Sugar transport regulation in avian red blood cells: role of Ca2+ in the stimulatory effects of anoxia, adrenaline, and ascorbic acid

1982 ◽  
Vol 60 (5) ◽  
pp. 615-621 ◽  
Author(s):  
I. Bihler ◽  
P. Charles ◽  
P. C. Sawh
Keyword(s):  
Ascorbic Acid ◽  
Sugar Transport ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Calcium Dependent ◽  
Transport Regulation ◽  
Intracellular Storage ◽  
Stimulation Of

Membrane transport of sugar and Ca2+ was studied in pigeon erythrocytes by measuring the cell to medium distribution of 3-O-[14C]methyl-D-glucose and 45Ca. We have found that stimulation of sugar transport by anoxia, adrenaline, or ascorbic acid was not dependent on external Ca2+, nor was it additive to the stimulatory effect of the calcium ionophore A23187. Stimulation by ascorbic acid was dependent on concentration and time. The slow basal 45Ca efflux was greatly accelerated by A23187, and this was further increased by adrenaline. A metabolic substrate mixture consisting of adenine, inosine, and fumarate (AIF) did not alter 45Ca efflux, except for antagonizing the effect of adrenaline in the presence of A23187. Sugar transport, whether basal or stimulated by adrenaline or ascorbic acid, was significantly decreased by AIF, independently of external Ca2+. Stimulation by A23187 in the absence of external Ca2+ was also antagonized by AIF. In cells depleted of Ca2+ by treatment with A23187 and EGTA, transport stimulation by adrenaline was abolished. These results suggest that release of Ca2+ from intracellular storage into the cytoplasm plays a role in the stimulation of sugar transport by adrenaline and anoxia and also by A23187 in the absence of external Ca2+. The data provide further indirect support for a calcium-dependent mechanism of sugar transport regulation in nucleated erythrocytes.

Role of calcium in the secretomotor response of the thyroid: effects of calcium ionophore A23187 on radioiodine turnover, membrane potential and fluid transport in cultured porcine thyroid cells

1988 ◽  
Vol 116 (3) ◽  
pp. 373-380 ◽  
Author(s):  
S. W. Manley ◽  
D. S. Rose ◽  
G. J. Huxham ◽  
J. R. Bourke
Keyword(s):  
Calcium Concentration ◽  
Fluid Transport ◽  
Calcium Ionophore ◽  
Feedback Mechanism ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Thyroid Cells ◽  
Negative Feedback Mechanism ◽  
Stimulation Of

ABSTRACT The calcium ionophore A23187 (0·1–1 μmol/l) inhibited membrane electrical polarization, uptake of 125I, fluid transport and TSH-stimulated release of radioiodine from the organic pool in follicular cultures of porcine thyroid cells. At higher concentrations (1–30 μmol/l), A23187 promoted release of radioiodine from the organic pool. Stimulation of release of radioiodine from the organic pool by veratridine (a sodium channel agonist, 0·4–1 mmol/l) and A23187 was dependent on the calcium concentration of the medium, while TSH action was independent. Incubation in medium of very low calcium concentration (0·0177 mmol/l) resulted in enhanced release from the organic pool, which was inhibited by TSH (256 μU/ml), A23187 (25 μmol/l) or veratridine (0·5 mmol/l). These data therefore do not support the hypothesis that calcium acts as a mediator of the secretomotor action of TSH, but suggest the possibility of a TSH-induced increase in intracellular calcium as a regulatory negative-feedback mechanism. J. Endocr. (1988) 116, 373–380

Role of cytosolic calcium in regulation of cytoskeletal gene expression by insulin

1993 ◽  
Vol 264 (4) ◽  
pp. E519-E525 ◽  
Author(s):  
R. S. Weinstock ◽  
C. M. Saville ◽  
J. L. Messina
Keyword(s):  
Calcium Ionophore ◽  
Cytosolic Calcium ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Actin Gene ◽  
Acetoxymethyl Ester ◽  
Alpha Tubulin ◽  
Calcium Dependent ◽  
Beta Actin

Insulin and calcium ionophores rapidly stimulated transcription of the cytoskeletal beta- and gamma-actin genes in serum-deprived rat H4-II-E hepatoma cells. The calcium ionophore A23187 (1 microM) stimulated transcription of the beta-actin gene by 7.3-, 5.4-, and 2.6-fold and the gamma-actin gene by 5.9-, 5.6-, and 2.6-fold at 15, 30, and 60 min, respectively. Ionomycin (1 microM) similarly increased beta- and gamma-actin transcription. Insulin stimulated beta-actin transcription 11.4-fold and gamma-actin 8.4-fold at 30 min. alpha-Tubulin transcription was induced by both insulin and calcium ionophores but to a lesser degree. The effects of A23187 or ionomycin together with insulin for 30 min were no greater than those of insulin alone. Insulin alone, however, did not significantly increase measurable intracellular calcium concentrations in fura-2-loaded cells. When cytosolic calcium was chelated using quin2 acetoxymethyl ester, the ability of A23187 to increase beta- and gamma-actin transcription was completely abolished, whereas insulin's ability to stimulate actin transcription was only partially inhibited. This suggests that the regulation of gene transcription by insulin may include calcium-dependent pathways but strongly implies that calcium-independent pathways are also utilized.

Release of 86Rb from rat submandibular gland slices: relation to sodium pump activity

1984 ◽  
Vol 246 (5) ◽  
pp. G484-G491 ◽  
Author(s):  
D. J. Stewart ◽  
M. Laansoo ◽  
A. K. Sen
Keyword(s):  
Submandibular Gland ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Chloride Ions ◽  
Detectable Effect ◽  
Ionophore A23187 ◽  
Tissue Slices ◽  
Release Process ◽  
Calcium Dependent ◽  
Rat Submandibular Gland

Slices of rat submandibular gland were preloaded with 86Rb, an isotope that can substitute for K+ in the K+ release process. The efflux of 86Rb was monitored in a superfusion apparatus that efficiently removed the 86Rb as it exited from the tissue slices. Carbachol and the calcium ionophore A23187 activated a calcium-dependent increase in 86Rb efflux. Dibutyryl cGMP had no detectable effect on 86Rb efflux in contrast to its activation of ouabain-sensitive uptake of 86Rb observed in an earlier study. The stimulated release of 86Rb was not dependent on the presence of either sodium or chloride ions. When 86Rb efflux was stimulated by carbachol, the efflux rate returned toward the basal rate after a few minutes of exposure to carbachol in the medium. If ouabain was then introduced into the superfusate, a large increase in efflux was stimulated. In the absence of carbachol, only a small increase in 86Rb efflux was stimulated by ouabain. The effect of ouabain indicates that there was a substantial recycling of 86Rb between the release and uptake processes in the extracellular space of the tissue slice. The significance of this observation is discussed.

Tobacco smoke releases performed mediators from canine mast cells and modulates prostaglandin production

1992 ◽  
Vol 263 (1) ◽  
pp. L67-L72
Author(s):  
P. S. Thomas ◽  
R. E. Schreck ◽  
S. C. Lazarus
Keyword(s):  
Mast Cells ◽  
Tobacco Smoke ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Prostaglandin D2 ◽  
Ionophore A23187 ◽  
Temperature Dependent ◽  
Prostaglandin Production ◽  
Lungs And Airways

The role of an extract of tobacco smoke in activating mast cells was studied. With the use of isolated, canine mast cells as a model, we found that cigarette smoke solution (CSS) induced the release of the performed mediators histamine and tryptase from these cells in an energy- and temperature-dependent, non-cytotoxic manner. There was no requirement for extracellular calcium. Nicotine tartrate did not reproduce the effect of CSS. Interestingly, mast cells produced little prostaglandin D2 (PGD2) in response to the CSS, and there was a concentration-related inhibition of calcium ionophore A23187-induced PGD2 synthesis. This suggests at least two mechanisms acting on the mast cell: tobacco smoke can directly activate mast cells to release performed mediators and can simultaneously inhibit prostaglandin production. These observations suggest a mechanism by which mast cells may participate in the bronchospastic and proinflammatory changes seen in the lungs and airways of smokers.

Differential control of type-I iodothyronine deiodinase expression by the activation of the cyclic AMP and phosphoinositol signalling pathways in cultured human thyrocytes

1995 ◽  
Vol 14 (2) ◽  
pp. 171-177 ◽  
Author(s):  
S G Beech ◽  
S W Walker ◽  
J R Arthur ◽  
D Lee ◽  
G J Beckett
Keyword(s):  
Cyclic Amp ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Signalling Pathways ◽  
Cell Labelling ◽  
Ionophore A23187 ◽  
Type I ◽  
Iodothyronine Deiodinase ◽  
Differential Control ◽  
Stimulation Of

ABSTRACT The effects of TSH and the activation of the cyclic AMP (cAMP) and Ca2+-phosphatidylinositol (Ca2+-PI) cascades on the activity and expression of the selenoenzyme thyroidal type-I iodothyronine deiodinase (ID-I) have been studied using human thyrocytes grown in primary culture. Stimulation of ID-I activity and expression was obtained with TSH and an analogue of cAMP, 8-bromo-cAMP. In the presence or absence of TSH, the addition of the phorbol ester, phorbol 12-myristate 13-acetate (PMA) together with the calcium ionophore A23187, caused a decrease in ID-I activity; a decrease in ID-I expression was also observed as assessed by cell labelling with [75 Se]selenite. PMA alone had no effect on ID-I activity in the presence or absence of TSH. A23187 alone produced a small but significant reduction in ID-I activity, but only in TSH-stimulated cells. These data provide evidence that the expression of thyroidal ID-I is negatively regulated by the Ca2+-PI cascade, and positively regulated by the cAMP cascade.

Hypoxic contractile response in isolated human pulmonary artery: role of calcium ion

1988 ◽  
Vol 65 (6) ◽  
pp. 2468-2474 ◽  
Author(s):  
Y. Hoshino ◽  
H. Obara ◽  
M. Kusunoki ◽  
Y. Fujii ◽  
S. Iwai
Keyword(s):  
Pulmonary Artery ◽  
Contractile Response ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Voltage Dependent ◽  
Pulmonary Arterial ◽  
Intracellular Storage ◽  
Human Pulmonary Artery

The mechanism for hypoxic pulmonary vasoconstriction (HPVC) was investigated in human pulmonary arterial strips. Hypoxia in the presence of histamine (10(-6) M) caused marked pulmonary arterial contraction, which was reversed by O2. The hypoxic contraction in the presence of histamine was inhibited by diphenhydramine, but not by cimetidine. The hypoxic histamine-mediated contraction was attenuated but still present in the absence of extracellular Ca2+, or by the inhibitors of voltage-dependent Ca2+ influx. However, it was inhibited significantly by a further depletion of intracellular Ca2+, or by HA 1004, an intracellular calcium antagonist. A low concentration (10(-7) M) of a calcium ionophore, A23187, enhanced the hypoxic contraction in the presence of histamine, whereas procaine completely inhibited it. W-7, a calmodulin inhibitor, significantly decreased the hypoxic histamine-mediated contraction, but 12-O-tetradecanoylphorbol-13-acetate (TPA), a C-kinase promotor, had no effect. The hypoxic contractile response was also observed in the presence of both A23187 and KCl instead of histamine, but the hypoxia-induced contraction with KCl alone was much smaller than that. These results indicate that hypoxia in the presence of certain other vasoactive agents has a potent contractile effect on the human pulmonary artery and that the response is dependent on Ca2+. Enhancement of both Ca2+ influx and Ca2+ release from intracellular storage sites by hypoxia, which interacts with calmodulin, were suggested to be involved in the mechanism of HPVC.

Leptin is involved in acrosome reaction by facilitating activation of MAPK cascades in the Chinese mitten crab, Eriocheir sinensis

2020 ◽  
Vol 70 (1) ◽  
pp. 81-95
Author(s):  
Qing Li ◽  
Haitao Zhao ◽  
Lin He ◽  
Hongdan Yang ◽  
Qun Wang
Keyword(s):  
Acrosome Reaction ◽  
Calcium Ionophore ◽  
Eriocheir Sinensis ◽  
Calcium Ionophore A23187 ◽  
Mitogen Activated Protein Kinase ◽  
Ionophore A23187 ◽  
Mapk Cascades ◽  
Mitten Crab ◽  
Mitogen Activated Protein

Abstract The role of leptin has been documented in several studies, including activated threonine phosphorylation of extracellular signal-regulated kinase (ERK1/2) in the reproduction of rodents and humans. Our previous studies have demonstrated that mitogen-activated protein kinase (MAPK) cascades ERK, P38, and c-Jun N-terminal kinase (JNK) are involved in the spermatogenesis and acrosome reaction of Eriocheir sinensis. Therefore, the aim of this study was to investigate the expression of leptin and its receptor (LepR), and the effect of leptin on MAPK cascades during calcium ionophore A23187-induced spermatozoa acrosome reaction in crabs. Successful western blotting revealed a 16 kDa band for leptin, and 120 kDa and 90 kDa bands for the obese receptor (LepR), respectively, in the tested male reproductive tissues. Both leptin and LepR were localized at the pro-acrosomal vesicle and apical cap (AC) of spermatids, suggesting their role in the subsequent acrosome reaction. Moreover, acrosome reaction can be enhanced by leptin, and this effect decreased due to the anti-LepR antibody. Afterwards, we investigated the effects of leptin on MAPK cascades. The results showed that leptin mainly activated the phosphorylation of ERK, P38 and JNK proteins in the apical cap during the acrosome reaction in crab spermatozoa. This study addresses the role of leptin on spermatozoa, and suggests that leptin may induce molecular changes associated with spermatozoa during acrosome reaction.

scholarly journals Nitric oxide and peroxynitrite trigger and enhance release of neutrophil extracellular traps

2019 ◽  
Vol 77 (15) ◽  
pp. 3059-3075 ◽  
Author(s):  
Aneta Manda-Handzlik ◽  
Weronika Bystrzycka ◽  
Adrianna Cieloch ◽  
Eliza Glodkowska-Mrowka ◽  
Ewa Jankowska-Steifer ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitrosative Stress ◽  
Calcium Ionophore ◽  
Neutrophil Extracellular Traps ◽  
Calcium Ionophore A23187 ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Inflammatory Reactions ◽  
Extracellular Traps

Abstract Despite great interest, the mechanism of neutrophil extracellular traps (NETs) release is not fully understood and some aspects of this process, e.g. the role of reactive nitrogen species (RNS), still remain unclear. Therefore, our aim was to investigate the mechanisms underlying RNS-induced formation of NETs and contribution of RNS to NETs release triggered by various physiological and synthetic stimuli. The involvement of RNS in NETs formation was studied in primary human neutrophils and differentiated human promyelocytic leukemia cells (HL-60 cells). RNS (peroxynitrite and nitric oxide) efficiently induced NETs release and potentiated NETs-inducing properties of platelet activating factor and lipopolysaccharide. RNS-induced NETs formation was independent of autophagy and histone citrullination, but dependent on the activity of phosphoinositide 3-kinases (PI3K) and myeloperoxidase, as well as selective degradation of histones H2A and H2B by neutrophil elastase. Additionally, NADPH oxidase activity was required to release NETs upon stimulation with NO, as shown in NADPH-deficient neutrophils isolated from patients with chronic granulomatous disease. The role of RNS was further supported by increased RNS synthesis upon stimulation of NETs release with phorbol 12-myristate 13-acetate and calcium ionophore A23187. Scavenging or inhibition of RNS formation diminished NETs release triggered by these stimuli while scavenging of peroxynitrite inhibited NO-induced NETs formation. Our data suggest that RNS may act as mediators and inducers of NETs release. These processes are PI3K-dependent and ROS-dependent. Since inflammatory reactions are often accompanied by nitrosative stress and NETs formation, our studies shed a new light on possible mechanisms engaged in various immune-mediated conditions.

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