Bradykinin-activated calcium influx pathway in bovine aortic endothelial cells

1992 ◽  
Vol 262 (4) ◽  
pp. H942-H948 ◽  
Author(s):  
D. Mendelowitz ◽  
K. Bacal ◽  
D. L. Kunze
Keyword(s):  
Endothelial Cells ◽  
Membrane Potential ◽  
Normal Saline ◽  
Voltage Pulse ◽  
Calcium Influx ◽  
Reversal Potential ◽  
Voltage Response ◽  
Aortic Endothelial Cells ◽  
Inward Current ◽  
Bovine Aortic Endothelial Cells

Clusters of electrically coupled endothelial cells were used to characterize a bradykinin (BK)-activated Ca2+ influx pathway. Spatial voltage control of clusters containing three to eight cells, evaluated as the ratio of the voltage response in one cell to a voltage pulse in the most distant cell of the cluster, was 0.96 at a holding potential of 0 mV in normal saline bath and 0.88 in the presence of BK. BK activated an inward current that was carried by either Na+ or Ca2+ when the membrane potential was held at -60 mV. Current was activated within 3 s of application of BK and peaked within 1 min. With Ca2+ as the permeable extracellular ion the current was stable for 1-3 min and then declined over a period of 5-8 min in the continued presence of BK. However, when Na+ carried the current it was sustained over a 10-min test period. The reversal potential of the BK-activated current was near 0 mV, suggesting activation of a nonspecific cation channel(s). The inward current at -60 mV averaged 13 +/- 4.5 pA (n = 9)/cell in Ca2+ and 12.2 +/- 9.3 pA (n = 5)/cell in Na+. Both Na+ and Ca2+ currents were blocked by 200 microM lanthanum.

Effect of membrane potential on cytosolic calcium of bovine aortic endothelial cells

1989 ◽  
Vol 257 (3) ◽  
pp. H778-H784 ◽  
Author(s):  
W. P. Schilling
Keyword(s):  
Endothelial Cells ◽  
Membrane Potential ◽  
Cytosolic Calcium ◽  
Membrane Depolarization ◽  
K Channel ◽  
Membrane Hyperpolarization ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells ◽  
K Concentration ◽  
Aortic Endothelial

The effect of bradykinin on membrane potential of cultured bovine aortic endothelial cells (BAECs) was estimated by measuring the uptake of the lipophilic cation, tetra[3H]phenylphosphonium ([3H]TPP+). Uptake of [3H]TPP+ was found to be 1) a function of extracellular K+ concentration, 2) sensitive to valinomycin, and 3) decreased by the K+ channel inhibitor, Ba2+, suggesting that the uptake of [3H]TPP+ responds to changes in membrane potential of the BAEC. Bradykinin (50 nM) produced an increase in [3H]TPP+ uptake in low K+ buffer consistent with a bradykinin-induced membrane hyperpolarization. The effect of membrane depolarization with high K+ buffer on the bradykinin-stimulated changes in cytosolic Ca2+ was determined using the fluorescent Ca2+ indicator, fura-2. The results of these experiments demonstrated that both basal cytosolic Ca2+ and bradykinin-stimulated release of Ca2+ from internal stores were not affected by membrane depolarization. However, bradykinin-stimulated influx of Ca2+ from the extracellular space decreased with membrane depolarization in a manner consistent with the movement of Ca2+ through a channel.

Bradykinin-stimulated calcium influx in cultured bovine aortic endothelial cells

1988 ◽  
Vol 255 (2) ◽  
pp. H219-H227 ◽  
Author(s):  
W. P. Schilling ◽  
A. K. Ritchie ◽  
L. T. Navarro ◽  
S. G. Eskin
Keyword(s):  
Endothelial Cells ◽  
Calcium Influx ◽  
Peak Level ◽  
Fold Increase ◽  
Aortic Endothelial Cells ◽  
Fourfold Increase ◽  
Bovine Aortic Endothelial Cells ◽  
Induced Changes ◽  
K Permeability ◽  
Aortic Endothelial

Bradykinin (BK)-stimulated release of endothelium-derived relaxing factor has been linked to a rise in cytosolic Ca2+ concentration and a change of K+ permeability of the endothelial cell. In the present study, measurement of BK-induced changes in fura-2 fluorescence and 86Rb+ efflux were used to monitor changes in cytosolic Ca2+ and K+ permeability in cultured bovine aortic endothelial cells. In the presence of normal extracellular Ca2+, BK induced a fourfold increase in cytosolic Ca2+, which peaked at 20 s and declined within 1 min to a value that was 50% of the peak level. Subsequently, cytosolic Ca2+ decreased and approached basal levels within 8 min. In the absence of Ca2+, BK produced a 1.5- to 2-fold increase in cytosolic Ca2+ that peaked within 20 s and declined to basal levels within 2 min. Addition of Ca2+ to the Ca-free reaction buffer 3-5 min after addition of BK resulted in a two-to threefold increase in cytosolic Ca2+ that declined slowly back to basal levels. Thus Ca2+ influx can occur in response to BK at a time when there is minimal elevation of cytosolic Ca2+ above the resting level. Under all conditions tested, 86Rb+ efflux paralleled changes in the cytosolic Ca2+, suggesting that efflux occurred through Ca2+-activated K+ channels. Isosmotic substitution of Na+ with N-methyl-D-glucamine did not affect the BK-stimulated changes in cytosolic Ca2+ or 86Rb+ efflux, suggesting that Na+-Ca2+ exchange plays little role in the BK response. These results suggest that BK stimulates Ca2+ influx via a BK receptor-operated channel or a channel activated by some internal messenger other than Ca2+.

Agonist-induced changes of [Ca2+]i and membrane currents in single bovine aortic endothelial cells

1994 ◽  
Vol 267 (5) ◽  
pp. C1338-C1350 ◽  
Author(s):  
H. M. Himmel ◽  
R. L. Rasmusson ◽  
H. C. Strauss
Keyword(s):  
Endothelial Cells ◽  
Outward Current ◽  
Cyclooxygenase Inhibitors ◽  
Current Response ◽  
Free Solution ◽  
Aortic Endothelial Cells ◽  
Inward Current ◽  
Bovine Aortic Endothelial Cells ◽  
K Current ◽  
Aortic Endothelial

Cultured bovine aortic endothelial cells (BAECs) possess an inward rectifier K+ current (IK1), a Ca(2+)-activated K+ current, a nonselective cation current (INS), and a Ca(2+)-activated Cl- current; however, their relative roles remain to be established. In single BAECs, cytosolic free Ca2+ concentration ([Ca2+]i) [K5-fura 2 (50 microM), ratio 340/380 nm] was measured simultaneously with whole cell currents at 22 degrees C. Bradykinin (BK, 2 microM), ATP (10 microM), ionomycin (100 nM), or 2,5-di-(tert-butyl)-1,4-benzohydroquinone (10 microM) were used as agonists. In physiological salt solution (PSS), agonist exposure caused a rapid [Ca2+]i increase, followed by an increase in outward current (greater than -50 mV) and a smaller increase in inward current (greater than -80 mV). Chelation of [Ca2+]i with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid attenuated agonist-induced [Ca2+]i and current responses. Inactivation of the cyclooxygenase pathway by acetylsalicyclic acid and ibuprofen (50 microM each) did not affect the BK-induced [Ca2+]i transient but abolished the current response. In K(+)-free solution, agonist-stimulated outward currents (at +50 mV) were 10 times smaller than in PSS and were consistent with the activation of both INS and a Cl- current. In Cl(-)-free solution, the outward current response following agonist exposure was virtually abolished; at the same time, a linear inward current component with a reversal potential near the equilibrium potential for Na+ was activated. The maximal amplitude of the agonist-induced outward current decreased with decreasing symmetrical Cl- concentrations. Our results suggest that 1) IKI is the dominant current in resting BAECs; 2) K+, Cl-, and nonselective cation conductances contribute to the agonist-induced current response; and 3) most of the agonist-induced activation of currents depends on increased [Ca2+]i and is sensitive to cyclooxygenase inhibitors.

Ornithine Decarboxylase Activity in Cultured Endothelial Cells Stimulated by Serum, Thrombin and Serotonin

1978 ◽  
Vol 39 (02) ◽  
pp. 496-503 ◽  
Author(s):  
P A D’Amore ◽  
H B Hechtman ◽  
D Shepro
Keyword(s):  
Endothelial Cells ◽  
Ornithine Decarboxylase ◽  
Decarboxylase Activity ◽  
Aortic Endothelial Cells ◽  
Ornithine Decarboxylase Activity ◽  
Rate Limiting Step ◽  
Bovine Aortic Endothelial Cells ◽  
Limiting Step ◽  
Rate Limiting ◽  
Serum Serotonin

SummaryOrnithine decarboxylase (ODC) activity, the rate-limiting step in the synthesis of polyamines, can be demonstrated in cultured, bovine, aortic endothelial cells (EC). Serum, serotonin and thrombin produce a rise in ODC activity. The serotonin-induced ODC activity is significantly blocked by imipramine (10-5 M) or Lilly 11 0140 (10-6M). Preincubation of EC with these blockers together almost completely depresses the 5-HT-stimulated ODC activity. These observations suggest a manner by which platelets may maintain EC structural and metabolic soundness.

Effects of Dipyrone on Prostaglandin Production by Human Platelets and Cultured Bovine Aortic Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 132-137 ◽  
Author(s):  
A Eldor ◽  
G Polliack ◽  
I Vlodavsky ◽  
M Levy
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Ionophore A23187 ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells ◽  
Aortic Endothelial

SummaryDipyrone and its metabolites 4-methylaminoantipyrine, 4-aminoantipyrine, 4-acetylaminoantipyrine and 4-formylaminoan- tipyrine inhibited the formation of thromboxane A2 (TXA2) during in vitro platelet aggregation induced by ADP, epinephrine, collagen, ionophore A23187 and arachidonic acid. Inhibition occurred after a short incubation (30–40 sec) and depended on the concentration of the drug or its metabolites and the aggregating agents. The minimal inhibitory concentration of dipyrone needed to completely block aggregation varied between individual donors, and related directly to the inherent capacity of their platelets to synthesize TXA2.Incubation of dipyrone with cultured bovine aortic endothelial cells resulted in a time and dose dependent inhibition of the release of prostacyclin (PGI2) into the culture medium. However, inhibition was abolished when the drug was removed from the culture, or when the cells were stimulated to produce PGI2 with either arachidonic acid or ionophore A23187.These results indicate that dipyrone exerts its inhibitory effect on prostaglandins synthesis by platelets or endothelial cells through a competitive inhibition of the cyclooxygenase system.

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