Effect of neomycin and ionophore A23187 on ATP levels and turnover of polyphosphoinositides in human erythrocytes

Lang, Verna; Pryhitka, Glen; Buckley, J. Thomas

doi:10.1139/o77-150

Cited by 49 publications

(20 citation statements)

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“…activation by carrageenan was still abolished, as much as in the presence of neomycin alone. These results indicate that neomycin inhibits carrageenan-induced platelet activation via its ability to bind to inositol phospholipids, as reported by others (Schacht, 1976;Lodhi et al 1979;Lang et al, 1977;Reid & Gajjar, 1987). The binding of neomycin to PtdIns4P and specifically to PtdIns(4,5)P2 has been shown to depend on the cationic charge of the molecule (Van Rooijen & Agranof, 1985).…”

Section: Discussionsupporting

confidence: 84%

Carrageenan‐induced activation of human platelets is dependent on the phospholipase C Pathway

et al. 1993

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Stimulation of washed human platelets by the pro-inflammatory polysaccharide carrageenan is accompanied by shape change, aggregation and release of granule contents and unaccompanied by thromboxane A2 synthesis. Carrageenan triggers platelet activation through a prostaglandin synthetase-independent mechanism. The phospholipase A2 (PLA2) inhibitor, p-bromophenacyl bromide suppresses platelet responses to carrageenan (Vargaftig et al, 1980) probably by mechanism(s) other than those which involve PLA2 activity. Exposure of platelets to carrageenan (2-25 micrograms/ml) induced inositol phosphate formation in a time- and concentration-dependent manner, the level of inositol phosphate formation correlating with the intensity of aggregation. Neomycin, an aminoglycoside antibiotic which inhibits the phospholipase C-mediated phosphatidylinositol 4,5-bisphosphate breakdown, suppressed both platelet activation and inositol phosphate formation. Inhibition was concentration-dependent with an IC50 value of about 180 microM. Platelet-activating factor (PAF) is not responsible for carrageenan-induced platelet activation and inositol phosphate formation, since exposure of platelets to carrageenan (25 micrograms/ml) in the presence of compound WEB 2086 (100 microM), a PAF antagonist, failed to inhibit carrageenan responses. However, compound Ro 19-3704, a structurally related antagonist of PAF reported to be also an inhibitor of phospholipases A2 and C, inhibited concentration-dependently (0.1-10 microM) aggregation and ATP release induced by carrageenan (25 micrograms/ml). These findings indicate that carrageenan activates human platelets through a phospholipase C-dependent mechanism and show that neomycin, at low concentrations, can be a selective inhibitor of phospholipase C-mediated PIP2-breakdown.

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Section: Discussionsupporting

confidence: 84%

Carrageenan‐induced activation of human platelets is dependent on the phospholipase C Pathway

et al. 1993

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“…It is well known that Ca2+ can directly stimulate this kind of enzyme (Downes and Michell, 1982;Rittenhouse, 1983;Irvine et al, 1984;Wilson et al, 1984;Nakanishi et al, 1985). Stimulation of the IP response as a consequence of Ca2+ influxes has also been reported in several systems (Lang et al, 1977;Griffin and Hawthorne, 1978;Pearce et al, 1986). The relative rates of phosphodiesterase hydrolysis were phosphatidylinositol-4-phosphate > phosphatidylinositol-4,5-bisphosphate > phosphatidylinositol (Rittenhouse, 1983;Wilson et al, 1984).…”

Section: Discussionmentioning

confidence: 90%

Neurotransmitter‐Induced Inositol Phosphate Formation in Neurons in Primary Culture

Weiss¹,

Schmidt²,

Sebben³

et al. 1988

Journal of Neurochemistry

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Inositol-1,4,5-trisphosphate, produced in cells as a breakdown product of phosphatidylinositol-4,5-bisphosphate, induces, in many cell types, release of calcium from intracellular stores. In murine striatal neurons, differentiated in primary culture, carbachol, norepinephrine, glutamate, and neurotensin stimulate 3H-labeled inositol phosphate (3H-IP) production. The glutamate response was recently characterized as being mediated primarily by receptors of the quisqualate subtype. In the present study, we found that major differences exist between glutamate-stimulated 3H-IP formation and those stimulated by the other neuromediators. The maximal response to glutamate occurred before and during synaptogenesis and declined thereafter, whereas the maximal response to either carbachol or norepinephrine required complete neuronal differentiation. Although the glutamate response appears to be mediated exclusively by direct interaction with the neurotransmitter receptors, responses to carbachol, norepinephrine, and neurotensin were partially or completely blocked by tetrodotoxin.

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“…The present study suggests that the phosphorylation of membrane bound phosphatidylinositol could result in an altered conformation of glycophorin. This finding may be of particular significance in view of the recent observation that a change in erythrocyte shape induced by a calcium ionophore is correlated with the loss of polyphosphoinositide from the membrane [16].…”

Section: Discussionmentioning

confidence: 58%

Phospholipid‐induced changes in the circular dichroism of glycophorin and its association with 8‐anilino‐1‐naphthalene sulfonate

Verpoorte

Palmer

1977

FEBS Letters

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Effect of neomycin and ionophore A23187 on ATP levels and turnover of polyphosphoinositides in human erythrocytes

Cited by 49 publications

References 0 publications

Carrageenan‐induced activation of human platelets is dependent on the phospholipase C Pathway

Carrageenan‐induced activation of human platelets is dependent on the phospholipase C Pathway

Neurotransmitter‐Induced Inositol Phosphate Formation in Neurons in Primary Culture

Phospholipid‐induced changes in the circular dichroism of glycophorin and its association with 8‐anilino‐1‐naphthalene sulfonate

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