased cardiovascular disease risk. Although the effects of habitual aerobic exercise on endothelium-dependent vasodilatation in overweight/obese adults have been studied, little is known regarding ET-1-mediated vasoconstriction. Accordingly, the aims of the present study were to determine the following: (i) whether regular aerobic exercise training reduces ET-1-mediated vasoconstrictor tone in overweight and obese adults; and, if so, (ii) whether the reduction in ET-1-mediated vasoconstriction contributes to exercise-induced improvement in endothelium-dependent vasodilatation in this population. Forearm blood flow (FBF) in response to intra-arterial infusion of selective ET A receptor blockade (BQ-123, 100 nmol min -1 for 60 min), acetylcholine [4.0, 8.0 and 16.0 μg (100 ml tissue) -1  min -1 ] in the absence and presence of ET A receptor blockade and sodium nitroprusside [1.0, 2.0 and 4.0 μg (100 ml tissue) -1  min -1 ] were determined before and after a 3 month aerobic exercise training intervention in 25 (16 men and nine women) overweight/obese (body mass index 30.1 ± 0.5 kg m -2 ) adults. The vasodilator response to BQ-123 was

  12. Association of endothelin-1 expression and cartilaginous endplate degeneration in humans.

    Directory of Open Access Journals (Sweden)

    Wei Yuan

    Full Text Available BACKGROUND: Inflammatory cytokines are involved in intervertebral disc (IVD degeneration. Endothelin-1 (ET-1, a 21-amino-acid cytokine implicated with cartilage degradation, is secreted by vascular endothelial cells and also by many other cell types. The expression of ET-1 in human IVD cartilage endplate (CEP and its role in disc degeneration have not been explored. METHODS AND FINDINGS: The expression of ET-1 in degenerated CEP was analyzed by immunohistochemical staining and Western blotting; ET-1 was demonstrated in cartilaginous endplate cells (CECs by immunofluorescent staining. The ET-1 mRNA expression and protein production by CECs stimulated by tumor necrosis factor alpha (TNF-α, a pro-inflammatory cytokine, were determined by real-time PCR analysis and Western blotting, respectively. The matrix metalloprotease-1 (MMP-1, MMP-13 and tissue inhibitor of metalloproteases-1 (TIMP-1 levels in the supernatant of cultured CECs treated with ET-1 were determined using enzyme-linked immunosorbent assays. Nitric oxide (NO release and nitric oxide synthase (NOS activity were measured using a spectrophotometric assay. The apoptosis of CECs by ET-1 was measured by an Annexin V-FITC detection assay. The production of ET-1 in degenerated cartilage endplate was significantly higher than normal CEP. The results showed that ET-1 was expressed by CECs and modulated by TNF-α in a dose-dependent manner. ET-1 increased production of MMP-1 and MMP-13, decreased TIMP-1 production, and induced NO and NOS release by cultured CECs. The direct stimulation of CECs by ET-1 did not promote cell apoptosis. CONCLUSION: The study results suggest that ET-1 played a pivotal role in human CEP degeneration, and may be a new target for development of therapies for this condition.

  13. Gestational hypoxia induces preeclampsia-like symptoms via heightened endothelin-1 signaling in pregnant rats.

    Science.gov (United States)

    Zhou, Jianjun; Xiao, Daliao; Hu, Yali; Wang, Zhiqun; Paradis, Alexandra; Mata-Greenwood, Eugenia; Zhang, Lubo

    2013-09-01

    Preeclampsia is a life-threatening pregnancy disorder. However, its pathogenesis remains unclear. We tested the hypothesis that gestational hypoxia induces preeclampsia-like symptoms via heightened endothelin-1 (ET-1) signaling. Time-dated pregnant and nonpregnant rats were divided into normoxic and hypoxic (10.5% O2 from the gestational day 6-21) groups. Chronic hypoxia had no significant effect on blood pressure or proteinuria in nonpregnant rats but significantly increased blood pressure on day 12 (systolic blood pressure, 111.7 ± 6.1 versus 138.5 ± 3.5 mm Hg; P=0.004) and day 20 (systolic blood pressure, 103.4 ± 4.6 versus 125.1 ± 6.1 mm Hg; P=0.02) in pregnant rats and urine protein (μg/μL)/creatinine (nmol/μL) ratio on day 20 (0.10 ± 0.01 versus 0.20 ± 0.04; P=0.04), as compared with the normoxic control group. This was accompanied with asymmetrical fetal growth restriction. Hypoxia resulted in impaired trophoblast invasion and uteroplacental vascular remodeling. In addition, plasma ET-1 levels, as well as the abundance of prepro-ET-1 mRNA, ET-1 type A receptor and angiotensin II type 1 receptor protein in the kidney and placenta were significantly increased in the chronic hypoxic group, as compared with the control animals. Treatment with the ET-1 type A receptor antagonist, BQ123, during the course of hypoxia exposure significantly attenuated the hypoxia-induced hypertension and other preeclampsia-like features. The results demonstrate that chronic hypoxia during gestation induces preeclamptic symptoms in pregnant rats via heightened ET-1 and ET-1 type A receptor-mediated signaling, providing a molecular mechanism linking gestational hypoxia and increased risk of preeclampsia.

  14. Air pollution alters brain and pituitary endothelin-1 and inducible nitric oxide synthase gene expression.

    Science.gov (United States)

    Thomson, Errol M; Kumarathasan, Prem; Calderón-Garcidueñas, Lilian; Vincent, Renaud

    2007-10-01

    Recent work suggests that air pollution is a risk factor for cerebrovascular and neurodegenerative disease. Effects of inhaled pollutants on the production of vasoactive factors such as endothelin (ET) and nitric oxide (NO) in the brain may be relevant to disease pathogenesis. Inhaled pollutants increase circulating levels of ET-1 and ET-3, and the pituitary is a potential source of plasma ET, but the effects of pollutants on the expression of ET and NO synthase genes in the brain and pituitary are not known. In the present study, Fischer-344 rats were exposed by nose-only inhalation to particles (0, 5, 50mg/m3 EHC-93), ozone (0, 0.4, 0.8 ppm), or combinations of particles and ozone for 4 h. Real-time reverse transcription polymerase chain reaction was used to measure mRNA levels in the cerebral hemisphere and pituitary 0 and 24 h post-exposure. Ozone inhalation significantly increased preproET-1 but decreased preproET-3 mRNAs in the cerebral hemisphere, while increasing mRNA levels of preproET-1, preproET-3, and the ET-converting enzyme (ECE)-1 in the pituitary. Inducible NO synthase (iNOS) was initially decreased in the cerebral hemisphere after ozone inhalation, but increased 24 h post-exposure. Particles decreased tumour necrosis factor (TNF)-alpha mRNA in the cerebral hemisphere, and both particles and ozone decreased TNF-alpha mRNA in the pituitary. Our results show that ozone and particulate matter rapidly modulate the expression of genes involved in key vasoregulatory pathways in the brain and pituitary, substantiating the notion that inhaled pollutants induce cerebrovascular effects.

  15. Correlation of plasma endothelin-1 levels with pulmonary hypertension after inhaled nitric oxide therapy

    International Nuclear Information System (INIS)

    Razzaq, Z.; Naqvi, S.; Aslam, M.

    2009-01-01

    Variable response to inhaled nitric oxide (iNO) therapy in patients with mitral stenosis (MS) having pulmonary hypertension (PH) has been documented in early studies. The objectives of this study were to measure plasma Endothelin-1 (ET-1) levels in those patients and to correlate them with pulmonary vascular indices after iNO therapy. It was Quesi-experimental study. Methods: Thirty patients with mitral or mixed mitral and aortic valve disease with severe pulmonary hypertension and enrolled for valve replacement surgery were included. Before the replacement, baseline pulmonary vascular indices and cardiac output were recorded. After the surgery, 10 - 20 was in administered for 1 hour and all the parameters were again recorded. Patients were grouped into responders and non responders on the basis of % reduction in Pulmonary Vascular Resistance (PVR) after iNO therapy. Plasma ET-1 levels were measured in both groups by ELISA before and after the iNO therapy. Paired sample t-test was used to compare mean values for significance. The correlations between variables were then calculated by using Pearson's coefficient. Results: The plasma ET-1 levels were very high in all patients. They reduced in responders after iNO therapy; non-responders paradoxically showed significant increase in the levels of ET-1 after iNO therapy. Moreover, a positive correlation was observed in plasma ET-1 levels and post operative levels of PVR. Conclusion: The correlation of changes in PVR and plasma ET-1 levels in responders suggests that high plasma ET-1 is a key mediator of poor response in PH secondary to MS, after iNO therapy. (author)

  16. Comparative studies of vertebrate endothelin-converting enzyme-like 1 genes and proteins

    Directory of Open Access Journals (Sweden)

    Holmes RS

    2013-01-01

    Full Text Available Roger S Holmes,1,2 Laura A Cox11Department of Genetics and Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA; 2Eskitis Institute for Cell and Molecular Therapies and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Queensland, AustraliaAbstract: Endothelin-converting enzyme-like 1 (ECEL1 is a member of the M13 family of neutral endopeptidases which play an essential role in the neural regulation of vertebrate respiration. Genetic deficiency of this protein results in respiratory failure soon after birth. Comparative ECEL1 amino acid sequences and structures and ECEL1 gene locations were examined using data from several vertebrate genome projects. Vertebrate ECEL1 sequences shared 66%–99% identity as compared with 30%–63% sequence identities with other M13-like family members, ECE1, ECE2, and NEP (neprilysin or MME. Three N-glycosylation sites were conserved among most vertebrate ECEL1 proteins examined. Sequence alignments, conserved key amino acid residues, and predicted secondary and tertiary structures were also studied, including cytoplasmic, transmembrane, and luminal sequences and active site residues. Vertebrate ECEL1 genes usually contained 18 exons and 17 coding exons on the negative strand. Exons 1 and 2 of the human ECEL1 gene contained 5'-untranslated (5'-UTR regions, a large CpG island (CpG256, and several transcription factor binding sites which may contribute to the high levels of gene expression previously reported in neural tissues. Phylogenetic analyses examined the relationships and potential evolutionary origins of the vertebrate ECEL1 gene with six other vertebrate neutral endopeptidase M13 family genes. These suggested that ECEL1 originated in an ancestral vertebrate genome from a duplication event in an ancestral neutral endopeptidase M13-like gene.Keywords: vertebrates, amino acid sequence, ECEL1, ECE1, ECE2, KELL, NEP, NEPL1, PHEX

  17. Comparison of Serum Levels of Endothelin-1 in Chronic Periodontitis Patients Before and After Treatment

    Science.gov (United States)

    Varghese, Sheeja S; Sankari, M.; Jayakumar, ND.

    2017-01-01

    Introduction Endothelin-1 (ET-1) is a potent vasoconstrictive peptide with multi functional activity in various systemic diseases. Previous studies indicate the detection of ET-1 in gingival tissues and gingival crevicular fluid. Aim The aim of this study was to estimate the serum ET-1 levels in clinically healthy subjects and subjects with chronic periodontitis, before and after treatment, and correlate it with the clinical parameters. Materials and Methods A total of 44 patients were included in the study. Group I comprised of 20 subjects with clinically healthy periodontium. Group II comprised of 24 subjects with chronic periodontitis. Group III comprised of same Group II subjects following periodontal management. Serum samples were collected from the subjects and an Enzyme Linked Immunosorbent Assay (ELISA) was done to estimate the ET-1 levels. The ET-1 levels were then correlated among the three groups with the clinical parameters namely, Plaque Index (PI), Sulcus Bleeding Index (SBI), probing pocket depth, clinical attachment loss and Periodontally Inflamed Surface Area (PISA). The independent t-test and paired t-test were used for comparison of clinical parameters and Pearson’s correlation coefficient test was used for correlating the ET-1 levels. Results ET-1 levels in chronic periodontitis subjects were significantly higher compared to healthy subjects (p<0.001). However, the clinical parameters did not statistically correlate with the ET-1 levels. There was a significant decrease in ET-1 levels following treatment (p<0.001). Conclusion Serum ET-1 is increased in chronic periodontitis and reduces after periodontal therapy. Further studies are required to establish ET-1 as a biomarker for periodontal disease. PMID:28571268

  18. Lactoferrin- Endothelin-1 Axis Contributes to the Development and Invasiveness of Triple Negative Breast Cancer Phenotypes

    Science.gov (United States)

    Ha, Ngoc-Han; Nair, Vasudha; Reddy, Divijendra Natha Sirigiri; Mudvari, Prakriti; Ohshiro, Kazufumi; Ghanta, Krishna Sumanth; Pakala, Suresh B.; Li, Da-Qiang; Costa, Luis; Lipton, Allan; Badwe, Rajendra A.; Fuqua, Suzanne; Wallon, Margaretha; Prendergast, George C.; Kumar, Rakesh

    2013-01-01

    Triple-negative breast cancer (TNBC) is characterized by the lack of expression of ERα, PR and HER-2 receptors and the pathway(s) responsible for this downregulation and thus aggressiveness, remains unknown. Here we discovered that lactoferrin (Lf) efficiently downregulates the levels of ERα, PR and HER-2 receptors in a proteasome-dependent manner in breast cancer cells, and accounts for the loss of responsiveness to ER- or HER-2- targeted therapies. Further we found that Lf increases migration and invasiveness of both non-TNBC and TNBC cell lines. We discovered that Lf directly stimulates the transcription of endothelin-1 (ET-1), a secreted pro-invasive polypeptide that acts through a specific receptor ET(A)R, leading to secretion of bioactive ET-1 peptide. Interestingly, a therapeutic ET-1 receptor antagonist drug completely blocked Lf-dependent motility and invasiveness of breast cancer cells. Physiologic significance of this newly discovered Lf-ET-1 axis in the manifestation of TNBC phenotypes is revealed by elevated plasma and tissue Lf and ET-1 levels in TNBC patients as compared to those in ER+ cases. These findings describe the first physiologically relevant polypeptide as a functional determinant of downregulating all three therapeutic receptors in breast cancer which utilizes another secreted ET-1 system to confer invasiveness. Results presented here provide proof-of-principle evidence in support of therapeutic effectiveness of ET-1 receptor antagonist to completely block the Lf-induced motility and invasiveness of the TNBC as well as non-TBNC cells, and thus, opening a remarkable opportunity to treat TNBC by targeting the Lf-ET-1 axis using an approved developmental drug. PMID:22006997

  19. Functional heterogeneity of NADPH oxidase-mediated contractions to endothelin with vascular aging.

    Science.gov (United States)

    Meyer, Matthias R; Barton, Matthias; Prossnitz, Eric R

    2014-11-24

    Aging, a physiological process and main risk factor for cardiovascular and renal diseases, is associated with endothelial cell dysfunction partly resulting from NADPH oxidase-dependent oxidative stress. Because increased formation of endothelium-derived endothelin-1 (ET-1) may contribute to vascular aging, we studied the role of NADPH oxidase function in age-dependent contractions to ET-1. Renal arteries and abdominal aortas from young and old C57BL6 mice (4 and 24 months of age) were prepared for isometric force measurements. Contractions to ET-1 (0.1-100 nmol/L) were determined in the presence and absence of the NADPH oxidase-selective inhibitor gp91ds-tat (3 μmol/L). To exclude age-dependent differential effects of NO bioactivity between vascular beds, all experiments were conducted in the presence of the NO synthase inhibitor L-NAME (300 μmol/L). In young animals, ET-1-induced contractions were 6-fold stronger in the renal artery than in the aorta (prenal artery and aorta, respectively (pAging had no effect on NADPH oxidase-dependent and -independent contractions to ET-1 in the renal artery. In contrast, contractions to ET-1 were markedly reduced in the aged aorta (5-fold, page-dependent heterogeneity of NADPH oxidase-mediated vascular contractions to ET-1, demonstrating an inherent resistance to functional changes in the renal artery but not in the aorta with aging. Thus, local activity of NADPH oxidase differentially modulates responses to ET-1 with aging in distinct vascular beds. Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Endothelin: Visualization of mRNAs by in situ hybridization provides evidence for local action

    International Nuclear Information System (INIS)

    MacCumber, M.W.; Ross, C.A.; Glaser, B.M.; Snyder, S.H.

    1989-01-01

    Endothelin (ET) is a recently identified vasoactive peptide with three isoforms for which three genes have been cloned. The cellular sites of synthesis of this peptide have not yet been identified in vivo. Using Northern blot analysis, we have detected two forms of ET mRNA in rat tissues: a 3.7-kilobase form in the kidney, eye, and brain, a 2.5-kilobase form in the intestine, and both forms in the lung. We have localized these forms of ET mRNA in several rat tissues using in situ hybridization. In the 19-day rat fetus, ET mRNA is highest in the lung, intestine, and meninges. At high resolution, ET mRNA is localized in the lung to respiratory epithelial cells of bronchioles and apparently in blood vessels. In adult tissues, ET mRNA is present throughout the lung, in the renal medulla vasa recta, and in the iris of the eye. ET mRNA is synthesized in close proximity to ET binding sites in many organs (e.g., lung, kidney, intestine, and eye), suggesting a local action of this peptide. However, in other areas (e.g., heart and renal cortex), ET binding sites are present in the absence of ET mRNA, suggesting an action of ET from the bloodstream or from neurons. Northern blot analysis of ET mRNA in microvascular endothelial cells in culture indicates that ET is synthesized in small blood vessels and regulated similarly to its regulation in large vessels. Our results provide evidence that ET, like other regulatory peptides, may serve in several tissues as a neuromodulator or local hormone

  1. Knockout of endothelial cell-derived endothelin-1 attenuates skin fibrosis but accelerates cutaneous wound healing.

    Directory of Open Access Journals (Sweden)

    Katsunari Makino

    Full Text Available Endothelin (ET-1 is known for the most potent vasoconstrictive peptide that is released mainly from endothelial cells. Several studies have reported ET-1 signaling is involved in the process of wound healing or fibrosis as well as vasodilation. However, little is known about the role of ET-1 in these processes. To clarify its mechanism, we compared skin fibrogenesis and wound repair between vascular endothelial cell-specific ET-1 knockout mice and their wild-type littermates. Bleomycin-injected fibrotic skin of the knockout mice showed significantly decreased skin thickness and collagen content compared to that of wild-type mice, indicating that bleomycin-induced skin fibrosis is attenuated in the knockout mice. The mRNA levels of transforming growth factor (TGF-β were decreased in the bleomycin-treated skin of ET-1 knockout mice. On the other hand, skin wound healing was accelerated in ET-1 knockout mice, which was indicated by earlier granulation tissue reduction and re-epithelialization in these mice. The mRNA levels of TGF-β, tumor necrosis factor (TNF-α and connective tissue growth factor (CTGF were reduced in the wound of ET-1 knockout mice. In endothelial ET-1 knockout mouse, the expression of TNF-α, CTGF and TGF-β was down-regulated. Bosentan, an antagonist of dual ET receptors, is known to attenuate skin fibrosis and accelerate wound healing in systemic sclerosis, and such contradictory effect may be mediated by above molecules. The endothelial cell-derived ET-1 is the potent therapeutic target in fibrosis or wound healing, and investigations of the overall regulatory mechanisms of these pathological conditions by ET-1 may lead to a new therapeutic approach.

  2. Exercise capacity is associated with endothelin-1 release during emotional excitement in coronary artery disease patients.

    Science.gov (United States)

    Tulppo, Mikko P; Piira, Olli-Pekka; Hautala, Arto J; Kiviniemi, Antti M; Miettinen, Johanna A; Huikuri, Heikki V

    2014-08-01

    Endothelin-1 (ET-1), a potent vasoconstrictor, IL-6, and catecholamines are increased and heart rate variability [SD of normal to normal R-R intervals (SDNN)] decreased during emotional excitement, but individual responses vary. We tested the hypothesis that exercise capacity is associated with physiological responses caused by real-life emotional excitement. We measured the plasma levels of ET-1, IL-6, catecholamines, heart rate, and SDNN in enthusiastic male ice hockey spectators (n = 51; age, 59 ± 9 years) with stable coronary artery disease (CAD) at baseline and during the Finnish National Ice Hockey League's final play-off matches. Maximal exercise capacity (METs) by bicycle exercise test and left ventricular ejection fraction (LVEF) were measured on a separate day. ET-1 response from baseline to emotional excitement correlated with maximal METs (r = -0.30; P = 0.040). In a linear stepwise regression analysis age, body mass index (BMI), METs, LVEF, basal ET-1, and subjective experience of excitement were entered the model as independent variables to explain ET-1 response. This model explained 27% of ET-1 response (P = 0.003). Maximal METs were most strongly correlated with ET-1 response (β = -0.45; partial correlation r = -0.43; P = 0.002), followed by BMI (β = -0.31; partial correlation r = -0.31; P = 0.033) and LVEF (β = -0.30; partial correlation r = -0.33; P = 0.023). Exercise capacity may protect against further cardiovascular events in CAD patients, because it is associated with reduced ET-1 release during emotional excitement. Copyright © 2014 the American Physiological Society.

  3. Endothelin-1 stimulates catalase activity through the PKCδ mediated phosphorylation of Serine 167

    Science.gov (United States)

    Rafikov, Ruslan; Kumar, Sanjiv; Aggarwal, Saurabh; Hou, Yali; Kangath, Archana; Pardo, Daniel; Fineman, Jeffrey R.; Black, Stephen M.

    2013-01-01

    Our previous studies have shown that endothelin-1 (ET-1) stimulates catalase activity in endothelial cells and lambs with acute increases in pulmonary blood flow (PBF), without altering gene expression. The purpose of this study was to investigate the molecular mechanism by which this occurs. Exposing pulmonary arterial endothelial cells (PAEC) to ET-1 increased catalase activity and decreased cellular hydrogen peroxide (H2O2) levels. These changes correlated with an increase in serine phosphorylated catalase. Using the inhibitory peptide δV1.1, this phosphorylation was shown to be PKCδ dependent. Mass spectrometry identified serine167 as the phosphorylation site. Site-directed mutagenesis was used to generate a phospho-mimic (S167D) catalase. Activity assays using recombinant protein purified from E.coli or transiently transfected COS-7 cells, demonstrated that S167D-catalase had an increased ability to degrade H2O2 compared to the wildtype enzyme. Using a phospho-specific antibody, we were able to verify that pS167 catalase levels are modulated in lambs with acute increases in PBF in the presence and absence of the ET receptor antagonist, tezosentan. S167 is being located on the dimeric interface suggesting it could be involved in regulating the formation of catalase tetramers. To evaluate this possibility we utilized analytical gel-filtration to examine the multimeric structure of recombinant wildtype- and S167D-catalase. We found that recombinant wildtype catalase was present as a mixture of monomers and dimers while S167D catalase was primarily tetrameric. Further, the incubation of wildtype catalase with PKCδ was sufficient to convert wildtype catalase into a tetrameric structure. In conclusion, this is the first report indicating that the phosphorylation of catalase regulates its multimeric structure and activity. PMID:24211614

  4. Inhibitory effect of rhynchophylline on contraction of cerebral arterioles to endothelin 1: role of rho kinase.

    Science.gov (United States)

    Hao, Hui-Feng; Liu, Li-Mei; Liu, Yu-Ying; Liu, Juan; Yan, Li; Pan, Chun-Shui; Wang, Ming-Xia; Wang, Chuan-She; Fan, Jing-Yu; Gao, Yuan-Sheng; Han, Jing-Yan

    2014-08-08

    Rhynchophylline (Rhy) is a major ingredient of Uncaria rhynchophylla (UR) used to reduce blood pressure and ameliorate brain ailments. This study was to examine the role of Rho kinase (ROCK) in the inhibition of Rhy on contraction of cerebral arterioles caused by endothelin 1 (ET-1). Cerebral arterioles of male Wistar rats were constricted with ET-1 for 10 min followed by perfusion of Rhy for 20 min. Changes in the diameters of the arterioles were recorded. The effects of Rhy on contraction of middle cerebral arteries (MCAs) were determined by a Multi-Myograph. Western blotting and immunofluorescent staining were used to examine the effects of Rhy on RhoA translocation and myosin phosphatase target subunit 1 (MYPT1) phosphorylation. In vivo, Rhy (30-300 µM) relaxed cerebral arterioles constricted with ET-1 dose-dependently. In vitro, Rhy at lower concentrations (1-100 µM) caused relaxation of rat MCAs constricted with KCl and Bay-K8644 (an agonist of L-type voltage-dependent calcium channels (L-VDCCs)). Rhy at higher concentrations (>100 µM) caused relaxation of rat MCAs constricted with ET-1, which was inhibited by Y27632, a ROCK׳s inhibitor. Western blotting of rat aortas showed that Rhy inhibited RhoA translocation and MYPT1 phosphorylation. Immunofluorescent staining of MCAs confirmed that phosphorylation of MYPT1 caused by ET-1 was inhibited by Rhy. These results demonstrate that Rhy is a potent inhibitor of contraction of cerebral arteries caused by ET-1 in vivo and in vitro. The effect of Rhy was in part mediated by inhibiting RhoA-ROCK signaling. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. The diagnosis value of endothelin, calcitonin gene-related peptide and the ratio in diabetic nephropathy

    International Nuclear Information System (INIS)

    Li Lusheng; Zhao Xin; Chi Liuying; Yang Xixiu; Mao Hongyu

    2007-01-01

    Objective: To evaluate the diagnosis value of Endothelin (ET), Calcitonin gene-related peptide(CGRP) and theratio in diabetic nephropathy(DN). Methods: To choose 54 healthy as the control group and 124 patients with diabetes or DN as test group. According to urinary albumin excretion rate (uAER), the test group was divided into three groups, which were diabetes group of normalalbuminmia (group A), early DN (group B) and clinical DN and renal failure group( group C ). Plasma concentration of ET and CGRP were measured with radioimmunossay for those in the Control group and patients with diabetes or DN. Results: The level of ET was significantly higher in diabetic nephropathy than that in the control group (P<0.01), and there was positive correlation between ET and uAER(r=0.591, P<0.01). The plasma level of CGRP was significantly lower in diabetic nephropathy than that in the control group (P<0.01), and there was negative correlation between CGRP and uAER(r-0.389, P<0.05). The level of ET, CGRP and ET/CGRP ratio have evidently changed with the uAER rised. Conclusion: (1)The level of ET, CGRP and type 2 diabetic nephropathy are closely related, and which probably plays a role in the development of DN. (2)ET/CGRP ratio, as a new way for diagnosis, can even more reflecte the seriousness of DN. (3)This experiment provide us a new way for the prevention and treatment of DN with extrinsic CGRP. (authors)

  6. Circulating levels of endothelin-1 in a homogenous Gulf Arab population with untreated essential hypertension

    International Nuclear Information System (INIS)

    Obinache, C.N.; Abdullah, A.M.; Pathan, J.Y.; Bokahri, A.M.; Gillett, M.P.T.

    2006-01-01

    Rectal variations are reported in the natural history of high-tension. For example hypertension is significantly more prevalent in blacks than whites. Endothelial cells are important regulators of vasculars tone and homeostasis, in part through secretions of vasoactive substances including endothelin-I (ET-1), a small peptide with potent vaspressor actions in black hypertensive and normotensive whites. Since ET-I might play a significant role to the development and severity of hypertension in the indigenous Arab population of United Arab Emirates; we investigated the circulatory levels of ET-1 in the homogenous population. ET-I levels were measured in plasma samples from 60 unteated hypertensive Arabs and compared with 60 age and sex matched normotensive controls. ET-I levels were significantly higher in hypertensive (10.1+-pmol/L) than normtensives (mean 2.2+-0.5 pmol/L). Body mass index (BMI) was slightly higher among the hypertensive. For all subjects these levels significantly (P<0.001) correlated with systolic blood pressure and less significantly (P<0.05) with diastolic blood pressure and body weight. The correlation with ET-1 and both systolic and diastolic blood pressure with persistently significant after adjusting for BMI. Plasma concentration of ET-I are significantly higher in hypertensive Gulf Arabs as compared with reported levels in which hypertensives and ET-I could be a risk factor for cardiovascular diseases in this population. The endothelial sate might be particularly important with respect to hypertension in this racial group and merits further study. (author)

  7. Preservation of endothelium-dependent relaxation in atherosclerotic mice with endothelium-restricted endothelin-1 overexpression.

    Science.gov (United States)

    Mian, Muhammad Oneeb Rehman; Idris-Khodja, Noureddine; Li, Melissa W; Leibowitz, Avshalom; Paradis, Pierre; Rautureau, Yohann; Schiffrin, Ernesto L

    2013-10-01

    In human atherosclerosis, which is associated with elevated plasma and coronary endothelin (ET)-1 levels, ETA receptor antagonists improve coronary endothelial function. Mice overexpressing ET-1 specifically in the endothelium (eET-1) crossed with atherosclerosis-prone apolipoprotein E knockout mice (Apoe(-/-)) exhibit exaggerated high-fat diet (HFD)-induced atherosclerosis. Since endothelial dysfunction often precedes atherosclerosis development, we hypothesized that mice overexpressing endothelial ET-1 on a genetic background deficient in apolipoprotein E (eET-1/Apoe(-/-)) would have severe endothelial dysfunction. To test this hypothesis, we investigated endothelium-dependent relaxation (EDR) to acetylcholine in eET-1/Apoe(-/-) mice. EDR in mesenteric resistance arteries from 8- and 16-week-old mice fed a normal diet or HFD was improved in eET-1/Apoe(-/-) compared with Apoe(-/-) mice. Nitric oxide synthase (NOS) inhibition abolished EDR in Apoe(-/-). EDR in eET-1/Apoe(-/-) mice was resistant to NOS inhibition irrespective of age or diet. Inhibition of cyclooxygenase, the cytochrome P450 pathway, and endothelium-dependent hyperpolarization (EDH) resulted in little or no inhibition of EDR in eET-1/Apoe(-/-) compared with wild-type (WT) mice. In eET-1/Apoe(-/-) mice, blocking of EDH or soluble guanylate cyclase (sGC), in addition to NOS inhibition, decreased EDR by 36 and 30%, respectively. The activation of 4-aminopyridine-sensitive voltage-dependent potassium channels (Kv) during EDR was increased in eET-1/Apoe(-/-) compared with WT mice. We conclude that increasing eET-1 in mice that develop atherosclerosis results in decreased mutual dependence of endothelial signaling pathways responsible for EDR, and that NOS-independent activation of sGC and increased activation of Kv are responsible for enhanced EDR in this model of atherosclerosis associated with elevated endothelial and circulating ET-1.

  8. Endothelin-A receptor blockade slows the progression of renal injury in experimental renovascular disease.

    Science.gov (United States)

    Kelsen, Silvia; Hall, John E; Chade, Alejandro R

    2011-07-01

    Endothelin (ET)-1, a potent renal vasoconstrictor with mitogenic properties, is upregulated by ischemia and has been shown to induce renal injury via the ET-A receptor. The potential role of ET-A blockade in chronic renovascular disease (RVD) has not, to our knowledge, been previously reported. We hypothesized that chronic ET-A receptor blockade would preserve renal hemodynamics and slow the progression of injury of the stenotic kidney in experimental RVD. Renal artery stenosis, a major cause of chronic RVD, was induced in 14 pigs and observed for 6 wk. In half of the pigs, chronic ET-A blockade was initiated (RVD+ET-A, 0.75 mg·kg(-1)·day(-1)) at the onset of RVD. Single-kidney renal blood flow, glomerular filtration rate, and perfusion were quantified in vivo after 6 wk using multidetector computer tomography. Renal microvascular density was quantified ex vivo using three-dimensional microcomputer tomography, and growth factors, inflammation, apoptosis, and fibrosis were determined in renal tissue. The degree of stenosis and increase in blood pressure were similar in RVD and RVD+ET-A pigs. Renal hemodynamics, function, and microvascular density were decreased in the stenotic kidney but preserved by ET-A blockade, accompanied by increased renal expression of vascular endothelial growth factor, hepatocyte growth factor, and downstream mediators such as phosphorilated-Akt, angiopoietins, and endothelial nitric oxide synthase. ET-A blockade also reduced renal apoptosis, inflammation, and glomerulosclerosis. This study shows that ET-A blockade slows the progression of renal injury in experimental RVD and preserves renal hemodynamics, function, and microvascular density in the stenotic kidney. These results support a role for ET-1/ET-A as a potential therapeutic target in chronic RVD.

  9. In vivo experimental stroke and in vitro organ culture induce similar changes in vasoconstrictor receptors and intracellular calcium handling in rat cerebral arteries

    DEFF Research Database (Denmark)

    Povlsen, Gro Klitgaard; Waldsee, Roya; Ahnstedt, Hilda

    2012-01-01

    Cerebral arteries subjected to different types of experimental stroke upregulate their expression of certain G-protein-coupled vasoconstrictor receptors, a phenomenon that worsens the ischemic brain damage. Upregulation of contractile endothelin B (ET(B)) and 5-hydroxytryptamine 1B (5-HT(1B......)) receptors has been demonstrated after subarachnoid hemorrhage and global ischemic stroke, but the situation is less clear after focal ischemic stroke. Changes in smooth muscle calcium handling have been implicated in different vascular diseases but have not hitherto been investigated in cerebral arteries...... and extracellular sources, whereas 5-HT(1B) receptor-mediated contraction was solely dependent on extracellular calcium. Organ culture and stroke increased basal intracellular calcium levels in MCA smooth muscle cells and decreased the expression of inositol triphosphate receptor and transient receptor potential...

  10. [Gallbladder contractility in children with functional abdominal pain or irritable bowel syndrome].

    Science.gov (United States)

    Iwańczak, Franciszek; Siedlecka-Dawidko, Jolanta; Iwanczak, Barbara

    2013-07-01

    III Rome Criteria of functional gastrointestinal disorders in children, distinguished the disturbances with abdominal pain, to which irritable bowel syndrome, functional abdominal pains, functional dyspepsia and abdominal migraine were included. THE AIM OF THE STUDY was sonographic assessment of the gallbladder and its contractility in functional abdominal pain and irritable bowel syndrome in children. The study comprised 96 children aged 6 to 18 years, 59 girls and 37 boys. Depending on diagnosis, the children were divided into three groups. 38 children with functional abdominal pain constituted the first group, 26 children with irritable bowel syndrome were included to the second group, the third group consisted of 32 healthy children (control group). Diagnosis of functional abdominal pain and irritable bowel syndrome was made based on the III Rome Criteria. In irritable bowel syndrome both forms with diarrhea (13) and with constipation (13) were observed. Anatomy and contractility of the gallbladder were assessed by ultrasound examination. The presence of septum, wall thickness, thick bile, vesicle volume in fasting state and 30th and 60th minute after test meal were taken into consideration. Test meal comprised about 15% of caloric requirement of moderate metabolism. Children with bile stones and organic diseases were excluded from the study. Thickened vesicle wall and thick bile were present more frequently in children with irritable bowel syndrome and functional abdominal pain than in control group (p functional abdominal pain than in irritable bowel syndrome and control group (p = 0.003, p = 0.05). Vesicle contractility after test meal was greatest in children with functional abdominal pain. Evaluation of diminished (smaller than 30%) and enlarged (greater then 80%) gallbladder contractility at 30th and 60th minute after test meal demonstrated disturbances of contractility in children with irritable bowel syndrome and functional abdominal pain. In children

  11. Anti-hypotensive treatment and endothelin blockade synergistically antagonize exercise fatigue in rats under simulated high altitude.

    Directory of Open Access Journals (Sweden)

    Daniel Radiloff

    Full Text Available Rapid ascent to high altitude causes illness and fatigue, and there is a demand for effective acute treatments to alleviate such effects. We hypothesized that increased oxygen delivery to the tissue using a combination of a hypertensive agent and an endothelin receptor A antagonist drugs would limit exercise-induced fatigue at simulated high altitude. Our data showed that the combination of 0.1 mg/kg ambrisentan with either 20 mg/kg ephedrine or 10 mg/kg methylphenidate significantly improved exercise duration in rats at simulated altitude of 4,267 m, whereas the individual compounds did not. In normoxic, anesthetized rats, ephedrine alone and in combination with ambrisentan increased heart rate, peripheral blood flow, carotid and pulmonary arterial pressures, breathing rate, and vastus lateralis muscle oxygenation, but under inspired hypoxia, only the combination treatment significantly enhanced muscle oxygenation. Our results suggest that sympathomimetic agents combined with endothelin-A receptor blockers offset altitude-induced fatigue in rats by synergistically increasing the delivery rate of oxygen to hypoxic muscle by concomitantly augmenting perfusion pressure and improving capillary conductance in the skeletal muscle. Our findings might therefore serve as a basis to develop an effective treatment to prevent high-altitude illness and fatigue in humans.

  12. Effect of changes in contractility on the index of myocardial performance in the dysfunctional left ventricle

    Directory of Open Access Journals (Sweden)

    Lavine Steven J

    2006-11-01

    Full Text Available Abstract Background The index of myocardial performance has prognostic power in patients with cardiomyopathy and following myocardial infarction. As the index of myocardial performance has been shown to be preload and afterload dependent, the effect of altering contractility on IMP and its components with left ventricular dysfunction has been incompletely delineated. Methods Chronic left ventricular dysfunction was induced in 10 canines using coronary microsphere embolization. Each dog was instrumented and imaged with 2D echo and Doppler. At the same atrially paced rate, contractility was increased with a dobutamine infusion and then following 4 weeks of oral digoxin. Results With chronic left ventricular dysfunction, a reduced left ventricular ejection fraction (42 ± 3%, p Conclusion Increased inotropy with digoxin and dobutamine reduced the index of myocardial performance in dogs with left ventricular dysfunction. Shortened isovolumic contraction time, increased diastolic filling period, and reduced left ventricular end diastolic pressure with digoxin may provide insight into its efficacy in heart failure.

  13. An Estimating Method of Contractile State Changes Come From Continuous Isometric Contraction of Skeletal Muscle

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.J.; Lee, S.J. [Wonkwang University, Iksan (Korea)

    2003-01-01

    In this study was proposed that a new estimating method for investigation of contractile state changes which generated from continuous isometric contraction of skeletal muscle. The physiological changes (EMG, ECG) and the psychological changes by CNS(central nervous system) were measured by experiments, while the muscle of subjects contracted continuously with isometric contraction in constant load. The psychological changes were represented as three-step-change named 'fatigue', 'pain' and 'sick(greatly pain)' from oral test, and the method which compared physiological change with psychological change on basis of these three steps was developed. The result of analyzing the physiological signals, EMG and ECG signal changes were observed at the vicinity of judging point in time of psychological changes. Namely, it is supposed that contractile states have three kind of states pattern (stable, fatigue, pain) instead of two states (stable, fatigue). (author). 24 refs., 7 figs.

  14. Measuring the Contractile Response of Isolated Tissue Using an Image Sensor

    Directory of Open Access Journals (Sweden)

    David Díaz-Martín

    2015-04-01

    Full Text Available Isometric or isotonic transducers have traditionally been used to study the contractile/relaxation effects of drugs on isolated tissues. However, these mechanical sensors are expensive and delicate, and they are associated with certain disadvantages when performing experiments in the laboratory. In this paper, a method that uses an image sensor to measure the contractile effect of drugs on blood vessel rings and other luminal organs is presented. The new method is based on an image-processing algorithm, and it provides a fast, easy and non-expensive way to analyze the effects of such drugs. In our tests, we have obtained dose-response curves from rat aorta rings that are equivalent to those achieved with classical mechanic sensors.

  15. Numerical investigation of perforated polymer microcantilever sensor for contractile behavior of cardiomyocytes

    Science.gov (United States)

    Khoa Nguyen, Trieu; Lee, Dong-Weon; Lee, Bong-Kee

    2017-06-01

    In this study, a numerical investigation of microcantilever sensors for detecting the contractile behavior of cardiomyocytes (CMs) was performed. Recently, a novel surface-patterned perforated SU-8 microcantilever sensor has been developed for the preliminary screening of cardiac toxicity. From the contractile motion of the CMs cultured on the microcantilever surface, a macroscopic bending of the microcantilever was obtained, which is considered to reflect a physiological change. As a continuation of the previous research, a novel numerical method based on a surface traction model was proposed and verified to further understand the bending behavior of the microcantilevers. Effects of various factors, including surface traction magnitude, focal area of CMs, and stiffness of microcantilever, on the bending displacement were investigated. From static and transient analyses, the focal area was found to be the most crucial factor. In addition, the current result can provide a design guideline for various micromechanical devices based on the same principle.

  16. Effect of a crude sulfated polysaccharide from Halymenia floresia (Rhodophyta on gastrointestinal smooth muscle contractility

    Directory of Open Access Journals (Sweden)

    José Ronaldo Vasconcelos Graça

    2011-10-01

    Full Text Available The aim of this work was to study the effect of Halymenia floresia (Hf on duodenum contractility, and on experimental protocols of gastric compliance (GC in rats. Fraction Hf2s exhibited a concentration-dependent myocontractile effect (EC50 12.48 µg/ml, and an inhibitory effect after consecutive washing. The contractile response promoted by Hf2s in the duodenum strips was completely inhibited by verapamil, and the effects were prevented in the presence of Ca2+-free medium. The pretreatment with atropine prevented the Hf2s myocontractile effect. Hf2s was also capable to decrease the GC (from 3.8±0.06 to 3.4±0.13 ml, P<0.05, which did not return to basal levels after more 50 min of observation. These results indicated that the algal polysaccharide possessed in vitro and in vivo gastrointestinal effects.

  17. Cell density and actomyosin contractility control the organization of migrating collectives within an epithelium

    Science.gov (United States)

    Loza, Andrew J.; Koride, Sarita; Schimizzi, Gregory V.; Li, Bo; Sun, Sean X.; Longmore, Gregory D.

    2016-01-01

    The mechanisms underlying collective migration are important for understanding development, wound healing, and tumor invasion. Here we focus on cell density to determine its role in collective migration. Our findings show that increasing cell density, as might be seen in cancer, transforms groups from broad collectives to small, narrow streams. Conversely, diminishing cell density, as might occur at a wound front, leads to large, broad collectives with a distinct leader–follower structure. Simulations identify force-sensitive contractility as a mediator of how density affects collectives, and guided by this prediction, we find that the baseline state of contractility can enhance or reduce organization. Finally, we test predictions from these data in an in vivo epithelium by using genetic manipulations to drive collective motion between predicted migratory phases. This work demonstrates how commonly altered cellular properties can prime groups of cells to adopt migration patterns that may be harnessed in health or exploited in disease. PMID:27605707

  18. New insights into roles of acidocalcisomes and contractile vacuole complex in osmoregulation in protists.

    Science.gov (United States)

    Docampo, Roberto; Jimenez, Veronica; Lander, Noelia; Li, Zhu-Hong; Niyogi, Sayantanee

    2013-01-01

    While free-living protists are usually subjected to hyposmotic environments, parasitic protists are also in contact with hyperosmotic habitats. Recent work in one of these parasites, Trypanosoma cruzi, has revealed that its contractile vacuole complex, which usually collects and expels excess water as a mechanism of regulatory volume decrease after hyposmotic stress, has also a role in cell shrinking when the cells are submitted to hyperosmotic stress. Trypanosomes also have an acidic calcium store rich in polyphosphate (polyP), named the acidocalcisome, which is involved in their response to osmotic stress. Here, we review newly emerging insights on the role of acidocalcisomes and the contractile vacuole complex in the cellular response to hyposmotic and hyperosmotic stresses. We also review the current state of knowledge on the composition of these organelles and their other roles in calcium homeostasis and protein trafficking. © 2013, Elsevier Inc. All Rights Reserved.

  19. New Insights into the Roles of Acidocalcisomes and the Contractile Vacuole Complex in Osmoregulation in Protists

    Science.gov (United States)

    Docampo, Roberto; Jimenez, Veronica; Lander, Noelia; Li, Zhu-Hong; Niyogi, Sayantanee

    2013-01-01

    While free-living protists are usually subjected to hyposmotic environments, parasitic protists are also in contact with hyperosmotic habitats. Recent work in one of these parasites, Trypanosoma cruzi, has revealed that its contractile vacuole complex, which usually collects and expels excess water as a mechanism of regulatory volume decrease after hyposmotic stress, has also a role in cell shrinking when the cells are submitted to hyperosmotic stress. Trypanosomes also have an acidic calcium store rich in polyphosphate (polyP), named the acidocalcisome, which is involved in their response to osmotic stress. Here, we review newly emerging insights on the role of acidocalcisomes and the contractile vacuole complex in the cellular response to hyposmotic and hyperosmotic stresses. We also review the current state of knowledge on the composition of these organelles and their other roles in calcium homeostasis and protein trafficking. PMID:23890380

  20. Effects of ageing on single muscle fibre contractile function following short-term immobilisation

    DEFF Research Database (Denmark)

    Hvid, Lars G; Ortenblad, Niels; Aagaard, Per

    2011-01-01

    Very little attention has been given to the combined effects of healthy ageing and short-term disuse on the contractile function of human single muscle fibres. Therefore, the present study investigated the effects of 2 weeks of lower limb cast immobilisation (i.e. disuse) on selected contractile...... IIa: young 18% and old 25%; P selective decrease in Ca(2+) sensitivity in MHC IIa fibres of young (P ....05), respectively. In conclusion, 2 weeks of lower limb immobilisation caused greater impairments in single muscle fibre force and specific force in MHC IIa than MHC I fibres independently of age. In contrast, immobilisation-induced changes in Ca(2+) sensitivity that were dependent on age and MHC isoform....

  1. Dual neural endopeptidase/endothelin-converting [corrected] enzyme inhibition improves endothelial function in mesenteric resistance arteries of young spontaneously hypertensive rats

    DEFF Research Database (Denmark)

    Lemkens, Pieter; Nelissen, Jelly; Meens, Merlijn J P M T

    2012-01-01

    BACKGROUND: Endothelin-1 (ET1) is a potent vasoconstrictor peptide with pro-mitogenic and pro-inflammatory properties and is therefore of interest in the development of endothelial dysfunction, endothelium-dependent flow-related remodeling, and hypertension-related remodeling. ET1 can be formed t...

  2. Impact of endothelin blockade on acute exercise-induced changes in blood flow and endothelial function in type 2 diabetes mellitus.

    NARCIS (Netherlands)

    Schreuder, T.H.A.; Lotringen, J.H. van; Hopman, M.T.E.; Thijssen, D.H.J.

    2014-01-01

    Positive vascular effects of exercise training are mediated by acute increases in blood flow. Type 2 diabetes patients show attenuated exercise-induced increases in blood flow, possibly mediated by the endothelin pathway, preventing an optimal stimulus for vascular adaptation. We examined the impact

  3. CaMKII inhibition with KN93 attenuates endothelin and serotonin receptor-mediated vasoconstriction and prevents subarachnoid hemorrhage-induced deficits in sensorimotor function

    DEFF Research Database (Denmark)

    Edvinsson, Lars; Povlsen, Gro Klitgaard; Ahnstedt, Hilda

    2014-01-01

    tested the hypothesis that inhibition of calcium calmodulin-dependent protein kinase II (CaMKII) may reduce cerebral vasoconstriction mediated by endothelin and serotonin receptors and improve neurological outcome after experimental SAH. METHODS: SAH was induced in adult rats by injection of 250 μ...

  4. Endothelin A receptor blocker atrasentan lowers blood pressure by the reduction of nifedipine-sensitive calcium influx in Ren-2 transgenic rats fed a high-salt diet

    Czech Academy of Sciences Publication Activity Database

    Vaněčková, Ivana; Dobešová, Zdenka; Kuneš, Jaroslav; Vernerová, Z.; Zicha, Josef

    2015-01-01

    Roč. 33, č. 1 (2015), s. 161-169 ISSN 0263-6352 R&D Projects: GA ČR(CZ) GAP304/12/0259 Institutional support: RVO:67985823 Keywords : endothelin * high-salt intake * hypertension * Ren-2 Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 5.062, year: 2015

  5. Levothyroxine treatment generates an abnormal uterine contractility patterns in an in vitro animal model.

    Science.gov (United States)

    Corriveau, Stéphanie; Blouin, Simon; Raiche, Évelyne; Nolin, Marc-Antoine; Rousseau, Éric; Pasquier, Jean-Charles

    2015-12-01

    Abnormal uterine contraction patterns were recently demonstrated in uterine strips from pregnant women treated with Levothyroxine (T4). These abnormalities were correlated with an increased risk of C-section delivery and associated surgical complications. To date, no study has investigated whether uterine contractility is modified by hypothyroidism or T4 treatment. Herein, we analyze the physiological role of T4 on uterine contractions. Female non-pregnant Sprague-Dawley rats ( N  = 22) were used and divided into four groups: 1) control, 2) hypothyroidism, 3) hypothyroidism treated with low T4 doses (20 μg/kg/day) and 4) with high T4 doses (100 μg/kg/day). Hypothyroidism was induced by an iodine-deficient diet. Isometric tension measurements were performed in vitro on myometrium tissues in isolated organ baths. Contractile activity parameters were quantified (amplitude, duration, frequency and area under the curve) using pharmacological tools to assess their effect. Screening of thyroid function confirmed a hypothyroid state for all rats under iodine-free diet to which T4 was subsequently administered to counterbalance hypothyroidism. Results demonstrate that hypothyroidism significantly decreased contractile duration (-17%) and increased contractile frequency (+26%), while high doses of T4 increased duration (+200%) and decreased frequency (-51%). These results thus mimic the pattern of abnormal contractions previously observed in uterine tissue from T4-treated hypothyroid pregnant women. Our data suggest that changes in myometrial reactivity are induced by T4 treatment. Thus, in conjunction with our previous observations on human myometrial strips, management of hypothyroidism should be improved to reduce the rate of C-sections in this group of patients.

  6. Functions of nonmuscle myosin II in assembly of the cellular contractile system.

    Directory of Open Access Journals (Sweden)

    Maria Shutova

    Full Text Available The contractile system of nonmuscle cells consists of interconnected actomyosin networks and bundles anchored to focal adhesions. The initiation of the contractile system assembly is poorly understood structurally and mechanistically, whereas system's maturation heavily depends on nonmuscle myosin II (NMII. Using platinum replica electron microscopy in combination with fluorescence microscopy, we characterized the structural mechanisms of the contractile system assembly and roles of NMII at early stages of this process. We show that inhibition of NMII by a specific inhibitor, blebbistatin, in addition to known effects, such as disassembly of stress fibers and mature focal adhesions, also causes transformation of lamellipodia into unattached ruffles, loss of immature focal complexes, loss of cytoskeleton-associated NMII filaments and peripheral accumulation of activated, but unpolymerized NMII. After blebbistatin washout, assembly of the contractile system begins with quick and coordinated recovery of lamellipodia and focal complexes that occurs before reappearance of NMII bipolar filaments. The initial formation of focal complexes and subsequent assembly of NMII filaments preferentially occurred in association with filopodial bundles and concave actin bundles formed by filopodial roots at the lamellipodial base. Over time, accumulating NMII filaments help to transform the precursor structures, focal complexes and associated thin bundles, into stress fibers and mature focal adhesions. However, semi-sarcomeric organization of stress fibers develops at much slower rate. Together, our data suggest that activation of NMII motor activity by light chain phosphorylation occurs at the cell edge and is uncoupled from NMII assembly into bipolar filaments. We propose that activated, but unpolymerized NMII initiates focal complexes, thus providing traction for lamellipodial protrusion. Subsequently, the mechanical resistance of focal complexes activates a

  7. Influence of genotype on contractile protein differentiation in different bovine muscles during foetal life

    OpenAIRE

    Gagnière , Hélène; Ménissier , François; Geay , Yves; Picard , Brigitte

    2000-01-01

    International audience; The purpose of this work was to compare muscle fibre differentiation in two genetic types: "normal charolais" and double-muscled (DM) "INRA 95" cattles displaying muscle hypertrophy. Six muscles with different contractile and metabolic characteristics in adult animal: Masseter, Diaphragma (Di), Biceps femoris (BF), Longissimus thoracis, Semitendinosus and Cutaneus trunci (CT) were excised from 60 to 260-day-old fœtuses of both genotypes. These muscles present different...

  8. Chronic clenbuterol treatment compromises force production without directly altering skeletal muscle contractile machinery

    Science.gov (United States)

    Py, G; Ramonatxo, C; Sirvent, P; Sanchez, A M J; Philippe, A G; Douillard, A; Galbès, O; Lionne, C; Bonnieu, A; Chopard, A; Cazorla, O; Lacampagne, A; Candau, R B

    2015-01-01

    Clenbuterol is a β2-adrenergic receptor agonist known to induce skeletal muscle hypertrophy and a slow-to-fast phenotypic shift. The aim of the present study was to test the effects of chronic clenbuterol treatment on contractile efficiency and explore the underlying mechanisms, i.e. the muscle contractile machinery and calcium-handling ability. Forty-three 6-week-old male Wistar rats were randomly allocated to one of six groups that were treated with either subcutaneous equimolar doses of clenbuterol (4 mg kg−1 day−1) or saline solution for 9, 14 or 21 days. In addition to the muscle hypertrophy, although an 89% increase in absolute maximal tetanic force (Po) was noted, specific maximal tetanic force (sPo) was unchanged or even depressed in the slow twitch muscle of the clenbuterol-treated rats (P muscle contraction and relaxation force kinetics indicated that clenbuterol treatment significantly reduced the rate constant of force development and the slow and fast rate constants of relaxation in extensor digitorum longus muscle (P fast rate constant of relaxation in soleus muscle (P fibres (fast twitch fibres) from clenbuterol-treated animals demonstrated decreased amplitude after 14 days (−19%, P < 0.01) and 21 days (−25%, P < 0.01). In conclusion, we showed that chronic clenbuterol treatment reduces contractile efficiency, with altered contraction and relaxation kinetics, but without directly altering the contractile machinery. Lower Ca2+ release during contraction could partially explain these deleterious effects. PMID:25656230

  9. Matching of sarcoplasmic reticulum and contractile properties in rat fast- and slow-twitch muscle fibres.

    Science.gov (United States)

    Trinh, Huong H; Lamb, Graham D

    2006-07-01

    1. The twitch characteristics (fast-twitch or slow-twitch) of skeletal muscle fibres are determined not only by the contractile apparatus properties of the fibre, but also by the time-course of Ca2+ release and re-uptake by the sarcoplasmic reticulum (SR). The present study examined, in individual fibres from non-transforming muscle of the rat, whether particular SR properties are matched to the contractile apparatus properties of the fibre, in particular in the case of fibres with fast-twitch contractile apparatus located in a slow-twitch muscle, namely the soleus. 2. Force was recorded in single, mechanically skinned fibres from extensor digitorum longus (EDL), gastrocnemius, peroneus longus and soleus muscles. Using repeated cycles in which the SR was emptied of all releasable Ca2+ and then reloaded, it was possible to determine the relative amount of Ca2+ present in the SR endogenously, the maximum SR capacity and the rate of Ca2+ loading. The sensitivity of the contractile apparatus to Ca2+ and Sr2+ was used to classify the fibres as fast-twitch (FT), slow-twitch (ST) or mixed (fibres examined) and thereby identify the likely troponin C and myosin heavy chain types present. 3. There was no significant difference in SR properties between the groups of FT fibres obtained from the four different muscles, including soleus. Despite some overlap in the SR properties of individual fibres between the FT and ST groups, the properties of the FT fibres in all four muscles studied were significantly different from those of the ST and mixed fibres. 4. In general, in FT fibres the SR had a larger capacity and the endogenous Ca2+ content was a relatively lower percentage of maximum compared with ST fibres. Importantly, in terms of their SR properties, FT fibres from soleus muscle more closely resembled FT fibres from other muscles than they did ST fibres from soleus muscle.

  10. Myosin phosphorylation improves contractile economy of mouse fast skeletal muscle during staircase potentiation.

    Science.gov (United States)

    Bunda, Jordan; Gittings, William; Vandenboom, Rene

    2018-01-30

    Phosphorylation of the myosin regulatory light chain (RLC) by skeletal myosin light chain kinase (skMLCK) potentiates rodent fast twitch muscle but is an ATP-requiring process. Our objective was to investigate the effect of skMLCK-catalyzed RLC phosphorylation on the energetic cost of contraction and the contractile economy (ratio of mechanical output to metabolic input) of mouse fast twitch muscle in vitro (25°C). To this end, extensor digitorum longus (EDL) muscles from wild-type (WT) and from skMLCK-devoid (skMLCK -/- ) mice were subjected to repetitive low-frequency stimulation (10 Hz for 15 s) to produce staircase potentiation of isometric twitch force, after which muscles were quick frozen for determination of high-energy phosphate consumption (HEPC). During stimulation, WT muscles displayed significant potentiation of isometric twitch force while skMLCK -/- muscles did not (i.e. 23% versus 5% change, respectively). Consistent with this, RLC phosphorylation was increased ∼3.5-fold from the unstimulated control value in WT but not in skMLCK -/- muscles. Despite these differences, the HEPC of WT muscles was not greater than that of skMLCK -/- muscles. As a result of the increased contractile output relative to HEPC, the calculated contractile economy of WT muscles was greater than that of skMLCK -/- muscles. Thus, our results suggest that skMLCK-catalyzed phosphorylation of the myosin RLC increases the contractile economy of WT mouse EDL muscle compared with skMLCK -/- muscles without RLC phosphorylation. © 2018. Published by The Company of Biologists Ltd.

  11. Cardiac-specific overexpression of catalase attenuates lipopolysaccharide-induced myocardial contractile dysfunction: role of autophagy.

    Science.gov (United States)

    Turdi, Subat; Han, Xuefeng; Huff, Anna F; Roe, Nathan D; Hu, Nan; Gao, Feng; Ren, Jun

    2012-09-15

    Lipopolysaccharide (LPS) from gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complications in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged with LPS (6 mg/kg) and cardiac function was evaluated. Levels of oxidative stress, autophagy, apoptosis, and protein damage were examined using fluorescence microscopy, Western blot, TUNEL assay, caspase-3 activity, and carbonyl formation. A Kaplan-Meier curve was constructed for survival after LPS treatment. Our results revealed a lower mortality in catalase mice compared with FVB mice after LPS challenge. LPS injection led to depressed cardiac contractile capacity as evidenced by echocardiography and cardiomyocyte contractile function, the effect of which was ablated by catalase overexpression. LPS treatment induced elevated TNF-α level, autophagy, apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), production of ROS and O(2)(-), and protein carbonyl formation, the effects of which were significantly attenuated by catalase overexpression. Electron microscopy revealed focal myocardial damage characterized by mitochondrial injury after LPS treatment, which was less severe in catalase mice. Interestingly, LPS-induced cardiomyocyte contractile dysfunction was prevented by the antioxidant N-acetylcysteine and the autophagy inhibitor 3-methyladenine. Taken together, our data revealed that catalase protects against LPS-induced cardiac dysfunction and mortality, which may be associated with inhibition of oxidative stress and autophagy. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Cardiac-Specific Overexpression of Catalase Attenuates Lipopolysaccharide-Induced Myocardial Contractile Dysfunction: Role of Autophagy

    OpenAIRE

    Turdi, Subat; Han, Xuefeng; Huff, Anna F.; Roe, Nathan D.; Hu, Nan; Gao, Feng; Ren, Jun

    2012-01-01

    Lipopolysaccharide (LPS) from Gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complication in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged ...

  13. A thermodynamical model for stress-fiber organization in contractile cells

    OpenAIRE

    Foucard, Louis; Vernerey, Franck J.

    2012-01-01

    Cell mechanical adaptivity to external stimuli is vital to many of its biological functions. A critical question is therefore to understand the formation and organization of the stress fibers from which emerge the cell’s mechanical properties. By accounting for the mechanical aspects and the viscoelastic behavior of stress fibers, we here propose a thermodynamic model to predict the formation and orientation of stress fibers in contractile cells subjected to constant or cyclic stretch and dif...

  14. Cardiac-Specific Overexpression of Catalase Attenuates Lipopolysaccharide-Induced Myocardial Contractile Dysfunction: Role of Autophagy

    Science.gov (United States)

    Turdi, Subat; Han, Xuefeng; Huff, Anna F.; Roe, Nathan D.; Hu, Nan; Gao, Feng; Ren, Jun

    2012-01-01

    Lipopolysaccharide (LPS) from Gram-negative bacteria is a major initiator of sepsis, leading to cardiovascular collapse. Accumulating evidence has indicated a role of reactive oxygen species (ROS) in cardiovascular complication in sepsis. This study was designed to examine the effect of cardiac-specific overexpression of catalase in LPS-induced cardiac contractile dysfunction and the underlying mechanism(s) with a focus on autophagy. Catalase transgenic and wild-type FVB mice were challenged with LPS (6 mg/kg) and cardiac function was evaluated. Levels of oxidative stress, autophagy, apoptosis and protein damage were examined using fluorescence microscopy, Western blot, TUNEL assay, caspase-3 activity and carbonyl formation. Kaplan-Meier curve was constructed for survival following LPS treatment. Our results revealed a lower mortality in catalase mice compared with FVB mice following LPS challenge. LPS injection led to depressed cardiac contractile capacity as evidenced by echocardiography and cardiomyocyte contractile function, the effect of which was ablated by catalase overexpression. LPS treatment induced elevated TNF-α level, autophagy, apoptosis (TUNEL, caspase-3 activation, cleaved caspase-3), production of ROS and O2−, and protein carbonyl formation, the effects of which were significantly attenuated by catalase overexpression. Electron microscopy revealed focal myocardial damage characterized by mitochondrial injury following LPS treatment, which was less severe in catalase mice. Interestingly, LPS-induced cardiomyocyte contractile dysfunction was prevented by antioxidant NAC and the autophagy inhibitor 3-methyladenine. Taken together, our data revealed that catalase protects against LPS-induced cardiac dysfunction and mortality, which may be associated with inhibition of oxidative stress and autophagy. PMID:22902401

  15. Cardiac myofibrillar contractile properties during the progression from hypertension to decompensated heart failure.

    Science.gov (United States)

    Hanft, Laurin M; Emter, Craig A; McDonald, Kerry S

    2017-07-01

    Heart failure arises, in part, from a constellation of changes in cardiac myocytes including remodeling, energetics, Ca 2+ handling, and myofibrillar function. However, little is known about the changes in myofibrillar contractile properties during the progression from hypertension to decompensated heart failure. The aim of the present study was to provide a comprehensive assessment of myofibrillar functional properties from health to heart disease. A rodent model of uncontrolled hypertension was used to test the hypothesis that myocytes in compensated hearts exhibit increased force, higher rates of force development, faster loaded shortening, and greater power output; however, with progression to overt heart failure, we predicted marked depression in these contractile properties. We assessed contractile properties in skinned cardiac myocyte preparations from left ventricles of Wistar-Kyoto control rats and spontaneous hypertensive heart failure (SHHF) rats at ~3, ~12, and >20 mo of age to evaluate the time course of myofilament properties associated with normal aging processes compared with myofilaments from rats with a predisposition to heart failure. In control rats, the myofilament contractile properties were virtually unchanged throughout the aging process. Conversely, in SHHF rats, the rate of force development, loaded shortening velocity, and power all increased at ~12 mo and then significantly fell at the >20-mo time point, which coincided with a decrease in left ventricular fractional shortening. Furthermore, these changes occurred independent of changes in β-myosin heavy chain but were associated with depressed phosphorylation of myofibrillar proteins, and the fall in loaded shortening and peak power output corresponded with the onset of clinical signs of heart failure. NEW & NOTEWORTHY This novel study systematically examined the power-generating capacity of cardiac myofilaments during the progression from hypertension to heart disease. Previously

  16. Robust gap repair in the contractile ring ensures timely completion of cytokinesis.

    OpenAIRE

    Silva, AM; Osório, DS; Pereira, AJ; Maiato, H; Pinto, IM; Rubinstein, B; Gassmann, R; Telley, IA; Carvalho, AX

    2016-01-01

    Cytokinesis in animal cells requires the constriction of an actomyosin contractile ring, whose architecture and mechanism remain poorly understood. We use laser microsurgery to explore the biophysical properties of constricting rings in Caenorhabditis elegans embryos. Laser cutting causes rings to snap open. However, instead of disintegrating, ring topology recovers and constriction proceeds. In response to severing, a finite gap forms and is repaired by recruitment of new material in an acti...

  17. Changes in contractile properties of muscles receiving repeat injections of botulinum toxin (Botox).

    Science.gov (United States)

    Fortuna, Rafael; Vaz, Marco Aurélio; Youssef, Aliaa Rehan; Longino, David; Herzog, Walter

    2011-01-04

    Botulinum toxin type A (BTX-A) is a frequently used therapeutic tool to denervate muscles in the treatment of neuromuscular disorders. Although considered safe by the US Food and Drug Administration, BTX-A can produce adverse effects in target and non-target muscles. With an increased use of BTX-A for neuromuscular disorders, the effects of repeat injections of BTX-A on strength, muscle mass and structure need to be known. Therefore, the purpose of this study was to investigate the changes in strength, muscle mass and contractile material in New Zealand White (NZW) rabbits. Twenty NZW rabbits were divided into 4 groups: control and 1, 3 and 6 months of unilateral, repeat injections of BTX-A into the quadriceps femoris. Outcome measures included knee extensor torque, muscle mass and the percentage of contractile material in the quadriceps muscles of the target and non-injected contralateral hindlimbs. Strength in the injected muscles was reduced by 88%, 89% and 95% in the 1, 3 and 6 months BTX-A injected hindlimbs compared to controls. Muscle mass was reduced by 50%, 42% and 31% for the vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM), respectively, at 1 month, by 68%, 51% and 50% at 3 months and by 76%, 44% and 13% at 6 months. The percentage of contractile material was reduced for the 3 and 6 months animals to 80-64%, respectively, and was replaced primarily by fat. Similar, but less pronounced results were also observed for the quadriceps muscles of the contralateral hindlimbs, suggesting that repeat BTX-A injections cause muscle atrophy and loss of contractile tissue in target muscles and also in non-target muscles that are far removed from the injection site. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Impact of tamsulosin and nifedipine on contractility of pregnant rat ureters in vitro.

    Science.gov (United States)

    Haddad, Lisette; Corriveau, Stéphanie; Rousseau, Eric; Blouin, Simon; Pasquier, Jean-Charles; Ponsot, Yves; Roy-Lacroix, Marie-Ève

    2018-01-01

    To evaluate the in vitro effect of tamsulosin and nifedipine on the contractility of pregnant rat ureters and to perform quantitative analysis of the pharmacological effects. Medical expulsive therapy (MET) is commonly used to treat urolithiasis. However, this treatment is seldom used in pregnant women since no studies support this practice. This was an in vitro study on animal tissue derived from pregnant Sprague-Dawley rats. A total of 124 ureteral segments were mounted in an organ bath system and contractile response to methacholine (MCh) was assessed. Tamsulosin or nifedipine were added at cumulative concentrations (0.001-1 μM). The area under the curve (AUC) from isometric tension measurements was calculated. The effect of pharmacological agents and the respective controls were assessed by calculating the AUC for each 5-min interval. Statistical analyses were performed using the Mann-Whitney-Wilcoxon nonparametric test. Both drugs displayed statistically significant inhibitory activity at concentrations of 0.1 and 1 μM for tamsulosin and 1 μM for nifedipine when calculated as the AUC as compared to DMSO controls. Tamsulosin and nifedipine directly inhibit MCh-induced contractility of pregnant rat ureters. Further work is needed to determine the clinical efficacy of these medications for MET in pregnancy.

  19. PTP1B triggers integrin-mediated repression of myosin activity and modulates cell contractility

    Directory of Open Access Journals (Sweden)

    Ana E. González Wusener

    2016-01-01

    Full Text Available Cell contractility and migration by integrins depends on precise regulation of protein tyrosine kinase and Rho-family GTPase activities in specific spatiotemporal patterns. Here we show that protein tyrosine phosphatase PTP1B cooperates with β3 integrin to activate the Src/FAK signalling pathway which represses RhoA-myosin-dependent contractility. Using PTP1B null (KO cells and PTP1B reconstituted (WT cells, we determined that some early steps following cell adhesion to fibronectin and vitronectin occurred robustly in WT cells, including aggregation of β3 integrins and adaptor proteins, and activation of Src/FAK-dependent signalling at small puncta in a lamellipodium. However, these events were significantly impaired in KO cells. We established that cytoskeletal strain and cell contractility was highly enhanced at the periphery of KO cells compared to WT cells. Inhibition of the Src/FAK signalling pathway or expression of constitutive active RhoA in WT cells induced a KO cell phenotype. Conversely, expression of constitutive active Src or myosin inhibition in KO cells restored the WT phenotype. We propose that this novel function of PTP1B stimulates permissive conditions for adhesion and lamellipodium assembly at the protruding edge during cell spreading and migration.

  20. PTP1B triggers integrin-mediated repression of myosin activity and modulates cell contractility

    Science.gov (United States)

    González Wusener, Ana E.; González, Ángela; Nakamura, Fumihiko; Arregui, Carlos O.

    2016-01-01

    ABSTRACT Cell contractility and migration by integrins depends on precise regulation of protein tyrosine kinase and Rho-family GTPase activities in specific spatiotemporal patterns. Here we show that protein tyrosine phosphatase PTP1B cooperates with β3 integrin to activate the Src/FAK signalling pathway which represses RhoA-myosin-dependent contractility. Using PTP1B null (KO) cells and PTP1B reconstituted (WT) cells, we determined that some early steps following cell adhesion to fibronectin and vitronectin occurred robustly in WT cells, including aggregation of β3 integrins and adaptor proteins, and activation of Src/FAK-dependent signalling at small puncta in a lamellipodium. However, these events were significantly impaired in KO cells. We established that cytoskeletal strain and cell contractility was highly enhanced at the periphery of KO cells compared to WT cells. Inhibition of the Src/FAK signalling pathway or expression of constitutive active RhoA in WT cells induced a KO cell phenotype. Conversely, expression of constitutive active Src or myosin inhibition in KO cells restored the WT phenotype. We propose that this novel function of PTP1B stimulates permissive conditions for adhesion and lamellipodium assembly at the protruding edge during cell spreading and migration. PMID:26700725

  1. Changes of contractile responses due to simulated weightlessness in rat soleus muscle

    Science.gov (United States)

    Elkhammari, A.; Noireaud, J.; Léoty, C.

    1994-08-01

    Some contractile and electrophysiological properties of muscle fibers isolated from the slow-twitch soleus (SOL) and fast-twitch extensor digitorum longus (EDL) muscles of rats were compared with those measured in SOL muscles from suspended rats. In suspendede SOL (21 days of tail-suspension) membrane potential (Em), intracellular sodium activity (aiNa) and the slope of the relationship between Em and log [K]o were typical of fast-twitch muscles. The relation between the maximal amplitude of K-contractures vs Em was steeper for control SOL than for EDL and suspended SOL muscles. After suspension, in SOL muscles the contractile threshold and the inactivation curves for K-contractures were shifted to more positive Em. Repriming of K-contractures was unaffected by suspencion. The exposure of isolated fibers to perchlorate (ClO4-)-containing (6-40 mM) solutions resulted ina similar concentration-dependent shift to more negative Em of activation curves for EDL and suspended SOL muscles. On exposure to a Na-free TEA solution, SOL from control and suspended rats, in contrast to EDL muscles, generated slow contractile responses. Suspended SOL showed a reduced sensitivity to the contracture-producing effect of caffeine compared to control muscles. These results suggested that the modification observed due to suspension could be encounted by changes in the characteristics of muscle fibers from slow to fast-twitch type.

  2. A human in vitro model of Duchenne muscular dystrophy muscle formation and contractility.

    Science.gov (United States)

    Nesmith, Alexander P; Wagner, Matthew A; Pasqualini, Francesco S; O'Connor, Blakely B; Pincus, Mark J; August, Paul R; Parker, Kevin Kit

    2016-10-10

    Tongue weakness, like all weakness in Duchenne muscular dystrophy (DMD), occurs as a result of contraction-induced muscle damage and deficient muscular repair. Although membrane fragility is known to potentiate injury in DMD, whether muscle stem cells are implicated in deficient muscular repair remains unclear. We hypothesized that DMD myoblasts are less sensitive to cues in the extracellular matrix designed to potentiate structure-function relationships of healthy muscle. To test this hypothesis, we drew inspiration from the tongue and engineered contractile human muscle tissues on thin films. On this platform, DMD myoblasts formed fewer and smaller myotubes and exhibited impaired polarization of the cell nucleus and contractile cytoskeleton when compared with healthy cells. These structural aberrations were reflected in their functional behavior, as engineered tongues from DMD myoblasts failed to achieve the same contractile strength as healthy tongue structures. These data suggest that dystrophic muscle may fail to organize with respect to extracellular cues necessary to potentiate adaptive growth and remodeling. © 2016 Nesmith et al.

  3. Carboxyl-terminal-dependent recruitment of nonmuscle myosin II to megakaryocyte contractile ring during polyploidization.

    Science.gov (United States)

    Badirou, Idinath; Pan, Jiajia; Legrand, Céline; Wang, Aibing; Lordier, Larissa; Boukour, Siham; Roy, Anita; Vainchenker, William; Chang, Yunhua

    2014-10-16

    Endomitosis is a unique megakaryocyte (MK) differentiation process that is the consequence of a late cytokinesis failure associated with a contractile ring defect. Evidence from in vitro studies has revealed the distinct roles of 2 nonmuscle myosin IIs (NMIIs) on MK endomitosis: only NMII-B (MYH10), but not NMII-A (MYH9), is localized in the MK contractile ring and implicated in mitosis/endomitosis transition. Here, we studied 2 transgenic mouse models in which nonmuscle myosin heavy chain (NMHC) II-A was genetically replaced either by II-B or by a chimeric NMHCII that combined the head domain of II-A with the rod and tail domains of II-B. This study provides in vivo evidence on the specific role of NMII-B on MK polyploidization. It demonstrates that the carboxyl-terminal domain of the heavy chains determines myosin II localization to the MK contractile ring and is responsible for the specific role of NMII-B in MK polyploidization.

  4. A contractile and counterbalancing adhesion system controls the 3D shape of crawling cells.

    Science.gov (United States)

    Burnette, Dylan T; Shao, Lin; Ott, Carolyn; Pasapera, Ana M; Fischer, Robert S; Baird, Michelle A; Der Loughian, Christelle; Delanoe-Ayari, Helene; Paszek, Matthew J; Davidson, Michael W; Betzig, Eric; Lippincott-Schwartz, Jennifer

    2014-04-14

    How adherent and contractile systems coordinate to promote cell shape changes is unclear. Here, we define a counterbalanced adhesion/contraction model for cell shape control. Live-cell microscopy data showed a crucial role for a contractile meshwork at the top of the cell, which is composed of actin arcs and myosin IIA filaments. The contractile actin meshwork is organized like muscle sarcomeres, with repeating myosin II filaments separated by the actin bundling protein α-actinin, and is mechanically coupled to noncontractile dorsal actin fibers that run from top to bottom in the cell. When the meshwork contracts, it pulls the dorsal fibers away from the substrate. This pulling force is counterbalanced by the dorsal fibers' attachment to focal adhesions, causing the fibers to bend downward and flattening the cell. This model is likely to be relevant for understanding how cells configure themselves to complex surfaces, protrude into tight spaces, and generate three-dimensional forces on the growth substrate under both healthy and diseased conditions.

  5. Local 3D matrix microenvironment regulates cell migration through spatiotemporal dynamics of contractility-dependent adhesions

    Science.gov (United States)

    Doyle, Andrew D.; Carvajal, Nicole; Jin, Albert; Matsumoto, Kazue; Yamada, Kenneth M.

    2015-11-01

    The physical properties of two-dimensional (2D) extracellular matrices (ECMs) modulate cell adhesion dynamics and motility, but little is known about the roles of local microenvironmental differences in three-dimensional (3D) ECMs. Here we generate 3D collagen gels of varying matrix microarchitectures to characterize their regulation of 3D adhesion dynamics and cell migration. ECMs containing bundled fibrils demonstrate enhanced local adhesion-scale stiffness and increased adhesion stability through balanced ECM/adhesion coupling, whereas highly pliable reticular matrices promote adhesion retraction. 3D adhesion dynamics are locally regulated by ECM rigidity together with integrin/ECM association and myosin II contractility. Unlike 2D migration, abrogating contractility stalls 3D migration regardless of ECM pore size. We find force is not required for clustering of activated integrins on 3D native collagen fibrils. We propose that efficient 3D migration requires local balancing of contractility with ECM stiffness to stabilize adhesions, which facilitates the detachment of activated integrins from ECM fibrils.

  6. Cellular contractility and substrate elasticity: a numerical investigation of the actin cytoskeleton and cell adhesion.

    Science.gov (United States)

    Ronan, William; Deshpande, Vikram S; McMeeking, Robert M; McGarry, J Patrick

    2014-04-01

    Numerous experimental studies have established that cells can sense the stiffness of underlying substrates and have quantified the effect of substrate stiffness on stress fibre formation, focal adhesion area, cell traction, and cell shape. In order to capture such behaviour, the current study couples a mixed mode thermodynamic and mechanical framework that predicts focal adhesion formation and growth with a material model that predicts stress fibre formation, contractility, and dissociation in a fully 3D implementation. Simulations reveal that SF contractility plays a critical role in the substrate-dependent response of cells. Compliant substrates do not provide sufficient tension for stress fibre persistence, causing dissociation of stress fibres and lower focal adhesion formation. In contrast, cells on stiffer substrates are predicted to contain large amounts of dominant stress fibres. Different levels of cellular contractility representative of different cell phenotypes are found to alter the range of substrate stiffness that cause the most significant changes in stress fibre and focal adhesion formation. Furthermore, stress fibre and focal adhesion formation evolve as a cell spreads on a substrate and leading to the formation of bands of fibres leading from the cell periphery over the nucleus. Inhibiting the formation of FAs during cell spreading is found to limit stress fibre formation. The predictions of this mutually dependent material-interface framework are strongly supported by experimental observations of cells adhered to elastic substrates and offer insight into the inter-dependent biomechanical processes regulating stress fibre and focal adhesion formation.

  7. EXERCISE PERFORMANCE AND MUSCLE CONTRACTILE PROPERTIES AFTER CREATINE MONOHYDRATE SUPPLEMENTATION IN AEROBIC-ANAEROBIC TRAINING RATS

    Directory of Open Access Journals (Sweden)

    Nickolay Boyadjiev

    2007-12-01

    Full Text Available The purpose of this study was to investigate the effects of creatine monohydrate supplementation on exercise performance and contractile variables in aerobic-anaerobic training rats. Twenty 90-day-old male Sprague Dawley rats were divided into two groups - creatine (Cr and controls (K. The creatine group received creatine monohydrate as a nutritional supplement, whereas the control group was given placebo. Both groups were trained 5 days a week on a treadmill for 20 days in a mixed (aerobic-anaerobic metabolic working regimen (27 m·min-1, 15% elevation for 40 min. The exercise performance (sprint-test, contractile properties (m. tibialis anterior, oxidative enzyme activity (SDH, LDH, NADH2 in m. soleus and blood hematological and chemical variables were assessed in the groups at the end of the experiment. It was found out that creatine supplementation improved the exercise performance after 20 days of administration in a dose of 60 mg per day on the background of a mixed (aerobic-anaerobic exercise training. At the end of the trial the Cr-group demonstrated better values for the variables which characterize the contractile properties of m. tibialis anterior containing predominantly types IIA and IIB muscle fibers. On the other hand, a higher oxidative capacity was found out in m. soleus (type I muscle fibers as a result of 20-day creatine supplementation. No side effects of creatine monohydrate supplementation were assessed by the hematological and blood biochemical indices measured in this study

  8. Robust gap repair in the contractile ring ensures timely completion of cytokinesis.

    Science.gov (United States)

    Silva, Ana M; Osório, Daniel S; Pereira, Antonio J; Maiato, Helder; Pinto, Inês Mendes; Rubinstein, Boris; Gassmann, Reto; Telley, Ivo Andreas; Carvalho, Ana Xavier

    2016-12-19

    Cytokinesis in animal cells requires the constriction of an actomyosin contractile ring, whose architecture and mechanism remain poorly understood. We use laser microsurgery to explore the biophysical properties of constricting rings in Caenorhabditis elegans embryos. Laser cutting causes rings to snap open. However, instead of disintegrating, ring topology recovers and constriction proceeds. In response to severing, a finite gap forms and is repaired by recruitment of new material in an actin polymerization-dependent manner. An open ring is able to constrict, and rings repair from successive cuts. After gap repair, an increase in constriction velocity allows cytokinesis to complete at the same time as controls. Our analysis demonstrates that tension in the ring increases while net cortical tension at the site of ingression decreases throughout constriction and suggests that cytokinesis is accomplished by contractile modules that assemble and contract autonomously, enabling local repair of the actomyosin network. Consequently, cytokinesis is a highly robust process impervious to discontinuities in contractile ring structure. © 2016 Silva et al.

  9. Adaptive responses of mouse skeletal muscle to contractile activity: The effect of age.

    Science.gov (United States)

    Vasilaki, A; McArdle, F; Iwanejko, L M; McArdle, A

    2006-11-01

    This study has characterised the time course of two major transcriptional adaptive responses to exercise (changes in antioxidant defence enzyme activity and heat shock protein (HSP) content) in muscles of adult and old male mice following isometric contractions and has examined the mechanisms involved in the age-related reduction in transcription factor activation. Muscles of B6XSJL mice were subjected to isometric contractions and analysed for antioxidant defence enzyme activities, heat shock protein content and transcription factor DNA binding activity. Data demonstrated a significant increase in superoxide dismutase (SOD) and catalase activity and HSP content of muscles of adult mice following contractile activity which was associated with increased activation of the transcription factors, nuclear factor-kappaB (NF-kappaB), activator protein-1 (AP-1) and heat shock factor (HSF) following contractions. Significant increases in SOD and catalase activity and heat shock cognate (HSC70) content were seen in quiescent muscles of old mice. The increase in antioxidant defence enzyme activity following contractile activity seen in muscles of adult mice was not seen in muscles of old mice and this was associated with a failure to fully activate NF-kappaB and AP-1 following contractions. In contrast, although the production of HSPs was also reduced in muscles of old mice following contractile activity compared with muscles of adult mice following contractions, this was not due to a gross reduction in the DNA binding activity of HSF.

  10. Galectin-3 and fibulin-1 in systolic heart failure - relation to glucose metabolism and left ventricular contractile reserve

    OpenAIRE

    Holmager, Pernille; Egstrup, Michael; Gustafsson, Ida; Schou, Morten; Dahl, Jordi S.; Rasmussen, Lars Melholt; M?ller, Jacob E.; Tuxen, Christian; Faber, Jens; Kistorp, Caroline

    2017-01-01

    Background: Heart failure (HF) patients with diabetes (DM) have an adverse prognosis and reduced functional capacity, which could be associated with cardiac fibrosis, increased chamber stiffness and reduced left ventricular (LV) contractile reserve. Galectin-3 (Gal-3) and fibulin-1 are circulating biomarkers potentially reflecting cardiac fibrosis. We hypothesize that plasma levels of Gal-3 and fibulin-1 are elevated in HF patients with DM and are associated with reduced LV contractile reserv...

  11. Endothelin-1 exacerbates development of hypertension and atherosclerosis in modest insulin resistant syndrome

    International Nuclear Information System (INIS)

    Lin, Yan-Jie; Juan, Chi-Chang; Kwok, Ching-Fai; Hsu, Yung-Pei; Shih, Kuang-Chung; Chen, Chin-Chang; Ho, Low-Tone

    2015-01-01

    Endothelin-1 (ET-1) is known as potent vasoconstrictor, by virtue of its mitogenic effects, and may deteriorate the process of hypertension and atherosclerosis by aggravating hyperplasia and migration in VSMCs. Our previous study demonstrated that insulin infusion caused sequential induction of hyperinsulinemia, hyperendothelinemia, insulin resistance, and then hypertension in rats. However, the underlying mechanism of ET-1 interfere insulin signaling in VSMCs remains unclear. To characterize insulin signaling during modest insulin resistant syndrome, we established and monitored rats by feeding high fructose-diet (HFD) until high blood pressure and modest insulin resistance occurred. To explore the role of ET-1/ET A R during insulin resistance, ET A R expression, ET-1 binding, and insulin signaling were investigated in the HFD-fed rats and cultured A-10 VSMCs. Results showed that high blood pressure, tunica medial wall thickening, plasma ET-1 and insulin, and accompanied with modest insulin resistance without overweight and hyperglycemia occurred in early-stage HFD-fed rats. In the endothelium-denuded aorta from HFD-fed rats, ET A R expression, but not ET B R, and ET-1 binding in aorta were increased. Moreover, decreasing of insulin-induced Akt phosphorylation and increasing of insulin-induced ERK phosphorylation were observed in aorta during modest insulin resistance. Interestingly, in ET-1 pretreated VSMCs, the increment of insulin-induced Akt phosphorylation was decreased whereas the increment of insulin-induced ERK phosphorylation was increased. In addition, insulin potentiated ET-1-induced VSMCs migration and proliferation due to increasing ET-1 binding. ETAR antagonist reversed effects of ET-1 on insulin-induced signaling and VSMCs migration and proliferation. In summary, modest insulin resistance syndrome accompanied with hyperinsulinemia leading to the potentiation on ET-1-induced actions in aortic VSMCs. ET-1 via ET A R pathway suppressed insulin

  12. Endothelin-1 levels in the pathophysiology of chronic obstructive pulmonary disease and bronchial asthma.

    Science.gov (United States)

    Spiropoulos, K; Trakada, G; Nikolaou, E; Prodromakis, E; Efremidis, G; Pouli, A; Koniavitou, A

    2003-08-01

    Endothelin-1 (ET-1) has been implicated in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). The ET-1 levels are elevated during exacerbations of asthma and COPD in bronchoalveolar lavage, serum, and sputum and fails with treatment of the exacerbations. Hypoxemia stimulates ET-1 secretion. The aim of this study was to examine the serum ET-1 levels in stable asthmatic and COPD patients. We examined 48 COPD and 26 asthmatic patients and 34 normal subjects. We collected arterial samples to measure baseline ET-1 levels in all patients and in the control group, during the day. All the patients underwent formal polysomnography (EEG, ECG, airflow, respiratory muscle movement, oximeter) to detect the presence of nocturnal, nonapneic, and oxyhemoglobin desaturation. Twelve of the COPD patients and six of the asthmatic patients were disqualified because of inadequate sleep or sleep apnea syndrome. Nineteen of the COPD patients desaturated below a baseline sleep saturation of 90% for 5 min or more, reaching a nadir saturation of at least 85%. We collected arterial samples to measure ET-1 levels, 5 min after the first period of desaturation in each of the 19 desaturators COPD patients. None of the 20 asthmatic patients exhibited oxyhemoglobin desaturation during sleep. Baseline arterial ET-1 levels during the day were significantly higher in "desaturators" COPD patients (2.08+/-0.28 pg/ml) compared to "non-desaturators" COPD patients (1.38+/-0.16 pg/ml) (P<0.001) and to asthmatics (0.7+/-0.85 pg/ml) (P<0.001). ET-1 Levels in normal subjects were 1.221+/-0.02 pg/ml. In "desaturators" COPD patients ET-1 levels during the night, 5 min after the first oxyhemoglobin desaturation, were significantly higher (4.28+/-1.10 pg/ml) compared to those during the day (2.08+/-0.28 pg/ml) (P<0.001). A significant negative correlation was observed between ET-1 levels and degree of desaturation during the day (P=0.005, r=0.632) and during the night (P<0.001, r=0

  13. Correlations between plasma endothelin-1 levels and breakthrough pain in patients with cancer

    Directory of Open Access Journals (Sweden)

    Yan XB

    2015-12-01

    Full Text Available Xue-bin Yan, Tuo-chao Peng, Dong Huang Department of Anesthesiologist, The Third Xiangya Hospital of Central South University, Changsha, Hunan Province, People’s Republic of China Abstract: Endothelin-1 (ET-1 may be involved in driving pain in patients with advanced cancer. However, a few studies focus on the role of ET-1 in breakthrough pain (BP. The aim of this pivotal study was to explore the correlation between the plasma (ET-1 level and BP intensity. A total of 40 patients were enrolled in the study, and they were divided into two groups: BP group and non-BP group. Moreover, 20 healthy adults were used as the normal control group. Pain intensity was measured using visual analog scale (VAS scores of 1–10. Plasma ET-1 levels were detected by an ET radioimmunoassay kit. Subsequently, the correlation of ET-1 level with the VAS score and cancer types was analyzed by Pearson’s correlation coefficient. The plasma ET-1 level in the BP group (35.31±8.02 pg/mL was higher than that in the non-BP group (29.51±6.78 pg/mL and the normal control group (24.77±10.10 pg/mL, P<0.05. In addition, the VAS score in the BP group (7.45±0.82 was higher than that in the non-BP group (2.80±1.23, P<0.05. The plasma ET-1 level was positively correlated with the VAS score of the BP group (Pearson’s r=0.42. There was no significant correlation between the plasma ET-1 level and VAS score of the non-BP group (Pearson’s r=–0.22 or/and cancer types (P>0.05. The elevated plasma ET-1 levels were positively related to BP, and targeting ET-1 may provide a novel pain-reducing therapeutic treatment in BP. Keywords: visual analog scale, correlation, cancer types, background pain

  14. Role of Protein Kinase C in Endothelin Converting Enzyme-1 trafficking and shedding from endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuruppu, Sanjaya, E-mail: Sanjaya.Kuruppu@med.monash.edu.au [Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Vic. 3800 (Australia); Tochon-Danguy, Natalie; Ian Smith, A. [Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, Vic. 3800 (Australia)

    2010-07-23

    Research highlights: {yields} PKC activation increases the trafficking of ECE-1 to the cell surface. {yields} This in turn leads to an increase in the amount of ECE-1 shed. {yields} Only the catalytically active C-terminal region is shed from the cell surface. -- Abstract: This study aimed to determine the consequences of Protein Kinase C (PKC) mediated Endothelin Converting Enzyme-1 (ECE-1) phosphorylation and its relationship to ECE-1 expression and shedding. The proteins on the surface of EA.hy926 cells were labelled with EZ-Link NHS-SS-Biotin both prior to (control) and following stimulation by 2 {mu}M phorbol 12-myristate 13-acetate (PMA) which activates PKC. The biotinylated proteins were isolated using neutravidin beads, resolved by gel electrophoresis and analysed by western blotting using anti-ECE-1 antibodies. Significant increase in ECE-1 expression at the cell surface was observed following stimulation by PMA, compared to unstimulated control cells (170 {+-} 32.3% of control, n = 5). The ECE-1 activity (expressed as {mu}M substrate cleaved/min) was determined by monitoring the cleavage of a quenched fluorescent substrate. The specificity of cleavage was confirmed using the ECE-1 inhibitor (CGS35066). The stimulation of cells by PMA (1 {mu}M, 6 h) significantly increased the ECE-1 activity (0.28 {+-} 0.02; n = 3) compared to the control (0.07 {+-} 0.02; n = 3). This increase was prevented by prior incubation with the PKC inhibitor bisindolymaleimide (BIM; 2 {mu}M for 1 h; 0.10 {+-} 0.01; n = 3). Treatment with PMA also increased the activity of ECE-1 in the media (0.18 {+-} 0.01; n = 3) compared to control (0.08 {+-} 0.01; n = 3). In addition, this study confirmed by western immunoblotting that only the extracellular region of ECE-1 is released from the cell surface. These data indicate for the first time that PKC activation induces the trafficking and shedding of ECE to and from the cell surface, respectively.

  15. Neuroprotective effects of curcumin on endothelin-1 mediated cell death in hippocampal neurons.

    Science.gov (United States)

    Stankowska, Dorota L; Krishnamoorthy, Vignesh R; Ellis, Dorette Z; Krishnamoorthy, Raghu R

    2017-06-01

    Alzheimer's disease is a progressive neurodegenerative disease characterized by loss of hippocampal neurons leading to memory deficits and cognitive decline. Studies suggest that levels of the vasoactive peptide endothelin-1 (ET-1) are increased in the brain tissue of Alzheimer's patients. Curcumin, the main ingredient of the spice turmeric, has been shown to have anti-inflammatory, anti-cancer, and neuroprotective effects. However, the mechanisms underlying some of these beneficial effects are not completely understood. The objective of this study was to determine if curcumin could protect hippocampal neurons from ET-1 mediated cell death and examine the involvement of c-Jun in this pathway. Primary hippocampal neurons from rat pups were isolated using a previously published protocol. Viability of the cells was measured by the live/dead assay. Immunoblot and immunohistochemical analyses were performed to analyze c-Jun levels in hippocampal neurons treated with either ET-1 or a combination of ET-1 and curcumin. Apoptotic changes were evaluated by immunoblot detection of cleaved caspase-3, cleaved fodrin, and a caspase 3/7 activation assay. ET-1 treatment produced a 2-fold increase in the levels of c-Jun as determined by an immunoblot analysis in hippocampal neurons. Co-treatment with curcumin significantly attenuated the ET-1 mediated increase in c-Jun levels. ET-1 caused increased neuronal cell death of hippocampal neurons indicated by elevation of cleaved caspase-3, cleaved fodrin and an increased activity of caspases 3 and 7 which was attenuated by co-treatment with curcumin. Blockade of JNK, an upstream effector of c-Jun by specific inhibitor SP600125 did not fully protect from ET-1 mediated activation of pro-apoptotic enzymes in primary hippocampal cells. Our data suggests that one mechanism by which curcumin protects against ET-1-mediated cell death is through blocking an increase in c-Jun levels. Other possible mechanisms include decreasing pro

  16. Endothelin-1 overexpression exacerbates atherosclerosis and induces aortic aneurysms in apolipoprotein E knockout mice.

    Science.gov (United States)

    Li, Melissa W; Mian, Muhammad Oneeb Rehman; Barhoumi, Tlili; Rehman, Asia; Mann, Koren; Paradis, Pierre; Schiffrin, Ernesto L

    2013-10-01

    Endothelin (ET)-1 plays a role in vascular reactive oxygen species production and inflammation. ET-1 has been implicated in human atherosclerosis and abdominal aortic aneurysm (AAA) development. ET-1 overexpression exacerbates high-fat diet-induced atherosclerosis in apolipoprotein E(-/-) (Apoe(-/-)) mice. ET-1-induced reactive oxygen species and inflammation may contribute to atherosclerosis progression and AAA development. Eight-week-old male wild-type mice, transgenic mice overexpressing ET-1 selectively in endothelium (eET-1), Apoe(-/-) mice, and eET-1/Apoe(-/-) mice were fed high-fat diet for 8 weeks. eET-1/Apoe(-/-) had a 45% reduction in plasma high-density lipoprotein (P<0.05) and presented ≥ 2-fold more aortic atherosclerotic lesions compared with Apoe(-/-) (P<0.01). AAAs were detected only in eET-1/Apoe(-/-) (8/21; P<0.05). Reactive oxygen species production was increased ≥ 2-fold in perivascular fat, media, or atherosclerotic lesions in the ascending aorta and AAAs of eET-1/Apoe(-/-) compared with Apoe(-/-) (P<0.05). Monocyte/macrophage infiltration was enhanced ≥ 2.5-fold in perivascular fat of ascending aorta and AAAs in eET-1/Apoe(-/-) compared with Apoe(-/-) (P<0.05). CD4(+) T cells were detected almost exclusively in perivascular fat (3/6) and atherosclerotic lesions (5/6) in ascending aorta of eET-1/Apoe(-/-) (P<0.05). The percentage of spleen proinflammatory Ly-6C(hi) monocytes was enhanced 26% by ET-1 overexpression in Apoe(-/-) (P<0.05), and matrix metalloproteinase-2 was increased 2-fold in plaques of eET-1/Apoe(-/-) (P<0.05) compared with Apoe(-/-). ET-1 plays a role in progression of atherosclerosis and AAA formation by decreasing high-density lipoprotein, and increasing oxidative stress, inflammatory cell infiltration, and matrix metalloproteinase-2 in perivascular fat, vascular wall, and atherosclerotic lesions.

  17. A global, myosin light chain kinase-dependent increase in myosin II contractility accompanies the metaphase-anaphase transition in sea urchin eggs.

    Science.gov (United States)

    Lucero, Amy; Stack, Christianna; Bresnick, Anne R; Shuster, Charles B

    2006-09-01

    Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase-anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase-anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus.

  18. A Global, Myosin Light Chain Kinase-dependent Increase in Myosin II Contractility Accompanies the Metaphase–Anaphase Transition in Sea Urchin Eggs

    Science.gov (United States)

    Lucero, Amy; Stack, Christianna; Bresnick, Anne R.

    2006-01-01

    Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase–anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase–anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus. PMID:16837551

  19. Myocardial contractility in the echo lab: molecular, cellular and pathophysiological basis

    Directory of Open Access Journals (Sweden)

    Bombardini Tonino

    2005-09-01

    Full Text Available Abstract In the standard accepted concept, contractility is the intrinsic ability of heart muscle to generate force and to shorten, independently of changes in the preload or afterload with fixed heart rates. At molecular level the crux of the contractile process lies in the changing concentrations of Ca2+ ions in the myocardial cytosol. Ca2+ ions enter through the calcium channel that opens in response to the wave of depolarization that travels along the sarcolemma. These Ca2+ ions "trigger" the release of more calcium from the sarcoplasmic reticulum (SR and thereby initiate a contraction-relaxation cycle. In the past, several attempts were made to transfer the pure physiological concept of contractility, expressed in the isolated myocardial fiber by the maximal velocity of contraction of unloaded muscle fiber (Vmax, to the in vivo beating heart. Suga and Sagawa achieved this aim by measuring pressure/volume loops in the intact heart: during a positive inotropic intervention, the pressure volume loop reflects a smaller end-systolic volume and a higher end-systolic pressure, so that the slope of the pressure volume relationship moves upward and to the left. The pressure volume relationship is the most reliable index for assessing myocardial contractility in the intact circulation and is almost insensitive to changes in preload and after load. This is widely used in animal studies and occasionally clinically. The limit of the pressure volume relationship is that it fails to take into account the frequency-dependent regulation of contractility: the frequency-dependent control of transmembrane Ca2+ entry via voltage-gated Ca2+ channels provides cardiac cells with a highly sophisticated short-term system for the regulation of intracellular Ca2+ homeostasis. An increased stimulation rate increases the force of contraction: the explanation is repetitive Ca2+ entry with each depolarization and, hence, an accumulation of cytosolic calcium. As the heart

  20. Celecoxib, but not indomethacin, ameliorates the hypertensive and perivascular fibrotic actions of cyclosporine in rats: Role of endothelin signaling

    International Nuclear Information System (INIS)

    El-Mas, Mahmoud M.; Helmy, Maged W.; Ali, Rabab M.; El-Gowelli, Hanan M.

    2015-01-01

    The immunosuppressant drug cyclosporine (CSA) is used with nonsteroidal antiinflammatory drugs (NSAIDs) in arthritic conditions. In this study, we investigated whether NSAIDs modify the deleterious hypertensive action of CSA and the role of endothelin (ET) receptors in this interaction. Pharmacologic, protein expression, and histopathologic studies were performed in rats to investigate the roles of endothelin receptors (ET A /ET B ) in the hemodynamic interaction between CSA and two NSAIDs, indomethacin and celecoxib. Tail-cuff plethysmography measurements showed that CSA (20 mg kg −1 day −1 , 10 days) increased systolic blood pressure (SBP) and heart rate (HR). CSA hypertension was associated with renal perivascular fibrosis and divergent changes in immunohistochemical signals of renal arteriolar ET A (increases) and ET B (decreases) receptors. While these effects of CSA were preserved in rats treated concomitantly with indomethacin (5 mg kg −1 day −1 ), celecoxib (10 mg kg −1 day −1 ) abolished the pressor, tachycardic, and fibrotic effects of CSA and normalized the altered renal ET A /ET B receptor expressions. Selective blockade of ET A receptors by atrasentan (5 mg kg −1 day −1 ) abolished the pressor response elicited by CSA or CSA plus indomethacin. Alternatively, BQ788 (ET B receptor blocker, 0.1 mg kg −1 day −1 ) caused celecoxib-sensitive elevations in SBP and potentiated the pressor response evoked by CSA. Together, the improved renovascular fibrotic and endothelin receptor profile (ET A downregulation and ET B upregulation) mediate, at least partly, the protective effect of celecoxib against the hypertensive effect of CSA. Clinically, the use of celecoxib along with CSA in the management of arthritic conditions might provide hypertension-free regimen. - Highlights: • Chronic CSA causes hypertension and renal perivascular fibrosis in rats. • CSA increased and decreased renal ET A and ET B receptor expression, respectively. • CSA

  1. Influence of specific and non-specific endothelin receptor antagonists on renal morphology in rats with surgical renal ablation.

    Science.gov (United States)

    Nabokov, A; Amann, K; Wagner, J; Gehlen, F; Münter, K; Ritz, E

    1996-03-01

    Studies in experimental models of chronic renal failure suggest an important role for the endothelin system in the development of renal scarring. Endothelin receptor (ETR) anatagonists interfere with progression, but it has not been resolved (i) whether this is true for all models of renal damage, (ii) to what extent the effect is modulated by systemic blood pressure and (iii) whether the effect is similar for ETAR and ETA/ETBR antagonists. 5/6 subtotal nephrectomy (SNX) by surgical ablation in male Sprague-Dawley rats. Comparison of ACE inhibitor Trandolapril (0.1 mg/kg/day), ETAR antagonist BMS 182874 (30 mg/kg/day) and ETAR/ETBR antagonist Ro 46-2005 (30 mg/kg/day) by gavage. Duration of the experiment eight weeks. Systolic blood pressure by tail plethysmography. Perfusion fixation of kidneys and morphometric analysis ET-1 and ETA/ETBR by quantitative PCR. SNX caused a significant (P < 0.01) increase of systolic blood pressure (170 +/- 8.6 mmHg) compared to sham operated controls (131 +/- 5.3 mmHg). Blood pressure was significantly (P < 0.001) lower with Trandolapril (128 +/- 5.3 mmHg), but not with BMS 182874 (153 +/- 5.9 mmHg) or Ro 46-2005 (167 +/- 7.6 mmHg). Compared to sham operated rats (0.03 +/- 0.01) glomerulosclerosis index (GSI) was significantly (P < 0.01) higher in the untreated SNX group (0.9 +/- 0.15). Significantly lower GSI was found in Trandolapril treated (0.29 +/- 0.04), BMS 182874 treated (0.36 +/- 0.05), and Ro 46-2005 treated animals (0.45 +/- 0.11). The effect of BMS 182874 was accompanied by lower tubulointerstitial damage index. Mean glomerular volume was dramatically increased (P < 0.001) in SNX rats as compared to sham operated animals. This glomerular enlargement was partially prevented by Trandolapril (P < 0.05), but not by either ETR antagonist. ET-1 mRNA tended to be higher in SNX irrespective of treatment, while ETAR and ETBR mRNA were significantly lower. Both specific (ETAR) and non-specific (ETA/ETBR) endothelin antagonists

  2. The Functional Lumen Imaging Probe Detects Esophageal Contractility Not Observed With Manometry in Patients With Achalasia.

    Science.gov (United States)

    Carlson, Dustin A; Lin, Zhiyue; Kahrilas, Peter J; Sternbach, Joel; Donnan, Erica N; Friesen, Laurel; Listernick, Zoe; Mogni, Benjamin; Pandolfino, John E

    2015-12-01

    The functional lumen imaging probe (FLIP) could improve the characterization of achalasia subtypes by detecting nonocclusive esophageal contractions not observed with standard manometry. We aimed to evaluate esophageal contractions during volumetric distention in patients with achalasia using FLIP topography. Fifty-one treatment-naive patients with achalasia, defined and subclassified by high-resolution esophageal pressure topography, and 10 asymptomatic individuals (controls) were evaluated with the FLIP during endoscopy. During stepwise distension, simultaneous intrabag pressures and 16 channels of cross-sectional areas were measured; data were exported to software that generated FLIP topography plots. Esophageal contractility was identified by noting periods of reduced luminal diameter. Esophageal contractions were characterized further by propagation direction, repetitiveness, and based on whether they were occluding or nonoccluding. Esophageal contractility was detected in all 10 controls: 8 of 10 had repetitive antegrade contractions and 9 of 10 had occluding contractions. Contractility was detected in 27% (4 of 15) of patients with type I achalasia and in 65% (18 of 26, including 9 with occluding contractions) of patients with type II achalasia. Contractility was detected in all 10 patients with type III achalasia; 8 of these patients had a pattern of contractility that was not observed in controls (repetitive retrograde contractions). Esophageal contractility not observed with manometry can be detected in patients with achalasia using FLIP topography. The presence and patterns of contractility detected with FLIP topography may represent variations in pathophysiology, such as mechanisms of panesophageal pressurization in patients with type II achalasia. These findings could have implications for additional subclassification to supplement prediction of the achalasia disease course. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights

  3. Resveratrol inhibits the intracellular calcium increase and angiotensin/endothelin system activation induced by soluble uric acid in mesangial cells

    Energy Technology Data Exchange (ETDEWEB)

    Albertoni, G.; Schor, N. [Divisão de Nefrologia, Departamento de Medicina, Universidade Federal de São Paulo, São Paulo, SP (Brazil)

    2014-10-24

    Resveratrol (Resv) is natural polyphenol found in grapes. This study evaluated the protective effect of Resv against the effects of uric acid (UA) in immortalized human mesangial cells (ihMCs). ihMCs were preincubated with Resv (12.5 µM) for 1 h and treated with UA (10 mg/dL) for 6 or 12 h. The intracellular calcium concentration [Ca{sup 2+}]i was quantified by fluorescence using flow cytometry. Angiotensinogen (AGT) and pre-pro endothelin-1 (ppET-1) mRNA were assayed by quantitative real-time RT-PCR. Angiotensin II (AII) and endothelin-1 (ET-1) were assayed by ELISA. UA significantly increased [Ca{sup 2+}]i. Pre-incubation with Resv significantly reduced the change in [Ca{sup 2+}]i induced by UA. Incubation with UA for 6 or 12 h also increased AGT mRNA expression and AII protein synthesis. Resv blunted these increases in AGT mRNA expression and AII protein. Incubation with UA in the ihMCs increased ppET-1 expression and ET-1 protein synthesis at 6 and 12 h. When ihMCs were pre-incubated with Resv, UA had a significantly diminished effect on ppET-1 mRNA expression and ET-1 protein synthesis at 6 and 12 h, respectively. Our results suggested that UA triggers reactions including AII and ET-1 production in mesangial cells. The renin-angiotensin system may contribute to the pathogenesis of renal function and chronic kidney disease. Resv can minimize the impact of UA on AII, ET-1 and the increase of [Ca{sup 2+}]i in mesangial cells, suggesting that, at least in part, Resv can prevent the effects of soluble UA in mesangial cells.

  4. The ocular endothelin system: a novel target for the treatment of endotoxin-induced uveitis with bosentan.

    Science.gov (United States)

    Keles, Sadullah; Halici, Zekai; Atmaca, Hasan Tarik; Yayla, Muhammed; Yildirim, Kenan; Ekinci, Metin; Akpinar, Erol; Altuner, Durdu; Cakici, Ozgur; Bayraktutan, Zafer

    2014-05-15

    We compared the anti-inflammatory effects of bosentan and dexamethasone in endotoxin-induced uveitis (EIU). Endotoxin-induced uveitis was induced by subcutaneous injection of lipopolysaccharide (LPS, 200 μg) in Wistar rats. Rats were divided randomly into 10 groups (n = 6). Bosentan at doses of 50 and 100 mg/kg were administered orally 1 hour before and 12 hours after LPS injection, and dexamethasone was administered by intraperitoneally 30 minutes before and 30 minutes after LPS injection at a dose of 1 mg/kg. Data were collected at two time points for each control and treatment; animals were killed at either 3 or 24 hours after LPS injection. Histopathologic evaluation and aqueous humour measurements of TNF-α level were performed, and endothelin-1 (ET-1), inducible nitric oxide synthase (iNOS), and endothelin receptor A and B (EDNRA and B) expression were analyzed. The group treated with 100 mg/kg bosentan at 24 hours displayed significantly milder uveitis and fewer inflammatory cells compared to LPS-injected animals, and there were similar findings in the dexamethasone-treated group at 24 hours. The TNF-α levels in the dexamethasone treatment group were lower than those in the LPS-induced uveitis control group (P treatment groups at 3 and 24 hours after LPS administration. Bosentan treatment at doses of 50 and 100 mg/kg significantly decreased iNOS expression compared to LPS-injected animals (P treatment groups was statistically significantly lower than that in the LPS-induced uveitis control group at 3 and 24 hours after LPS administration (P < 0.05). Bosentan reduces intraocular inflammation and has similar effects as dexamethasone in a rat model of EIU. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  5. Significance of the Melanocortin 1 and Endothelin B Receptors in Melanocyte Homeostasis and Prevention of Sun-Induced Genotoxicity

    Directory of Open Access Journals (Sweden)

    Zalfa A. Abdel-Malek

    2016-08-01

    Full Text Available The membrane bound melanocortin 1 receptor (MC1R, and the endothelin B receptor (ENDBR are two G-protein coupled receptors that play important roles in constitutive regulation of melanocytes and their response to ultraviolet radiation (UVR, the main etiological factor for melanoma. The human MC1R is a Gs protein-coupled receptor, which is activated by its agonists α-melanocyte stimulating hormone (α-melanocortin; α-MSH and adrenocorticotropic hormone (ACTH. The ENDBR is a Gq coupled-receptor, which is activated by Endothelin (ET-3 during embryonic development, and ET-1 postnatally. Pigmentation and the DNA repair capacity are two major factors that determine the risk for melanoma. Activation of the MC1R by its agonists stimulates the synthesis of eumelanin, the dark brown photoprotective pigment. In vitro studies showed that α-MSH and ET-1 interact synergistically in the presence of basic fibroblast growth factor (bFGF to stimulate human melanocyte proliferation and melanogenesis, and to inhibit UVR-induced apoptosis. An important function of the MC1R is reduction of oxidative stress and activation of DNA repair pathways. The human MC1R is highly polymorphic, and MC1R variants, particularly those that cause loss of function of the expressed receptor, are associated with increased melanoma risk independently of pigmentation. These variants compromise the DNA repair and antioxidant capacities of human melanocytes. Recently, activation of ENDBR by ET-1 was reported to reduce the induction and enhance the repair of UVR-induced DNA photoproducts. We conclude that α-MSH and ET-1 and their cognate receptors MC1R and ENDBR reduce the risk for melanoma by maintaining genomic stability of melanocytes via modulating the DNA damage response to solar UVR. Elucidating the response of melanocytes to UVR should improve our understanding of the process of melanomagenesis, and lead to effective melanoma chemoprevention, as well as therapeutic strategies.

  6. Prognostic value of plasma midregional pro-adrenomedullin and C-terminal-pro-endothelin-1 in chronic heart failure outpatients.

    Science.gov (United States)

    Adlbrecht, Christopher; Hülsmann, Martin; Strunk, Guido; Berger, Rudolf; Mörtl, Deddo; Struck, Joachim; Morgenthaler, Nils G; Bergmann, Andreas; Jakowitsch, Johannes; Maurer, Gerald; Lang, Irene M; Pacher, Richard

    2009-04-01

    The identification of chronic heart failure (CHF) patients at high risk of adverse outcome remains a challenge. New peptides are emerging that may give additional information. In CHF patients, endothelin (ET) levels predict mortality risk. Adrenomedullin has been shown to predict mortality in ischaemic heart failure, but not in unselected or non-ischaemic CHF patients. Moreover, ADM and ET have never been assessed in one model. The aim of the present study was to assess the prognostic value of midregional-pro-adrenomedullin (MR-proADM) and C-terminal-pro-endothelin-1 (CT-proET-1) in outpatients with CHF. We measured plasma MR-proADM and CT-proET-1 levels in 786 consecutive CHF outpatients and compared them with B-type natriuretic peptide (BNP) levels. At 24-month follow-up, 233 patients had died. A stepwise forward Cox regression model with age, sex, estimated glomerular filtration rate, NYHA > II, left ventricular ejection fraction (LVEF), MR-proADM, CT-proET-1, and BNP as possible predictors revealed that MR-proADM levels [hazard ratio (HR) = 1.77, P II (HR = 1.86, P < 0.001) were predictors of death at 24 months. When the analysis was repeated dependent on NYHA-stage, MR-proADM (HR = 2.12, P < 0.001) and LVEF (HR = 0.96, P = 0.006) were significant markers, but only in patients with mild/moderate CHF. Our data suggest that MR-proADM may be an important prognostic humoral marker, especially in mild/moderately symptomatic and non-ischaemic CHF patients.

  7. Myoendothelial coupling in the mesenteric arterial bed; segmental differences and interplay between nitric oxide and endothelin-1

    Science.gov (United States)

    Hilgers, RHP; De Mey, JGR

    2009-01-01

    Background and purpose: We tested the hypothesis that activated arterial smooth muscle (ASM) stimulates endothelial vasomotor influences via gap junctions and that the significance of this myoendothelial coupling increases with decreasing arterial diameter. Experimental approach: From WKY rats, first-, second-, third-and fourth-order branches of the superior mesenteric artery (MA1, MA2, MA3 and MA4 respectively) were isolated and mounted in wire-myographs to record vasomotor responses to 0.16–20 µmol·L−1 phenylephrine. Key results: Removal of endothelium increased the sensitivity (pEC50) to phenylephrine in all arteries. The nitric oxide (NO) synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) (100 µmol·L−1) did not modify pEC50 to phenylephrine in all denuded arteries, and increased it in intact MA1, MA2 and MA3 to the same extent as denudation. However, in intact MA4, the effect of L-NAME was significantly larger (ΔpEC50 0.57 ± 0.02) than the effect of endothelium removal (ΔpEC50 0.20 ± 0.06). This endothelium-dependent effect of L-NAME in MA4 was inhibited by (i) steroidal and peptidergic uncouplers of gap junctions; (ii) a low concentration of the NO donor sodium nitroprusside; and (iii) by the endothelin-receptor antagonist bosentan. It was also observed during contractions induced by (i) calcium channel activation (BayK 8644, 0.001–1 µmol·L−1); (ii) depolarization (10–40 mmol·L−1 K+); and (iii) sympathetic nerve stimulation (0.25–32 Hz). Conclusions and implications: These pharmacological observations indicated feedback control by endothelium of ASM reactivity involving gap junctions and a balance between endothelium-derived NO and endothelin-1. This myoendothelial coupling was most prominent in distal resistance arteries. PMID:19302591

  8. Flavonol-rich dark cocoa significantly decreases plasma endothelin-1 and improves cognitive responses in urban children.

    Directory of Open Access Journals (Sweden)

    Lilian eCalderon-Garciduenas

    2013-08-01

    Full Text Available Air pollution exposures are linked to systemic inflammation, cardiovascular and respiratory morbidity and mortality, neuroinflammation and neuropathology in young urbanites. In particular, most Mexico City Metropolitan Area (MCMA children exhibit subtle cognitive deficits, and neuropathology studies show 40% of them exhibiting frontal tau hyperphosphorylation and 51% amyloid-β diffuse plaques (compared to 0% in low pollution control children. We assessed whether a short cocoa intervention can be effective in decreasing plasma endothelin 1 (ET-1 and/or inflammatory mediators in MCMA children. Thirty g of dark cocoa with 680 mg of total flavonols were given daily for 10.11± 3.4 days (range 9 to 24 days to 18 children (10.55yrs, SD =1.45; 11F/7M. Key metabolite ratios in frontal white matter and in hippocampus pre and during cocoa intervention were quantified by magnetic resonance spectroscopy. ET-1 significantly decreased after cocoa treatment (p=0.0002. Fifteen children (83% showed a marginally significant individual improvement in one or both of the applied simple short memory tasks. Endothelial dysfunction is a key feature of exposure to particulate matter and decreased endothelin-1 bioavailability is likely useful for brain function in the context of air pollution. Our findings suggest that cocoa interventions may be critical for early implementation of neuroprotection of highly exposed urban children. Multi-domain nutraceutical interventions could limit the risk for endothelial dysfunction, cerebral hypoperfusion, neuroinflammation, cognitive deficits, structural volumetric detrimental brain effects, and the early development of the neuropathological hallmarks of Alzheimer’s and Parkinson’s diseases.

  9. Endothelin-1 exacerbates development of hypertension and atherosclerosis in modest insulin resistant syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yan-Jie [Institute of Physiology, National Yang-Ming University, Taipei, Taiwan (China); Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan (China); Juan, Chi-Chang [Institute of Physiology, National Yang-Ming University, Taipei, Taiwan (China); Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan (China); Kwok, Ching-Fai [Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan (China); Hsu, Yung-Pei [Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan (China); Shih, Kuang-Chung [Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Chen, Chin-Chang [Institute of Physiology, National Yang-Ming University, Taipei, Taiwan (China); Ho, Low-Tone, E-mail: ltho@vghtpe.gov.tw [Institute of Physiology, National Yang-Ming University, Taipei, Taiwan (China); Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan (China); Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan (China); Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan (China)

    2015-05-08

    Endothelin-1 (ET-1) is known as potent vasoconstrictor, by virtue of its mitogenic effects, and may deteriorate the process of hypertension and atherosclerosis by aggravating hyperplasia and migration in VSMCs. Our previous study demonstrated that insulin infusion caused sequential induction of hyperinsulinemia, hyperendothelinemia, insulin resistance, and then hypertension in rats. However, the underlying mechanism of ET-1 interfere insulin signaling in VSMCs remains unclear. To characterize insulin signaling during modest insulin resistant syndrome, we established and monitored rats by feeding high fructose-diet (HFD) until high blood pressure and modest insulin resistance occurred. To explore the role of ET-1/ET{sub A}R during insulin resistance, ET{sub A}R expression, ET-1 binding, and insulin signaling were investigated in the HFD-fed rats and cultured A-10 VSMCs. Results showed that high blood pressure, tunica medial wall thickening, plasma ET-1 and insulin, and accompanied with modest insulin resistance without overweight and hyperglycemia occurred in early-stage HFD-fed rats. In the endothelium-denuded aorta from HFD-fed rats, ET{sub A}R expression, but not ET{sub B}R, and ET-1 binding in aorta were increased. Moreover, decreasing of insulin-induced Akt phosphorylation and increasing of insulin-induced ERK phosphorylation were observed in aorta during modest insulin resistance. Interestingly, in ET-1 pretreated VSMCs, the increment of insulin-induced Akt phosphorylation was decreased whereas the increment of insulin-induced ERK phosphorylation was increased. In addition, insulin potentiated ET-1-induced VSMCs migration and proliferation due to increasing ET-1 binding. ETAR antagonist reversed effects of ET-1 on insulin-induced signaling and VSMCs migration and proliferation. In summary, modest insulin resistance syndrome accompanied with hyperinsulinemia leading to the potentiation on ET-1-induced actions in aortic VSMCs. ET-1 via ET{sub A}R pathway

  10. Confirmation of translatability and functionality certifies the dual endothelin1/VEGFsp receptor (DEspR) protein.

    Science.gov (United States)

    Herrera, Victoria L M; Steffen, Martin; Moran, Ann Marie; Tan, Glaiza A; Pasion, Khristine A; Rivera, Keith; Pappin, Darryl J; Ruiz-Opazo, Nelson

    2016-06-14

    In contrast to rat and mouse databases, the NCBI gene database lists the human dual-endothelin1/VEGFsp receptor (DEspR, formerly Dear) as a unitary transcribed pseudogene due to a stop [TGA]-codon at codon#14 in automated DNA and RNA sequences. However, re-analysis is needed given prior single gene studies detected a tryptophan [TGG]-codon#14 by manual Sanger sequencing, demonstrated DEspR translatability and functionality, and since the demonstration of actual non-translatability through expression studies, the standard-of-excellence for pseudogene designation, has not been performed. Re-analysis must meet UNIPROT criteria for demonstration of a protein's existence at the highest (protein) level, which a priori, would override DNA- or RNA-based deductions. To dissect the nucleotide sequence discrepancy, we performed Maxam-Gilbert sequencing and reviewed 727 RNA-seq entries. To comply with the highest level multiple UNIPROT criteria for determining DEspR's existence, we performed various experiments using multiple anti-DEspR monoclonal antibodies (mAbs) targeting distinct DEspR epitopes with one spanning the contested tryptophan [TGG]-codon#14, assessing: (a) DEspR protein expression, (b) predicted full-length protein size, (c) sequence-predicted protein-specific properties beyond codon#14: receptor glycosylation and internalization, (d) protein-partner interactions, and (e) DEspR functionality via DEspR-inhibition effects. Maxam-Gilbert sequencing and some RNA-seq entries demonstrate two guanines, hence a tryptophan [TGG]-codon#14 within a compression site spanning an error-prone compression sequence motif. Western blot analysis using anti-DEspR mAbs targeting distinct DEspR epitopes detect the identical glycosylated 17.5 kDa pull-down protein. Decrease in DEspR-protein size after PNGase-F digest demonstrates post-translational glycosylation, concordant with the consensus-glycosylation site beyond codon#14. Like other small single-transmembrane proteins, mass

  11. Isolation and maintenance-free culture of contractile myotubes from Manduca sexta embryos.

    Directory of Open Access Journals (Sweden)

    Amanda L Baryshyan

    Full Text Available Skeletal muscle tissue engineering has the potential to treat tissue loss and degenerative diseases. However, these systems are also applicable for a variety of devices where actuation is needed, such as microelectromechanical systems (MEMS and robotics. Most current efforts to generate muscle bioactuators are focused on using mammalian cells, which require exacting conditions for survival and function. In contrast, invertebrate cells are more environmentally robust, metabolically adaptable and relatively autonomous. Our hypothesis is that the use of invertebrate muscle cells will obviate many of the limitations encountered when mammalian cells are used for bioactuation. We focus on the tobacco hornworm, Manduca sexta, due to its easy availability, large size and well-characterized muscle contractile properties. Using isolated embryonic cells, we have developed culture conditions to grow and characterize contractile M. sexta muscles. The insect hormone 20-hydroxyecdysone was used to induce differentiation in the system, resulting in cells that stained positive for myosin, contract spontaneously for the duration of the culture, and do not require media changes over periods of more than a month. These cells proliferate under normal conditions, but the application of juvenile hormone induced further proliferation and inhibited differentiation. Cellular metabolism under normal and low glucose conditions was compared for C2C12 mouse and M. sexta myoblast cells. While differentiated C2C12 cells consumed glucose and produced lactate over one week as expected, M. sexta muscle did not consume significant glucose, and lactate production exceeded mammalian muscle production on a per cell basis. Contractile properties were evaluated using index of movement analysis, which demonstrated the potential of these cells to perform mechanical work. The ability of cultured M. sexta muscle to continuously function at ambient conditions without medium replenishment

  12. Changes in muscle fiber contractility and extracellular matrix production during skeletal muscle hypertrophy.

    Science.gov (United States)

    Mendias, Christopher L; Schwartz, Andrew J; Grekin, Jeremy A; Gumucio, Jonathan P; Sugg, Kristoffer B

    2017-03-01

    Skeletal muscle can adapt to increased mechanical loads by undergoing hypertrophy. Transient reductions in whole muscle force production have been reported during the onset of hypertrophy, but contractile changes in individual muscle fibers have not been previously studied. Additionally, the extracellular matrix (ECM) stores and transmits forces from muscle fibers to tendons and bones, and determining how the ECM changes during hypertrophy is important in understanding the adaptation of muscle tissue to mechanical loading. Using the synergist ablation model, we sought to measure changes in muscle fiber contractility, collagen content, and cross-linking, and in the expression of several genes and activation of signaling proteins that regulate critical components of myogenesis and ECM synthesis and remodeling during muscle hypertrophy. Tissues were harvested 3, 7, and 28 days after induction of hypertrophy, and nonoverloaded rats served as controls. Muscle fiber specific force (sF o ), which is the maximum isometric force normalized to cross-sectional area, was reduced 3 and 7 days after the onset of mechanical overload, but returned to control levels by 28 days. Collagen abundance displayed a similar pattern of change. Nearly a quarter of the transcriptome changed over the course of overload, as well as the activation of signaling pathways related to hypertrophy and atrophy. Overall, this study provides insight into fundamental mechanisms of muscle and ECM growth, and indicates that although muscle fibers appear to have completed remodeling and regeneration 1 mo after synergist ablation, the ECM continues to be actively remodeling at this time point. NEW & NOTEWORTHY This study utilized a rat synergist ablation model to integrate changes in single muscle fiber contractility, extracellular matrix composition, activation of important signaling pathways in muscle adaption, and corresponding changes in the muscle transcriptome to provide novel insight into the basic

  13. The effect of exercise hypertrophy and disuse atrophy on muscle contractile properties: a mechanomyographic analysis.

    Science.gov (United States)

    Than, Christian; Tosovic, Danijel; Seidl, Laura; Mark Brown, J

    2016-12-01

    To determine whether mechanomyographic (MMG) determined contractile properties of the biceps brachii change during exercise-induced hypertrophy and subsequent disuse atrophy. Healthy subjects (mean ± SD, 23.7 ± 2.6 years, BMI 21.8 ± 2.4, n = 19) performed unilateral biceps curls (9 sets × 12 repetitions, 5 sessions per week) for 8 weeks (hypertrophic phase) before ceasing exercise (atrophic phase) for the following 8 weeks (non-dominant limb; treatment, dominant limb; control). MMG measures of muscle contractile properties (contraction time; T c , maximum displacement; D max , contraction velocity; V c ), electromyographic (EMG) measures of muscle fatigue (median power frequency; MPF), strength measures (maximum voluntary contraction; MVC) and measures of muscle thickness (ultrasound) were obtained. Two-way repeated measures ANOVA showed significant differences (P muscle thickness was greater than control, reflecting gross hypertrophy. MMG variables Dmax (weeks 2, 7) and Vc (weeks 7, 8) declined. During the atrophic phase, MVC (weeks 9-12) and muscle thickness (weeks 9, 10) initially remained high before declining to control levels, reflecting gross atrophy. MMG variables D max (weeks 9, 14) and V c (weeks 9, 14, 15) also declined during the atrophic phase. No change in T c was found throughout the hypertrophic or atrophic phases. MMG detects changes in contractile properties during stages of exercise-induced hypertrophy and disuse atrophy suggesting its applicability as a clinical tool in musculoskeletal rehabilitation.

  14. Myocardial mitochondrial and contractile function are preserved in mice lacking adiponectin.

    Directory of Open Access Journals (Sweden)

    Martin Braun

    Full Text Available Adiponectin deficiency leads to increased myocardial infarct size following ischemia reperfusion and to exaggerated cardiac hypertrophy following pressure overload, entities that are causally linked to mitochondrial dysfunction. In skeletal muscle, lack of adiponectin results in impaired mitochondrial function. Thus, it was our objective to investigate whether adiponectin deficiency impairs mitochondrial energetics in the heart. At 8 weeks of age, heart weight-to-body weight ratios were not different between adiponectin knockout (ADQ-/- mice and wildtypes (WT. In isolated working hearts, cardiac output, aortic developed pressure and cardiac power were preserved in ADQ-/- mice. Rates of fatty acid oxidation, glucose oxidation and glycolysis were unchanged between groups. While myocardial oxygen consumption was slightly reduced (-24% in ADQ-/- mice in isolated working hearts, rates of maximal ADP-stimulated mitochondrial oxygen consumption and ATP synthesis in saponin-permeabilized cardiac fibers were preserved in ADQ-/- mice with glutamate, pyruvate or palmitoyl-carnitine as a substrate. In addition, enzymatic activity of respiratory complexes I and II was unchanged between groups. Phosphorylation of AMP-activated protein kinase and SIRT1 activity were not decreased, expression and acetylation of PGC-1α were unchanged, and mitochondrial content of OXPHOS subunits was not decreased in ADQ-/- mice. Finally, increasing energy demands due to prolonged subcutaneous infusion of isoproterenol did not differentially affect cardiac contractility or mitochondrial function in ADQ-/- mice compared to WT. Thus, mitochondrial and contractile function are preserved in hearts of mice lacking adiponectin, suggesting that adiponectin may be expendable in the regulation of mitochondrial energetics and contractile function in the heart under non-pathological conditions.

  15. Separate effects of ischemia, hypoxia, and contractility on thallium-201 kinetics in rabbit myocardium

    International Nuclear Information System (INIS)

    Leppo, J.A.; Macneil, P.B.; Moring, A.F.; Apstein, C.S.

    1986-01-01

    The effects of hypoxia and ischemia, as well as altered contractility, on thallium-201 ( 201 TI) kinetics were evaluated in 42 isolated isovolumetrically contracting rabbit hearts. In Group A, three subgroups (n = 7 each) were studied that had either normal flow and oxygenation, hypoxia and normal flow, or ischemic flow and normal perfusate oxygen content. In Group B, three subgroups (n = 7 each) were studied and all hearts had normal flow but the contractile state was either enhanced with isoproterenol or impaired by hypocalcemia. A hemoglobin-free buffer perfusate was used in all experiments and multiple timed collections of arterial and coronary sinus effluent were used to model myocardial isotope activity during 30 min of constant uptake followed by 30 min of tracer clearance. During ischemia, hypoxia and hypocalcemia peak developed pressure and peak positive and negative dP/dt were all significantly reduced when compared to normal hemodynamic parameters (p less than 0.01). As expected, isoproterenol significantly elevated these parameters (p less than 0.04). Myocardial 201 TI kinetics were adequately described utilizing a bi-exponential model having a fast and slow component. Only ischemic hearts had significantly lower rate constants for 201 TI uptake and clearance than normal hearts (p less than 0.001). The mean (+/- s.d.) myocardial uptake and clearance rates for 201 TI (%/min) varied between 4.86 +/- 0.87 and 7.18 +/- 1.45 for the remaining groups of hearts. Therefore, myocardial 201 TI kinetics appear to be dominated by coronary flow and may not reflect marked alterations in the metabolic and contractile state. These data suggest that normal 201 TI uptake in impaired or hypercontractile cells, receiving normal flow, may not represent normal cellular function

  16. Opportunities to Target Specific Contractile Abnormalities with Smooth Muscle Protein Kinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Annegret Ulke-Lemée

    2010-05-01

    Full Text Available Smooth muscle is a major component of most hollow organ systems (e.g., airways, vasculature, bladder and gut/gastrointestine; therefore, the coordinated regulation of contraction is a key property of smooth muscle. When smooth muscle functions normally, it contributes to general health and wellness, but its dysfunction is associated with morbidity and mortality. Rho-associated protein kinase (ROCK is central to calcium-independent, actomyosin-mediated contractile force generation in the vasculature, thereby playing a role in smooth muscle contraction, cell motility and adhesion. Recent evidence supports an important role for ROCK in the increased vasoconstriction and remodeling observed in various models of hypertension. This review will provide a commentary on the development of specific ROCK inhibitors and their clinical application. Fasudil will be discussed as an example of bench-to-bedside development of a clinical therapeutic that is used to treat conditions of vascular hypercontractility. Due to the wide spectrum of biological processes regulated by ROCK, many additional clinical indications might also benefit from ROCK inhibition. Apart from the importance of ROCK in smooth muscle contraction, a variety of other protein kinases are known to play similar roles in regulating contractile force. The zipper-interacting protein kinase (ZIPK and integrin-linked kinase (ILK are two well-described regulators of contraction. The relative contribution of each kinase to contraction depends on the muscle bed as well as hormonal and neuronal stimulation. Unfortunately, specific inhibitors for ZIPK and ILK are still in the development phase, but the success of fasudil suggests that inhibitors for these other kinases may also have valuable clinical applications. Notably, the directed inhibition of ZIPK with a pseudosubstrate molecule shows unexpected effects on the contractility of gastrointestinal smooth muscle.

  17. The role of apical contractility in determining cell morphology in multilayered epithelial sheets and tubes

    Science.gov (United States)

    Zhen Tan, Rui; Lai, Tanny; Chiam, K.-H.

    2017-08-01

    A multilayered epithelium is made up of individual cells that are stratified in an orderly fashion, layer by layer. In such tissues, individual cells can adopt a wide range of shapes ranging from columnar to squamous. From histological images, we observe that, in flat epithelia such as the skin, the cells in the top layer are squamous while those in the middle and bottom layers are columnar, whereas in tubular epithelia, the cells in all layers are columnar. We develop a computational model to understand how individual cell shape is governed by the mechanical forces within multilayered flat and curved epithelia. We derive the energy function for an epithelial sheet of cells considering intercellular adhesive and intracellular contractile forces. We determine computationally the cell morphologies that minimize the energy function for a wide range of cellular parameters. Depending on the dominant adhesive and contractile forces, we find four dominant cell morphologies for the multilayered-layered flat sheet and three dominant cell morphologies for the two-layered curved sheet. We study the transitions between the dominant cell morphologies for the two-layered flat sheet and find both continuous and discontinuous transitions and also the presence of multistable states. Matching our computational results with histological images, we conclude that apical contractile forces from the actomyosin belt in the epithelial cells is the dominant force determining cell shape in multilayered epithelia. Our computational model can guide tissue engineers in designing artificial multilayered epithelia, in terms of figuring out the cellular parameters needed to achieve realistic epithelial morphologies.

  18. Contractile profile of esophageal and gastric fundus strips in experimental doxorubicin-induced esophageal atresia

    Directory of Open Access Journals (Sweden)

    F.A. Capeto

    2015-05-01

    Full Text Available Esophageal atresia (EA is characterized by esophageal and gastric motility changes secondary to developmental and postsurgical damage. This study evaluated the in vitro contractile profile of the distal esophagus and gastric fundus in an experimental model of EA induced by doxorubicin (DOXO. Wistar pregnant rats received DOXO 2.2 mg/kg on the 8th and 9th gestational days. On day 21.5, fetuses were collected, sacrificed, and divided into groups: control, DOXO without EA (DOXO-EA, and DOXO with EA (DOXO+EA. Strips from the distal esophagus and gastric fundus were mounted on a wire myograph and isolated organ-bath system, respectively, and subjected to increasing concentrations of carbamylcholine chloride (carbachol, CCh. The isolated esophagus was also stimulated with increasing concentrations of KCl. In esophagus, the concentration-effect curves were reduced in response to CCh in the DOXO+EA and DOXO-EA groups compared to the control group (P0.05. In response to KCl, the distal esophagus samples in the three groups were not statistically different with regard to Emax or EC50 values (P>0.05. No significant difference was noted for EC50 or Emax values in fundic strips stimulated with CCh (P>0.05. In conclusion, exposure of dams to DOXO during gestation inhibited the contractile behavior of esophageal strips from offspring in response to CCh but not KCl, regardless of EA induction. The gastric fundus of DOXO-exposed offspring did not have altered contractile responsiveness to cholinergic stimulation.

  19. Contractility-afterload mismatch in patients with protein-losing enteropathy after the Fontan operation.

    Science.gov (United States)

    Ozawa, Hideto; Ueno, Takayoshi; Iwai, Shigemitsu; Kawata, Hiroaki; Nishigaki, Kyouichi; Kishimoto, Hidefumi; Sawa, Yoshiki

    2014-10-01

    This study aimed to clarify the relationship between onset of protein-losing enteropathy (PLE) and Fontan circulation, with special reference to the development of contractility-afterload mismatch. The PLE group comprised 9 patients who experienced PLE after undergoing the Fontan operation, and the control group consisted of 32 patients had did not experienced PLE more than 10 years after the Fontan operation. The study compared the pre- and postoperative values of arterial elastance (Ea), end-systolic elastance (Ees), and contractility-afterload mismatch (Ea/Ees). Furthermore, the variations in the values were examined during the preoperative, postoperative, and midterm postoperative periods in seven PLE patients who underwent cardiac catheterization at the onset of PLE and during the pre- and postintervention periods in three PLE patients who underwent surgical intervention to improve the Fontan circulation after the onset of PLE. Comparison of the values obtained before and after Fontan operations showed that the Ea values increased significantly in the PLE group. However, the pre- and postoperative Ees values did not differ in the two groups. During the postoperative period, Ea/Ees increased significantly, and the Ea and Ea/Ees values increased continuously until the onset of PLE in the PLE group. In the patients who underwent surgical intervention to improve the Fontan circulation after the onset of PLE, the Ea/Ees decreased significantly, and the serum albumin levels improved after the intervention. Contractility-afterload mismatch, mainly caused by the increase in the afterload of the systemic ventricle, may have an important role in the development of PLE after the Fontan operation.

  20. Altered Ca fluxes and contractile state during pH changes in cultured heart cells

    International Nuclear Information System (INIS)

    Kim, D.; Smith, T.W.

    1987-01-01

    The authors studied mechanisms underlying changes in myocardial contractile state produced by intracellular (pH/sub i/) or extracellular (pH 0 ) changes in pH using cultured chick embryo ventricular cells. A change in pH 0 of HEPES-buffered medium from 7.4 to 6.0 or to 8.8 changed the amplitude of cell motion by -85 or +60%, and 45 Ca uptake at 10 s by -29 or +22%, respectively. The pH 0 induced change in Ca uptake was not sensitive to nifedipine but was Na gradient dependent. Changes in pH/sub i/ produced by NH 4 Cl or preincubation in media at pH values ranging from 6.0 to 8.8 failed to alter significantly 45 Ca uptake or efflux. However, larger changes in pH/sub i/ were associated with altered Ca uptake. Changes in pH 0 from 7.5 to 6.0 or to 8.8 were associated with initial changes in 45 Ca efflux by +17 or -18%, respectively, and these effects were not Na dependent. Exposure of cells to 20 mM NH 4 Cl produced intracellular alkalinization and a positive inotropic effect, whereas subsequent removal of NH 4 Cl caused intracellular acidification and a negative inotropic effect. There was, however, a lack of close temporal relationships between pH/sub i/ and contractile state. These results indicated that pH 0 -induced changes in contractile state in cultured heart cells are closely correlated with altered transarcolemmal Ca movements and presumably are due to these Ca flux changes

  1. Acute exposure to lead increases myocardial contractility independent of hypertension development

    International Nuclear Information System (INIS)

    Fioresi, M.; Furieri, L.B.; Simões, M.R.; Ribeiro, R.F. Junior; Meira, E.F.; Fernandes, A.A.; Stefanon, I.; Vassallo, D.V.

    2013-01-01

    We studied the effects of the acute administration of small doses of lead over time on hemodynamic parameters in anesthetized rats to determine if myocardial contractility changes are dependent or not on the development of hypertension. Male Wistar rats received 320 µg/kg lead acetate iv once, and their hemodynamic parameters were measured for 2 h. Cardiac contractility was evaluated in vitro using left ventricular papillary muscles as were Na + ,K + -ATPase and myosin Ca 2+ -ATPase activities. Lead increased left- (control: 112 ± 3.7 vs lead: 129 ± 3.2 mmHg) and right-ventricular systolic pressures (control: 28 ± 1.2 vs lead: 34 ± 1.2 mmHg) significantly without modifying heart rate. Papillary muscles were exposed to 8 µM lead acetate and evaluated 60 min later. Isometric contractions increased (control: 0.546 ± 0.07 vs lead: 0.608 ± 0.06 g/mg) and time to peak tension decreased (control: 268 ± 13 vs lead: 227 ± 5.58 ms), but relaxation time was unchanged. Post-pause potentiation was similar between groups (n = 6 per group), suggesting no change in sarcoplasmic reticulum activity, evaluated indirectly by this protocol. After 1-h exposure to lead acetate, the papillary muscles became hyperactive in response to a β-adrenergic agonist (10 µM isoproterenol). In addition, post-rest contractions decreased, suggesting a reduction in sarcolemmal calcium influx. The heart samples treated with 8 µM lead acetate presented increased Na + ,K + -ATPase (approximately 140%, P < 0.05 for control vs lead) and myosin ATPase (approximately 30%, P < 0.05 for control vs lead) activity. Our results indicated that acute exposure to low lead concentrations produces direct positive inotropic and lusitropic effects on myocardial contractility and increases the right and left ventricular systolic pressure, thus potentially contributing to the early development of hypertension

  2. Facilitated ethanol metabolism promotes cardiomyocyte contractile dysfunction through autophagy in murine hearts.

    Science.gov (United States)

    Guo, Rui; Hu, Nan; Kandadi, Machender R; Ren, Jun

    2012-04-01

    Chronic drinking leads to myocardial contractile dysfunction where ethanol metabolism plays an essential role. Acetaldehyde, the main ethanol metabolite, mediates alcohol-induced cell injury although the underlying mechanism is still elusive. This study was designed to examine the mechanism involved in accelerated ethanol metabolism-induced cardiac defect with a focus on autophagy. Wild-type FVB and cardiac-specific overexpression of alcohol dehydrogenase mice were placed on a 4% nutrition-balanced alcohol diet for 8 weeks. Myocardial histology, immunohistochemistry, autophagy markers and signal molecules were examined. Expression of micro RNA miR-30a, a potential target of Beclin 1, was evaluated by real-time PCR. Chronic alcohol intake led to cardiac acetaldehyde accumulation, hypertrophy and overt autophagosome accumulation (LC3-II and Atg7), the effect of which was accentuated by ADH. Signaling molecules governing autophagy initiation including class III PtdIns3K, phosphorylation of mTOR and p70S6K were enhanced and dampened, respectively, following alcohol intake. These alcohol-induced signaling responses were augmented by ADH. ADH accentuated or unmasked alcohol-induced downregulation of Bcl-2, Bcl-xL and MiR-30a. Interestingly, ADH aggravated alcohol-induced p62 accumulation. Autophagy inhibition using 3-MA abolished alcohol-induced cardiomyocyte contractile anomalies. Moreover, acetaldehyde led to cardiomyocyte contractile dysfunction and autophagy induction, which was ablated by 3-MA. Ethanol or acetaldehyde increased GFP-LC3 puncta in H9c2 cells, the effect of which was ablated by 3-MA but unaffected by lysosomal inhibition using bafilomycin A(1), E64D and pepstatin A. In summary, these data suggested that facilitated acetaldehyde production via ADH following alcohol intake triggered cardiac autophagosome formation along with impaired lysosomal degradation, en route to myocardial defect.

  3. Pulmonary artery radiocardiography and rheography in the diagnosis of hemodynamic and contractile function impairments of the right ventricle in patients with obstructive bronchitis

    International Nuclear Information System (INIS)

    Paleev, N.P.; Cherejskaya, N.K.; Tsar'kova, L.N.; Baklykova, S.N.; Novoderezhkina, L.B.; Oblovatskaya, O.G.; Dubinina, E.B.

    1990-01-01

    Radiocardiography and rheography of the pulmonary artery were used to examine impairments in hemodynamics and contractile function of the right ventricle in 40 patients with chronic obstructive bronchitis complicated with persistent hypertension. Right ventricular hemodynamic and contractile impairments were shown to be not equivalent with similar clinical and functional signs of pulmonary hypertension. This fact indicates that the use of special techiques is of practical value in the determination of right ventricular hemodynamics and myocardial contractility in patients with chronic obstructive bronchitis. Radiocardiography and rheography of the pulmonary artery are sufficiently reliable noninvasive techniques for examining the hemodynamics and contractile function of the right ventricular myocardium

  4. Bladder contractility is modulated by Kv7 channels in pig detrusor

    DEFF Research Database (Denmark)

    Svalø, Julie; Bille, Michala; Parameswaran Theepakaran, Neeraja

    2013-01-01

    Kv7 channels are involved in smooth muscle relaxation, and accordingly we believe that they constitute potential targets for the treatment of overactive bladder syndrome. We have therefore used myography to examine the function of Kv7 channels in detrusor, i.e. pig bladder, with a view...... relaxation, suggesting that Kv7.2 and/or Kv7.4 channels constitute the subtypes that are relevant to bladder contractility. The effects of retigabine and ML213 were attenuated by pre-incubation with 10µM XE991 (Kv7.1-7.5 channel blocker) (P...

  5. A thermodynamical model for stress-fiber organization in contractile cells.

    Science.gov (United States)

    Foucard, Louis; Vernerey, Franck J

    2012-01-02

    Cell mechanical adaptivity to external stimuli is vital to many of its biological functions. A critical question is therefore to understand the formation and organization of the stress fibers from which emerge the cell's mechanical properties. By accounting for the mechanical aspects and the viscoelastic behavior of stress fibers, we here propose a thermodynamic model to predict the formation and orientation of stress fibers in contractile cells subjected to constant or cyclic stretch and different substrate stiffness. Our results demonstrate that the stress fibers viscoelastic behavior plays a crucial role in their formation and organization and shows good consistency with various experiments.

  6. Targeting the ROS-HIF-1-endothelin axis as a therapeutic approach for the treatment of obstructive sleep apnea-related cardiovascular complications.

    Science.gov (United States)

    Belaidi, Elise; Morand, Jessica; Gras, Emmanuelle; Pépin, Jean-Louis; Godin-Ribuot, Diane

    2016-12-01

    Obstructive sleep apnea (OSA) is now recognized as an independent and important risk factor for cardiovascular diseases such as hypertension, coronary heart disease, heart failure and stroke. Clinical and experimental data have confirmed that intermittent hypoxia is a major contributor to these deleterious consequences. The repetitive occurrence of hypoxia-reoxygenation sequences generates significant amounts of free radicals, particularly in moderate to severe OSA patients. Moreover, in addition to hypoxia, reactive oxygen species (ROS) are potential inducers of the hypoxia inducible transcription factor-1 (HIF-1) that promotes the transcription of numerous adaptive genes some of which being deleterious for the cardiovascular system, such as the endothelin-1 gene. This review will focus on the involvement of the ROS-HIF-1-endothelin signaling pathway in OSA and intermittent hypoxia and discuss current and potential therapeutic approaches targeting this pathway to treat or prevent cardiovascular disease in moderate to severe OSA patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Over, and Underexpression of Endothelin 1 and TGF-Beta Family Ligands and Receptors in Lung Tissue of Broilers with Pulmonary Hypertension

    Science.gov (United States)

    Dominguez-Avila, Norma; Ruiz-Castañeda, Gabriel; González-Ramírez, Javier; Fernandez-Jaramillo, Nora; Escoto, Jorge; Sánchez-Muñoz, Fausto; Marquez-Velasco, Ricardo; Bojalil, Rafael; Espinosa-Cervantes, Román; Sánchez, Fausto

    2013-01-01

    Transforming growth factor beta (TGFβ) is a family of genes that play a key role in mediating tissue remodeling in various forms of acute and chronic lung disease. In order to assess their role on pulmonary hypertension in broilers, we determined mRNA expression of genes of the TGFβ family and endothelin 1 in lung samples from 4-week-old chickens raised either under normal or cold temperature conditions. Both in control and cold-treated groups of broilers, endothelin 1 mRNA expression levels in lungs from ascitic chickens were higher than levels from healthy birds (P 0.05). BAMBI mRNA gene expression was lowest in birds with ascites only in the control group as compared with the values from healthy birds (P < 0.05). PMID:24286074

  8. Isosorbide 5 mononitrate administration increases nitric oxide blood levels and reduces proteinuria in IgA glomerulonephritis patients with abnormal urinary endothelin/cyclic GMP ratio.

    Science.gov (United States)

    Roccatello, D; Mengozzi, G; Ferro, M; Cesano, G; Polloni, R; Mosso, R; Bonetti, G; Inconis, T; Paradisi, L; Sena, L M

    1995-09-01

    An endothelin urinary hyperexcretion, which is not counterbalanced by an adequate increase in cGMP biosynthesis, was previously detected in some patients with IgA Nephropathy (IgAN). Since this imbalance might potentiate local ET1-mediated hemodynamics effects, 9 IgAN patients with an increased (> or = 0.1) urinary ET1/cGMP ratio (group 1) and 5 IgAN patients with comparable renal function and reduced ET1/cGMP ratio (group 2) were given standard doses of isosorbide 5 mononitrate (as a nitric oxide source). Blood nitric oxide (NO) levels, as detected by electron paramagnetic resonance, significantly increased after isosorbide administration (p effective renal plasma flow (p counterbalancing effects of nitric oxide on endothelin-mediated mesangial contraction.

  9. Cerebrovascular endothelin-1 hyper-reactivity is associated with transient receptor potential canonical channels 1 and 6 activation and delayed cerebral hypoperfusion after forebrain ischaemia in rats

    DEFF Research Database (Denmark)

    Johansson, S E; Andersen, X E D R; Hansen, R H

    2015-01-01

    . METHODS: Experimental forebrain ischaemia was induced in Wistar male rats by a two-vessel occlusion model, and the cerebral blood flow was measured by magnetic resonance imaging two days after reperfusion. In vitro vasoreactivity studies, immunofluorescence and quantitative PCR were performed on cerebral...... in the vascular smooth muscle cells was enhanced and correlated with decreased cerebral blood flow two days after forebrain ischaemia. Furthermore, under conditions when voltage-dependent calcium channels were inhibited, endothelin-1-induced cerebrovascular contraction was enhanced and this enhancement...... was presumably mediated by Ca(2+) influx via upregulated transient receptor potential canonical channels 1 and 6. CONCLUSIONS: Our data demonstrates that endothelin-1-mediated influx of extracellular Ca(2+) activates transient receptor potential canonical channels 1 and 6 in cerebral vascular smooth muscle cells...

  10. Endothelin B Receptors on Primary Chicken Müller Cells and the Human MIO-M1 Müller Cell Line Activate ERK Signaling via Transactivation of Epidermal Growth Factor Receptors.

    Directory of Open Access Journals (Sweden)

    Mohammad Harun-Or-Rashid

    Full Text Available Injury to the eye or retina triggers Müller cells, the major glia cell of the retina, to dedifferentiate and proliferate. In some species they attain retinal progenitor properties and have the capacity to generate new neurons. The epidermal growth factor receptor (EGFR system and extracellular signal-regulated kinase (ERK signaling are key regulators of these processes in Müller cells. The extracellular signals that modulate and control these processes are not fully understood. In this work we studied whether endothelin receptor signaling can activate EGFR and ERK signaling in Müller cells. Endothelin expression is robustly upregulated at retinal injury and endothelin receptors have been shown to transactivate EGFRs in other cell types. We analyzed the endothelin signaling system in chicken retina and cultured primary chicken Müller cells as well as the human Müller cell line MIO-M1. The Müller cells were stimulated with receptor agonists and treated with specific blockers to key enzymes in the signaling pathway or with siRNAs. We focused on endothelin receptor mediated transactivation of EGFRs by using western blot analysis, quantitative reverse transcriptase PCR and immunocytochemistry. The results showed that chicken Müller cells and the human Müller cell line MIO-M1 express endothelin receptor B. Stimulation by the endothelin receptor B agonist IRL1620 triggered phosphorylation of ERK1/2 and autophosphorylation of (Y1173 EGFR. The effects could be blocked by Src-kinase inhibitors (PP1, PP2, EGFR-inhibitor (AG1478, EGFR-siRNA and by inhibitors to extracellular matrix metalloproteinases (GM6001, consistent with a Src-kinase mediated endothelin receptor response that engage ligand-dependent and ligand-independent EGFR activation. Our data suggest a mechanism for how injury-induced endothelins, produced in the retina, may modulate the Müller cell responses by Src-mediated transactivation of EGFRs. The data give support to a view in

  11. Polyphenol fraction of extra virgin olive oil protects against endothelial dysfunction induced by high glucose and free fatty acids through modulation of nitric oxide and endothelin-1

    OpenAIRE

    Storniolo, Carolina Emilia; Roselló-Catafau, Joan; Pintó, Xavier; Mitjavila, María Teresa; Moreno, Juan José

    2014-01-01

    © 2014 The Authors. Epidemiological and clinical studies have reported that olive oil reduces the incidence of cardiovascular disease. However, the mechanisms involved in this beneficial effect have not been delineated. The endothelium plays an important role in blood pressure regulation through the release of potent vasodilator and vasoconstrictor agents such as nitric oxide (NO) and endothelin-1 (ET-1), respectively, events that are disrupted in type 2 diabetes. Extra virgin olive oil conta...

  12. Intrahippocampal injection of endothelin-1 in immature rats results in neuronal death, development of epilepsy and behavioral abnormalities later in life

    Czech Academy of Sciences Publication Activity Database

    Máttéffyová, Adéla; Otáhal, Jakub; Tsenov, Grygoriy; Mareš, Pavel; Kubová, Hana

    2006-01-01

    Roč. 24, č. 2 (2006), s. 351-360 ISSN 0953-816X R&D Projects: GA ČR(CZ) GA305/06/0713; GA ČR(CZ) GD305/03/H148; GA MŠk(CZ) LC554 Institutional research plan: CEZ:AV0Z50110509 Keywords : endothelin-1 * epilepsy * immature rats Subject RIV: ED - Physiology Impact factor: 3.709, year: 2006

  13. Chronic endothelin A receptor blockade attenuates contribution of sympathetic nervous system to salt hypertension development in adult but not in young Dahl rats

    Czech Academy of Sciences Publication Activity Database

    Zicha, Josef; Dobešová, Zdenka; Kuneš, Jaroslav; Vaněčková, Ivana

    2012-01-01

    Roč. 205, č. 1 (2012), s. 124-132 ISSN 1748-1708 R&D Projects: GA MŠk(CZ) 1M0510; GA ČR(CZ) GA305/09/0336; GA AV ČR(CZ) IAA500110902 Institutional research plan: CEZ:AV0Z50110509 Keywords : Endothelin-1 * salt hypertension * Dahl rats Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 4.382, year: 2012

  14. A stepwise procedure to test contractility and susceptibility to injury for the rodent quadriceps muscle

    Directory of Open Access Journals (Sweden)

    Stephen J.P. Pratt

    2014-07-01

    Full Text Available In patients with muscle injury or muscle disease, assessment of muscle damage is typically limited to clinical signs, such as tenderness, strength, range of motion, and more recently, imaging studies.  Biological markers can also be used in measuring muscle injury, such as increased creatine kinase levels in the blood, but these are not always correlated with loss in muscle function (i.e. loss of force production.  This is even true of histological findings from animals, which provide a “direct measure” of damage, but do not account for loss of function.  The most comprehensive measure of the overall health of the muscle is contractile force.  To date, animal models testing contractile force have been limited to the muscle groups moving the ankle.  Here we describe an in vivo animal model for the quadriceps, with abilities to measure torque, produce a reliable muscle injury, and follow muscle recovery within the same animal over time.  We also describe a second model used for direct measurement of force from an isolated quadriceps muscle in situ. 

  15. Influence of intracellular acidosis on contractile function in the working rat heart

    International Nuclear Information System (INIS)

    Jeffrey, F.M.H.; Malloy, C.R.; Radda, G.K.

    1987-01-01

    The decrease in myocardial contractility during ischemia, hypoxia, and extracellular acidosis has been attributed to intracellular acidosis. Previous studies of the relationship between pH and contractile state have utilized respiratory or metabolic acidosis to alter intracellular pH. The authors developed a model in the working perfused rat heart to study the effects of intracellular acidosis with normal external pH and optimal O 2 delivery. Intracellular pH and high-energy phosphates were monitored by 31 P nuclear magnetic resonance spectroscopy. Hearts were perfused to a steady state with a medium containing 10 mM NH 4 Cl. Acidosis induced a substantial decrease in aortic flow and stroke volume which was associated with little change in peak systolic pressure. It was concluded that (1) for the same intracellular acidosis the influence on tension development was more pronounced with a combined extra- and intracellular acidosis than with an isolated intracellular acidosis, and (2) stroke volume at constant preload was impaired by intracellular acidosis even though changes in developed pressure were minimal. These observations suggest that isolated intracellular acidosis has adverse effects on diastolic compliance and/or relaxation

  16. Oscillatory behaviors and hierarchical assembly of contractile structures in intercalating cells

    International Nuclear Information System (INIS)

    Fernandez-Gonzalez, Rodrigo; Zallen, Jennifer A

    2011-01-01

    Fluctuations in the size of the apical cell surface have been associated with apical constriction and tissue invagination. However, it is currently not known if apical oscillatory behaviors are a unique property of constricting cells or if they constitute a universal feature of the force balance between cells in multicellular tissues. Here, we set out to determine whether oscillatory cell behaviors occur in parallel with cell intercalation during the morphogenetic process of axis elongation in the Drosophila embryo. We applied multi-color, time-lapse imaging of living embryos and SIESTA, an integrated tool for automated and semi-automated cell segmentation, tracking, and analysis of image sequences. Using SIESTA, we identified cycles of contraction and expansion of the apical surface in intercalating cells and characterized them at the molecular, cellular, and tissue scales. We demonstrate that apical oscillations are anisotropic, and this anisotropy depends on the presence of intact cell–cell junctions and spatial cues provided by the anterior–posterior patterning system. Oscillatory cell behaviors during axis elongation are associated with the hierarchical assembly and disassembly of contractile actomyosin structures at the medial cortex of the cell, with actin localization preceding myosin II and with the localization of both proteins preceding changes in cell shape. We discuss models to explain how the architecture of cytoskeletal networks regulates their contractile behavior and the mechanisms that give rise to oscillatory cell behaviors in intercalating cells

  17. Dependence of intramyocardial pressure and coronary flow on ventricular loading and contractility: a model study.

    Science.gov (United States)

    Bovendeerd, Peter H M; Borsje, Petra; Arts, Theo; van De Vosse, Frans N

    2006-12-01

    The phasic coronary arterial inflow during the normal cardiac cycle has been explained with simple (waterfall, intramyocardial pump) models, emphasizing the role of ventricular pressure. To explain changes in isovolumic and low afterload beats, these models were extended with the effect of three-dimensional wall stress, nonlinear characteristics of the coronary bed, and extravascular fluid exchange. With the associated increase in the number of model parameters, a detailed parameter sensitivity analysis has become difficult. Therefore we investigated the primary relations between ventricular pressure and volume, wall stress, intramyocardial pressure and coronary blood flow, with a mathematical model with a limited number of parameters. The model replicates several experimental observations: the phasic character of coronary inflow is virtually independent of maximum ventricular pressure, the amplitude of the coronary flow signal varies about proportionally with cardiac contractility, and intramyocardial pressure in the ventricular wall may exceed ventricular pressure. A parameter sensitivity analysis shows that the normalized amplitude of coronary inflow is mainly determined by contractility, reflected in ventricular pressure and, at low ventricular volumes, radial wall stress. Normalized flow amplitude is less sensitive to myocardial coronary compliance and resistance, and to the relation between active fiber stress, time, and sarcomere shortening velocity.

  18. Modulation of cardiac contractility by the phospholamban/SERCA2a regulatome.

    Science.gov (United States)

    Kranias, Evangelia G; Hajjar, Roger J

    2012-06-08

    Heart disease remains the leading cause of death and disability in the Western world. Current therapies aim at treating the symptoms rather than the subcellular mechanisms, underlying the etiology and pathological remodeling in heart failure. A universal characteristic, contributing to the decreased contractile performance in human and experimental failing hearts, is impaired calcium sequestration into the sarcoplasmic reticulum (SR). SR calcium uptake is mediated by a Ca(2+)-ATPase (SERCA2), whose activity is reversibly regulated by phospholamban (PLN). Dephosphorylated PLN is an inhibitor of SERCA and phosphorylation of PLN relieves this inhibition. However, the initial simple view of a PLN/SERCA regulatory complex has been modified by our recent identification of SUMO, S100 and the histidine-rich Ca-binding protein as regulators of SERCA activity. In addition, PLN activity is regulated by 2 phosphoproteins, the inhibitor-1 of protein phosphatase 1 and the small heat shock protein 20, which affect the overall SERCA-mediated Ca-transport. This review will highlight the regulatory mechanisms of cardiac contractility by the multimeric SERCA/PLN-ensemble and the potential for new therapeutic avenues targeting this complex by using small molecules and gene transfer methods.

  19. Effects of Silodosin and Tamsulosin on the Seminal Vesicle Contractile Response.

    Science.gov (United States)

    Hayashi, Tokumasa; Takeya, Mitsue; Nakamura, Kei-ichiro; Matsuoka, Kei

    2016-01-01

    To understand the mechanisms underlying ejaculation dysfunction caused by α1A-adrenocetor (AR) antagonists, the effects of α1A-AR antagonists on the contractile responses of the seminal vesicle were investigated. Isolated seminal vesicles from guinea pigs were cannulated and pressurized, and the changes in the intraluminal pressure were recorded. Periodic applications of electrical stimulation (ES) caused biphasic increase in the intraluminal pressure, that is, initial and subsequent contractions. The effects of silodosin and tamsulosin, α1A-AR antagonists, on the contractile responses were examined. The ES-induced biphasic contractions were blocked by tetrodotoxin (TTX). Silodosin and tamsulosin suppressed the initial contractions in a dose-dependent manner, while also exerting various inhibitory effects on the subsequent contractions. Increases in the intraluminal pressure facilitated spontaneous phasic contractions. The spontaneous contractions were not affected by TTX or α1A-AR antagonists, but were abolished by nifedipine. The initial contractions triggered by neuronal excitations were suppressed by silodosin and tamsulosin, suggesting that the ejaculation dysfunction may be attributed to the α1A-AR antagonist-mediated suppression of nerve-evoked contractions in the seminal vesicle. The subsequent contractions may be induced by mechanical stimulation associated with the initial, nerve-evoked contractions. Alternatively, other transmitters may be involved to various degrees in the neuromuscular transmission of the seminal vesicle. © 2014 Wiley Publishing Asia Pty Ltd.

  20. Dietary nitrate increases tetanic [Ca2+]i and contractile force in mouse fast-twitch muscle.

    Science.gov (United States)

    Hernández, Andrés; Schiffer, Tomas A; Ivarsson, Niklas; Cheng, Arthur J; Bruton, Joseph D; Lundberg, Jon O; Weitzberg, Eddie; Westerblad, Håkan

    2012-08-01

    Dietary inorganic nitrate has profound effects on health and physiological responses to exercise. Here, we examined if nitrate, in doses readily achievable via a normal diet, could improve Ca(2+) handling and contractile function using fast- and slow-twitch skeletal muscles from C57bl/6 male mice given 1 mm sodium nitrate in water for 7 days. Age matched controls were provided water without added nitrate. In fast-twitch muscle fibres dissected from nitrate treated mice, myoplasmic free [Ca(2+)] was significantly greater than in Control fibres at stimulation frequencies from 20 to 150 Hz, which resulted in a major increase in contractile force at ≤ 50 Hz. At 100 Hz stimulation, the rate of force development was ∼35% faster in the nitrate group. These changes in nitrate treated mice were accompanied by increased expression of the Ca(2+) handling proteins calsequestrin 1 and the dihydropyridine receptor. No changes in force or calsequestrin 1 and dihydropyridine receptor expression were measured in slow-twitch muscles. In conclusion, these results show a striking effect of nitrate supplementation on intracellular Ca(2+) handling in fast-twitch muscle resulting in increased force production. A new mechanism is revealed by which nitrate can exert effects on muscle function with applications to performance and a potential therapeutic role in conditions with muscle weakness.

  1. Dynamics of myosin II organization into cortical contractile networks and fibers

    Science.gov (United States)

    Nie, Wei; Wei, Ming-Tzo; Ou-Yang, Daniel; Jedlicka, Sabrina; Vavylonis, Dimitrios

    2014-03-01

    The morphology of adhered cells critically depends on the formation of a contractile meshwork of parallel and cross-linked stress fibers along the contacting surface. The motor activity and mini-filament assembly of non-muscle myosin II is an important component of cell-level cytoskeletal remodeling during mechanosensing. To monitor the dynamics of myosin II, we used confocal microscopy to image cultured HeLa cells that stably express myosin regulatory light chain tagged with GFP (MRLC-GFP). MRLC-GFP was monitored in time-lapse movies at steady state and during the response of cells to varying concentrations of blebbistatin which disrupts actomyosin stress fibers. Using image correlation spectroscopy analysis, we quantified the kinetics of disassembly and reassembly of actomyosin networks and compared them to studies by other groups. This analysis suggested that the following processes contribute to the assembly of cortical actomyosin into fibers: random myosin mini-filament assembly and disassembly along the cortex; myosin mini-filament aligning and contraction; stabilization of cortical myosin upon increasing contractile tension. We developed simple numerical simulations that include those processes. The results of simulations of cells at steady state and in response to blebbistatin capture some of the main features observed in the experiments. This study provides a framework to help interpret how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness.

  2. Evolutionarily conserved sites in yeast tropomyosin function in cell polarity, transport and contractile ring formation

    Directory of Open Access Journals (Sweden)

    Susanne Cranz-Mileva

    2015-08-01

    Full Text Available Tropomyosin is a coiled-coil protein that binds and regulates actin filaments. The tropomyosin gene in Schizosaccharomyces pombe, cdc8, is required for formation of actin cables, contractile rings, and polar localization of actin patches. The roles of conserved residues were investigated in gene replacement mutants. The work validates an evolution-based approach to identify tropomyosin functions in living cells and sites of potential interactions with other proteins. A cdc8 mutant with near-normal actin affinity affects patch polarization and vacuole fusion, possibly by affecting Myo52p, a class V myosin, function. The presence of labile residual cell attachments suggests a delay in completion of cell division and redistribution of cell patches following cytokinesis. Another mutant with a mild phenotype is synthetic negative with GFP-fimbrin, inferring involvement of the mutated tropomyosin sites in interaction between the two proteins. Proteins that assemble in the contractile ring region before actin do so in a mutant cdc8 strain that cannot assemble condensed actin rings, yet some cells can divide. Of general significance, LifeAct-GFP negatively affects the actin cytoskeleton, indicating caution in its use as a biomarker for actin filaments.

  3. Dynamics of myosin II organization into contractile networks and fibers at the medial cell cortex

    Science.gov (United States)

    Nie, Wei

    The cellular morphology of adhered cells depends crucially on the formation of a contractile meshwork of parallel and cross-linked stress fibers along the contacting surface. The motor activity and mini-filament assembly of non-muscle myosin II is an important component of cell-level cytoskeletal remodeling during mechanosensing. To monitor the dynamics of non-muscle myosin II, we used confocal microscopy to image cultured HeLa cells that stably express myosin regulatory light chain tagged with GFP (MRLC-GFP). MRLC-GFP was monitored in time-lapse movies at steady state and during the response of cells to varying concentrations of blebbistatin (which disrupts actomyosin stress fibers). Using image correlation spectroscopy analysis, we quantified the kinetics of disassembly and reassembly of actomyosin networks and compared to studies by other groups. This analysis suggested the following processes: myosin minifilament assembly and disassembly; aligning and contraction; myosin filament stabilization upon increasing contractile tension. Numerical simulations that include those processes capture some of the main features observed in the experiments. This study provides a framework to help interpret how different cortical myosin remodeling kinetics may contribute to different cell shape and rigidity depending on substrate stiffness. We discuss methods to monitor myosin reorganization using non-linear imaging methods.

  4. EFFECT OF HYDROGEN SULFIDE ON ATRIUM CONTRACTILITY IN CONTROL AND DIABETHIC MICE

    Directory of Open Access Journals (Sweden)

    A. S. Lifanova

    2014-01-01

    Full Text Available Hydrogen sulfide (H2S is endogenously synthesized gasotransmitter that has a regulatory effect in cardiovascular system. Diabetes mellitus leads to an increased risk of hypertension and cardiovascular diseases, so the purpose of the study was to analyze the contractility of the atria mice after application of L-cysteine and H2S. Contractile activity of the myocardium was investigated in the experiment on isolated mouse atria. Alloxan was used for modeling diabetes. Intraperitoneal injection of alloxan resulted in a significant increase of glucose concentration in blood, whereas the concentration of glucose didn’t change at the injection of physiological solution. In control, the addition of NaHS resulted in a significant dose-dependent decrease of the amplitude of contraction of the myocardium, whereas the negative inotropic effect of NaHS was significantly lower in terms of modeling diabetes compare to control conditions. In the control, L-cysteine reduced the amplitude contractions significantly, whereas L-cysteine did not lead to significant changes in the amplitude of contractions in terms of modeling diabetes. These data indicate that the sensitivity of mice’s atria reduced for H2S and L-cysteine in diabetes mellitus.

  5. The effectiveness of two novel techniques in establishing the mechanical and contractile responses of biceps femoris

    International Nuclear Information System (INIS)

    Ditroilo, Massimiliano; De Vito, Giuseppe; Hunter, Angus M; Haslam, Samuel

    2011-01-01

    Portable tensiomyography (TMG) and myotonometry (MMT) devices have been developed to measure mechanical and contractile properties of skeletal muscle. The aim of this study was to explore the sensitivity of the aforementioned techniques in detecting a change in passive mechanical properties of the biceps femoris (BF) muscle as a result of change in knee joint angle (i.e. muscle length). BF responses were assessed in 16 young participants (23.4 ± 4.9 years), at three knee joint angles (0°, 45° and 90°), for maximal isometric torque (MIT) along with myo-electrical activity. Contractile and mechanical properties were measured in a relaxed state. Inter-day reliability of the TMG and MMT was also assessed. MIT changed significantly (p < 0.01) across the three angles, so did stiffness and other parameters measured with MMT (p < 0.01). Conversely, TMG could detect changes only at two knee angles (0° and 45°, p < 0.01), when there is enough tension in the muscle. Reliability was overall insufficient for TMG whilst absolute reliability was excellent (coefficient of variation < 5%) for MMT. The ability of MMT more than TMG to detect an inherent change in stiffness can be conceivably exploited in a number of clinical/therapeutic applications that have to do with unnatural changes in passive muscle stiffness

  6. Scintigraphic measurement of the contractile activity of the gastric antrum using factor analysis

    International Nuclear Information System (INIS)

    Bergmann, H.; Hoebart, J.; Kugi, A.; Stacher, G.; Granser, G.V.

    1990-01-01

    The motor activity of the gastric antrum is difficult to record by manometric means and scintigraphic methods have proved unsatisfactory so far as no consistent relationship between antral contractile activity and gastric emptying rate could be detected. We investigated, using data recorded in 16 healthy human subjects after the ingestion of a semisolid standard meal, whether a newly developed method employing factor analysis would yield more meaningful and reproducible results. Factor analysis was applied to sequential scintigraphic images (3-s frame time) of gastric antrum. The computed factor images and the respective factor curves are representative of distinct dynamic structures of the antrum. From the more or less sinusoidal excursions of the factor curves, which exhibited the 3 cycles per minute frequency characteristic for the stomach, amplitude, frequency and propagation velocity of antral contractions can be calculated. The amplitudes of the factor curves were used to calculate a contraction index. This contraction index was found to be correlated significantly negatively with the gastric half-emptying time of the ingested meal. The employed factor analytical approach thus seems a promising tool to further investigate the role of antral contractility in the process of gastric emptying. (Authors)

  7. Izalpinin from fruits of Alpinia oxyphylla with antagonistic activity against the rat bladder contractility.

    Science.gov (United States)

    Yuan, Yuan; Tan, Yin-Feng; Xu, Peng; Li, Hailong; Li, Yong-Hui; Chen, Wen-Ya; Zhang, Jun-Qing; Chen, Feng; Huang, Guo-Jun

    2014-01-01

    Alpinia oxyphylla (Zingiberaceae), an herbaceous perennial plant, its capsular fruit is commonly used in traditional Chinese medicine for the treatment of different urinary incontinence symptoms including frequency, urgency and nocturia. These symptoms are similar to the overactive bladder syndrome. In our lab, we found that the 95% ethanol extract of the capsular fruits exhibited significant anti-muscarinic activity. Some constituents in capsular fruits including flavonoids (e.g., izalpinin and tectochrysin), diarylheptanoids (e.g., yakuchinone A and yakuchinone B) and sesquiterpenes (e.g., nootkatone), are regarded as representative chemicals with putative pharmacological activities. This study aimed to evaluate the in vitro antagonistic actions of izalpinin on carbachol-induced contraction of the rat detrusor muscle. In vitro inhibition of rat detrusor contractile response to carbachol was used to study the functional activity of izalpinin. The isolated detrusor strips of rats were mounted in organ baths containing oxygenated Krebs' solution. The cumulative consecutive concentration-response curves to carbachol-evoked contractions in strips of rat bladder were obtained. Carbachol induced concentration-dependent contractions of isolated rat bladder detrusor strips. The vehicle DMSO had no impact on the contraction response. The contraction effects were concentration-dependently antagonized by izalpinin, with a mean EC50 value of 0.35 µM. The corresponding cumulative agonist concentration-response curves shifted right-ward. Izalpinin exhibits inhibitory role of muscarinic receptor-related detrusor contractile activity, and it may be a promising lead compound to treat overactive bladder.

  8. PPARγ Ligands Regulate Noncontractile and Contractile Functions of Airway Smooth Muscle: Implications for Asthma Therapy

    Directory of Open Access Journals (Sweden)

    Chantal Donovan

    2012-01-01

    Full Text Available In asthma, the increase in airway smooth muscle (ASM can contribute to inflammation, airway wall remodeling and airway hyperresponsiveness (AHR. Targetting peroxisome proliferator-activated receptor γ (PPARγ, a receptor upregulated in ASM in asthmatic airways, may provide a novel approach to regulate these contributions. This review summarises experimental evidence that PPARγ ligands, such as rosiglitazone (RGZ and pioglitazone (PGZ, inhibit proliferation and inflammatory cytokine production from ASM in vitro. In addition, inhaled administration of these ligands reduces inflammatory cell infiltration and airway remodelling in mouse models of allergen-induced airways disease. PPARγ ligands can also regulate ASM contractility, with acute treatment eliciting relaxation of mouse trachea in vitro through a PPARγ-independent mechanism. Chronic treatment can protect against the loss of bronchodilator sensitivity to β2-adrenoceptor agonists and inhibit the development of AHR associated with exposure to nicotine in utero or following allergen challenge. Of particular interest, a small clinical trial has shown that oral RGZ treatment improves lung function in smokers with asthma, a group that is generally unresponsive to conventional steroid treatment. These combined findings support further investigation of the potential for PPARγ agonists to target the noncontractile and contractile functions of ASM to improve outcomes for patients with poorly controlled asthma.

  9. Long-term vascular contractility assay using genipin-modified muscular thin films

    International Nuclear Information System (INIS)

    Hald, Eric S; Steucke, Kerianne E; Reeves, Jack A; Win, Zaw; Alford, Patrick W

    2014-01-01

    Vascular disease is a leading cause of death globally and typically manifests chronically due to long-term maladaptive arterial growth and remodeling. To date, there is no in vitro technique for studying vascular function over relevant disease time courses that both mimics in vivo-like tissue structure and provides a simple readout of tissue stress. We aimed to extend tissue viability in our muscular thin film contractility assay by modifying the polydimethylsiloxane (PDMS) substrate with micropatterned genipin, allowing extracellular matrix turnover without cell loss. To achieve this, we developed a microfluidic delivery system to pattern genipin and extracellular matrix proteins on PDMS prior to cell seeding. Tissues constructed using this method showed improved viability and maintenance of in vivo-like lamellar structure. Functional contractility of tissues fabricated on genipin-modified substrates remained consistent throughout two weeks in culture. These results suggest that muscular thin films with genipin-modified PDMS substrates are a viable method for conducting functional studies of arterial growth and remodeling in vascular diseases. (paper)

  10. Increasing plasma fibrinogen, but unchanged levels of intraplatelet cyclic nucleotides, plasma endothelin-1, factor VII, and neopterin during cholesterol lowering with fluvastatin.

    Science.gov (United States)

    Gottsäter, A; Anwaar, I; Lind, P; Mattiasson, I; Lindgärde, F

    1999-04-01

    Lipid-lowering statin treatment reduces cardiovascular morbidity and mortality and improves endothelial function in patients with hypercholesterolemia. The aim of the present study was to evaluate plasma levels of fibrinogen, factor VII, and the macrophage-derived inflammatory mediator neopterin during lipid lowering. In addition, the endothelial production of platelet antiaggregatory and vasodilatory factors such as nitric oxide and prostacyclin, and vasoconstrictive factors such as endothelin-1, was assessed. Plasma fibrinogen, factor VII, endothelin-1, and the neopterin and intraplatelet nitric oxide and prostacyclin mediators cyclic 3'-5'guanosine monophosphate (cGMP) and cyclic 3'-5'adenosine monophosphate (cAMP) were measured before and 6 months after the institution of treatment with fluvastatin in 17 patients (eight men and nine women, median age 60 years) with vascular disease and previously untreated hypercholesterolemia. After 6 months, a decrease of 1.62 mmol/l [1.26-2.18 (19%); P factor VII [from 1.14 IE/ml (0.58-1.38) to 1.22 IE/ml (0.96-1.46); NS], or plasma neopterin [from 8.6 nmol/l (7.1-11.5) to 8.7 nmol/l (7.9-11.3); NS]. In conclusion, during cholesterol-lowering treatment with fluvastatin, plasma levels of fibrinogen increased whereas intraplatelet cyclic nucleotide levels and plasma endothelin-1, factor VII and neopterin levels were unchanged.

  11. A homozygous mutation in the endothelin-3 gene associated with a combined Waardenburg type 2 and Hirschsprung phenotype (Shah-Waardenburg syndrome).

    Science.gov (United States)

    Hofstra, R M; Osinga, J; Tan-Sindhunata, G; Wu, Y; Kamsteeg, E J; Stulp, R P; van Ravenswaaij-Arts, C; Majoor-Krakauer, D; Angrist, M; Chakravarti, A; Meijers, C; Buys, C H

    1996-04-01

    Hirschsprung disease (HSCR) or colonic aganglionosis is a congenital disorder characterized by an absence of intramural ganglia along variable lengths of the colon resulting in intestinal obstruction. The incidence of HSCR is 1 in 5,000 live births. Mutations in the RET gene, which codes for a receptor tyrosine kinase, and in EDNRB which codes for the endothelin-B receptor, have been shown to be associated with HSCR in humans. The lethal-spotted mouse which has pigment abnormalities, but also colonic aganglionosis, carries a mutation in the gene coding for endothelin 3 (Edn3), the ligand for the receptor protein encoded by EDNRB. Here, we describe a mutation of the human gene for endothelin 3 (EDN3), homozygously present in a patient with a combined Waardenburg syndrome type 2 (WS2) and HSCR phenotype (Shah-Waardenburg syndrome). The mutation, Cys159Phe, in exon 3 in the ET-3 like domain of EDN3, presumably affects the proteolytic processing of the preproendothelin to the mature peptide EDN3. The patient's parents were first cousins. A previous child in this family had been diagnosed with a similar combination of HSCR, depigmentation and deafness. Depigmentation and deafness were present in other relatives. Moreover, we present a further indication for the involvement of EDNRB in HSCR by reporting a novel mutation detected in one of 40 unselected HSCR patients.

  12. Influence of radiographic contrast media (Iodixanol and Iomeprol) on the endothelin-1 release from human arterial and venous endothelial cells cultured on an extracellular matrix.

    Science.gov (United States)

    Franke, R P; Fuhrmann, R; Hiebl, B; Jung, F

    2012-01-01

    Various radiographic contrast media (RCM) are available for visualization of blood vessels in interventional cardiology which can vary widely in their physicochemical properties thereby influencing different functions of blood cells. In the in vitro study described here the influence of two RCMs on arterial as well as on venous endothelial cells was compared to control cultures and examined under statical culture conditions, thus eliminating the influence of RCM viscosity almost completely. The supplementation of the culture medium with RCM (30% v/v) resulted in clearly different reactions of the endothelial cells exposed. Exposition to Iodixanol supplemented culture medium was followed by endothelin-1 release from venous endothelial cells which was equivalent to the endothelin-1 release from venous control cultures. Compared to control cultures, venous endothelial cells exposed to culture medium supplemented with Iomeprol displayed a completely different reaction, the increase in endothelin-1 secretion was missing completely after a 12 hours exposure. Following a 12 hours exposure to both RCMs there were no longer endothelial cells adherent, neither in venous nor in arterial endothelial cell cultures. The study showed that not the wall shear stress was responsible for the differing effects visible after 1.5 min, 5 min, and 12 hours exposure to culture media supplemented with RCM but differences in chemotoxicity of the RCM applied.

  13. La participación del público como valor añadido de servicio público para la televisión de proximidad. Estudio de caso de La noche de…, en ETB 2

    Directory of Open Access Journals (Sweden)

    A Azurmendi

    2015-09-01

    Full Text Available Introducción. Objeto: Frente a la crítica tradicional que señala a la televisión pública centrada en las audiencias como una televisión más cercana a los modelos comerciales que al servicio público, la literatura contemporánea sitúa, precisamente, en la participación de las audiencias una de las claves de la televisión pública en la era de la digitalización y la convergencia (Castro 2012; Doyle 2010; Kjus 2009; Bardoel 2007. El artículo se centra en el estudio de la participación en las televisiones públicas autonómicas, en particular en dos cuestiones: 1. Si la variedad de cauces de participación existentes en las producciones crossmedia –programa de televisión que cuenta con web propia, foros de expresión de opinión y cuentas sociales en Twitter y Facebook– aumentan la participación efectiva de las audiencias; y 2. Si esta participación puede encuadrarse en el cumplimiento de las obligaciones de servicio público de televisión, especialmente, de las de proximidad. Metodología: Se parte de un análisis descriptivo de la literatura sobre participación de las audiencias y de las formas de participación promovidas por las políticas europeas, estatales y autonómicas. A partir de los resultados obtenidos, se estudia el caso de “la noche de…” un programa de ETB 2. Resultados: Se comprueba que la atención creciente a la participación del público, tanto en la literatura europea y española como en la regulación existente, no tiene un reflejo proporcional en la realidad de la gestión de las televisiones públicas, en particular en las televisiones públicas autonómicas.

  14. Elevated levels of plasma Big endothelin-1 and its relation to hypertension and skin lesions in individuals exposed to arsenic

    International Nuclear Information System (INIS)

    Hossain, Ekhtear; Islam, Khairul; Yeasmin, Fouzia; Karim, Md. Rezaul; Rahman, Mashiur; Agarwal, Smita; Hossain, Shakhawoat; Aziz, Abdul; Al Mamun, Abdullah; Sheikh, Afzal; Haque, Abedul; Hossain, M. Tofazzal; Hossain, Mostaque; Haris, Parvez I.; Ikemura, Noriaki; Inoue, Kiyoshi; Miyataka, Hideki; Himeno, Seiichiro; Hossain, Khaled

    2012-01-01

    Chronic arsenic (As) exposure affects the endothelial system causing several diseases. Big endothelin-1 (Big ET-1), the biological precursor of endothelin-1 (ET-1) is a more accurate indicator of the degree of activation of the endothelial system. Effect of As exposure on the plasma Big ET-1 levels and its physiological implications have not yet been documented. We evaluated plasma Big ET-1 levels and their relation to hypertension and skin lesions in As exposed individuals in Bangladesh. A total of 304 study subjects from the As-endemic and non-endemic areas in Bangladesh were recruited for this study. As concentrations in water, hair and nails were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The plasma Big ET-1 levels were measured using a one-step sandwich enzyme immunoassay kit. Significant increase in Big ET-1 levels were observed with the increasing concentrations of As in drinking water, hair and nails. Further, before and after adjusting with different covariates, plasma Big ET-1 levels were found to be significantly associated with the water, hair and nail As concentrations of the study subjects. Big ET-1 levels were also higher in the higher exposure groups compared to the lowest (reference) group. Interestingly, we observed that Big ET-1 levels were significantly higher in the hypertensive and skin lesion groups compared to the normotensive and without skin lesion counterpart, respectively of the study subjects in As-endemic areas. Thus, this study demonstrated a novel dose–response relationship between As exposure and plasma Big ET-1 levels indicating the possible involvement of plasma Big ET-1 levels in As-induced hypertension and skin lesions. -- Highlights: ► Plasma Big ET-1 is an indicator of endothelial damage. ► Plasma Big ET-1 level increases dose-dependently in arsenic exposed individuals. ► Study subjects in arsenic-endemic areas with hypertension have elevated Big ET-1 levels. ► Study subjects with arsenic

  15. Elevated levels of plasma Big endothelin-1 and its relation to hypertension and skin lesions in individuals exposed to arsenic

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Ekhtear; Islam, Khairul; Yeasmin, Fouzia [Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205 (Bangladesh); Karim, Md. Rezaul [Department of Applied Nutrition and Food Technology, Islamic University, Kushtia-7003 (Bangladesh); Rahman, Mashiur; Agarwal, Smita; Hossain, Shakhawoat; Aziz, Abdul; Al Mamun, Abdullah; Sheikh, Afzal; Haque, Abedul; Hossain, M. Tofazzal [Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205 (Bangladesh); Hossain, Mostaque [Department of Medicine, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM), Dhaka (Bangladesh); Haris, Parvez I. [Faculty of Health and Life Sciences, De Montfort University, Leicester, LE1 9BH (United Kingdom); Ikemura, Noriaki; Inoue, Kiyoshi; Miyataka, Hideki; Himeno, Seiichiro [Laboratory of Molecular Nutrition and Toxicology, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima 770–8514 (Japan); Hossain, Khaled, E-mail: khossain69@yahoo.com [Department of Biochemistry and Molecular Biology, Rajshahi University, Rajshahi-6205 (Bangladesh)

    2012-03-01

    Chronic arsenic (As) exposure affects the endothelial system causing several diseases. Big endothelin-1 (Big ET-1), the biological precursor of endothelin-1 (ET-1) is a more accurate indicator of the degree of activation of the endothelial system. Effect of As exposure on the plasma Big ET-1 levels and its physiological implications have not yet been documented. We evaluated plasma Big ET-1 levels and their relation to hypertension and skin lesions in As exposed individuals in Bangladesh. A total of 304 study subjects from the As-endemic and non-endemic areas in Bangladesh were recruited for this study. As concentrations in water, hair and nails were measured by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). The plasma Big ET-1 levels were measured using a one-step sandwich enzyme immunoassay kit. Significant increase in Big ET-1 levels were observed with the increasing concentrations of As in drinking water, hair and nails. Further, before and after adjusting with different covariates, plasma Big ET-1 levels were found to be significantly associated with the water, hair and nail As concentrations of the study subjects. Big ET-1 levels were also higher in the higher exposure groups compared to the lowest (reference) group. Interestingly, we observed that Big ET-1 levels were significantly higher in the hypertensive and skin lesion groups compared to the normotensive and without skin lesion counterpart, respectively of the study subjects in As-endemic areas. Thus, this study demonstrated a novel dose–response relationship between As exposure and plasma Big ET-1 levels indicating the possible involvement of plasma Big ET-1 levels in As-induced hypertension and skin lesions. -- Highlights: ► Plasma Big ET-1 is an indicator of endothelial damage. ► Plasma Big ET-1 level increases dose-dependently in arsenic exposed individuals. ► Study subjects in arsenic-endemic areas with hypertension have elevated Big ET-1 levels. ► Study subjects with arsenic

  16. The Role of Phosphoramidon on the Biological Activity of Big Endothelin-1 in the Rat Mesenteric Microcirculation in Vivo

    International Nuclear Information System (INIS)

    Abdelhalim, Mohamed A K

    2008-01-01

    The goal of the present study was to clarify the role of metalloprotease inhibitor phosphoramidon on the effects induced by big endothelin-1 (big ET-1) in the rat mesenteric microcirculation in vivo, through investigating the systemic blood pressure, diameter and blood flow velocity of arterioles and venules of the rat mesentery. For this purpose, the rat mesentery was arranged for in situ intravital microscopic observation under transillumination and separate cumulative injections of big ET-1 and phosphoramidon were infused into the right jugular vein, respectively. In these experiments twenty-five rats (Charles River, 130 - 140 g) were used. The experiments were divided into two groups. In the first group of experiments, cumulative injections of big ET-1 (1000-8000 pmole/kg) were infused through a catheter inserted into the right jugular vein. Each dose of big ET-1 was infused 25 min prior to the infusion of the following dose. Infusion of big ET-1 (1000-8000 pmole/kg) elicited a long-lasting pressor effect. The infusion of low doses of big ET-1 (1000-2000 pmole/kg) elicited a significant (p < 0.05) dose-dependent increase in the microvascular blood flow velocity both in arterioles (20 - 30 ?m) and venules (30 - 50 ?m), and diameters of arterioles and venules exhibited a slight not significant vasodilator effect. The infusion of high doses of big ET-1 (4000-8000 pmole/kg) elicited significant dose-dependant decrease in the blood flow velocity of arterioles and venules, and diameters returned to the control runs. This may be attributed to the gradual conversion of big ET-1 to ET-1, and ET-1 is a potent vasoconstrictor. In the second group of experiments, cumulative injections of phosphoramidon (30 mg/kg /10 min) were administered 10 min prior to the infusion of big ET-1. These findings suggested that phosphoramidon significantly suppressed long-lasting pressor effect, dose-dependent increase, dose-dependent decrease and slow vasodilator effect produced by big ET-1

  17. Acute exposure to lead increases myocardial contractility independent of hypertension development

    Energy Technology Data Exchange (ETDEWEB)

    Fioresi, M. [Programa de Pós-Graduação em Ciências Fisiológicas, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Vitória, ES (Brazil); Departamento de Enfermagem, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Vitória, ES (Brazil); Furieri, L.B.; Simões, M.R.; Ribeiro, R.F. Junior; Meira, E.F.; Fernandes, A.A.; Stefanon, I. [Programa de Pós-Graduação em Ciências Fisiológicas, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Vitória, ES (Brazil); Vassallo, D.V. [Programa de Pós-Graduação em Ciências Fisiológicas, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Vitória, ES (Brazil); Centro de Ciências da Saúde de Vitória, Escola Superior de Ciências da Santa Casa de Misericórdia de Vitória, Vitória, ES (Brazil)

    2013-02-01

    We studied the effects of the acute administration of small doses of lead over time on hemodynamic parameters in anesthetized rats to determine if myocardial contractility changes are dependent or not on the development of hypertension. Male Wistar rats received 320 µg/kg lead acetate iv once, and their hemodynamic parameters were measured for 2 h. Cardiac contractility was evaluated in vitro using left ventricular papillary muscles as were Na{sup +},K{sup +}-ATPase and myosin Ca{sup 2+}-ATPase activities. Lead increased left- (control: 112 ± 3.7 vs lead: 129 ± 3.2 mmHg) and right-ventricular systolic pressures (control: 28 ± 1.2 vs lead: 34 ± 1.2 mmHg) significantly without modifying heart rate. Papillary muscles were exposed to 8 µM lead acetate and evaluated 60 min later. Isometric contractions increased (control: 0.546 ± 0.07 vs lead: 0.608 ± 0.06 g/mg) and time to peak tension decreased (control: 268 ± 13 vs lead: 227 ± 5.58 ms), but relaxation time was unchanged. Post-pause potentiation was similar between groups (n = 6 per group), suggesting no change in sarcoplasmic reticulum activity, evaluated indirectly by this protocol. After 1-h exposure to lead acetate, the papillary muscles became hyperactive in response to a β-adrenergic agonist (10 µM isoproterenol). In addition, post-rest contractions decreased, suggesting a reduction in sarcolemmal calcium influx. The heart samples treated with 8 µM lead acetate presented increased Na{sup +},K{sup +}-ATPase (approximately 140%, P < 0.05 for control vs lead) and myosin ATPase (approximately 30%, P < 0.05 for control vs lead) activity. Our results indicated that acute exposure to low lead concentrations produces direct positive inotropic and lusitropic effects on myocardial contractility and increases the right and left ventricular systolic pressure, thus potentially contributing to the early development of hypertension.

  18. Na+,K+-pump stimulation improves contractility in isolated muscles of mice with hyperkalemic periodic paralysis.

    Science.gov (United States)

    Clausen, Torben; Nielsen, Ole Bækgaard; Clausen, Johannes D; Pedersen, Thomas Holm; Hayward, Lawrence J

    2011-07-01

    In patients with hyperkalemic periodic paralysis (HyperKPP), attacks of muscle weakness or paralysis are triggered by K(+) ingestion or rest after exercise. Force can be restored by muscle work or treatment with β(2)-adrenoceptor agonists. A missense substitution corresponding to a mutation in the skeletal muscle voltage-gated Na(+) channel (Na(v)1.4, Met1592Val) causing human HyperKPP was targeted into the mouse SCN4A gene (mutants). In soleus muscles prepared from these mutant mice, twitch, tetanic force, and endurance were markedly reduced compared with soleus from wild type (WT), reflecting impaired excitability. In mutant soleus, contractility was considerably more sensitive than WT soleus to inhibition by elevated [K(+)](o). In resting mutant soleus, tetrodotoxin (TTX)-suppressible (22)Na uptake and [Na(+)](i) were increased by 470 and 58%, respectively, and membrane potential was depolarized (by 16 mV, P Na(+),K(+) pump-mediated (86)Rb uptake was 83% larger than in WT. Salbutamol stimulated (86)Rb uptake and reduced [Na(+)](i) both in mutant and WT soleus. Stimulating Na(+),K(+) pumps with salbutamol restored force in mutant soleus and extensor digitorum longus (EDL). Increasing [Na(+)](i) with monensin also restored force in soleus. In soleus, EDL, and tibialis anterior muscles of mutant mice, the content of Na(+),K(+) pumps was 28, 62, and 33% higher than in WT, respectively, possibly reflecting the stimulating effect of elevated [Na(+)](i) on the synthesis of Na(+),K(+) pumps. The results confirm that the functional disorders of skeletal muscles in HyperKPP are secondary to increased Na(+) influx and show that contractility can be restored by acute stimulation of the Na(+),K(+) pumps. Calcitonin gene-related peptide (CGRP) restored force in mutant soleus but caused no detectable increase in (86)Rb uptake. Repeated excitation and capsaicin also restored contractility, possibly because of the release of endogenous CGRP from nerve endings in the isolated

  19. Contractile function and motor unit firing rates of the human hamstrings.

    Science.gov (United States)

    Kirk, Eric A; Rice, Charles L

    2017-01-01

    Neuromuscular properties of the lower limb in health, aging, and disease are well described for major lower limb muscles comprising the quadriceps, triceps surae, and dorsiflexors, with the notable exception of the posterior thigh (hamstrings). The purpose of this study was to further characterize major muscles of the lower limb by comprehensively exploring contractile properties in relation to spinal motor neuron output expressed as motor unit firing rates (MUFRs) in the hamstrings of 11 (26.5 ± 3.8) young men. Maximal isometric voluntary contraction (MVC), voluntary activation, stimulated contractile properties including a force-frequency relationship, and MUFRs from submaximal to maximal voluntary contractile intensities were assessed in the hamstrings. Strength and MUFRs were assessed at two presumably different muscle lengths by varying the knee joint angles (90° and 160°). Knee flexion MVCs were 60-70% greater in the extended position (160°). The frequency required to elicit 50% of maximum tetanic torque was 16-17 Hz. Mean MUFRs at 25-50% MVC were 9-31% less in the biceps femoris compared with the semimembranosus-semitendinosus group. Knee joint angle (muscle length) influenced MUFRs such that mean MUFRs were greater in the shortened (90°) position at 50% and 100% MVC. Compared with previous reports, mean maximal MUFRs in the hamstrings are greater than those in the quadriceps and triceps surae and somewhat less than those in the tibialis anterior. Mean maximal MUFRs in the hamstrings are influenced by changes in knee joint angle, with lower firing rates in the biceps femoris compared with the semimembranosus-semitendinosus muscle group. We studied motor unit firing rates (MUFRs) at various voluntary contraction intensities in the hamstrings, one of the only major lower limb muscles to have MUFRs affected by muscle length changes. Within the hamstrings muscle-specific differences have greater impact on MUFRs than length changes, with the biceps femoris

  20. Muscle contractility decrement and correlated morphology during the pathogenesis of streptozotocin-diabetic mice.

    Science.gov (United States)

    Fahim, M A; el-Sabban, F; Davidson, N

    1998-06-01

    Peripheral neuropathy of both motor and sensory nerves has been well documented in diabetes mellitus, but the evidence for physiological and correlated morphological changes during the pathogenesis of myopathy is scarce. In the present report, we have chosen the dorsiflexor muscle of adult male mice as a model for studying in situ muscle contraction and neuromuscular ultrastructure during the pathogenesis of streptozotocin-induced diabetes. Thirty mice (30 g bodyweight) were injected once i.p. with streptozotocin solution (200 mg/Kg) to induce experimental diabetes mellitus. Comparative analyses of in situ muscle isometric contractile characteristics were studied (at 1 Hz, 5 Hz and 30 Hz nerve stimulation) in urethane-anesthetized (2 mg/g, i.p.) control and diabetic mice at three time points, 2 weeks, 4 weeks, and 8 weeks postinjection. Synaptic delay was also recorded in diabetic and age-matched control mice. There was a significant increase in synaptic delay in both 4-week and 8-week diabetic mice compared with control mice (8.9 +/- 1.2 msec and 7.6 +/- 0.6 msec, respectively, compared with 6.1 +/- 0.5 msec). At all three stimulation frequencies, diabetes did not affect muscle contractile speed but significantly reduced the twitch tension after 8 weeks, with no changes at 2 weeks or 4 weeks. The recorded single-twitch tension values were 2.6 +/- 0.3 g, 2.1 +/- 0.6 g, 2.2 +/- 0.7 g, and 1.2 +/- 0.1 g for control, 2 weeks, 4 weeks, and 8 weeks, respectively. At 30 Hz, the recorded tension values were 4.6 +/- 1.6 g, 3.1 +/- 1.2 g, 3.1 +/- 1.1 g, and 2.1 +/- 1.0 g for control, 2 weeks, 4 weeks, and 8 weeks, respectively. Ultrastructural changes in neuromuscular junctions were similar to those that have been described in disuse and aging. These changes were observed after 8 weeks and included serve loss of synaptic vesicles, electron-dense bodies, and myelin-like figures as well as degeneration of mitochondria. The results reveal that streptozotocin-induced diabetes

  1. Beta adrenergic overstimulation impaired vascular contractility via actin-cytoskeleton disorganization in rabbit cerebral artery.

    Directory of Open Access Journals (Sweden)

    Hyoung Kyu Kim

    Full Text Available BACKGROUND AND PURPOSE: Beta adrenergic overstimulation may increase the vascular damage and stroke. However, the underlying mechanisms of beta adrenergic overstimulation in cerebrovascular dysfunctions are not well known. We investigated the possible cerebrovascular dysfunction response to isoproterenol induced beta-adrenergic overstimulation (ISO in rabbit cerebral arteries (CAs. METHODS: ISO was induced in six weeks aged male New Zealand white rabbit (0.8-1.0 kg by 7-days isoproterenol injection (300 μg/kg/day. We investigated the alteration of protein expression in ISO treated CAs using 2DE proteomics and western blot analysis. Systemic properties of 2DE proteomics result were analyzed using bioinformatics software. ROS generation and following DNA damage were assessed to evaluate deteriorative effect of ISO on CAs. Intracellular Ca(2+ level change and vascular contractile response to vasoactive drug, angiotensin II (Ang II, were assessed to evaluate functional alteration of ISO treated CAs. Ang II-induced ROS generation was assessed to evaluated involvement of ROS generation in CA contractility. RESULTS: Proteomic analysis revealed remarkably decreased expression of cytoskeleton organizing proteins (e.g. actin related protein 1A and 2, α-actin, capping protein Z beta, and vimentin and anti-oxidative stress proteins (e.g. heat shock protein 9A and stress-induced-phosphoprotein 1 in ISO-CAs. As a cause of dysregulation of actin-cytoskeleton organization, we found decreased level of RhoA and ROCK1, which are major regulators of actin-cytoskeleton organization. As functional consequences of proteomic alteration, we found the decreased transient Ca(2+ efflux and constriction response to angiotensin II and high K(+ in ISO-CAs. ISO also increased basal ROS generation and induced oxidative damage in CA; however, it decreased the Ang II-induced ROS generation rate. These results indicate that ISO disrupted actin cytoskeleton proteome network

  2. The Effect of Cleft Palate Repair on Contractile Properties of Single Permeabilized Muscle Fibers From Congenitally Cleft Goats Palates

    Science.gov (United States)

    A cleft palate goat model was used to study the contractile properties of the levator veli palatini (LVP) muscle which is responsible for the movement of the soft palate. In 15-25% of patients that undergo palatoplasty, residual velopharyngeal insufficiency (VPI) remains a problem and often require...

  3. Reduced Contractility and Motility of Prostatic Cancer-Associated Fibroblasts after Inhibition of Heat Shock Protein 90

    Directory of Open Access Journals (Sweden)

    Alex Henke

    2016-08-01

    Full Text Available Background: Prostate cancer-associated fibroblasts (CAF can stimulate malignant progression and invasion of prostatic tumour cells via several mechanisms including those active in extracellular matrix; Methods: We isolated CAF from prostate cancer patients of Gleason Score 6–10 and confirmed their cancer-promoting activity using an in vivo tumour reconstitution assay comprised of CAF and BPH1 cells. We tested the effects of heat shock protein 90 (HSP90 inhibitors upon reconstituted tumour growth in vivo. Additionally, CAF contractility was measured in a 3D collagen contraction assay and migration was measured by scratch assay; Results: HSP90 inhibitors dipalmitoyl-radicicol and 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG reduced tumour size and proliferation in CAF/BPH1 reconstituted tumours in vivo. We observed that the most contractile CAF were derived from patients with lower Gleason Score and of younger age compared with the least contractile CAF. HSP90 inhibitors radicicol and 17-DMAG inhibited contractility and reduced the migration of CAF in scratch assays. Intracellular levels of HSP70 and HSP90 were upregulated upon treatment with HSP90 inhibitors. Inhibition of HSP90 also led to a specific increase in transforming growth factor beta 2 (TGFβ2 levels in CAF; Conclusions: We suggest that HSP90 inhibitors act not only upon tumour cells, but also on CAF in the tumour microenvironment.

  4. Investigating Cardiac MRI Based Right Ventricular Contractility As A Novel Non-Invasive Metric of Pulmonary Arterial Pressure

    Science.gov (United States)

    Menon, Prahlad G; Adhypak, Srilakshmi M; Williams, Ronald B; Doyle, Mark; Biederman, Robert WW

    2014-01-01

    BACKGROUND We test the hypothesis that cardiac magnetic resonance (CMR) imaging-based indices of four-dimensional (4D) (three dimensions (3D) + time) right ventricle (RV) function have predictive values in ascertaining invasive pulmonary arterial systolic pressure (PASP) measurements from right heart catheterization (RHC) in patients with pulmonary arterial hypertension (PAH). METHODS We studied five patients with idiopathic PAH and two age and sex-matched controls for RV function using a novel contractility index (CI) for amplitude and phase to peak contraction established from analysis of regional shape variation in the RV endocardium over 20 cardiac phases, segmented from CMR images in multiple orientations. RESULTS The amplitude of RV contractility correlated inversely with RV ejection fraction (RVEF; R2 = 0.64, P = 0.03) and PASP (R2 = 0.71, P = 0.02). Phase of peak RV contractility also correlated inversely to RVEF (R2 = 0.499, P = 0.12) and PASP (R2 = 0.66, P = 0.04). CONCLUSIONS RV contractility analyzed from CMR offers promising non-invasive metrics for classification of PAH, which are congruent with invasive pressure measurements. PMID:25624777

  5. 5-HT4 receptors mediating enhancement of contractility in canine stomach; an in vitro and in vivo study

    NARCIS (Netherlands)

    Prins, NH; van der Grijn, A; Lefebvre, RA; Akkermans, LMA; Schuurkes, JAJ

    1 We aimed to study 5-HT4 receptors in canine stomach contractility both in vivo and in vitro. 2 In anaesthetized Beagle dogs, the selective 5-HT4 receptor agonist prucalopride (i.v.) induced dose-dependent tonic stomach contractions under isobaric conditions, an effect that was antagonized by the

  6. Inhibition of MMP-2 Expression with siRNA Increases Baseline Cardiomyocyte Contractility and Protects against Simulated Ischemic Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Han-Bin Lin

    2014-01-01

    Full Text Available Matrix metalloproteinases (MMPs significantly contribute to ischemia reperfusion (I/R injury, namely, by the degradation of contractile proteins. However, due to the experimental models adopted and lack of isoform specificity of MMP inhibitors, the cellular source and identity of the MMP(s involved in I/R injury remain to be elucidated. Using isolated adult rat cardiomyocytes, subjected to chemically induced I/R-like injury, we show that specific inhibition of MMP-2 expression and activity using MMP-2 siRNA significantly protected cardiomyocyte contractility from I/R-like injury. This was also associated with increased expression of myosin light chains 1 and 2 (MLC1/2 in comparison to scramble siRNA transfection. Moreover, the positive effect of MMP-2 siRNA transfection on cardiomyocyte contractility and MLC1/2 expression levels was also observed under control conditions, suggesting an important additional role for MMP-2 in physiological sarcomeric protein turnover. This study clearly demonstrates that intracellular expression of MMP-2 plays a significant role in sarcomeric protein turnover, such as MLC1 and MLC2, under aerobic (physiological conditions. In addition, this study identifies intracellular/autocrine, cardiomyocyte-produced MMP-2, rather than paracrine/extracellular, as responsible for the degradation of MLC1/2 and consequent contractile dysfunction in cardiomyocytes subjected to I/R injury.

  7. Effect of Propafenone on the Contractile Activity of Latissimus Dorsi Muscle Isolated in an Organ Chamber: Experimental Study in Rats

    Directory of Open Access Journals (Sweden)

    Ricardo Simões

    2002-03-01

    Full Text Available OBJECTIVE: To study the effect of propafenone on the contractile function of latissimus dorsi muscle isolated from rats in an organ chamber. METHODS: We studied 20 latissimus dorsi muscles of Wistar rats and divided them into 2 groups: group I (n=10, or control group - we studied the feasibility of muscle contractility; group II (n=10, in which the contralateral muscles were grouped - we analyzed the effect of propafenone on muscle contractility. After building a muscle ring, 8 periods of sequential 2-minute baths were performed, with intervals of preprogrammed electrical stimulation using a pacemaker of 50 stimuli/min. In group II, propafenone, at the concentration of 9.8 µg/mL, was added to the bath in period 2 and withdrawn in period 4. RESULTS: In group I, no significant depression in muscle contraction occurred up to period 5 (p>0.05. In group II, a significant depression occurred in all periods, except between the last 2 periods (p0.05. CONCLUSION: Propafenone had a depressing effect on the contractile function of latissimus dorsi muscle isolated from rats and studied in an organ chamber.

  8. Effect of acute and chronic simvastatin treatment on post-ischemic contractile dysfunction in isolated rat heart

    Czech Academy of Sciences Publication Activity Database

    Szárszoi, Ondrej; Malý, J.; Ošťádal, P.; Netuka, I.; Bešík, J.; Kolář, František; Ošťádal, Bohuslav

    2008-01-01

    Roč. 57, č. 5 (2008), s. 793-796 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : simvastatin * contractile dysfunction * protection Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 1.653, year: 2008

  9. [A basis for application of cardiac contractility variability in the Evaluation and assessment of exercise and fitness].

    Science.gov (United States)

    Bu, Bin; Wang, Aihua; Han, Haijun; Xiao, Shouzhong

    2010-06-01

    Cardiac contractility variability (CCV) is a new concept which is introduced in the research field of cardiac contractility in recent years, that is to say, there are some disparities between cardiac contractilities when heart contracts. The changing signals of cardiac contractility contain a plenty of information on the cardiovascular function and disorder. In order to collect and analyze the message, we could quantitatively evaluate the tonicity and equilibrium of cardiac sympathetic nerve and parasympathetic nerve, and the effects of bio-molecular mechanism on the cardiovascular activities. By analyzing CCV, we could further understand the background of human being's heritage characteristics, nerve types, the adjusting mechanism, the molecular biology, and the adjustment of cardiac automatic nerve. With the development of the computing techniques, the digital signal processing method and its application in medical field, this analysis has been progressing greatly. By now, the assessment of CCV, just like the analysis of heart rate variability, is mainly via time domain and frequency domain analysis. CCV is one of the latest research fields in human cardiac signals being scarcely reported in the field of sports medicine; however, its research progresses are of important value for cardiac physiology and pathology in sports medicine and rehabilitation medicine.

  10. Effects of testosterone on contractile properties of sexually dimorphic forelimb muscles in male bullfrogs (Rana catesbeiana, Shaw 1802

    Directory of Open Access Journals (Sweden)

    Aaron R. Kampe

    2013-07-01

    This study examined the effects of testosterone (T on the contractile properties of two sexually dimorphic forelimb muscles and one non-dimorphic muscle in male bullfrogs (Rana catesbeiana, Shaw 1802. The dimorphic muscles in castrated males with testosterone replacement (T+ achieved higher forces and lower fatigability than did castrated males without replaced testosterone (T0 males, but the magnitude of the differences was low and many of the pair-wise comparisons of each muscle property were not statistically significant. However, when taken as a whole, the means of seven contractile properties varied in the directions expected of masculine values in T+ animals in the sexually dimorphic muscles. Moreover, these data, compared with previous data on male and female bullfrogs, show that values for T+ males are similar to normal males and are significantly different from females. The T0 males tended to be intermediate in character between T+ males and females, generally retaining masculine values. This suggests that the exposure of young males to T in their first breeding season produces a masculinizing effect on the sexually dimorphic muscles that is not reversed between breeding seasons when T levels are low. The relatively minor differences in contractile properties between T+ and T0 males may indicate that as circulating T levels rise during breeding season in normal males, contractile properties can be enhanced rapidly to maximal functional levels for breeding success.

  11. Microtubule depolymerization normalizes in vivo myocardial contractile function in dogs with pressure-overload left ventricular hypertrophy

    Science.gov (United States)

    Koide, M.; Hamawaki, M.; Narishige, T.; Sato, H.; Nemoto, S.; DeFreyte, G.; Zile, M. R.; Cooper G, I. V.; Carabello, B. A.

    2000-01-01

    BACKGROUND: Because initially compensatory myocardial hypertrophy in response to pressure overloading may eventually decompensate to myocardial failure, mechanisms responsible for this transition have long been sought. One such mechanism established in vitro is densification of the cellular microtubule network, which imposes a viscous load that inhibits cardiocyte contraction. METHODS AND RESULTS: In the present study, we extended this in vitro finding to the in vivo level and tested the hypothesis that this cytoskeletal abnormality is important in the in vivo contractile dysfunction that occurs in experimental aortic stenosis in the adult dog. In 8 dogs in which gradual stenosis of the ascending aorta had caused severe left ventricular (LV) pressure overloading (gradient, 152+/-16 mm Hg) with contractile dysfunction, LV function was measured at baseline and 1 hour after the intravenous administration of colchicine. Cardiocytes obtained by biopsy before and after in vivo colchicine administration were examined in tandem. Microtubule depolymerization restored LV contractile function both in vivo and in vitro. CONCLUSIONS: These and additional corroborative data show that increased cardiocyte microtubule network density is an important mechanism for the ventricular contractile dysfunction that develops in large mammals with adult-onset pressure-overload-induced cardiac hypertrophy.

  12. Effect of a Periodized Power Training Program on the Functional Performances and Contractile Properties of the Quadriceps in Sprinters

    Science.gov (United States)

    Kamandulis, Sigitas; Skurvydas, Albertas; Brazaitis, Marius; Stanislovaitis, Aleksas; Duchateau, Jacques; Stanislovaitiene, Jurate

    2012-01-01

    Our purpose was to compare the effect of a periodized preparation consisting of power endurance training and high-intensity power training on the contractile properties of the quadriceps muscle and functional performances in well trained male sprinters (n = 7). After 4 weeks of high-intensity power training, 60-m sprint running time improved by an…

  13. Alterations in serotonin receptor-induced contractility of bovine lateral saphenous vein in cattle grazing endophyte-infected tall fescue

    Science.gov (United States)

    As part of a large 2-year study documenting the physiologic impact of grazing endophyte-infected tall fescue on growing cattle, 2 experiments were conducted to characterize and evaluate the effects of grazing 2 levels of toxic endophyte-infected tall fescue pastures on vascular contractility and ser...

  14. Bidirectional Interplay between Vimentin Intermediate Filaments and Contractile Actin Stress Fibers

    Directory of Open Access Journals (Sweden)

    Yaming Jiu

    2015-06-01

    Full Text Available The actin cytoskeleton and cytoplasmic intermediate filaments contribute to cell migration and morphogenesis, but the interplay between these two central cytoskeletal elements has remained elusive. Here, we find that specific actin stress fiber structures, transverse arcs, interact with vimentin intermediate filaments and promote their retrograde flow. Consequently, myosin-II-containing arcs are important for perinuclear localization of the vimentin network in cells. The vimentin network reciprocally restricts retrograde movement of arcs and hence controls the width of flat lamellum at the leading edge of the cell. Depletion of plectin recapitulates the vimentin organization phenotype of arc-deficient cells without affecting the integrity of vimentin filaments or stress fibers, demonstrating that this cytoskeletal cross-linker is required for productive interactions between vimentin and arcs. Collectively, our results reveal that plectin-mediated interplay between contractile actomyosin arcs and vimentin intermediate filaments controls the localization and dynamics of these two cytoskeletal systems and is consequently important for cell morphogenesis.

  15. Transcellular tunnel dynamics: Control of cellular dewetting by actomyosin contractility and I-BAR proteins.

    Science.gov (United States)

    Lemichez, Emmanuel; Gonzalez-Rodriguez, David; Bassereau, Patricia; Brochard-Wyart, Françoise

    2013-03-01

    Dewetting is the spontaneous withdrawal of a liquid film from a non-wettable surface by nucleation and growth of dry patches. Two recent reports now propose that the principles of dewetting explain the physical phenomena underpinning the opening of transendothelial cell macroaperture (TEM) tunnels, referred to as cellular dewetting. This was discovered by studying a group of bacterial toxins endowed with the property of corrupting actomyosin cytoskeleton contractility. For both liquid and cellular dewetting, the growth of holes is governed by a competition between surface forces and line tension. We also discuss how the dynamics of TEM opening and closure represent remarkable systems to investigate actin cytoskeleton regulation by sensors of plasma membrane curvature and investigate the impact on membrane tension and the role of TEM in vascular dysfunctions. Copyright © 2013 Soçiété Française des Microscopies and Soçiété de Biologie Cellulaire de France.

  16. Nonequilibrium phase transitions, fluctuations and correlations in an active contractile polar fluid.

    Science.gov (United States)

    Gowrishankar, Kripa; Rao, Madan

    2016-02-21

    We study the patterning, fluctuations and correlations of an active polar fluid consisting of contractile polar filaments on a two-dimensional substrate, using a hydrodynamic description. The steady states generically consist of arrays of inward pointing asters and show a continuous transition from a moving lamellar phase, a moving aster street, to a stationary aster lattice with no net polar order. We next study the effect of spatio-temporal athermal noise, parametrized by an active temperature TA, on the stability of the ordered phases. In contrast to its equilibrium counterpart, we find that the active crystal shows true long range order at low TA. On increasing TA, the asters dynamically remodel, concomitantly we find novel phase transitions characterized by bond-orientational and polar order upon "heating".

  17. Image Processing Techniques for Assessing Contractility in Isolated Adult Cardiac Myocytes

    Directory of Open Access Journals (Sweden)

    Carlos Bazan

    2009-01-01

    The physiologic application of the methodology is evaluated by assessing overall contraction in enzymatically dissociated adult rat cardiocytes. Our results demonstrate the effectiveness of the proposed approach in characterizing the true, two-dimensional, “shortening” in the contraction process of adult cardiocytes. We compare the performance of the proposed method to that of a popular edge detection system in the literature. The proposed method not only provides a more comprehensive assessment of the myocyte contraction process but also can potentially eliminate historical concerns and sources of errors caused by myocyte rotation or translation during contraction. Furthermore, the versatility of the image processing techniques makes the method suitable for determining myocyte shortening in cells that usually bend or move during contraction. The proposed method can be utilized to evaluate changes in contractile behavior resulting from drug intervention, disease modeling, transgeneity, or other common applications to mammalian cardiocytes.

  18. A new strain gage method for measuring the contractile strain ratio of Zircaloy tubing

    International Nuclear Information System (INIS)

    Hwang, S.K.; Sabol, G.P.

    1988-01-01

    An improved strain gage method for determining the contractile strain ratio (CSR) of Zircaloy tubing was developed. The new method consists of a number of load-unload cyclings at approximately 0.2% plastic strain interval. With this method the CSR of Zircaloy-4 tubing could be determined accurately because it was possible to separate the plastic strains from the elastic strain involvement. The CSR values determined by use of the new method were in good agreement with those calculated from conventional post-test manual measurements. The CSR of the tubing was found to decrease with the amount of deformation during testing because of uneven plastic flow in the gage section. A new technique of inscribing gage marks by use of a YAG laser is discussed. (orig.)

  19. Leucine elicits myotube hypertrophy and enhances maximal contractile force in tissue engineered skeletal muscle in vitro.

    Science.gov (United States)

    Martin, Neil R W; Turner, Mark C; Farrington, Robert; Player, Darren J; Lewis, Mark P

    2017-10-01

    The amino acid leucine is thought to be important for skeletal muscle growth by virtue of its ability to acutely activate mTORC1 and enhance muscle protein synthesis, yet little data exist regarding its impact on skeletal muscle size and its ability to produce force. We utilized a tissue engineering approach in order to test whether supplementing culture medium with leucine could enhance mTORC1 signaling, myotube growth, and muscle function. Phosphorylation of the mTORC1 target proteins 4EBP-1 and rpS6 and myotube hypertrophy appeared to occur in a dose dependent manner, with 5 and 20 mM of leucine inducing similar effects, which were greater than those seen with 1 mM. Maximal contractile force was also elevated with leucine supplementation; however, although this did not appear to be enhanced with increasing leucine doses, this effect was completely ablated by co-incubation with the mTOR inhibitor rapamycin, showing that the augmented force production in the presence of leucine was mTOR sensitive. Finally, by using electrical stimulation to induce chronic (24 hr) contraction of engineered skeletal muscle constructs, we were able to show that the effects of leucine and muscle contraction are additive, since the two stimuli had cumulative effects on maximal contractile force production. These results extend our current knowledge of the efficacy of leucine as an anabolic nutritional aid showing for the first time that leucine supplementation may augment skeletal muscle functional capacity, and furthermore validates the use of engineered skeletal muscle for highly-controlled investigations into nutritional regulation of muscle physiology. © 2017 The Authors. Journal of Cellular Physiology Published by wiley periodicals, Inc.