Fluxes and distribution of calcium in rat liver cells: kinetic analysis and identification of pools

Claret-Berthon, B; Claret, M; Mazet, Jean-Luc

doi:10.1113/jphysiol.1977.sp012058

Cited by 100 publications

(56 citation statements)

References 38 publications

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“…However, Claret-Berthon et al (1977) proposed that the rate of exchange of Ca by mitochondria is significantly faster than the rate of Ca exchange across the plasma membrane. The present results, including those from the measurement of 45Ca exchange by isolated mitochondria, indicate that such a rapid exchange of Ca by mitochondria is unlikely.…”

Section: Compartments Of Exchangeable Ca In Untreated Cellsmentioning

confidence: 99%

“…(a) Cells were routinely separated from the incubation medium by centrifugation through a solution with contained La3+. This cation should have displaced all rapidly exchangeable extracellular Ca (Claret-Berthon et al 1977;Hellman, 1978). (b) Separation of the cells from the incubation medium in the presence of EGTA or 4OCa2+ in place of La3+ did not significantly alter the kinetics of the '6Ca exchange curves.…”

Section: Compartments Of Exchangeable Ca In Untreated Cellsmentioning

confidence: 99%

“…This experimental system was chosen because it permits a study of the effects ofadrenaline on kinetically distinct compartments ofexchangeable Ca at physiological concentrations of extracellular Ca (compare with the recent studies of Blackmore et al (1979b)) without disruption of the cells. Isolated liver cells offer two important advantages over the perfused liver system which was employed by Claret-Berthon, Claret & Mazet (1977) for studies of liver cell Ca distribution. These are the ability to obtain points on the Ca exchange curve at early times, and to make accurate correction for 45Ca present in the extracellular fluid.…”

Section: Introductionmentioning

confidence: 99%

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A kinetic analysis of the effects of adrenaline on calcium distribution in isolated rat liver parenchymal cells

Barritt

Parker

Wadsworth³

1981

The Journal of Physiology

130

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SUMMARY1. The effects of adrenaline on Ca distribution in isolated rat liver parenchymal cells were studied using a 45Ca exchange technique under steady-state conditions with respect to the net movement ofCa. 45Ca was initially introduced into the extracellular medium. The amount of cellular 45Ca was determined after separation ofthe cells from the medium by centrifugation through a solution which contained LaCl3 (to displace 45Ca bound to sites on the outside of the cell membrane) and silicon oil. At 1-3 and 2-4 mM-extracellular Ca, a stimulation of the initial rate of 45Ca exchange was observed in the presence of 10-7 M-adrenaline (or 10-6 M-phenylephrine) with a 7 % decrease, and no change, respectively, in the plateau of the exchange curve. The same degree of stimulation was observed when 45Ca was added at 1, 15, 30 or 45 min after the adrenaline.2. No stimulation of the initial rate of exchange was observed at 0-1 mMextracellular Ca, or at 2-4 mM-extracellular Ca in the presence of antimycin A and oligomycin. At 0'1 mM-Ca, a 60 % decrease in the plateau of the exchange curve was observed in the presence of adrenaline. The concentration of adrenaline (10-7 M) which caused half-maximal stimulation of the initial rate of 45Ca exchange at 1'3 mM-Ca was similar to that (2 x 10-7 M) which caused half-maximal decrease in the plateau at 0-1 mM-Ca.3. The addition of adrenaline to cells equilibrated with 45Ca at either 2-4 or 1-3 mM-Ca caused a transient loss of 45Ca followed by a return to a new steady state after 1 or 10 min, respectively. A loss of 45Ca was also observed at 0-1 mM-Ca, but the 45Ca content of the cells remained maximally depressed for at least 30 min.4. A non-linear least-squares iterative curve-fitting technique was used to demonstrate that (a) an equation which includes two exponential terms and (b) a parallel or series arrangement of three compartments of exchangeable Ca (the medium and two compartments associated with the cell) are consistent with each set of data obtained at 1-3 or 2-4 mM-Ca in the presence or absence ofadrenaline (or phenylephrine). G. J. BARRITT, J. C. PARKER AND J. C. WADSWORTH At 1P3 mM-Ca, the quantities of exchangeable Ca in the two kinetically defined cellular compartments were 0-04-0-07 and 034-4037 nmol per mg wet weight with rate constants for Ca outflow of 1P2-1P5 and 0-06-0-08 min-', respectively. 5. Analysis of the changes induced by adrenaline or phenylephrine showed that at 1-3 and 2-4 mM-extracellular Ca these agents caused a 75-150 % increase in the quantity ofexchangeable Ca in the small kinetically defined compartment and a 20 % decrease in the quantity of exchangeable Ca in the large kinetically defined compartment. These changes were mediated by an 80-160 % increase in the rate constant for the inflow of Ca from the medium to the small kinetically defined compartment, and either a 20-60 % decrease in the rate constant for inflow to, or a 20 % increase in the rate constant for outflow from, the large compartment.6. Replacement of the LaCl3 in the solution...

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Section: Compartments Of Exchangeable Ca In Untreated Cellsmentioning

confidence: 99%

Section: Compartments Of Exchangeable Ca In Untreated Cellsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A kinetic analysis of the effects of adrenaline on calcium distribution in isolated rat liver parenchymal cells

Barritt

Parker

Wadsworth³

1981

The Journal of Physiology

130

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“…The cells in a 2 ml sample of the stock suspension were spun down (50 g for 2 min) and resuspended in 10 ml of Eagle medium containing 45Ca (1,1Ci/ml) but without vitamins or other supplements and, in some instances, albumin (see Results). The incubation was continued for 30-40 min, long enough to allow most of the intracellular Ca to exchange (Claret-Berthon, Claret & Mazet, 1977). The quantity of 45Ca in the cells could then serve as an index of their Ca content, and of the effects of drugs thereon.…”

Section: G M Burgess M Claret and D H Jenkinsonmentioning

confidence: 99%

Effects of quinine and apamin on the calcium‐dependent potassium permeability of mammalian hepatocytes and red cells.

Burgess¹,

Claret²,

Jenkinson³

1981

The Journal of Physiology

283

181

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SUMMARY1. K-sensitive electrodes placed in the extracellular fluid have been used to show that ATP and noradrenaline cause a rapid loss of up to 10 % of the K content of isolated guinea-pig hepatocytes.2. The hypothesis that this response is a consequence of a rise in the K permeability of the hepatocyte membrane triggered by an increase in cytosolic Ca is supported by the finding that the divalent cation ionophore A23187 also initiated K loss, in this instance of up to 20-25 % of the amount in the cells.3. Under similar conditions A23187 caused a transient increase, followed by a larger decrease, in the 45Ca content of guinea-pig hepatocytes equilibrated with this isotope. The decrease alone was seen with ATP and noradrenaline.4. Quinine (1 mM) and the bee venom neurotoxin apamin (10 nM) greatly reduced the effect of ATP, noradrenaline and A23187 on K content without affecting the changes in 45Ca movement.5. Apamin (10 nM) also abolished the increase in 42K efflux which follows the application of the a-adrenoceptor agonist amidephrine to rabbit liver slices; the concurrent rises in 45Ca efflux and glucose release were unaffected.6. It was concluded that quinine and apamin are able to block either the Ca-dependent K channels present in guinea-pig and rabbit liver cell membranes or the mechanism that controls them.7. Surprisingly, rat hepatocytes took up rather than lost K when treated with the concentrations of ATP, noradrenaline or A23187 that initiated K loss from guinea-pig cells. This response was greatly reduced by ouabain.8. Application of large concentrations of A23187 to rat hepatocytes caused K loss associated with cell death.9. The influence of apamin (10-1000 nM) and quinine (200-1000 UM) on the Ca-dependent K permeability of red blood cells and ghosts was also studied. Apamin was without effect even when applied to both sides of the ghost membrane, whereas quinine caused inhibition, as reported by others.10. The results suggest that Ca-dependent K channels or carriers are present in

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“…1 In addition, the energy failure of ischemia results in a release of calcium from its normal ATP-dependent sites of sequestration in the endoplasmic reticulum. 5 Finally, ischemia impairs the ability of mitochondria to accumulate calcium. 6 The resulting increase in free cytoplasmic calcium activity disrupts a variety of cellular functions 6 and, in particular, may be responsible in part for the breakdown of membrane phospholipids and massive release of free fatty acids due to stimulation of phospholipases.…”

mentioning

confidence: 99%

Verapamil: failure of metabolic amelioration following global forebrain ischemia in the rat.

Berger

Busto

Ginsberg³

1984

Stroke

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1029SUMMARY The potential efficacy of the calcium channel blocker verapamil in modifying ischemic brain injury was evaluated in anesthetized rats subjected to 60 or 90 min of diffuse forebrain ischemia produced by bilateral occlusion of the carotid and vertebral arteries. Treated animals received verapamil, 2 mg/kg intravenously, prior to ischemia. Four hours of postischemic recirculation was permitted by reversing the carotid occlusions. Intermittent high-voltage slow-wave activity was noted on electroencephalograms shortly after verapamil infusion, prior to ischemia. The ischemic insult induced an isoelectric EEG, which tended to persist during recirculation in both treated and untreated animals. Similarly, verapamil pretreatment failed to influence brain water content or cerebral energy metabolites (phosphocreatine, ATP, ADP, AMP) or cerebral energy charge when assayed after four hours of recirculation. Thus, verapamil failed to confer a protective effect on brain electrical activity, water content, or energy metabolites following ischemia in this model. Stroke Vol 15, No 6, 1984 CONSIDERABLE RECENT ATTENTION has been devoted to the role of perturbed calcium ion homeostasis in contributing to hypoxic-ischemic cellular injury.1 ' 2 Normally, intracellular calcium ion activity is regulated at a level several orders of magnitude less than that of the extracellular space.3 During cerebral ischemia, extracellular calcium ion activity has been shown to decline at cerebral blood flows below 6-9 ml/ 100 g/min, concomitant with membrane depolarization as signalled by rising extracellular potassium ion activity, 4 suggesting that the opening of voltage-dependent calcium ion channels within the plasma membrane has permitted the intracellular influx of this ion. 1In addition, the energy failure of ischemia results in a release of calcium from its normal ATP-dependent sites of sequestration in the endoplasmic reticulum. 5 Finally, ischemia impairs the ability of mitochondria to accumulate calcium. 6 The resulting increase in free cytoplasmic calcium activity disrupts a variety of cellular functions 6 and, in particular, may be responsible in part for the breakdown of membrane phospholipids and massive release of free fatty acids due to stimulation of phospholipases.1 ' 7i 8 The latter events, in turn, have been implicated in contributing to irreversible cellular injury.A deleterious effect of the intracellular influx of calcium is strongly suggested by recent studies in extracerebral tissue. Schanne et al 9 reported that hepatocytes cultured in a calcium-depleted medium were able to withstand exposure to a variety of otherwise noxious membrane-active toxins. Farber and colleagues demonstrated that survival of heart and liver cells following prolonged ischemia is markedly improved by blocking calcium influx with chlorpromazine.7 Calcium channel blockers, including verapamil, have been demonstrated to preserve myocardial function in the face of ischemic injury.1(M2 In isolated rat hearts subjected to global ischemia, ver...

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Fluxes and distribution of calcium in rat liver cells: kinetic analysis and identification of pools

Cited by 100 publications

References 38 publications

A kinetic analysis of the effects of adrenaline on calcium distribution in isolated rat liver parenchymal cells

A kinetic analysis of the effects of adrenaline on calcium distribution in isolated rat liver parenchymal cells

Effects of quinine and apamin on the calcium‐dependent potassium permeability of mammalian hepatocytes and red cells.

Verapamil: failure of metabolic amelioration following global forebrain ischemia in the rat.

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