On the mechanism of mercurial‐induced permeability of the mitochondrial membrane to K<sup>+</sup>

Cited by 39 publications

(10 citation statements)

References 23 publications

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“…This latter finding is in accordance with conclusions reached by Bogucka and Wojtczak (2) for mitochondrial membranes, Knauf and Rothstein (11) for red blood cells, and others (reviewed in Rothstein, Ref. 25).…”

Section: Discussionsupporting

confidence: 92%

Effect of Sulfhydryl Reagents on the Biophysical Properties of the Plasmalemma of Chara corallina

Lichtner¹,

Lucas²,

Spanswick³

1981

Plant Physiol.

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The administration of the sulfhydryl reagent N-ethyl-maleimide (NEM) to internodal cells of Chara coralina caused alterations in the biophysical properties of the plasmalemma, as measured with electrophysiological and radioactive tracer techniques. The membrane potential depolarized to, or near, the calculated Nermst potential for potassium (EK) after 30 seconds' exposure to 0.1 millimolar NEM. During this time, the ATP level did not decrease below the control value, and the specific membrane resistance did not increase; only upon further exposure to NEM did the resistance approach the value observed in the dark. In the depolarized state, the membrane potential responded to changes in the external potassium concentration in the manner of a K -electrode, but it retained it's relative insensitivity to external sodium.These results are interpreted in the following manner. NEM causes a) an increase in the membrane permeability to K+ (ie. an increase in K+ conductance); and b) perturbation of the electrogenic transport system(s) of the plasma membrane. The latter effect is manifested in a manner that is not consistent with an inhibition of ATP catalysis by a voltage-dependent ATPase possessing conductance. The nonpermeant sulfhydryl modifier, pchloromercuribenzenesulfonic acid, appeared to affect membrane properties in a similar, but reversible, way.The biochemical and biophysical properties of the plasmalemma play an undisputed key role in the organization and function of membrane transport phenomena. Increasingly, heavy metals and sulfhydryl reagents have been used to probe the interrelationships of these processes (4-6, 12, 18, 31 amino-1,3-naphthalene disulfonic acid; Rm, specific membrane resistance (K _-cm2); gm, total membrane conductance; PK, potassium permeability. tion of the external medium. Because the electrophysiology and ionic relations of Chara corallina are relatively well understood and since certain transport processes in this alga appear to be differentially susceptible to -SH reactive agents (18), we investigated the biophysical properties in C. corallina before and after treatment with thiol-modifying reagents. This approach has allowed us to conclude that sulfhydryl reagents affect the passive permeability of the membrane by increasing potassium conductance and act upon the electrogenic transport processes of the cell membrane. Experimental Solutions. Solutions were prepared using high purity glass-distilled H20. The CPW contained 1.0 mm NaCl, 0.2 mm KCI, 0.2 mm CaSO4, 1.0 mm TAPS (pH 8.0); modifications to this medium will be detailed in the text. Bicarbonate-free solutions were prepared by bubbling solutions with air that had been passed through C02-absorbent material (Ascarite; Arthur H. Thomas Co.). All chemicals were of Analar reagent grade and, except for PCMBS, were not purified further. Stock (100 mm) NEM solutions were titrated to pH 7, using fresh NaOH solution, and stored at 4 C for a maximum of 4 days. Because hydrolytic ring opening in the NEM molecule occurs at alkaline...

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Section: Discussionsupporting

confidence: 92%

Effect of Sulfhydryl Reagents on the Biophysical Properties of the Plasmalemma of Chara corallina

Lichtner¹,

Lucas²,

Spanswick³

1981

Plant Physiol.

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“…In rat liver mito-chondria, 4% of the total magnesium content is in the outer membrane, 50% in the intermembraneous compartment, 5% in the inner membrane and 41% in the matrix (14). The high magnesium content in the intermembranous compartment is explained by a high magnesium binding capacity of certain proteins.…”

Section: Distribution Of Magnesium In the Organismmentioning

confidence: 94%

“…One protein with a molecular weight of 150 000 daltons binds 300 nmol/mg protein with a dissociation constant of 0.37 mmol/1. Another protein with a molecular weight of 100 000 daltons binds 20 nmol/mg protein with a dissociation constant of 1.0 μτηοΐ/l (15). In addition, magnesium is bound by phospholipids, not only in mitochondria but also in the endoplasmic reticulum.…”

Section: Distribution Of Magnesium In the Organismmentioning

confidence: 99%

Magnesium Metabolism: A Review

Ebel¹,

Günther²

1980

CCLM

156

122

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Summary: The main literature concerning the physiology and biochemistry as well as the pathophysiology and pathobiochemistry of magnesium is reviewed, including:Distribution and physico-chemical state of magnesium in the extracellular and intracellular fluid as well as in the subcellular organelles (membranes, mitochondria, microsomes, ribosomes).Intestinal resorption, transport across membranes and excretion by the kidney.Hormonal regulation of magnesium distribution and its clinical disturbances.Biochemical mechanism and the clinical effects of hypo-and hypermagnesemia. Magnesium-Stoffwechsel: Eine ÜbersichtZusammenfassung: Die wichtigsten Arbeiten über die Physiologie und Biochemie sowie Pathophysiologie und Pathobiochemie des Magnesiums werden dargestellt.Die Darstellung bezieht sich im wesentlichen auf: Die Verteilung und den physikalisch-chemischen Zustand des Mg in der extrazellulären und intrazellulären Flüssigkeit und in den Zellorgänellen (Membranen, Mitochondrien, Mikrosomen, Ribosomen). Die Resorption im Darm, Transport durch Membranen und die Ausscheidung durch die Niere.Die hormonale Regulation der Mg-Verteilung und ihre klinischen Störungen. Biochemische Mechanismen und klinische Erscheinungen bei Hypo-und Hypermagnesiämie.

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“…The mechanism of activation of K + influx by mersalyl remains unclear. It was earlier proposed that mercurials may enhance K + permeability by causing discharge of endogenous Mg 2+ (Bogucka & Wojtczak, 1979). However, this hypothesis has not been supported by measurements of mitochondrial Mg > (Diwan, Aronson & Gonsalves, 1980) or by the observed sensitivity to mersalyl of K* flux into divalent cation-depleted mitochondria (Jung et al, 1981).…”

Section: Discussionmentioning

confidence: 48%

Ba2+ uptake and the inhibition by Ba2+ of K+ flux into rat liver mitochondria

Diwan

1985

J. Membrain Biol.

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Rapid uptake of Ba2+ by respiring rat liver mitochondria is accompanied by a transient stimulation of respiration. Following accumulation of Ba2+, e.g. at a concentration of 120 nmol per mg protein, the mitochondria exhibit reduced rates of state 3 and uncoupler-stimulated respiration. ADP-stimulated respiration is inhibited at a lower concentration of Ba2+ than is required to affect uncoupler-stimulated respiration, suggesting a distinct effect of Ba2+ on mechanisms involved in synthesis of ATP. Ba2+, which has an ionic radius similar to that of K+, inhibits unidirectional K+ flux into respiring rat liver mitochondria. This effect on K+ influx is observable at concentrations of Ba2+, e.g. 23 to 37 nmol per mg protein, which cause no significant change in state 4 or uncoupler-stimulated respiration. The accumulated Ba2+ decreases the measured Vmax of K+ influx, while having little effect on the apparent Km for K+. The inhibition of K+ influx by Ba2+ is seen in the presence and absence of mersalyl, an activator of K+ influx. In contrast, under the conditions studied, Ba2+ has no apparent effect on the rate of unidirectional K+ efflux. These data are consistent with the idea that K+ may enter and leave mitochondria via separate mechanisms.

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On the mechanism of mercurial‐induced permeability of the mitochondrial membrane to K⁺

Cited by 39 publications

References 23 publications

Effect of Sulfhydryl Reagents on the Biophysical Properties of the Plasmalemma of Chara corallina

Effect of Sulfhydryl Reagents on the Biophysical Properties of the Plasmalemma of Chara corallina

Magnesium Metabolism: A Review

Ba2+ uptake and the inhibition by Ba2+ of K+ flux into rat liver mitochondria

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On the mechanism of mercurial‐induced permeability of the mitochondrial membrane to K+

Cited by 39 publications

References 23 publications

Effect of Sulfhydryl Reagents on the Biophysical Properties of the Plasmalemma of Chara corallina

Effect of Sulfhydryl Reagents on the Biophysical Properties of the Plasmalemma of Chara corallina

Magnesium Metabolism: A Review

Ba2+ uptake and the inhibition by Ba2+ of K+ flux into rat liver mitochondria

Contact Info

Product

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On the mechanism of mercurial‐induced permeability of the mitochondrial membrane to K⁺