Permeation of Pb2+ through calcium channels: fura-2 measurements of voltage- and dihydropyridine-sensitive Pb2+ entry in isolated bovine chromaffin cells

Tomsig, Jose L.; Suszkiw, Janusz B.

doi:10.1016/0005-2736(91)90124-q

Cited by 89 publications

(52 citation statements)

References 8 publications

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“…30) Lead characteristically perturbs the calcium-dependent intracellular regulation pathway by increasing the intracellular calcium level and/or mimicking calcium in various cell types, [12][13][14][15][16][17] although the metal can be an effective antagonist of calcium transients under certain conditions. [31][32][33] In the present study, it was shown that A23187 suppresses the synthesis of proteoglycans, and lead increases the accumulation of intracellular calcium, suggesting that lead inhibition of endothelial proteoglycan synthesis 7,8) is mediated by the intracellular calcium increased by the metal. On the other hand, A23187 stimulates the secretion of tissue plasminogen activator but sup- presses that of plasminogen activator inhibitor type 1,6) whereas lead inhibits the secretion of the activator but does not influence that of the inhibitor; 34) this effect of lead was suggested to be mediated by the cyclic AMP-dependent pathway.…”

Section: Discussionsupporting

confidence: 48%

Suppression of Proteoglycan Synthesis by Calcium Ionophore A23187 in Cultured Vascular Endothelial Cells: Implication of Intracellular Calcium Accumulation in Lead Inhibition of Endothelial Proteoglycan Synthesis.

Fujiwara

Kaji

2002

JOURNAL OF HEALTH SCIENCE

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The purpose of the present study is to address the question of whether accumulation of intracellular calcium modulates the regulation of proteoglycan synthesis in vascular endothelial cells. Bovine aortic endothelial cells were treated with calcium ionophore A23187 in the presence of [ 35 S]sulfate, and the labeled proteoglycans were analyzed by the cetylpyridinium chloride precipitation method and DEAE-Sephacel ion-exchange chromatography. The results showed that A23187 significantly decreases the accumulation of proteoglycans, especially heparan sulfate proteoglycans, in the cell layer and the conditioned medium of vascular endothelial cells. On the other hand, it was shown that lead, a heavy metal that inhibits endothelial heparan sulfate proteoglycan synthesis, significantly increased the intracellular calcium accumulation when the accumulation was assessed by calcium-45. The present data suggest that accumulation of intracellular calcium results in a suppression of heparan sulfate proteoglycan synthesis in vascular endothelial cells; the suppression may be one of the intracellular mechanisms for lead inhibition of endothelial heparan sulfate proteoglycan synthesis.

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Section: Discussionsupporting

confidence: 48%

Suppression of Proteoglycan Synthesis by Calcium Ionophore A23187 in Cultured Vascular Endothelial Cells: Implication of Intracellular Calcium Accumulation in Lead Inhibition of Endothelial Proteoglycan Synthesis.

Fujiwara

Kaji

2002

JOURNAL OF HEALTH SCIENCE

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“…The inhibition of Ca-channel activity by Pb 2+ could result either from competitive transport of Pb 2+ through Cachannel or from its blockage by Pb. While monitoring Pb entry into isolated cells, Tomsig and Suszkiw (1991) observed permeation of Pb through Ca-channels. In maize and wheat plasma membrane vesicles the Ca 2+ channel is very sensitive to La 3+ (Tyerman and Skerrett 1999).…”

Section: Discussionmentioning

confidence: 99%

Organic acids enhance the uptake of lead by wheat roots

Wang

Shan

Liu

et al. 2006

Planta

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The uptake and bioavailability of lead (Pb) in soil-plant systems remain poorly understood. This study indicates that acetic and malic acids enhance the uptake of Pb by wheat (Triticum aestivum L.) roots under hydroponic conditions. The net concentration-dependent uptake influx of Pb in the presence and absence of organic acids was characterized by Michaelis-Menten type nonsaturating kinetic curves that could be resolved into linear and saturable components. Fitted maximum uptake rates (V max ) of the Michaelis-Menton saturable component in the presence of acetic and malic acids were, respectively, 2.45 and 1.63 times those of the control, while the Michaelis-Menten K m values of 5.5, 3.7 and 2.2 lM, respectively, remained unchanged. Enhanced Pb uptake by organic acids was partially mediated by Ca 2+ and K + channels, and also depended upon the physiological function of the plasma membrane P-type ATPase. Uptake may have been further enhanced by an effectively thinner unstirred layer of Pb adjacent to the roots, leading to more rapid diffusion towards roots. X-ray absorption spectroscopic studies provided evidence that the coordination environment of Pb in wheat roots was similar to that of Pb(CH 3 COO) 2 Á3H 2 O in that one Pb atom was coordinated to four oxygen atoms via the carboxylate group.

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“…Lead competes with Ca for the same coupling site in the cell (Godbold and Kettner, 1991). Moreover, Pb can be transported through Ca channels to the symplast (Tomsig and Suszkiw, 1991).…”

Section: Tolerance and Prospection Of Phytoremediator Woody Speciesmentioning

confidence: 99%

Tolerance and prospection of phytoremediator woody species of Cd, Pb, Cu and Cr

Almeida

Valle

Mielke

et al. 2007

Braz. J. Plant Physiol.

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High concentrations of Cd, Pb, Cu and Cr can cause harmful effects to the environment. These highly toxic pollutants constitute a risk for aquatic and terrestrial life. They are associated with diverse bioavailable geochemical fractions, like the water-soluble fraction and the exchangeable fraction, and non-available fractions like those associated with the crystalline net of clays and silica minerals. Depending upon their chemical and physical properties we can distinguish different mechanisms of metal toxicity in plants, such as production of reactive oxygen species from auto-oxidation, blocking and/or displacement of essential functional groups or metallic ions of biomolecules, changes in the permeability of cellular membranes, reactions of sulphydryl groups with cations, affinity for reactions with phosphate groups and active groups of ADP or ATP, substitution of essential ions, induction of chromosomal anomalies and decrease of the cellular division rate. However, some plant species have developed tolerance or resistance to these metals naturally. Such evolution of ecotypes is a classic example of local adaptation and microevolution, restricted to species with appropriate genetic variability. Phytoremediator woody species, with (i) high biomass production, (ii) a deep root system, (iii) high growth rate, (iv) high capacity to grow in impoverished soils, and (v) high capacity to allocate metals in the trunk, can be an alternative for the recovery of degraded soils due to excess of metallic elements. Phytoremediation using woody species presents advantageous characteristics as an economic and ecologically viable system, making it an appropriate, practical and successful technology. Key-words: decontamination, heavy metals, hyperaccumulation, phytodegradation, phytostabilization, phytotoxicity Tolerância e prospecção de espécies lenhosas fitorremediadoras de Cd, Pb, Cu e Cr: Altas concentrações de Cd, Pb, Cu e Cr podem provocar efeitos danosos ao ambiente. Esses poluentes altamente tóxicos constituem um risco para a vida aquática e terrestre. Encontram-se associados às diversas frações geoquímicas biodisponíveis, a exemplo da fração solúvel em água e da fração trocável, e as não disponíveis como a fração associada à rede cristalina de argilas e de minerais silicatados. Conforme as suas propriedades químicas e físicas podem-se distinguir mecanismos diferentes de toxicidade de metais em plantas, tais como produção de espécies reativas de oxigênio pela auto-oxidação, bloqueio e, ou, deslocamento de grupos funcionais ou de íons metálicos essenciais de biomoléculas, mudanças na permeabilidade de membranas celulares, reações de grupos sulfidrílicos com cátions, afinidade para reações com grupos fosfatos e grupos ativos de ADP ou ATP, substituição de íons essenciais, indução de anomalias cromossomais e decréscimo da taxa de divisão celular. Várias espécies vegetais desenvolveram, naturalmente, tolerância ou resistência a esses metais. Essa evolução de ecótipos é exemplo clássico de adaptação local e de microevolução,...

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Permeation of Pb2+ through calcium channels: fura-2 measurements of voltage- and dihydropyridine-sensitive Pb2+ entry in isolated bovine chromaffin cells

Cited by 89 publications

References 8 publications

Suppression of Proteoglycan Synthesis by Calcium Ionophore A23187 in Cultured Vascular Endothelial Cells: Implication of Intracellular Calcium Accumulation in Lead Inhibition of Endothelial Proteoglycan Synthesis.

Suppression of Proteoglycan Synthesis by Calcium Ionophore A23187 in Cultured Vascular Endothelial Cells: Implication of Intracellular Calcium Accumulation in Lead Inhibition of Endothelial Proteoglycan Synthesis.

Organic acids enhance the uptake of lead by wheat roots

Tolerance and prospection of phytoremediator woody species of Cd, Pb, Cu and Cr

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