Up4A stimulates endothelium-independent contraction of isolated rat pulmonary artery

2008 ◽  
Vol 294 (4) ◽  
pp. L733-L738 ◽  
Author(s):  
Yu Gui ◽  
Michael P. Walsh ◽  
Vera Jankowski ◽  
Joachim Jankowski ◽  
Xi-Long Zheng
Keyword(s):  
Pulmonary Artery ◽  
Vascular Tone ◽  
Rho Kinase ◽  
P2y Receptors ◽  
Extracellular Nucleotides ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
P2x And P2y Receptors ◽  
Potent Vasoconstrictor ◽  
Isolated Rat

Extracellular nucleotides, such as ATP, UDP, and UTP, regulate pulmonary vascular tone through P2X and P2Y receptors. Recently, uridine adenosine tetraphosphate (Up4A) was reported as a novel endothelium-derived vasoconstrictive factor. Up4A contains both purine and pyrimidine moieties, which potentially activate P2X and P2Y receptors. The present study examined the effect of Up4A on contractility of isolated rat pulmonary artery. Up4A at 1–100 μM stimulated contraction in a concentration-dependent manner. Up4A was equipotent as UTP and UDP in the endothelium-denuded artery while much more effective than UTP and UDP in endothelium-intact preparations. The vasoconstrictor effect of Up4A was inhibited by suramin but not IP5I or desensitization of P2X receptors with α,β-methylene-ATP (α,β-Me-ATP). Up4A-induced contraction was also inhibited by pretreatment with thapsigargin, nitrendipine, or EGTA but unaffected by H1152. Furthermore, unlike ATP and UTP, Up4A did not induce relaxation of endothelium-intact preparations precontracted with phenylephrine. These results suggest that Up4A is a potent vasoconstrictor, but not a vasodilator, of the rat pulmonary artery. Up4A likely acts through a suramin-sensitive P2Y receptor. The contractile effect of Up4A involves the entry of extracellular Ca2+ and release of Ca2+ from intracellular stores but not Ca2+ sensitization via the RhoA/Rho kinase pathway. Up4A, therefore, potentially plays an important role in the regulation of pulmonary vascular tone.

Epoxyeicosatrienoic acids constrict isolated pressurized rabbit pulmonary arteries

2000 ◽  
Vol 278 (2) ◽  
pp. L335-L343 ◽  
Author(s):  
Daling Zhu ◽  
Michael Bousamra ◽  
Darryl C. Zeldin ◽  
John R. Falck ◽  
Mary Townsley ◽  
...  
Keyword(s):  
Methyl Ester ◽  
Pulmonary Artery ◽  
Vascular Tone ◽  
Pulmonary Arteries ◽  
Epoxyeicosatrienoic Acids ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Peripheral Lung

Little information is available regarding the vasoactive effects of epoxyeicosatrienoic acids (EETs) in the lung. We demonstrate that 5,6-, 8,9-, 11,12-, and 14,15-EETs contract pressurized rabbit pulmonary arteries in a concentration-dependent manner. Constriction to 5,6-EET methyl ester or 14,15-EET is blocked by indomethacin or ibuprofen (10− 5 M), SQ-29548, endothelial denuding, or submaximal preconstriction with the thromboxane mimetic U-46619. Constriction of pulmonary artery rings to phenylephrine is blunted by treatment with the epoxygenase inhibitor N-methylsulfonyl-6-(2-propargyloxyphenyl)hexanamide. Pulmonary arteries and peripheral lung microsomes metabolize arachidonate to products that comigrate on reverse-phrase HPLC with authentic regioisomers of 5,6-, 8,9-, 11,12-, and 14,15-EETs, but no cyclooxygenase products of EETs could be demonstrated. Proteins of the CYP2B, CYP2E, CYP2J, CYP1A, and CYP2C subfamilies are present in pulmonary artery and peripheral lung microsomes. Constriction of isolated rabbit pulmonary arteries to EETs is nonregioselective and depends on intact endothelium and cyclooxygenase, consistent with the formation of a pressor prostanoid compound. These data raise the possibility that EETs may contribute to regulation of pulmonary vascular tone.

Sevoflurane Inhibits Guanosine 5′-[γ-thio]triphosphate–stimulated, Rho/Rho-kinase–mediated Contraction of Isolated Rat Aortic Smooth Muscle

2003 ◽  
Vol 99 (3) ◽  
pp. 646-651 ◽  
Author(s):  
Jingui Yu ◽  
Koji Ogawa ◽  
Yasuyuki Tokinaga ◽  
Yoshio Hatano
Keyword(s):  
Smooth Muscle ◽  
Kinase Inhibitor ◽  
Isometric Force ◽  
Rho Kinase ◽  
Force Transducer ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Aortic Smooth Muscle ◽  
Gamma S ◽  
Kinase Pathway

Background The Rho/Rho-kinase signaling pathway plays an important role in mediating Ca2+ sensitization of vascular smooth muscle. The effect of anesthetics on Rho/Rho-kinase-mediated vasoconstriction has not been determined to date. This study is designed to examine the possible inhibitory effects of sevoflurane on the Rho/Rho-kinase pathway by measuring guanosine 5'-[gamma-thio]triphosphate (GTP gamma S)-stimulated contraction and translocation of RhoA (one of the three Rho subtypes) and Rock-2 (one of the two Rho-kinase subtypes) from the cytosol to the membrane in rat aortic smooth muscle. Methods GTP gamma S-induced contraction of rat aortic endothelium-denuded rings was measured using an isometric force transducer, and GTP gamma S-stimulated membrane translocation of RhoA and Rock-2 in smooth muscle cells was detected with Western blotting in the presence and absence of sevoflurane. Results GTP gamma S (10(-4) m) induced a sustained contraction, which was significantly inhibited by the Rho-kinase inhibitor, Y27632 (3 x 10(-6) m). Before treatment with GTP gamma S, RhoA and Rock-2 were detected primarily in the cytosolic fraction. GTP gamma S (10(-4) m) stimulated the translocation of RhoA and Rock-2 from the cytosol to the membrane, which was sustained for more than 60 min. Sevoflurane (1.7, 3.4, and 5.1%) concentration dependently inhibited the GTP gamma S-induced constriction of rat aortic smooth muscle with a reduction of constriction of 52-75% (P < 0.01, n = 8), and attenuated the translocation of RhoA and Rock-2 by 31-66% and 34-78%, respectively (P < 0.05-0.01, respectively; n = 4). Conclusion The current findings show that sevoflurane depresses the GTP gamma S-stimulated contraction and translocation of both Rho and Rho-kinase from the cytosol in a concentration-dependent manner, indicating that sevoflurane is able to inhibit vasoconstriction mediated by the Rho/Rho-kinase pathway in rat aortic smooth muscle.

O2 and rat pulmonary artery tone: effects of endothelium, Ca2+, cyanide, and monocrotaline

1991 ◽  
Vol 71 (1) ◽  
pp. 30-36 ◽  
Author(s):  
R. Mathew ◽  
T. Burke-Wolin ◽  
M. H. Gewitz ◽  
M. S. Wolin
Keyword(s):  
Pulmonary Artery ◽  
Significant Enhancement ◽  
Relaxation Response ◽  
Dependent Manner ◽  
Contractile Responses ◽  
Relaxation Phase ◽  
Pulmonary Arterial ◽  
Tone Generation ◽  
Isolated Rat

The present study examines the influence of the endothelium (E), Ca2+ concentration, cyanide and monocrotaline (MCT) pretreatment on the responses of isolated rat hilar pulmonary arterial rings (PA) to hypoxia. In PA precontracted with phenylephrine, hypoxia induced an initial E-dependent relaxation phase followed by an E-independent transient contraction and a final relaxation. An increase in Ca2+ concentration from 1.5 to 2.5 mM produced an E-dependent reduction in tone generation under O2 and a significant enhancement of the hypoxia-elicited initial relaxation and the transient contractile responses. Addition of cyanide (0.1 mM) to precontracted PA produced a transient contraction similar to that caused by hypoxia. Preincubation with cyanide led to inhibition of tone generation and abolition of the contraction to hypoxia. However, the final relaxation response to hypoxia was not inhibited by cyanide. Thus, hypoxia produces an E-independent contraction via a mechanism that appears also to be activated by cyanide, and this response is not altered by MCT. The endothelium alters the response to hypoxia in a Ca(2+)-dependent manner.

Effects of ω-hydroxylase product on distal human pulmonary arteries

2008 ◽  
Vol 294 (3) ◽  
pp. H1435-H1443 ◽  
Author(s):  
Caroline Morin ◽  
Christelle Guibert ◽  
Marco Sirois ◽  
Vincent Echave ◽  
Marcio M. Gomes ◽  
...  
Keyword(s):  
Pulmonary Arteries ◽  
Rho Kinase ◽  
Dependent Manner ◽  
Response Curves ◽  
Inhibitory Protein ◽  
Concentration Dependent Manner ◽  
Intracellular Process ◽  
Free Arachidonic Acid ◽  
Kinase Pathway

The aim of the present study was to provide a mechanistic insight into how 20-hydroxyeicosatetraenoic acid (20-HETE) relaxes distal human pulmonary arteries (HPAs). This compound is produced by ω-hydroxylase from free arachidonic acid. Tension measurements, performed on either fresh or 1 day-cultured pulmonary arteries, revealed that the contractile responses to 1 μM 5-hydroxytryptamine were largely relaxed by 20-HETE in a concentration-dependent manner (0.01–10 μM). Iberiotoxin pretreatments (10 nM) partially decreased 20-HETE-induced relaxations. However, 10 μM indomethacin and 3 μM SC-560 pretreatments significantly reduced the relaxations to 20-HETE in these tissues. The relaxing responses induced by the eicosanoid were likely related to a reduced Ca2+ sensitivity of the myofilaments since free Ca2+ concentration ([Ca2+])-response curves performed on β-escin-permeabilized cultured explants were shifted toward higher [Ca2+]. 20-HETE also abolished the tonic responses induced by phorbol-ester-dibutyrate (a PKC-sensitizing agent). Western blot analyses, using two specific primary antibodies against the PKC-potentiated inhibitory protein CPI-17 and its PKC-dependent phosphorylated isoform pCPI-17, confirmed that 20-HETE interferes with this intracellular process. We also investigated the effect of 20-HETE on the activation of Rho-kinase pathway-induced Ca2+ sensitivity. The data demonstrated that 20-HETE decreased U-46619-induced Ca2+ sensitivity on arteries. Hence, this observation was correlated with an increased staining of p116Rip, a RhoA-binding protein. Together, these results strongly suggest that the 20-hydroxyarachidonic acid derivative is a potent modulator of tone in HPAs in vitro.

scholarly journals Effect of ATP on preadipocyte migration and adipocyte differentiation by activating P2Y receptors in 3T3-L1 cells

2005 ◽  
Vol 393 (1) ◽  
pp. 171-180 ◽  
Author(s):  
Mariko Omatsu-Kanbe ◽  
Kazuko Inoue ◽  
Yusuke Fujii ◽  
Takefumi Yamamoto ◽  
Takahiro Isono ◽  
...  
Keyword(s):  
Cell Line ◽  
Adipocyte Differentiation ◽  
P2y Receptors ◽  
Extracellular Atp ◽  
Dependent Manner ◽  
Fat Cell ◽  
Proliferating Cells ◽  
Concentration Dependent Manner ◽  
Membrane Ruffling

The effect of extracellular ATP on adipogenesis was investigated using the mouse 3T3-L1 cell line. Incubation of cells with ATP (1–100 μM) for 5 min induced actin filament reorganization and membrane ruffling mediated through P2Y receptors. Enhancement of preadipocyte migration into fat cell clusters is one of the essential processes of adipose tissue development in vivo and cell migration assays revealed that stimulation of P2Y receptors enhanced chemokinesis (migration) in a concentration dependent manner. In this cell line, growth arrest is required before initiation of differentiation and growth-arrested post-confluent cells can be converted into adipocytes by the presence of the adipogenic hormones dexamethasone, 3-isobutyl-1-methylxanthine and insulin. On the other hand, those hormones alone do not trigger differentiation in proliferating cells. ATP did not induce differentiation when applied alone to either proliferating or postconfluent cells. By contrast, proliferating cells (density <50%) preincubated with ATP for 5 min and subsequently given the adipogenic hormones in the continued presence of ATP, underwent adipocyte differentiation mediated through phospholipase C-coupled P2Y receptors. These adipocytes were found to show very similar characteristics, including morphology and intracellular triacylglycerol accumulation compared with adipocytes differentiated from post-confluent preadipocytes with those adipogenic hormones. When proliferating cells were preincubated with ATP before the addition of the adipogenic hormones, gene expression of aP2 (adipose protein 2) was markedly increased within 6 days, whereas without ATP pretreatment the expression level stayed very low. These results suggest that extracellular ATP renders preadipocytes responsive to adipogenic hormones during the growth phase.

Enkephalin-induced inhibition of the isolated rat ileum is not blocked by naloxone

1981 ◽  
Vol 59 (8) ◽  
pp. 901-903 ◽  
Author(s):  
K. Nakatsu ◽  
E. Goldenberg ◽  
D. Penning ◽  
K. Jhamandas
Keyword(s):  
Dependent Manner ◽  
Narcotic Antagonist ◽  
Concentration Dependent Manner ◽  
Rat Ileum ◽  
Leucine Enkephalin ◽  
Isolated Rat

Both methionine- and leucine-enkephalin caused the isolated rat ileum to relax in a concentration-dependent manner; the EC50 values were in the order of 10−8 to 10−7 M. This isolated preparation was generally not sensitive to morphine. The enkephalin-induced inhibitions were not blocked by the classical narcotic antagonist, naloxone.

Lyn and Fyn Kinases Positively Regulate Thromboxane Generation in Platelets.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3656-3656
Author(s):  
Kamala Bhavaraju ◽  
Soochong Kim ◽  
Satya P. Kunapuli
Keyword(s):  
Tyrosine Kinases ◽  
P2y Receptors ◽  
P2y12 Receptor ◽  
Dependent Manner ◽  
Receptor Antagonists ◽  
Concentration Dependent Manner ◽  
Fibrinogen Receptor ◽  
Adp Receptors ◽  
Src Activation ◽  
Mrs 2179

Abstract Src family Kinases (SFKs) are important tyrosine kinases in platelets. The family consists of 9 members (viz., Blk, Fgr, Fyn, Hck, Lck, Lyn, Src, Yes and Yrk) and many of the isoforms are expressed in platelets. SFKs are key kinases in glycoprotein (GPVI) mediated platelet activation and we have shown that these kinases play an important role in thromboxane generation. Until now, the role of specific SFKs downstream of G protein signaling in platelets is not well understood. In the present study we characterized functional roles of specific SFK members Fyn, Lyn, Lck and Src Kinases downstream of ADP receptors. Src, Lyn and Fyn are activated downstream of ADP receptors (P2Y) receptors in a time and concentration dependent manner. The presence of fibrinogen receptor antagonist, GR144053, did not affect the activation of Src and Fyn; however, Lyn is not activated in the presence of GR144053, suggesting that Lyn requires outside-in signaling for it’s activation. On the other hand, Lck kinase is not activated downstream of ADP receptors. ADP activates P2Y1 and P2Y12 receptors which in turn couple to Gq and Gi, respectively. In order to further delineate the Src activation pathways we used P2Y1 and P2Y12 receptor antagonists MRS 2179 and AR-C69931MX respectively. Src activation is not inhibited by either P2Y1 or P2Y12 receptor antagonists, suggesting that both receptors independently contribute to the activation of Src kinase. Platelets from mice deficient in Src, Fyn or Lyn were analyzed for thromboxane generation upon stimulation with ADP. Lyn and Fyn KO mice had reduced levels of thromboxane A2 compared to wild type littermates. However, thromboxane generation from platelets lacking Src was unaffected. Hence, we conclude Lyn and Fyn kinases, but not Src, positively regulate thromboxane generation downstream of ADP receptors. We also conclude that Lyn requires outside-in signaling for its activation.

scholarly journals Effects of dexmedetomidine on porcine pulmonary artery vascular smooth muscle

2019 ◽  
Author(s):  
Mami Chikuda ◽  
Kenichi Sato
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Vascular Smooth Muscle ◽  
Local Anesthetics ◽  
Pulmonary Arteries ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Duration Of Action ◽  
Porcine Pulmonary Artery ◽  
Ca2 Channels

Abstract Background Dexmedetomidine is added to local anesthetics to increase their potency and extend their duration of action, thus providing postoperative analgesia with a single administration. However, the effects and mechanism of action of dexmedetomidine on pulmonary arteries have not been determined. The aim of this study was to investigate the effect of dexmedetomidine on pulmonary artery vascular smooth muscle, evaluating changes in contraction tension. Methods Endothelium-denuded porcine pulmonary arteries were sliced into 2- to 3-mm rings. Changes in isometric contraction tension were measured with the addition of various substances at various concentrations, under different conditions of baseline stimulation (with KCl, Adrenaline, caffeine, or histamine) and different conditions of Ca2+ depletion with intracellular reservoirs or extracellular stores depleted. Results Dexmedetomidine increased the contraction tension induced by high-KCl depolarization in a concentration-dependent manner. Dexmedetomidine inhibited receptor-activated Ca2+ channels (RACCs) and phosphatidylinositol-1,4,5-triphosphate-induced Ca2+ release (IICR), but not Ca2+-induced Ca2+ release (CICR). Conclusions Dex increased the contraction tension resulting from depolarization stimulation by high KCl in a concentration-dependent manner in porcine pulmonary artery vascular smooth muscle. The enhancement of high KCl-induced contraction with Dex addition was mediated by α2 receptors. Dex suppressed increases in contraction tension induced by receptor stimulation with adrenaline, also in a concentration-dependent manner. Dex inhibited RACC and IICR, but not CICR. Elucidating the effects and mechanisms of action of Dex in the central arteries is likely to be useful as basic data for creating Dex-containing local anesthetics.

Effects of Rho kinase inhibition on cerebral artery myogenic tone and reactivity

2005 ◽  
Vol 98 (5) ◽  
pp. 1940-1948 ◽  
Author(s):  
Natalia I. Gokina ◽  
Kristen M. Park ◽  
Keara McElroy-Yaggy ◽  
George Osol
Keyword(s):  
Smooth Muscle ◽  
Cerebral Artery ◽  
Rho Kinase ◽  
Oscillatory Activity ◽  
Comparable Efficacy ◽  
Myogenic Tone ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Kinase Inhibition ◽  
Kinase Pathway

Several recent studies have implicated the RhoA-Rho kinase pathway in arterial myogenic behavior. The goal of this study was to determine the effects of Rho kinase inhibition (Y-27632) on cerebral artery calcium and diameter responses as a function of transmural pressure. Excised segments of rat posterior cerebral arteries (100–200 μm) were cannulated and pressurized in an arteriograph at 37°C. Increasing pressure from 10 to 60 mmHg triggered an elevation of cytosolic calcium concentration ([Ca2+]i) from 113 ± 9 to 199 ± 12 nM and development of myogenic tone. Further elevation of pressure to 120 mmHg induced only a minor additional increase in [Ca2+]i and constriction. Y-27632 (0.3–10 μM) inhibited myogenic tone in a concentration-dependent manner at 60 and 120 mmHg with comparable efficacy; conversely, sensitivity was decreased at 120 vs. 60 mmHg (50% inhibitory concentration: 2.5 ± 0.3 vs. 1.4 ± 0.1 μM; P < 0.05). Dilation was accompanied by further increases in [Ca2+]i and an enhancement of Ca2+ oscillatory activity. Y-27632 also effectively dilated the vessels permeabilized with α-toxin in a concentration-dependent manner. However, dilator effects of Y-27632 at low concentrations were larger at 60 vs. 100 mmHg. In summary, the results support a significant role for RhoA-Rho kinase pathway in cerebral artery mechanotransduction of pressure into sustained vasoconstriction (myogenic tone and reactivity) via mechanisms that augment smooth muscle calcium sensitivity. Potential downstream events may involve inhibition of myosin phosphatase and/or stimulation of actin polymerization, both of which are associated with increased smooth muscle force production.

Abstract P127: Angiotensin II Priming Enhances Prostaglandin E2 Vasoconstrictor Effects

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Maria P Kraemer ◽  
Fred Lamb ◽  
Richard M Breyer
Keyword(s):  
Blood Pressure ◽  
Angiotensin Ii ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Area Under The Curve ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Ang Ii ◽  
Concentration Dependent Manner ◽  
Femoral Arteries

Prostaglandins are key modulators of blood pressure and arterial tone. Prostaglandin E 2 (PGE 2 ), is a prostanoid that has vasodepressor effects; however, under certain circumstances PGE 2 can induce vasopressor responses. Recent reports demonstrated that sub-threshold concentrations of vasoconstrictors augment PGE 2 -mediated constriction in rat femoral arteries. However, whether angiotensin II (Ang II) could affect PGE 2 -mediated contraction is not known. Using a wire myograph, we demonstrated that PGE 2 had no significant effect on mouse femoral arterial rings at doses up to 1 μM. However, priming of arterial rings with 1 nM Ang II potentiated PGE 2 -evoked constriction in a concentration dependent manner (Area Under the Curve, AUC untreated 1.784 ± 0.353, AUC Ang II 23.27± 9.820, P<0.05). We tested femoral arteries from EP1, EP2, and EP3 receptor knockout mice. Only the EP3-/- arteries were unable to respond to PGE 2 after Ang II priming (figure below). Pretreatment of arterial rings with 1 μM losartan, an angiotensin receptor antagonist, blocked PGE 2 -induced constrictor effects primed with Ang II (% of KCl, Ang II 21.72 ± 5.296, Ang II + losartan 3.025 ± 1.046, n=3). We have determined that re-addition of extracellular Ca 2+ to a Ca 2+ -free artery restores PGE 2 -induced contractions (n=5) and that the Rho-kinase inhibitor Y-27632 blocks contraction (n=3). Taken together these data are consistent with angiotensin AT1 and prostaglandin EP3 receptors mediating a synergistic Rho-kinase-dependent contractile response. We are continuing to investigate the relationship between Ang II and PGE 2 to determine the physiological relevance this may have in modulating blood pressure.

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