Pre- and postjunctional effects of some prostanoids in human isolated vas deferens

The effects of prostaglandin (PG) E1, PGE2, the thromboxane A2 analogue U-44069, and the prostacyclin derivative iloprost were studied on isometric contractions induced by norepinephrine (NE) and by electrical field stimulation of nerves in isolated preparations of the human vas deferens. The effects of these agents on the electrically induced release of 3H from preparations preincubated with [3H]NE were also investigated. PGE1 and PGE2 inhibited the electrically induced contractions concentration dependently. U-44069 augmented the contractions without affecting baseline tension, and in preparations where the contractions had been inhibited by PGE1 or PGE2, U-44069 restored the contractions almost to starting levels. The thromboxane A2-receptor antagonist BM 13505, having no effect or inhibitory effects on electrically induced contractions, abolished the stimulatory effect of U-44069. Contractions induced by exogenous NE were augmented by U-44069, whereas PGE1 and BM 13505 were without effects. The electrically induced release of 3H was inhibited by PGE1 and PGE2 in a concentration-dependent manner, whereas U-44069 and BM 13505 increased the release of 3H. Furthermore, the inhibitory effect of PGE1 on 3H release was partly counteracted by U-44069. Iloprost had no significant effect on electrically induced contractions or on 3H release. These results suggest that, in the human vas deferens, thromboxane A2 augments contractions predominantly through a postjunctional site of action, whereas PGs of the E type have a prejunctional inhibitory effect. In addition, the pre- and post-junctional effect profiles of U-44069 and BM 13505 suggest that there may be more than one thromboxane receptor.

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Comparative Effects of Bupivacaine and Ropivacaine on Intracellular Calcium Transients and Tension in Ferret Ventricular Muscle

Anesthesiology ◽

10.1097/00000542-200410000-00013 ◽

2004 ◽

Vol 101 (4) ◽

pp. 888-894 ◽

Cited By ~ 16

Author(s):

Yasushi Mio ◽

Norio Fukuda ◽

Yoichiro Kusakari ◽

Yoshikiyo Amaki ◽

Yasumasa Tanifuji ◽

...

Keyword(s):

Inhibitory Effect ◽

Bay K 8644 ◽

Clinical Settings ◽

Ca Channel ◽

Dependent Manner ◽

Inhibitory Effects ◽

Concentration Dependent Manner ◽

Intracellular Ca ◽

Slope Difference ◽

The Relationship

Background Recent evidence suggests that ropivacaine exerts markedly less cardiotoxicity compared with bupivacaine; however, the mechanisms are not fully understood at the molecular level. Methods Isolated ferret ventricular papillary muscles were microinjected with the Ca-binding photoprotein aequorin, and intracellular Ca transients and tension were simultaneously measured during twitch in the absence and presence of bupivacaine or ropivacaine. Results Bupivacaine and ropivacaine (10, 30, and 100 microm) reduced peak systolic [Ca]i and tension in a concentration-dependent manner. The effects were significantly greater for bupivacaine, particularly on tension (approximately twofold). The percentage reduction of tension was linearly correlated with that of [Ca]i for both anesthetics, with the slope of the relationship being approximately equal to 1.0 for ropivacaine and approximately equal to 1.3 for bupivacaine (slope difference, P < 0.05), suggesting that the cardiodepressant effect of ropivacaine results predominantly from inhibition of Ca transients, whereas bupivacaine suppresses Ca transients and the reaction beyond Ca transients, i.e., myofibrillar activation, as well. BAY K 8644, a Ca channel opener, abolished the inhibitory effects of ropivacaine on Ca transients and tension, whereas BAY K 8644 only partially inhibited the effects of bupivacaine, particularly the effects on tension. Conclusion The cardiodepressant effect of bupivacaine is approximately twofold greater than that of ropivacaine. Bupivacaine suppresses Ca transients more markedly than does ropivacaine and reduces myofibrillar activation, which may at least in part underlie the greater inhibitory effect of bupivacaine on cardiac contractions. These results suggest that ropivacaine has a more favorable profile as a local anesthetic in the clinical settings.

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Inhibitory effect of Sphagnum palustre extract and its bioactive compounds on aromatase activity

Bangladesh Journal of Pharmacology ◽

10.3329/bjp.v11i3.26776 ◽

2016 ◽

Vol 11 (3) ◽

pp. 661

Author(s):

Hee Jeong Eom ◽

Yong Joo Park ◽

Hee Rae Kang ◽

Ha Ryong Kim ◽

In Jae Bang ◽

...

Keyword(s):

Video Clip ◽

Inhibitory Effect ◽

The Other ◽

Aromatase Activity ◽

Dependent Manner ◽

Inhibitory Effects ◽

Aromatase Inhibition ◽

Concentration Dependent Manner ◽

Cardiac Pain ◽

Sphagnum Palustre

Sphagnum palustre (a moss) has been traditionally used in Korea for the cure of several diseases such as cardiac pain and stroke. In this research, the inhibitory effect of S. palustre on aromatase (cytochrome P450 19, CYP19) activity was studied. [1β-3H] androstenedione was used as a substrate and incubated with S. palustre extract and recombinant human CYP19 in the presence of NADPH. S. palustre extract inhibited aromatase in a concentration-dependent manner (IC50 value: 36.4 ± 8.1 µg/mL). To elucidate the major compounds responsible for the aromatase inhibitory effects of S. palustre extract, nine compounds were isolated from the extract and tested for their inhibition of aromatase activity. Compounds 1, 6, and 7 displayed aromatase inhibition, while the inhibition by the other compounds was negligible.Video Clip<a href="https://youtube.com/v/n6xeo3RXJVY">Aromatase enzyme activity:</a> 4 min 16 sec

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Sa12b Peptide from Solitary Wasp Inhibits ASIC Currents in Rat Dorsal Root Ganglion Neurons

Toxins ◽

10.3390/toxins11100585 ◽

2019 ◽

Vol 11 (10) ◽

pp. 585 ◽

Cited By ~ 2

Author(s):

Hernández ◽

Konno ◽

Salceda ◽

Vega ◽

Zaharenko ◽

...

Keyword(s):

Dorsal Root Ganglion ◽

Dorsal Root ◽

Inhibitory Effect ◽

Dorsal Root Ganglion Neurons ◽

Dependent Manner ◽

Inhibitory Effects ◽

Drg Neurons ◽

Concentration Dependent Manner ◽

Acid Sensing Ion Channels ◽

Ganglion Neurons

In this work, we evaluate the effect of two peptides Sa12b (EDVDHVFLRF) and Sh5b (DVDHVFLRF-NH2) on Acid-Sensing Ion Channels (ASIC). These peptides were purified from the venom of solitary wasps Sphex argentatus argentatus and Isodontia harmandi, respectively. Voltage clamp recordings of ASIC currents were performed in whole cell configuration in primary culture of dorsal root ganglion (DRG) neurons from (P7-P10) CII Long-Evans rats. The peptides were applied by preincubation for 25 s (20 s in pH 7.4 solution and 5 s in pH 6.1 solution) or by co-application (5 s in pH 6.1 solution). Sa12b inhibits ASIC current with an IC50 of 81 nM, in a concentration-dependent manner when preincubation application was used. While Sh5b did not show consistent results having both excitatory and inhibitory effects on the maximum ASIC currents, its complex effect suggests that it presents a selective action on some ASIC subunits. Despite the similarity in their sequences, the action of these peptides differs significantly. Sa12b is the first discovered wasp peptide with a significant ASIC inhibitory effect.

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Concentration-dependent duality of bFGF in regulation of barrier properties of human brain endothelial cells

10.1101/2021.01.07.425677 ◽

2021 ◽

Author(s):

Karolina Kriauciunaite ◽

Agne Pociute ◽

Aida Kausyle ◽

Justina Pajarskiene ◽

Alexei Verkhratsky ◽

...

Keyword(s):

Endothelial Cells ◽

Human Brain ◽

Barrier Function ◽

Nuclear Translocation ◽

Barrier Properties ◽

Inhibitory Effect ◽

Dependent Manner ◽

Inhibitory Effects ◽

Concentration Dependent Manner ◽

Paracrine Factors

Multiple paracrine factors regulate barrier properties of human brain capillary endothelial cells (BCECs). Understanding precise mode of action of these factors remains a challenging task because of the limited availability of functionally competent BCECs and use of serum-containing medium. In the present study we employed defined protocol for producing BCECs from human inducible pluripotent stem cells. We found that autocrine secretion of basic fibroblast growth factor (bFGF) is necessary for the establishment a tight BCECs barrier, as revealed by measurements of trans-endothelial electric resistance (TEER). In contrast, exogenous bFGF in concentrations exceeding 4 ng/ml inhibited TEER and proliferation of BCECs in a concentration-dependent manner. Exogenous bFGF did not significantly affect expression and distribution of tight junction proteins claudin-5, occludin and ZO-1. Treatment with FGF receptor blocker PD173074 (15 uM) suppressed inhibitory effects of bFGF and induced nuclear translocation of protein ZO-1. Inhibition of phosphoinositide 3-Kinase (PI-3K) with LY294002 (25 uM) significantly potentiated inhibitory effect of bFGF on TEER indicating that PI-3K signalling pathway partially suppress inhibitory effects of bFGF on TEER. In conclusion we show that autocrine bFGF secretion is necessary for the proper barrier function of BCECs, whereas exogenous bFGF suppresses barrier resistance in a concentration-dependent manner. Our findings demonstrate a dual role for bFGF in the regulation of BCEC barrier function.

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Neutrophil Elastase Potentiates Cathepsin G-lnduced Platelet Activation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1646319 ◽

1992 ◽

Vol 68 (05) ◽

pp. 570-576 ◽

Cited By ~ 20

Author(s):

Mary A Selak

Keyword(s):

Neutrophil Elastase ◽

Cell Activation ◽

Thromboxane A2 ◽

Creatine Phosphate ◽

Dense Granule ◽

Cathepsin G ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Low Concentrations ◽

High Concentrations

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.

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Brassinolide Enhances the Level of Brassinosteroids, Protein, Pigments, and Monosaccharides in Wolffia arrhiza Treated with Brassinazole

Plants ◽

10.3390/plants10071311 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1311

Author(s):

Magdalena Chmur ◽

Andrzej Bajguz

Keyword(s):

Plant Growth ◽

Growth And Development ◽

Inhibitory Effect ◽

Dependent Manner ◽

Plant Growth And Development ◽

Concentration Dependent Manner ◽

Spectrophotometric Methods ◽

Synthetic Inhibitor ◽

Wolffia Arrhiza ◽

First Time

Brassinolide (BL) represents brassinosteroids (BRs)—a group of phytohormones that are essential for plant growth and development. Brassinazole (Brz) is as a synthetic inhibitor of BRs’ biosynthesis. In the present study, the responses of Wolffia arrhiza to the treatment with BL, Brz, and the combination of BL with Brz were analyzed. The analysis of BRs and Brz was performed using LC-MS/MS. The photosynthetic pigments (chlorophylls, carotenes, and xanthophylls) levels were determined using HPLC, but protein and monosaccharides level using spectrophotometric methods. The obtained results indicated that BL and Brz influence W. arrhiza cultures in a concentration-dependent manner. The most stimulatory effects on the growth, level of BRs (BL, 24-epibrassinolide, 28-homobrassinolide, 28-norbrassinolide, catasterone, castasterone, 24-epicastasterone, typhasterol, and 6-deoxytyphasterol), and the content of pigments, protein, and monosaccharides, were observed in plants treated with 0.1 µM BL. Whereas the application of 1 µM and 10 µM Brz caused a significant decrease in duckweed weight and level of targeted compounds. Application of BL caused the mitigation of the Brz inhibitory effect and enhanced the BR level in duckweed treated with Brz. The level of BRs was reported for the first time in duckweed treated with BL and/or Brz.

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Adenosine A1 receptor-mediated inhibition of vasopressin action in inner medullary collecting duct

AJP Renal Physiology ◽

10.1152/ajprenal.1994.266.5.f791 ◽

1994 ◽

Vol 266 (5) ◽

pp. F791-F796 ◽

Cited By ~ 11

Author(s):

R. M. Edwards ◽

W. S. Spielman

Keyword(s):

Receptor Agonist ◽

Collecting Duct ◽

Basolateral Membrane ◽

Inhibitory Effect ◽

Dependent Manner ◽

Camp Accumulation ◽

Concentration Dependent Manner ◽

Cgs 21680 ◽

Camp Generation ◽

A1 Receptor

We examined the effects of adenosine and adenosine analogues on arginine vasopressin (AVP)-induced increases in osmotic water permeability (Pf; micron/s) and adenosine 3',5'-cyclic monophosphate (cAMP) accumulation in rat inner medullary collecting ducts (IMCDs). When added to the bath, the A1 receptor agonist N6-cyclohexyladenosine (CHA) produced a rapid and reversible inhibition of AVP-stimulated (10 pM) Pf (1,781 +/- 195 to 314 +/- 85 microns/s at 0.3 microM CHA; n = 9). The inhibitory effect of CHA was concentration dependent, with a 50% inhibitory concentration of 10 nM. The effect of CHA was inhibited by prior exposure of IMCDs to the A1 receptor antagonist 1,3-dipropylxanthine-8-cyclopentylxanthine (DP-CPX; 1 microM) or by preincubation with pertussis toxin. CHA had no effect on cAMP-induced increases in Pf. In addition to CHA, adenosine and the nonselective agonist 5'-(N-ethylcarboxamido)-adenosine (NECA) inhibited AVP-dependent Pf by > or = 70%, whereas the A2 receptor agonist CGS-21680 had no effect. Luminal adenosine (0.1 mM) had no effect on basal or AVP-stimulated Pf. CHA, NECA, and adenosine but not CGS-21680 inhibited AVP-stimulated cAMP accumulation in a concentration-dependent manner (50% inhibitory concentrations 0.1–300 nM). The inhibitory effect of CHA on AVP-stimulated cAMP accumulation was attenuated by DPCPX. We conclude that adenosine, acting at the basolateral membrane, inhibits AVP action in the IMCD via interaction with A1 receptors. The inhibition occurs proximal to cAMP generation and likely involves an inhibitory G protein.

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Fibrinogen binding to the integrin αIIbβ3 modulates store-mediated calcium entry in human platelets

Blood ◽

10.1182/blood.v97.9.2648 ◽

2001 ◽

Vol 97 (9) ◽

pp. 2648-2656 ◽

Cited By ~ 22

Author(s):

Juan A. Rosado ◽

Else M. Y. Meijer ◽

Karly Hamulyak ◽

Irena Novakova ◽

Johan W. M. Heemskerk ◽

...

Keyword(s):

Actin Cytoskeleton ◽

Actin Polymerization ◽

Adenosine Diphosphate ◽

Inhibitory Effect ◽

Human Platelets ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Integrin Αiibβ3 ◽

Fibrinogen Binding

Abstract Effects of the occupation of integrin αIIbβ3 by fibrinogen on Ca++signaling in fura-2–loaded human platelets were investigated. Adding fibrinogen to washed platelet suspensions inhibited increases in cytosolic [Ca++] concentrations ([Ca++]i) evoked by adenosine diphosphate (ADP) and thrombin in a concentration-dependent manner in the presence of external Ca++ but not in the absence of external Ca++ or in the presence of the nonselective cation channel blocker SKF96365, indicating selective inhibition of Ca++entry. Fibrinogen also inhibited store-mediated Ca++ entry (SMCE) activated after Ca++ store depletion using thapsigargin. The inhibitory effect of fibrinogen was reversed if fibrinogen binding to αIIbβ3 was blocked using RDGS or abciximab and was absent in platelets from patients homozygous for Glanzmann thrombasthenia. Fibrinogen was without effect on SMCE once activated. Activation of SMCE in platelets occurs through conformational coupling between the intracellular stores and the plasma membrane and requires remodeling of the actin cytoskeleton. Fibrinogen inhibited actin polymerization evoked by ADP or thapsigargin in control cells and in cells loaded with the Ca++ chelator dimethyl BAPTA. It also inhibited the translocation of the tyrosine kinase p60src to the cytoskeleton. These results indicate that the binding of fibrinogen to integrin αIIbβ3 inhibits the activation of SMCE in platelets by a mechanism that may involve modulation of the reorganization of the actin cytoskeleton and the cytoskeletal association of p60src. This action may be important in intrinsic negative feedback to prevent the further activation of platelets subjected to low-level stimuli in vivo.

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Thrombin activatable fibrinolysis inhibitor (TAFI) affects fibrinolysis in a plasminogen activator concentration-dependent manner

Thrombosis and Haemostasis ◽

10.1160/th03-06-0377 ◽

2004 ◽

Vol 91 (03) ◽

pp. 473-479 ◽

Cited By ~ 15

Author(s):

Ana Guimarães ◽

Dingeman Rijken

Keyword(s):

Plasminogen Activator ◽

In Vitro Study ◽

Inhibitory Effect ◽

Retardation Factor ◽

Clot Lysis ◽

Dependent Manner ◽

Plasma Clot ◽

Concentration Dependent Manner ◽

Plasmin Inhibitor

SummaryTAFIa was shown to attenuate fibrinolysis. In our in vitro study, we investigated how the inhibitory effect of TAFIa depended on the type and concentration of the plasminogen activator (PA). We measured PA-mediated lysis times of plasma clots under conditions of maximal TAFI activation by thrombin-thrombomodulin in the absence and presence of potato carboxypeptidase inhibitor. Seven different PAs were compared comprising both tPA-related (tPA, TNK-tPA, DSPA), bacterial PA-related (staphylokinase and APSAC) and urokinase-related (tcu-PA and k2tu-PA) PAs. The lysis times and the retardation factor were plotted against the PA concentration. The retardation factor plots were bell-shaped. At low PA concentrations, the retardation factor was low, probably due to the limited stability of TAFIa. At intermediate PA concentrations the retardation factor was maximal (3-6 depending on the PA), with TNK-tPA, APSAC and DSPA exhibiting the strongest effect. At high PA concentrations, the retardation factor was again low, possibly due to inactivation of TAFIa by plasmin or to a complete conversion of glu-plasminogen into lys-plasminogen. Using individual plasmas with a reduced plasmin inhibitor activity (plasmin inhibitor Enschede) the bell-shaped curve of the retardation factor shifted towards lower tPA and DSPA concentrations, but the height did not decrease. In conclusion, TAFIa delays the lysis of plasma clots mediated by all the plasminogen activators tested. This delay is dependent on the type and concentration of the plasminogen activator, but not on the fibrin specificity of the plasminogen activator. Furthermore, plasmin inhibitor does not play a significant role in the inhibition of plasma clot lysis by TAFI.

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Lung injury in a surfactant-deficient lung is modified by indomethacin

Journal of Applied Physiology ◽

10.1152/jappl.1990.69.6.2067 ◽

1990 ◽

Vol 69 (6) ◽

pp. 2067-2071 ◽

Cited By ~ 11

Author(s):

R. Burger ◽

D. Fung ◽

A. C. Bryan

Keyword(s):

Pulmonary Hypertension ◽

Lung Injury ◽

Thromboxane A2 ◽

Neutrophil Infiltration ◽

Lung Lavage ◽

Thromboxane A2 Receptor ◽

Beneficial Effects ◽

Thromboxane Receptor ◽

Pulmonary Arterial ◽

Arterial Po2

Repetitive total lung lavage in adult rabbits leads to a reproducible severe surfactant-deficient lung injury. Hypoxemia requiring mechanical ventilation occurs, accompanied by a substantial pulmonary hypertension, a large intra-alveolar protein leak, peripheral neutropenia, and pathological features of marked neutrophil infiltration with extensive hyaline membrane formation. Pretreatment with indomethacin abolishes postlavage pulmonary hypertension, preserves a slightly better lung function with higher arterial PO2, and prevents the postlavage peripheral neutropenia found in untreated animals. Pretreatment with a thromboxane A2 receptor blocker (L 655,240, Merck Frosst, Canada) also completely attenuated pulmonary hypertension, providing evidence that thromboxane A2 mediates pulmonary arterial hypertension after lung lavage. However, specific thromboxane receptor blockade had no other long-lasting beneficial effects on the ongoing injury in this model.

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