Nonpeptidic antagonists of ETA and ETB receptors reverse the ET-1-induced sustained increase of cytosolic and nuclear calcium in human aortic vascular smooth muscle cellsThis article is one of a selection of papers published in the special issue (part 2 of 2) on Forefronts in Endothelin.

2008 ◽  
Vol 86 (8) ◽  
pp. 546-556 ◽  
Author(s):  
Ghassan Bkaily ◽  
Sanaa Choufani ◽  
Levon Avedanian ◽  
Lena Ahmarani ◽  
Moni Nader ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Receptor Antagonist ◽  
G Protein ◽  
Calcium Influx ◽  
Receptor Activation ◽  
3 Dimensional ◽  
Intracellular Ca ◽  
Selection Of ◽  
Sustained Increase

Our previous work showed that ET-1 induced a concentration-dependent increase of cytosolic Ca2+ ([Ca]c) and nuclear Ca2+ ([Ca]n) in human aortic vascular smooth muscle cells (hVSMCs). In the present study, using hVSMCs and 3-dimensional confocal microscopy coupled to the Ca2+ fluorescent probe Fluo-3, we showed that peptidic antagonists of ETA and ETB receptors (BQ-123 (10−6 mol/L) and BQ-788 (10−7 mol/L), respectively) prevented, but did not reverse, ET-1-induced sustained increase of [Ca]c and [Ca]n. In contrast, nonpeptidic antagonists of ETA and ETB (respectively, BMS-182874 (10−8–10−6 mol/L) and A-192621 (10−7 mol/L)) both prevented and reversed ET-1-induced sustained increase of [Ca]c and [Ca]n. Furthermore, activation of the ETB receptor alone using the specific agonist IRL-1620 (10−9 mol/L) induced sustained increases of [Ca]c and [Ca]n, and subsequent administration of ET-1 (10−7 mol/L) further increased nuclear Ca2+. ET-1-induced increase of [Ca]c and [Ca]n was completely blocked by extracellular application of the Ca2+ chelator EGTA. Pretreatment with the G protein inhibitors pertussis toxin (PTX) and cholera toxin (CTX) also prevented the ET-1 response; however, strong membrane depolarization with KCl (30 mmol/L) subsequently induced sustained increase of [Ca]c and [Ca]n. Pretreatment of hVSMCs with either the PKC activator phorbol-12,13-dibutyrate or the PKC inhibitor bisindolylmaleimide did not affect ET-1-induced sustained increase of intracellular Ca2+. These results suggest that both ETA- and ETB-receptor activation contribute to ET-1-induced sustained increase of [Ca]c and [Ca]n in hVSMCs. Moreover, in contrast to the peptidic antagonists of ET-1 receptors, the nonpeptidic ETA-receptor antagonist BMS-182874 and the nonpeptidic ETB-receptor antagonist A-192621 were able to reverse the effect of ET-1. Nonpeptidic ETA- and ETB-receptor antagonists may therefore be better pharmacological tools for blocking ET-1-induced sustained increase of intracellular Ca2+ in hVSMCs. Our results also suggest that the ET-1-induced sustained increase of [Ca]c and [Ca]n is not mediated via activation of PKC, but via a PTX- and CTX-sensitive G protein calcium influx through the R-type Ca2+ channel.

Neuropeptide Y induced increase of cytosolic and nuclear Ca2+ in heart and vascular smooth muscle cells

2000 ◽  
Vol 78 (2) ◽  
pp. 162-172 ◽  
Author(s):  
Danielle Jacques ◽  
Sawsan Sader ◽  
Nesrine El-Bizri ◽  
Sanaa Chouffani ◽  
Ghada Hassan ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Confocal Microscopy ◽  
Vascular Smooth Muscle ◽  
Neuropeptide Y ◽  
Receptor Antagonist ◽  
Spontaneous Contraction ◽  
Receptor Type ◽  
Heart Cells ◽  
Intracellular Ca ◽  
Sustained Increase

It was reported that neuropeptide Y (NPY) affects cardiac and vascular smooth muscle (VSM) function probably by increasing intracellular Ca2+. In this study, using fura-2 microfluorometry and fluo-3 confocal microscopy techniques for intracellular Ca2+ measurement, we attempted to verify whether the action of NPY receptor's stimulation in heart and VSM cells modulates intracellular Ca2+ and whether this effect is mediated via the Y1 receptor type. Using spontaneously contracting single ventricular heart cells of 10-day-old embryonic chicks and the fluo-3 confocal microscopy Ca2+ measurement technique to localize cytosolic ([Ca]c) and nuclear ([Ca]n) free Ca2+ level and distribution, 10-10 M of human (h) NPY significantly (P < 0.05) increased the frequency of cytosolic and nuclear Ca2+ transients during spontaneous contraction. Increasing the concentration of hNPY (10-9 M) did not further increase the frequency of Ca2+ transients. The L-type Ca2+ channel blocker, nifedipine (10-5 M), significantly (P < 0.001) blocked the spontaneous rise of intracellular Ca2+ in the absence and presence of hNPY (10-10 and 10-9 M). However, the selective Y1 receptor antagonist, BIBP3226 (10-6 M), significantly decreased the hNPY-induced (10-10 and 10-9 M) increase in the frequency of Ca2+ transients back to near the control level (P < 0.05). In resting nonworking heart and human aortic VSM cells, hNPY induced a dose-dependent sustained increase of basal resting intracellular Ca2+ with an EC50 near 10-9 M. This sustained increase was cytosolic and nuclear and was completely blocked by the Ca2+ chelator EGTA, and was significantly decreased by the Y1 receptor antagonist BIBP3226 in both heart (P < 0.05) and VSM (P < 0.01) cells. These results strongly suggest that NPY stimulates the resting basal steady-state Ca2+ influx through the sarcolemma and induces sustained increases of cytosolic and nuclear calcium, in good part, via the activation of the sarcolemma membrane Y1 receptor type in both resting heart and VSM cells. In addition, NPY also increased the frequency of Ca2+ transients during spontaneous contraction of heart cells mainly via the activation of the Y1 receptor type, which may explain in part the active cardiovascular action of this peptide.Key words: heart, vascular smooth muscle, neuropeptide Y, BIBP3226, calcium, nucleus.

Cyclooxygenase-2 induction by bradykinin in aortic vascular smooth muscle cells

2006 ◽  
Vol 290 (1) ◽  
pp. H30-H36 ◽  
Author(s):  
Jorge A. Rodriguez ◽  
Paula De la Cerda ◽  
Eileen Collyer ◽  
Valerie Decap ◽  
Carlos P. Vio ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Receptor Activation ◽  
Atheromatous Plaque ◽  
Protein Levels ◽  
Cox 2

Vascular smooth muscle cell proliferation and migration play an important role in the pathophysiology of several vascular diseases, including atherosclerosis. Prostaglandins that have been implicated in this process are synthesized by two isoforms of cyclooxygenase (COX), with the expression of the regulated COX-2 isoform increased in atherosclerotic plaques. Bradykinin (BK), a vasoactive peptide increased in inflammation, induces the formation of prostaglandins through specific receptor activation. We hypothesized that BK plays an important role in the regulation of COX-2, contributing to the increase in production of prostaglandins in vascular smooth muscle cells. Herein we examined the signaling pathways that participate in the BK regulation of COX-2 protein levels in primary cultured aortic vascular smooth muscle cells. We observed an increase in COX-2 protein levels induced by BK that was maximal at 24 h. This increase was blocked by a B2 kinin receptor antagonist but not a B1 receptor antagonist, suggesting that the B2 receptor is involved in this pathway. In addition, we conclude that the activation of mitogen-activated protein kinases p42/p44, protein kinase C, and nitric oxide synthase is necessary for the increase in COX-2 levels induced by BK because either of the specific inhibitors for these enzymes blocked the effect of BK. Using a similar approach, we further demonstrated that reactive oxygen species and cAMP were not mediators on this pathway. These results suggest that BK activates several intracellular pathways that act in combination to increase COX-2 protein levels. This study suggests a role for BK on the evolution of the atheromatous plaque by virtue of controlling the levels of COX-2.

scholarly journals Rapid desensitization of vasopressin-stimulated phosphatidylinositol 4,5-bisphosphate and phosphatidylcholine hydrolysis questions the role of these pathways in sustained diacylglycerol formation in A10 vascular-smooth-muscle cells

1992 ◽  
Vol 285 (3) ◽  
pp. 759-766 ◽  
Author(s):  
R Plevin ◽  
M J O Wakelam
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Inositol Phosphates ◽  
Muscle Cells ◽  
Receptor Activation ◽  
V1a Receptor ◽  
In Cells

The kinetics of vasopressin-stimulated PtdIns(4,5)P2 and phosphatidylcholine (PtdCho) hydrolysis in relation to sustained diacylglycerol (DAG) formation was investigated in A10 vascular-smooth-muscle cells in culture. Vasopressin stimulated a transient increase in Ins(1,4,5)P3 mass formation, which was mirrored by a decrease in PtdIns(4,5)P2 mass levels. Vasopressin stimulated sustained accumulation of total [3H]inositol phosphates ([3H]IP) in the presence of Li+; however, this was significantly decreased by adding a vasopressin-receptor antagonist at different times after initial stimulation. Vasopressin-stimulated phospholipase D (PLD) activity was found to be a transient phenomenon lasting approx. 2 min. Experiments involving agonist preincubation with subsequent addition of butanol confirmed that vasopressin-stimulated PLD activity was desensitized. Vasopressin stimulated an increase in formation of choline, but not of phosphocholine, suggesting that PLD was the major catalytic route of PtdCho hydrolysis in this cell line. The roles of choline and inositol phospholipid hydrolysis in the prolonged phase of DAG formation was examined by comparing vasopressin-stimulated changes in DAG levels in the presence of butanol, the protein kinase C inhibitor Ro-31-8220 or a V1a-receptor antagonist. Vasopressin-stimulated DAG formation was decreased by 40-50% in the presence of butanol between 1 and 10 min; however, during more prolonged stimulation butanol was without significant effect. In cells pretreated with Ro-31-8220, vasopressin-stimulated DAG formation was decreased by approx. 30% at 2 min, but was significantly potentiated at later times. This coincided with an enhancement of vasopressin-stimulated [3H]IP accumulation. In cells exposed to the V1a-receptor antagonist 5 min after addition of vasopressin, subsequent DAG formation was significantly decreased, indicating that sustained formation of DAG, like [3H]IP accumulation, was dependent on continual agonist receptor activation. The results are discussed in terms of different phospholipid-hydrolytic pathways providing DAG generation.

Evidence for Des-Tyr1-D-Ala2-leucine5-enkephalinamide calcium agonist activity in vascular smooth muscle

1987 ◽  
Vol 65 (2) ◽  
pp. 120-123 ◽  
Author(s):  
Michael B. Given ◽  
Gary E. Sander ◽  
Thomas D. Giles
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Calcium Channel ◽  
Receptor Antagonist ◽  
Calcium Influx ◽  
Pressor Response ◽  
Significant Inhibition ◽  
Conscious Dogs

Intravenous administration of the enkephalin analog Des-Tyr1-D-Ala2-Leu5-enkephalinamide (DTALE) to conscious dogs produces a pressor response that is not inhibited by naloxone. In an attempt to explain this observed pressor activity in vivo, the effect of DTALE on vascular smooth muscle was investigated in vitro. DTALE was found to contract rat thoracic aorta strips in a dose-dependent and naloxone-insensitive manner. Pretreatment with reserpine (5 mg/kg) or prazosin was without significant effect. However, a significant inhibition was obtained with cyproheptadine (p < 0.001, n = 5), a 5-hydroxytryptamine (5-HT) receptor antagonist that also has calcium channel blocking activity. Treatment with ketanserin (0.1 μM), a selective 5-HT2-receptor antagonist, had no effect. Reduction of the extracellular calcium concentration from 1.6 to 1.2 mM or 0.8 mM significantly diminished DTALE activity (1.2 mM, p < 0.025; 0.8 mM, p < 0.01; n = 3). Pretreatment with the calcium channel antagonists verapamil (0.1 μM) and nitrendipine (0.05 μM) significantly inhibited DTALE activity (p < 0.001 for both treatments). DTALE also exhibited increased potency in partially depolarized smooth muscle preparations. These results suggest that DTALE may produce vasoconstriction by inducing or facilitating calcium influx. This activity upon arterial vascular strips may provide explanation for the observed pressor response in chronically instrumented conscious dogs.

Resting calcium influx in airway smooth muscle

2005 ◽  
Vol 83 (8-9) ◽  
pp. 717-723 ◽  
Author(s):  
Luis M Montaño ◽  
Blanca Bazán-Perkins
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Calcium Influx ◽  
Physiological Role ◽  
Resting Membrane Potential ◽  
Voltage Dependent ◽  
Intracellular Ca ◽  
Influx Pathways

Plasma membrane Ca2+ leak remains the most uncertain of the cellular Ca2+ regulation pathways. During passive Ca2+ influx in non-stimulated smooth muscle cells, basal activity of constitutive Ca2+ channels seems to be involved. In vascular smooth muscle, the 3 following Ca2+ entry pathways contribute to this phenomenon: (i) via voltage-dependent Ca2+ channels, (ii) receptor gated Ca2+ channels, and (iii) store operated Ca2+ channels, although, in airway smooth muscle it seems only 2 passive Ca2+ influx pathways are implicated, one sensitive to SKF 96365 (receptor gated Ca2+ channels) and the other to Ni2+ (store operated Ca2+ channels). Resting Ca2+ entry could provide a sufficient amount of Ca2+ and contribute to resting intracellular Ca2+ concentration ([Ca2+]i), maintenance of the resting membrane potential, myogenic tone, and sarcoplasmic reticulum-Ca2+ refilling. However, further research, especially in airway smooth muscle, is required to better explore the physiological role of this passive Ca2+ influx pathway as it could be involved in airway hyperresponsiveness.Key words: basal Ca2+ entry, constitutive Ca2+ channels, airway and vascular smooth muscle, SKF 96365, Ni2+.

Abstract 465: The CB2 Cannabinoid Receptor Mediates the Anti-Proliferative Actions of Angiotensin-(1-7) in Vascular Smooth Muscle Cells

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
E. Ann Tallant ◽  
Allyn Howlett ◽  
Megan Grabenauer ◽  
Brian F Thomas ◽  
Patricia E Gallagher
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Receptor Antagonist ◽  
Vascular Smooth Muscle Cells ◽  
Vascular Injury ◽  
Muscle Cells ◽  
Receptor Activation ◽  
Cb2 Receptor ◽  
Vascular Proliferation

Therapeutic interventions to reduce vascular proliferation are critical for the effective treatment of hypertension-induced end-organ damage, restenosis and atherosclerosis. We showed that angiotensin-(1-7) [Ang-(1-7)] reduces neointimal formation following vascular injury and inhibits vascular growth, through activation of the AT7 receptor mas and production of arachidonic acid derivatives. Endocannaboids (ECs) derived from membrane phospholipids also inhibit vascular proliferation and reduce growth following vascular injury, by stimulation of the CB2 receptor. The impact of CB2 receptor blockade on the anti-proliferative actions of Ang-(1-7) was investigated to assess a potential interaction between the EC and Ang-(1-7)/mas receptor systems. Rat thoracic aortic vascular smooth muscle cells (VSMCs) were treated with platelet-derived growth factor (PDGF) to stimulate growth and incubated with Ang-(1-7), the AT7 receptor antagonist [D-alanine7]-angiotensin-(1-7) [Dala], the CB2 receptor agonist HU308 and/or the CB2 receptor antagonist AM630. PDGF-stimulated VSMC growth was markedly reduced by Ang-(1-7) (74 ± 6% of control, n = 10, p<0.0001) and this effect was blocked by Dala (116 ± 14% of control, n = 4; n.s.). The Ang-(1-7)-mediated reduction in growth was abolished by the CB2 receptor antagonist AM630 (136 ± 16% of control, n = 4; n.s.); AM630 alone had no effect. In contrast, the CB1 receptor antagonist AM281 did not prevent the inhibitory actions of Ang-(1-7) on VSMC growth. CB2 receptor activation by the agonist HU308 also reduced PDGF-stimulated VSMC proliferation to a similar extent as Ang-(1-7) (67 ± 4% of control, n = 5, p<0.001); Dala did not influence the response to HU308 (50 ± 10% of control, n = 5, p<0.005). Ang-(1-7) significantly increased the endogenous cannabinoid 2-arachidonoylglycerol (2-AG) by 48% in VSMC by 24 h (p<0.05, n = 4). We conclude that the growth inhibitory properties of Ang-(1-7) involve a novel pathway culminating in the downstream formation of 2-AG and subsequent activation of the CB2 receptor in VSMC. Thus, Ang-(1-7) and/or CB2 receptor activation may constitute a new and beneficial therapeutic strategy for the prevention of vascular proliferation that is prevalent in cardiovascular disease.

Sign in / Sign up

Export Citation Format

Share Document