scholarly journals Cytosolic free calcium changes induced by chemotactic peptide in neutrophils from patients with chronic granulomatous disease

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 231-233 ◽  
Author(s):  
PD Lew ◽  
C Wollheim ◽  
RA Seger ◽  
T Pozzan
Keyword(s):  
Chronic Granulomatous Disease ◽  
Calcium Concentration ◽  
Cytosolic Calcium ◽  
Human Neutrophils ◽  
Free Calcium ◽  
Granulomatous Disease ◽  
Chemotactic Peptide ◽  
Intact Cells ◽  
Calcium Indicator ◽  
Free Calcium Concentration

Abstract Cytoplasmic free calcium concentration (Ca2+)i was measured in neutrophils from patients with the classical X-linked form of chronic granulomatous disease (CGD) by trapping the fluorescent calcium indicator Quin 2 in intact cells. CGD neutrophils do not produce superoxide and are only slightly depolarized upon stimulation by the chemotactic peptide. N-formyl-methionyl-leucyl-phenylalanine (FMLP). The resting levels, as well as (Ca2+)i changes induced by FMLP in CGD cells, were quantitatively and kinetically similar to those observed in normal cells. We conclude that the defect in CGD cells is distal to, or independent of, the changes in (Ca2+)i induced by FMLP stimulation and that normal membrane depolarization does not seem to be necessary for receptor-mediated rise in free cytosolic calcium in human neutrophils.

scholarly journals Cytosolic free calcium changes induced by chemotactic peptide in neutrophils from patients with chronic granulomatous disease

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 231-233
Author(s):  
PD Lew ◽  
C Wollheim ◽  
RA Seger ◽  
T Pozzan
Keyword(s):  
Chronic Granulomatous Disease ◽  
Calcium Concentration ◽  
Cytosolic Calcium ◽  
Human Neutrophils ◽  
Free Calcium ◽  
Granulomatous Disease ◽  
Chemotactic Peptide ◽  
Intact Cells ◽  
Calcium Indicator ◽  
Free Calcium Concentration

Cytoplasmic free calcium concentration (Ca2+)i was measured in neutrophils from patients with the classical X-linked form of chronic granulomatous disease (CGD) by trapping the fluorescent calcium indicator Quin 2 in intact cells. CGD neutrophils do not produce superoxide and are only slightly depolarized upon stimulation by the chemotactic peptide. N-formyl-methionyl-leucyl-phenylalanine (FMLP). The resting levels, as well as (Ca2+)i changes induced by FMLP in CGD cells, were quantitatively and kinetically similar to those observed in normal cells. We conclude that the defect in CGD cells is distal to, or independent of, the changes in (Ca2+)i induced by FMLP stimulation and that normal membrane depolarization does not seem to be necessary for receptor-mediated rise in free cytosolic calcium in human neutrophils.

Angiotensin II causes sustained elevations in cytosolic calcium in glomerulosa cells

1988 ◽  
Vol 255 (3) ◽  
pp. E338-E346 ◽  
Author(s):  
R. E. Kramer
Keyword(s):  
Angiotensin Ii ◽  
Calcium Concentration ◽  
Cytosolic Calcium ◽  
Calcium Signal ◽  
Free Calcium ◽  
Cytosolic Free Calcium ◽  
Cytosolic Calcium Concentration ◽  
Free Calcium Concentration ◽  
Cytosolic Free Calcium Concentration ◽  
Glomerulosa Cells

Studies were conducted to examine the effects of angiotensin II on cytosolic free calcium concentration in bovine adrenal glomerulosa cells maintained in primary culture. The calcium indicator, fura-2, and discontinuous dual-wavelength fluorescence spectroscopy were used to measure cytosolic free calcium in superfused adherent cell monolayers. Basal cytosolic free calcium concentration was 63.7 +/- 3.3 nM. The threshold concentration for angiotensin II-stimulated increases in cytosolic calcium was 10(-14)-10(-13) M, and maximal elevation of cytosolic calcium was produced by 10(-9) M angiotensin II. Angiotensin II (10(-13) M) produced a gradual increase in cytosolic calcium concentration that plateaued after 3-5 min of superfusion at a level approximately 1.2 times that of control cells. The calcium signal invoked by a maximal concentration (10(-9) M) of angiotensin II, in contrast, was characterized by an immediate, intense (approximately 8-fold) increase in cytosolic calcium concentration that decayed within 5 min to a lower, but sustained, level 2.5-3 times that of control cells. The calcium signals invoked by intermediate concentrations (10(-12)-10(-10) M) of angiotensin II exhibited dose-dependent increases in magnitude and a gradual transition in nature between those invoked by threshold and maximal concentrations of the peptide. The effect of angiotensin II to increase cytosolic calcium concentration was accompanied by an increase in aldosterone output. The increase in steroidogenesis was most closely correlated with the magnitude of the initial calcium signal. At high concentrations (10(-10) and 10(-9) M) of angiotensin II, there was a clear dissociation between aldosterone output and the magnitude of the sustained calcium signal.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Attachment to fibronectin or vitronectin makes human neutrophil migration sensitive to alterations in cytosolic free calcium concentration.

1991 ◽  
Vol 112 (1) ◽  
pp. 149-158 ◽  
Author(s):  
P W Marks ◽  
B Hendey ◽  
F R Maxfield
Keyword(s):  
Calcium Concentration ◽  
Neutrophil Migration ◽  
Human Neutrophils ◽  
Free Calcium ◽  
Cytosolic Free Calcium ◽  
Coated Glass ◽  
Free Calcium Concentration ◽  
Cytosolic Free Calcium Concentration ◽  
Migration Of Cells

Transient increases in cytosolic free calcium concentration, [Ca2+]i, appear to be required for the migration of human neutrophils on poly-D-lysine-coated glass in the presence of dilute serum (Marks, P. W., and F. R. Maxfield. 1990. J. Cell Biol. 110:43-52). In contrast, no requirement for [Ca2+]i transients exists when neutrophils migrate on albumin-coated glass in the absence of serum. To determine the mechanism that necessitates [Ca2+]i transients on poly-D-lysine in the presence of serum, migration was examined on substrates consisting of purified adhesive glycoproteins. In the absence of external Ca2+, a treatment which causes the cessation of [Ca2+]i transients, migration on fibronectin (fn) and vitronectin (vn) was significantly inhibited. Migration was also inhibited in Ca2(+)-buffered cells on these substrates, indicating that this effect was the result of an alteration of [Ca2+]i. In the absence of external Ca2+, the inhibition of migration on fn or vn was more pronounced when soluble fn or vn was added to cells migrating on these substrates. This effect of soluble adhesive glycoprotein was specific: in the absence of external Ca2+, soluble fn did not affect the migration of cells on vn, and soluble vn did not affect the migration on fn. No additional inhibition of migration was observed in Ca2(+)-buffered cells with the addition of soluble adhesive glycoprotein. These data indicate that [Ca2+]i transients are involved in continued migration of human neutrophils on fn or vn, proteins which are part of the extracellular matrix that neutrophils encounter in vivo.

Depressed intracellular calcium transients and contraction in myocytes from hypertrophied and failing guinea pig hearts

1991 ◽  
Vol 261 (2) ◽  
pp. H514-H530 ◽  
Author(s):  
F. M. Siri ◽  
J. Krueger ◽  
C. Nordin ◽  
Z. Ming ◽  
R. S. Aronson
Keyword(s):  
Calcium Concentration ◽  
Sarcomere Length ◽  
Pressure Overload ◽  
Left Ventricular ◽  
Free Calcium ◽  
Impaired Left Ventricular Function ◽  
Intact Cells ◽  
Fura 2 ◽  
Free Calcium Concentration ◽  
Gradual Pressure

We investigated the basis for impaired left ventricular function of hearts in which hypertrophy was produced by gradual pressure overload. We measured myoplasmic free calcium concentration ([Ca2+]i) with fura-2 and sarcomere shortening in single myocytes isolated from control hearts and hypertrophied failing hearts. Diastolic [Ca2+]i was normal, but [Ca2+]i at the peak of contraction was depressed in myocytes from failing hypertrophied hearts. Increasing drive rate from 0.20 Hz to 5.00 Hz increased both diastolic and peak [Ca2+]i. Norepinephrine (3 x 10(-6) M) increased diastolic [Ca2+]i in all cells and tended to normalize peak [Ca2+]i in myocytes from hypertrophied failing hearts during 5.00 Hz drive. Depressed peak [Ca2+]i in the hypertrophied cells was paralleled by significant decreases in both the velocity and percent of sarcomere shortening, which were measured in cells not loaded with fura-2. Sarcomere length was correlated with estimates of [Ca2+]i in intact cells and with controlled levels of [Ca2+] in chemically "skinned" myocytes. A plot of sarcomere length against [Ca2+] gave a single continuous relationship that spanned resting and peak values at all drive rates in both the control and hypertrophied myocytes. Thus heart failure in this model is reflected in impaired myocyte contraction, which is closely related to reduced levels of [Ca2+]i during systole rather than to depressed myofilament sensitivity to Ca2+.

scholarly journals The dynamics of exocytosis in human neutrophils.

1988 ◽  
Vol 107 (6) ◽  
pp. 2117-2123 ◽  
Author(s):  
O Nüsse ◽  
M Lindau
Keyword(s):  
Calcium Concentration ◽  
Cytochalasin B ◽  
Intracellular Free Calcium ◽  
Morphological Data ◽  
Human Neutrophils ◽  
Free Calcium ◽  
Membrane Area ◽  
Intracellular Free Calcium Concentration ◽  
Free Calcium Concentration ◽  
Gamma S

We have investigated the dynamics of exocytosis in single human neutrophils. The increase of membrane area associated with granule fusion was followed by time-resolved patch-clamp capacitance measurements. Intracellular application of 20 microM guanosine-5'-O(3-thiotriphosphate) (GTP gamma S) in the presence of 2.5 mM ATP stimulated exocytosis and led to an increase of membrane capacitance from 3.0 to integral of 8.4 pF corresponding to a 540 micron 2 increase of membrane area. This capacitance change is very close to the value expected from morphological data if all primary and secondary granules fuse with the plasma membrane. High resolution measurements revealed stepwise capacitance changes corresponding to the fusion of individual granules. GTP gamma S-stimulated exocytosis did not require pretreatment with cytochalasin B and the amplitude was independent of the intracellular-free calcium concentration between 10 nM and integral of 2.5 microM. In the absence of GTP gamma S elevation of intracellular-free calcium concentration to the micromolar range led to the fusion of only a limited number of granules. Degranulation stimulated with GTP gamma S started after a lag phase of 2-7 min and was usually complete within 5-20 min. The time course was affected by the intracellular ATP and calcium concentration. Exocytosis was markedly accelerated by pretreatment with cytochalasin B. Our results demonstrate that the final steps leading to primary and secondary granule fusion are controlled by a guanine nucleotide-binding protein and do not require an elevation of intracellular calcium. Calcium and other factors are, however, involved in the regulation having pronounced effects on the dynamics of exocytosis.

IMAGING CALCIUM WAVES IN EGGS AND EMBRYOS

1993 ◽  
Vol 184 (1) ◽  
pp. 213-219 ◽  
Author(s):  
I Gillot ◽  
M Whitaker
Keyword(s):  
Latent Period ◽  
Calcium Concentration ◽  
Calcium Influx ◽  
Embryonic Cell ◽  
Calcium Wave ◽  
Free Calcium ◽  
Calcium Indicator ◽  
Free Calcium Concentration ◽  
Indicator Dyes ◽  
Indicator Dye

Sea urchin eggs and those of most other deuterostomes are activated at fertilization by an increase in cytoplasmic free calcium concentration ([Ca2+]i) that triggers the onset of the embryonic cell division cycles. We can image the calcium wave using fluorescent calcium indicator dyes and confocal microscopy. There are two components to the [Ca2+]i increase at fertilization. The first is due to a rapid calcium influx caused by a calcium action potential; this leads to a small increase in [Ca2+]i just beneath the plasma membrane with spherical symmetry. After a latent period of some 15 s, there is a second large and rapid increase in [Ca2+]i localized to the region of sperm-egg contact: during the latent period [Ca2+]i does not change but within 1 s of the end of the latent period [Ca2+]i reaches 2 micromolar. The calcium wave then spreads across the egg with a velocity of 5 micrometre s-1. Behind the advancing wavefront, the calcium concentration is uniformly high, even within the egg nucleus, though there are no indications that intranuclear calcium concentration differs from [Ca2+]i. [Ca2+]i falls uniformly towards resting levels over the next 500 s. In cases where there is an apparent inhomogeneity in [Ca2+]i in either the cortex or the nucleus, we find that the calcium indicator dye is inhomogeneously distributed. This appears to be due to uptake of the indicator dye (Fluo-3), probably into mitochondria. The artefact can be avoided by using a dextran-conjugated dye.

Correlation of Blood Pressure in End-Stage Renal Disease with Platelet Cytosolic Free Calcium Concentration during Treatment of Renal Anemia with Recombinant Human Erythropoietin

1992 ◽  
Vol 15 (6) ◽  
pp. 343-348 ◽  
Author(s):  
H. Schiffl
Keyword(s):  
Blood Pressure ◽  
Recombinant Human Erythropoietin ◽  
Body Fluid ◽  
Calcium Concentration ◽  
Plasma Renin ◽  
Cytosolic Calcium ◽  
Free Calcium ◽  
Human Erythropoietin ◽  
Induced Hypertension ◽  
Free Calcium Concentration

The hemodynamic hallmark of hypertension complicating the treatment of renal anemia with recombinant human erythropoietin (rHu-EPO) is increased total peripheral vascular resistance, but the mechanisms underlying the arteriolar vasoconstriction are still an enigma. We studied body fluid volumes, plasma renin activity, plasma norepinephrine, and calcium metabolism in platelets in 40 previously normotensive hemodialysis patients before and after 12 weeks of rHu-EPO treatment. Partial correction of anemia caused a rise in arterial pressure (94 ± 6 mmHg vs 124 ± 7 mmHg, p < 0.05) and in platelet cytosolic calcium concentration (113 ± 5 nM vs 171 ± 18 nM, p < 0.05) in eight patients. Hypertensive patients had significantly higher plasma noradrenaline concentrations, but they did not differ significantly in body fluid volumes and plasma renin activities. There was a close correlation between free calcium concentration in platelets and mean arterial pressure in patients developing rHu-EPO-induced-hypertension (r = 0.95). Short-term antihypertensive treatment resulted in a reduction of free calcium concentrations in platelets and a concomitant fall in blood pressure. The main results of the present studies suggest that rHu-EPO-induced hypertension might be associated with altered cellular calcium homeostasis and hyperactivity of the sympathetic nervous system. If rHu-EPO therapy induces alterations of pressor factors or the hormone itself raises the cytosolic calcium not only in platelets but also in vascular smooth muscle cells, altered cellular calcium influx may contribute to the arteriolar vasoconstriction.

scholarly journals Flunarizine Blocks Elevation of Free Cytosolic Calcium in Synaptosomes following Sustained Depolarization

1993 ◽  
Vol 13 (6) ◽  
pp. 947-954 ◽  
Author(s):  
Stanley L. Cohan ◽  
David J. Redmond ◽  
Mei Chen ◽  
Dahlia Wilson ◽  
Philip Cyr
Keyword(s):  
Cerebral Ischemia ◽  
Calcium Concentration ◽  
Cytosolic Calcium ◽  
Free Calcium ◽  
Protective Effects ◽  
Cytosolic Free Calcium ◽  
Free Calcium Concentration ◽  
Cytosolic Free Calcium Concentration ◽  
Presynaptic Calcium

Gerbil cerebral cortical synaptosomes loaded with the fluorescent calcium probe FURA-2 were used to study depolarization-induced presynaptic cytosolic free calcium concentration, as an in vitro model of cerebral ischemia. The depolarization-induced increase in intrasynaptosomal cytosolic free calcium concentration is not sodium-dependent or sodium channel-dependent and may be due to an influx of extrasynaptosomal calcium resulting from a cadmium- and omega-conotoxin-sensitive, nickel-, nifedipine-, and nimodipine-insensitive voltage-regulated channel. The depolarization-induced increase in intrasynaptosomal free cytosolic calcium concentration is also inhibited by flunarizine, a calcium antagonist that has protective effects in animal models of cerebral anoxia and ischemia. Our results suggest that presynaptic calcium uptake following depolarization may be mediated in part by an N-type channel. Flunarizine may block presynaptic calcium accumulation, in part, by blocking this N-type channel; this blockade may be just one of several mechanisms by which flunarizine exerts protective effects following cerebral ischemia.

Hypothalamic Hypophyseal Inhibitory Factor (HHIF) Increases Intrasynaptosomal Free Calcium Concentration

Hypertension ◽  
1997 ◽  
Vol 29 (6) ◽  
pp. 1337-1343 ◽  
Author(s):  
Mercedes Ricote ◽  
Elena Garcia-Martin ◽  
Jose Sancho ◽  
Carlos Gutierrez-Merino
Keyword(s):  
Calcium Concentration ◽  
Inhibitory Factor ◽  
Free Calcium ◽  
Free Calcium Concentration

Identification of ecto-PKC on surface of human platelets: role in maintenance of latent fibrinogen receptors

2000 ◽  
Vol 278 (6) ◽  
pp. H2008-H2019 ◽  
Author(s):  
Anna Babinska ◽  
Michael V. Hogan ◽  
Tomasz Sobocki ◽  
Malgorzata B. Sobocka ◽  
Yigal H. Ehrlich ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Calcium Concentration ◽  
Surface Protein ◽  
Human Platelets ◽  
Surface Proteins ◽  
Free Calcium ◽  
Platelet Surface ◽  
Inhibitory Peptides ◽  
Intracellular Free Calcium Concentration ◽  
Free Calcium Concentration

Human platelets express a protein phosphorylation system on their surface. A specific protein kinase C (PKC) antibody, monoclonal antibody (MAb) 1.9, which binds to the catalytic domain of PKC and inhibits its activity, causes the aggregation of intact platelets while inhibiting the phosphorylation of platelet surface proteins. Photoaffinity labeling with 100 nM 8-azido-[α32P]ATP identified this ecto-PKC as a single surface protein of 43 kDa sensitive to proteolysis by extracellular 0.0005% trypsin. Inhibition of the binding of 8-azido-[α32P]ATP to the 43-kDa surface protein by MAb 1.9 identified this site as the active domain of ecto-PKC. Covalent binding of the azido-ATP molecule to the 43-kDa surface protein inhibited the phosphorylative activity of the platelet ecto-PKC. Furthermore, PKC pseudosubstrate inhibitory peptides directly induced the aggregation of platelets and inhibited azido-ATP binding to the 43-kDa protein. Platelet aggregation induced by MAb 1.9 and by PKC inhibitory peptides required the presence of fibrinogen and resulted in an increase in the level of intracellular free calcium concentration. This increase in intracellular free calcium concentration induced by MAb 1.9 was found to be dependent on the binding of fibrinogen to activated GPIIb/IIIa integrins, suggesting that MAb 1.9 causes Ca2+flux through the fibrinogen receptor complex. We conclude that a decrease in the state of phosphorylation of platelet surface proteins caused by inhibition of ecto-PKC results in membrane rearrangements that can induce the activation of latent fibrinogen receptors, leading to platelet aggregation. Accordingly, the maintenance of a physiological steady state of phosphorylation of proteins on the platelet surface by ecto-PKC activity appears to be one of the homeostatic mechanisms that maintain fibrinogen receptors of circulating platelets in a latent state that cannot bind fibrinogen.

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