Alkaline Earths, Transition Metals, and Lanthanides

Evans, Christopher H.

doi:10.1007/978-3-642-71806-9_25

Cited by 5 publications

(4 citation statements)

References 70 publications

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“…The Ca2+ influx across the plasma membrane may be solely responsible for ZT-A-induced aggregation of platelets. Thus, ZT-A-induced platelet aggregation was inhibited by inorganic Ca2+ channel antagonists such as Cd2+, Co2+ and Mn2+ (Evans, 1988). Doyle & Riiegg (1985) reported that depolarization of platelets with 50 mM KC1 did not induce Ca2+ entry into platelets and that a Ca2+ channel agonist, Bay K 8644, did not affect the Ca2+ influx or [Ca21], in platelets, showing that platelets may lack voltage-gated Ca2+ channels (Siess, 1989; Rink & Sage, 1990).…”

Section: Discussionmentioning

confidence: 99%

“…Figure 5 shows the external Ca2+-dependency of ZT-A (2 gM)-induced platelet aggregation and increase in [Ca21],. Since Co2+, Cd2`and Mn2+ are known to interfere with Ca2" influx through Ca2+ channels at the plasma membrane (Evans, 1988), we investigated the effects of these divalent cations on the platelet aggregation induced by ZT-A (2 uM) in the presence of 1 mM Ca2" (Figure 6). Cd2+ (0.1-1 mM), Co2+ (1-10 mM) and Mn2+ (1-10 mM) inhibited platelet aggregation induced by ZT-A (2 gM) ( Figure 6).…”

Section: Effects Of Zt-a On Platelet Aggregation and [Ca2"]mentioning

confidence: 99%

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Activation of rabbit platelets by Ca²⁺ influx and thromboxane A₂ release in an external Ca²⁺‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Rho

Nakahata

Nakamura

et al. 1995

British J Pharmacology

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Zooxanthellatoxin‐A (ZT‐A), a novel polyhydroxylated long chain compound, isolated from a symbiotic marine alga Simbiodinium sp., caused aggregation in rabbit washed platelets in a concentration‐dependent manner (1–4 μM), accompanied by an increase in cytosolic Ca2+ concentration ([Ca2+]i). ZT‐A did not cause platelet aggregation or increase [Ca2+]i in a Ca2+‐free solution, and Cd2+ (0.1‐1 mM), Co2+ (1–10 mM) and Mn2+ (1–10 mM) inhibited ZT‐A‐induced aggregation. SK&F96365 (1–100 μM), a receptor operated Ca2+ channel antagonist, and mefenamic acid (0.1–10 μM), a non‐specific divalent cation channel antagonist, inhibited platelet aggregation and the increase in [Ca2+], induced by ZT‐A. Indomethacin (0.1–10 μM), a cyclo‐oxygenase inhibitor, and SQ‐29548 (0.1–10 μM), a thromboxane A2 (TXA2) receptor antagonist, inhibited platelet aggregation and the increase in [Ca2+]i induced by ZT‐A. Methysergide (0.01‐1 μM), a 5‐HT2 receptor antagonist, inhibited ZT‐A‐induced platelet aggregation but did not affect the increase in [Ca2+]i induced by ZT‐A. Tetrodotoxin (1 μM), a Na+ channel blocker and chlorpheniramine (1 μM), a H1‐histamine receptor antagonist, neither affected ZT‐A‐induced platelet aggregation nor the increase in [Ca2+]i induced by ZT‐A. Genistein (1–100 μM), a protein tyrosine kinase inhibitor, and staurosporine (0.01‐1 μM), a protein kinase C inhibitor, also inhibited ZT‐A‐induced platelet aggregation. The present results suggest that ZT‐A elicits Ca2+‐influx from platelet plasma membranes. The resulting increase in [Ca2+]i subsequently stimulates the secondary release of TXA2 from platelets. Furthermore, the response to ZT‐A may be associated with tyrosine phosphorylation.

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Section: Discussionmentioning

confidence: 99%

Section: Effects Of Zt-a On Platelet Aggregation and [Ca2"]mentioning

confidence: 99%

Activation of rabbit platelets by Ca²⁺ influx and thromboxane A₂ release in an external Ca²⁺‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Rho

Nakahata

Nakamura

et al. 1995

British J Pharmacology

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“…The rate of MTX-induced aggregation in the presence of Ba2+ was approximately 45% lower than in the presence of Ca2 , while aggregation was nearly maximal (Table 1). This suggests that, like many other Ca2+dependent responses of a number of cells (review: Evans, 1988), Ba2+ is capable of substituting for Ca2+ in the MTXinduced aggregation response of the platelet. Figure 4 shows concentration-response relationships for external Ca2+ in the MTX (30 ng ml-')-induced aggregation and [Ca2+]i-increase of the fura-2-loaded platelets.…”

Section: Effects Of Varying External Ca2 Concentration and Ba2`-substmentioning

confidence: 85%

“…Inhibitory effects of divalent ions and various blockers on platelet aggregation Since Co2", Cd24 and Ni24 are known to interfere with a Ca2'-influx through Ca2" channels at the plasma membrane (Evans, 1988), we investigated effects of these divalent cations on MTX (30 ng ml-')-induced platelet aggregation in the presence of 1 mM Ca24 (Table 2). Co2" and Cd24 (both 0.3 mM) significantly inhibited the platelet aggregation by approximately 20-30% of control.…”

Section: Effects Of Maitotoxin and Thrombin On Aggregation And [Ca2+]imentioning

confidence: 99%

Ca²⁺‐dependent aggregation of rabbit platelets induced by maitotoxin, a potent marine toxin, isolated from a dinoflagellate

Watanabe

Ishida

Honda

et al. 1993

British J Pharmacology

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1 Administration of maitotoxin (MTX), a dinoflagellate toxin, caused aggregation of rabbit washed platelets. The cytosolic Ca2`concentration ([Ca2+]i), measured by fura-2 fluorescence technique, was also increased by the presence of MTX. Rates of aggregation response and [Ca2"Ji-increase were dependent on tested concentrations (3-100ng ml-') of the toxin.2 The MTX-induced platelet aggregation and [Ca2+]i-increase were totally abolished in a Ca2+-free solution. The successive administration of Ca2" in the presence of MTX elicited the aggregation and increase in [Ca2+]i.3 Ba" was capable of substituting for Ca2+ in the MTX-induced platelet aggregation. In the presence of external Ca2+, transition metals, Co2+, Cd2+ and Ni2+, inhibited the aggregation response to MTX. 4 Organic calcium antagonists (verapamil and nifedipine) as well as a cyclo-oxygenase-inhibitor (aspirin) did not apparently inhibit the aggregation response to MTX, except for a high concentration (10-'M) of verapamil, while procaine (10mM) reduced the rate of platelet aggregation.5 MTX also elicited a release of ATP from platelets, which was abolished in the absence of external Ca2+.6 In contrast, thrombin 0.5 unitml-' could elicit platelet shape change, [Ca2+]i-increase and ATPrelease in the absence of external Ca2 . 7 These results suggest that the MTX-induced platelet activation is caused by an enhanced Ca2+-influx presumably through voltage-independent Ca2+ channels on the plasma membrane.

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Interactions of Lanthanides with Tissues, Cells, and Cellular Organelles

Evans

1990

Biochemistry of the Lanthanides

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Alkaline Earths, Transition Metals, and Lanthanides

Cited by 5 publications

References 70 publications

Activation of rabbit platelets by Ca²⁺ influx and thromboxane A₂ release in an external Ca²⁺‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Activation of rabbit platelets by Ca²⁺ influx and thromboxane A₂ release in an external Ca²⁺‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Ca²⁺‐dependent aggregation of rabbit platelets induced by maitotoxin, a potent marine toxin, isolated from a dinoflagellate

Interactions of Lanthanides with Tissues, Cells, and Cellular Organelles

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Alkaline Earths, Transition Metals, and Lanthanides

Cited by 5 publications

References 70 publications

Activation of rabbit platelets by Ca2+ influx and thromboxane A2 release in an external Ca2+‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Activation of rabbit platelets by Ca2+ influx and thromboxane A2 release in an external Ca2+‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Ca2+‐dependent aggregation of rabbit platelets induced by maitotoxin, a potent marine toxin, isolated from a dinoflagellate

Interactions of Lanthanides with Tissues, Cells, and Cellular Organelles

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Activation of rabbit platelets by Ca²⁺ influx and thromboxane A₂ release in an external Ca²⁺‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Activation of rabbit platelets by Ca²⁺ influx and thromboxane A₂ release in an external Ca²⁺‐dependent manner by zooxanthellatoxin‐A, a novel polyol

Ca²⁺‐dependent aggregation of rabbit platelets induced by maitotoxin, a potent marine toxin, isolated from a dinoflagellate