scholarly journals Estrogen replacement enhances EDHF-mediated vasodilation of mesenteric and uterine resistance arteries: role of endothelial cell Ca2+

2009 ◽  
Vol 296 (3) ◽  
pp. E503-E512 ◽  
Author(s):  
Natalie Z. Burger ◽  
Olga Y. Kuzina ◽  
George Osol ◽  
Natalia I. Gokina
Keyword(s):  
Endothelial Cell ◽  
Underlying Mechanism ◽  
Mature Female ◽  
Mesenteric Arteries ◽  
Female Rats ◽  
Estrogen Replacement ◽  
Resistance Arteries ◽  
Uterine Arteries ◽  
Small Resistance

Endothelium-derived hyperpolarizing factor (EDHF) plays an important role in the regulation of vascular microcirculatory tone. This study explores the role of estrogen in controlling EDHF-mediated vasodilation of uterine resistance arteries of the rat and also analyzes the contribution of endothelial cell (EC) Ca2+ signaling to this process. A parallel study was also performed with mesenteric arteries to provide comparison with a nonreproductive vasculature. Mature female rats underwent ovariectomy, with one half receiving 17β-estradiol replacement (OVX+E) and the other half serving as estrogen-deficient controls (OVX). Uterine or mesenteric resistance arteries were harvested, cannulated, and pressurized. Nitric oxide and prostacyclin production were inhibited with 200 μM NG-nitro-l-arginine and 10 μM indomethacin, respectively. ACh effectively dilated the arteries preconstricted with phenylephrine but failed to induce dilation of vessels preconstricted with high-K+ solution. ACh EC50 values were decreased by estrogen replacement by five- and twofold in uterine and mesenteric arteries, respectively. As evidenced by fura-2-based measurements of EC cytoplasmic Ca2+ concentration ([Ca2+]i), estrogen replacement was associated with increased basal and ACh-stimulated EC [Ca2+]i rise in uterine, but not mesenteric, vessels. These data demonstrate that EDHF contributes to endothelium-dependent vasodilation of uterine and mesenteric resistance arteries and that estrogen controls EDHF-related mechanism(s) more efficiently in reproductive vs. nonreproductive vessels. Enhanced endothelial Ca2+ signaling may be an important underlying mechanism in estrogenic modulation of EDHF-mediated vasodilation in small resistance uterine arteries.

Upregulation of endothelial cell Ca2+ signaling contributes to pregnancy-enhanced vasodilation of rat uteroplacental arteries

2006 ◽  
Vol 290 (5) ◽  
pp. H2124-H2135 ◽  
Author(s):  
Natalia I. Gokina ◽  
Tara Goecks
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Critical Role ◽  
Late Pregnancy ◽  
Underlying Mechanism ◽  
Late Gestation ◽  
Intraluminal Pressure ◽  
Fura 2 ◽  
Uterine Arteries

Normal pregnancy is characterized by an increased uterine blood flow due to growth and remodeling of the maternal uterine vasculature and enhanced vasodilation of the uterine arteries. The objective of the present study was to examine the role of endothelial cell Ca2+ signaling in augmented endothelium-mediated vasodilation of uteroplacental arteries in late pregnancy. We performed fura-2-based measurements of the intracellular Ca2+ concentration ([Ca2+]i) in the cytoplasm of endothelial cells simultaneously with diameter in pressurized uterine arteries from nonpregnant (NP) and late-pregnant (LP) rats. Basal levels of endothelial cell [Ca2+]i were higher in arteries from LP rats compared with NP controls. Withdrawal of extracellular Ca2+ resulted in a decrease in the level of basal [Ca2+]i that was significantly larger in arteries of LP than NP rats. The rate of Mn2+-induced quenching of fura-2 fluorescence was significantly elevated in late pregnancy, implicating augmented Ca2+ influx as a cause of increased basal levels of [Ca2+]i in endothelial cells. Elevation of intraluminal pressure resulted in a transient increase in endothelial [Ca2+]i that was markedly potentiated in late gestation. ACh-induced [Ca2+]i and vasodilator responses were significantly augmented in arteries of LP compared with NP rats and were abolished by BAPTA treatment, demonstrating a critical role of [Ca2+]i elevation in the production of endothelium-derived vasodilators. Together, these results indicate that late pregnancy is a state of enhanced basal and stimulated Ca2+ signaling in endothelial cells of uterine vessels, which may represent an important underlying mechanism for augmented vasodilation in the maternal uterine circulation.

scholarly journals Pregnancy Enhances the Angiotensin (Ang)-(1–7) Vasodilator Response in Mesenteric Arteries and Increases the Renal Concentration and Urinary Excretion of Ang-(1–7)

Endocrinology ◽  
2003 ◽  
Vol 144 (8) ◽  
pp. 3338-3343 ◽  
Author(s):  
Liomar A. A. Neves ◽  
Aleck F. Williams ◽  
David B. Averill ◽  
Carlos M. Ferrario ◽  
Michael P. Walkup ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Excretion Rate ◽  
Virgin Female ◽  
Cardiovascular Regulation ◽  
Mesenteric Arteries ◽  
Female Rats ◽  
Resistance Arteries ◽  
Urinary Excretion Rate ◽  
Response Curves ◽  
Mesenteric Vessels

Abstract The vasoactive effect of angiotensin (Ang)-(1–7) in mesenteric resistance arteries together with its plasma and kidney concentration and urinary excretion was assessed in pregnant and virgin rats. Mesenteric arteries (230–290 μm) were mounted in a pressurized myograph system and Ang-(1–7) concentration-dependent response curves (10−10–10−5m) were determined in arteries preconstricted with endothelin-1 (10−7m). The Ang-(1–7) response was investigated in vessels with and without pretreatment with the Ang-(1–7) antagonist [d-[Ala7]-Ang-(1–7)] (10−7m). Ang-(1–7) caused a significantly enhanced, concentration-dependent dilation of mesenteric vessels (EC50 = 2.7 nm) from pregnant compared with virgin female rats. d-[Ala7]-Ang-(1–7) eliminated the vasodilator effect of Ang-(1–7). There was no significant change in plasma concentration of Ang-(1–7) in pregnant animals. On the other hand, 24 h urinary excretion and kidney concentration of Ang-(1–7) were significantly higher in pregnant animals. The increased mesenteric dilation to Ang-(1–7) with enhanced kidney concentration and 24 h urinary excretion rate of Ang-(1–7) suggests an important role for this peptide in cardiovascular regulation during pregnancy.

Abstract P287: Endothelial Dysfunction in Small Resistance Arteries of Patients with Severe Obesity: Role of Arginase

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Agostino Virdis ◽  
Emiliano Duranti ◽  
Monica Nannipieri ◽  
Marco Anselmino ◽  
Andrea Grazi ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Severe Obesity ◽  
Subcutaneous Tissue ◽  
Age Groups ◽  
Inhibitory Effect ◽  
Resistance Arteries ◽  
Small Arteries ◽  
Laparoscopic Surgical Procedure ◽  
Small Resistance

Nitric oxide (NO) is produced by endothelial NO synthase (eNOS) using the aminoacid L-Arginine. Arginase (Arg) also uses L-Arginine as substrate, converting it in L-Ornitine and urea. An increased Arg activity causes a progressive L-Arginine depletion, which in turn determines a lower NO bioavailability. Studies in murine models of obesity identify Arg as a determinant of endothelial dysfunction. In this study, we evaluated whether Arg might play a role in determining the lower bioavailability of NO in small resistance arteries isolated from subcutaneous tissue of patients with severe obesity (Ob), split in age groups (younger than 30 aa, range 21-29, n=5; older than 30 aa, range 35-56, n=5) vs normoweight controls (Ctrl younger 30 years, range 20-29, n=5; older than 30 yrs, range 36-58, n=5). Each patient underwent a subcutaneous biopsy during a laparoscopic surgical procedure. Small arteries, isolated from periadvential fat, were evaluated on a pressurized micromyograph. Endothelium-dependent vasodilation (VD) was assessed by acetylcholine (Ach, 0,001-100μM). NO availability was assessed by repeating Ach with L-NAME (100μM). Ach was also infused in the presence of norNOHA (10μM, Arg inhibitor). In Ctrl, VD induced by Ach was inhibited by L-NAME and not modified by norNOHA. Ob younger exhibited a reduced VD induced by Ach vs Ctrl of the same age, a reduced inhibition by L-NAME, and a potentiating effect by norNOHA, which also normalized the inhibitory effect of L-NAME on Ach. In Ob older, VD induced by Ach was reduced vs Ob younger, resistant to L-NAME and not modified by norNOHA. In conclusions, in small arteries from younger Ob, the Arg inhibition improves endothelial function by increasing the NO availability, while in older Ob Arg does not seem to play any role in endothelial dysfunction.

scholarly journals PC-PLC/sphingomyelin synthase activity plays a central role in the development of myogenic tone in murine resistance arteries

2015 ◽  
Vol 308 (12) ◽  
pp. H1517-H1524 ◽  
Author(s):  
Joseph R. H. Mauban ◽  
Joseph Zacharia ◽  
Seth Fairfax ◽  
Withrow Gil Wier
Keyword(s):  
Specific Inhibitor ◽  
Intrinsic Property ◽  
Tissue Perfusion ◽  
Pressure Control ◽  
Mesenteric Arteries ◽  
Myogenic Tone ◽  
Resistance Arteries ◽  
Virtual Absence ◽  
Sphingomyelin Synthase

Myogenic tone is an intrinsic property of the vasculature that contributes to blood pressure control and tissue perfusion. Earlier investigations assigned a key role in myogenic tone to phospholipase C (PLC) and its products, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Here, we used the PLC inhibitor, U-73122, and two other, specific inhibitors of PLC subtypes (PI-PLC and PC-PLC) to delineate the role of PLC in myogenic tone of pressurized murine mesenteric arteries. U-73122 inhibited depolarization-induced contractions (high external K+ concentration), thus confirming reports of nonspecific actions of U-73122 and its limited utility for studies of myogenic tone. Edelfosine, a specific inhibitor of PI-PLC, did not affect depolarization-induced contractions but modulated myogenic tone. Because PI-PLC produces IP3, we investigated the effect of blocking IP3 receptor-mediated Ca2+ release on myogenic tone. Incubation of arteries with xestospongin C did not affect tone, consistent with the virtual absence of Ca2+ waves in arteries with myogenic tone. D-609, an inhibitor of PC-PLC and sphingomyelin synthase, strongly inhibited myogenic tone and had no effect on depolarization-induced contraction. D-609 appeared to act by lowering cytoplasmic Ca2+ concentration to levels below those that activate contraction. Importantly, incubation of pressurized arteries with a membrane-permeable analog of DAG induced vasoconstriction. The results therefore mandate a reexamination of the signaling pathways activated by the Bayliss mechanism. Our results suggest that PI-PLC and IP3 are not required in maintaining myogenic tone, but DAG, produced by PC-PLC and/or SM synthase, is likely through multiple mechanisms to increase Ca2+ entry and promote vasoconstriction.

Role of Endothelium in the Action of Isoflurane on Vascular Smooth Muscle of Isolated Mesenteric Resistance Arteries

2001 ◽  
Vol 95 (4) ◽  
pp. 990-998 ◽  
Author(s):  
Kaoru Izumi ◽  
Takashi Akata ◽  
Shosuke Takahashi
Keyword(s):  
Contractile Response ◽  
Isometric Force ◽  
Direct Action ◽  
Control Level ◽  
Mesenteric Arteries ◽  
Systemic Resistance ◽  
Resistance Arteries ◽  
Mesenteric Resistance Artery

Background It is believed that isoflurane decreases blood pressure predominantly by decreasing systemic vascular resistance with modest myocardial depression. Nevertheless, little information is available regarding the direct action of isoflurane on systemic resistance arteries. Methods With use of the isometric force recording method, the action of isoflurane on contractile response to norepinephrine, a neurotransmitter that plays a central role in sympathetic maintenance of vascular tone in vivo, was investigated in isolated rat small mesenteric arteries. Results In the endothelium-intact strips, the norepinephrine response was initially enhanced after application of isoflurane (2-5%), but it was subsequently almost normalized to the control level during exposure to isoflurane. However, the norepinephrine response was notably inhibited after washout of isoflurane. In the endothelium-denuded strips, the norepinephrine response was gradually inhibited during exposure to isoflurane (> or = 3%), and the inhibition was prolonged after wash-out of isoflurane. The isoflurane-induced enhancement of norepinephrine response was still observed after inhibitions of the nitric oxide, endothelium-derived hyperpolarizing factor, cyclooxygenase and lipoxygenase pathways, or after blockade of endothelin-1, angiotensin-II, and serotonin receptors; however, it was prevented by superoxide dismutase. Conclusions In isolated mesenteric resistance artery, the action of isoflurane on contractile response to norepinephrine consists of two distinct components: an endothelium-dependent enhancing component and an endothelium-independent inhibitory component. During exposure to isoflurane, the former counteracted the latter, preventing the norepinephrine response from being strongly inhibited. However, only the endothelium-independent component persists after washout of isoflurane, causing prolonged inhibition of the norepinephrine response. Superoxide anions may be involved in the enhanced response to norepinephrine.

Lack of prognostic role of endothelial dysfunction in subcutaneous small resistance arteries of hypertensive patients

2006 ◽  
Vol 24 (5) ◽  
pp. 867-873 ◽  
Author(s):  
Damiano Rizzoni ◽  
Enzo Porteri ◽  
Carolina De Ciuceis ◽  
Gianluca EM Boari ◽  
Francesca Zani ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Resistance Arteries ◽  
Prognostic Role ◽  
Hypertensive Patients ◽  
Small Resistance

Role of CO in attenuated vasoconstrictor reactivity of mesenteric resistance arteries after chronic hypoxia

2002 ◽  
Vol 282 (1) ◽  
pp. H30-H37 ◽  
Author(s):  
Rayna J. Gonzales ◽  
Benjimen R. Walker
Keyword(s):  
Chronic Hypoxia ◽  
Protoporphyrin Ix ◽  
Aortic Ring ◽  
Mesenteric Arteries ◽  
Zinc Protoporphyrin ◽  
Sprague Dawley ◽  
Resistance Arteries ◽  
Sprague Dawley Rats ◽  
Oxide Synthase

Chronic hypoxia (CH) is associated with a persistent reduction in systemic vasoconstrictor reactivity. Experiments on aortic ring segments isolated from CH rats suggest that enhanced vascular expression of heme oxygenase (HO) and resultant production of the vasodilator carbon monoxide (CO) may underlie this attenuated vasoreactivity after hypoxia. Similar to the aorta, small arteries from CH rats exhibit blunted reactivity; however, the regulatory role of CO in the resistance vasculature has not been established. Therefore, we examined the significance of HO activity on responsiveness to phenylephrine (PE) in the mesenteric circulation of control and CH rats. To document that the mesenteric bed demonstrates reduced reactivity after CH, we determined the vasoconstrictor responses of conscious, chronically instrumented male Sprague-Dawley rats to PE under control conditions and then immediately after exposure to 48 h CH (0.5 atm). All rats showed reduced mesenteric vasoconstriction to PE after CH. To examine the role of CO in reduced reactivity, small mesenteric arteries (100–200 μm intraluminal diameter) from control and 48-h CH rats were isolated and mounted on glass cannulas, pressurized to 60 mmHg and superfused with increasing concentrations of PE under normoxic conditions. Similar to the intact circulation, vessels from CH rats exhibited reduced vasoconstrictor sensitivity to PE compared with controls that persisted in the presence of nitric oxide synthase inhibition. The HO inhibitor, zinc protoporphyrin IX (5 μM) enhanced reactivity only in CH vessels. Additionally, a range of concentrations of the HO substrate heme-l-lysinate caused vasodilation in CH vessels but not in controls. Thus we conclude that CO contributes a significant vasodilator influence in resistance vessels after CH that may account for diminished vasoconstrictor responsiveness under these conditions.

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