scholarly journals Sulfate Flux in High Sodium Cat Red Cells

1972 ◽  
Vol 59 (2) ◽  
pp. 155-166 ◽  
Author(s):  
R. I. Sha'afi ◽  
E. Pascoe
Keyword(s):  
Steady State ◽  
Cell Volume ◽  
Rate Constant ◽  
Incubation Medium ◽  
Red Cells ◽  
Bathing Medium ◽  
High Sodium ◽  
Sulfate Flux ◽  
Na Uptake

The transport of radioactive sulfate in cat red cells has been studied. The rate constant for 35SO4 inward movement under steady-state conditions is 0.24 ± 0.02/hr. This movement was found to be sensitive to osmotic changes in cell volume and to the nature of anions in the incubation medium; it increases with increasing cell volume and decreases with decreasing cell volume. The anions SCN, NO3, and I were found to inhibit the uptake of 35SO4. Furthermore, 1-fluoro-2,4-dinitrobenzene at a concentration of 1 mM inhibits (>90%) this uptake. The inward movement of erythritol-14C shows qualitatively the same dependence on cell volume as 35SO4, but it is insensitive to the nature of the anion present in the bathing medium. It was also found that the usually observed inhibition of radioactive Na uptake by SCN in cat red cells can be reversed when cell volume is increased.

scholarly journals Cation Movements in the High Sodium Erythrocyte of the Cat

1967 ◽  
Vol 50 (6) ◽  
pp. 1751-1764 ◽  
Author(s):  
R. I. Sha'afi ◽  
W. R. Lieb
Keyword(s):  
Steady State ◽  
Mammalian Cells ◽  
Red Cells ◽  
The Other ◽  
K Uptake ◽  
High Sodium

The uptake of 42K and 24Na by cat erythrocytes was investigated. Under steady-state conditions, the nontransient component of 42K influx was found to be 0.18 ± 0.01 meq/liter RBC/hr and insensitive to ouabain (100 µM); the corresponding value for 24Na was 17 ± meq/liter RBC/hr. A study was made of the effects of anions upon cation movements in these and other mammalian red cells. Iodide was found to inhibit markedly (>50%) Na inward movements in cat and dog but not in the other erythrocytes. An increase (15–30%) in K uptake in the presence of iodide was noted in all the mammalian cells studied.

scholarly journals Anion transport in dog, cat, and human red cells. Effects of varying cell volume and Donnan ratio.

1979 ◽  
Vol 74 (3) ◽  
pp. 319-334 ◽  
Author(s):  
V Castranova ◽  
M J Weise ◽  
J F Hoffman
Keyword(s):  
Membrane Potential ◽  
Cell Volume ◽  
Rate Constant ◽  
Rate Constants ◽  
Anion Transport ◽  
Atp Depletion ◽  
Red Cells ◽  
Cell Swelling ◽  
Equilibrium Ratio ◽  
Human Red Cells

Membrane potential and the rate constants for anion self-exchange in dog, cat, and human red blood cells have been shown to vary with cell volume. For dog and cat red cells, the outward rate constants for SO4 and Cl increase while the inward rate constant for SO4 decreases as cells swell or shrink. These changes coincide with the membrane potential becoming more negative as a result of changes in cell volume. Human red cells exhibit a similar change in the rate constants for SO4 and Cl efflux in response to cell swelling, but shrunken cells exhibit a decreased rate constant for SO4 efflux and a more positive membrane potential. Hyperpolarization of shrunken dog and cat red cells is due to a volume-dependent rate constant for SO4 efflux and a more positive membrane potential. Hyperpolarization of shrunken dog and cat red cells is due to a volume-dependent increase in PNa. If this increase in PNa is prevented by ATP depletion or if the outward Na gradient is removed, the response to shrinking is identical to human red cells. These results suggest that the volume dependence of anion permeability may be secondary to changes in the anion equilibrium ratio which in red cells is reflected by the membrane potential. When the membrane potential and cell volume of human red cells were varied independently by a method involving pretreatment with nystatin, it was found that the rate of anion transport (for SO4 and Cl) does not vary with cell volume but rather with membrane potential (anion equilibrium ratio); that is, the rate constant for anion efflux is decreased and that for influx is increased as the membrane potential becomes more positive (internal anion concentration increases) while the opposite is true with membrane hyperpolarization (a fall in internal anion concentration).

scholarly journals Adrenergic Swelling of Nucleated Erythrocytes: Cellular Mechanisms in a Bird, Domestic Goose, and two Teleosts, Striped Bass and Rainbow Trout

1984 ◽  
Vol 113 (1) ◽  
pp. 215-224 ◽  
Author(s):  
MIKKO NIKINMAA ◽  
WRAY H. HUESTIS
Keyword(s):  
Rainbow Trout ◽  
Cell Volume ◽  
Intracellular Ph ◽  
Striped Bass ◽  
Incubation Medium ◽  
Red Cells ◽  
Red Cell ◽  
Volume Changes ◽  
Cellular Mechanisms ◽  
Loosely Coupled

The mechanism of adrenergic swelling and associated pH changes was investigated in avian (goose) and teleost (striped bass and rainbow trout) erythrocytes. The swelling of goose red cells was probably caused by Na+/K+/Cl− co-transport and consecutive osmotic flow of water into the cell. Goose red cells swelled when exposed to isoproterenol in the presence of elevated extracellular K+, but not at physiological K+ concentrations. The swelling was quantitatively inhibited by furosemide, and by removing Cl− from the incubation medium, but was not affected by DIDS. The isoproterenol-induced swelling of fish erythrocytes may be due to loosely coupled Na+/H+ and Cl−/HCO3− exchanges. Furosemide did not completely inhibit the swelling of striped bass red cells. The cell volume increased even if K+ was completely removed from the incubation medium. In contrast, both DIDS and amiloride treatment, and the removal of Na+ from the incubation medium, inhibited the volume changes. In fish red cells the swelling is associated with a clear acidification of the medium and alkalinization of the red cell contents. This phenomenon was most pronounced when the cells were treated simultaneously with DIDS and isoproterenol; the intracellular pH became higher than the extracellular one. Both amiloride and removal of Na+ from the incubation medium prevented the reversal of the transmembrane pH gradient in cells treated simultaneously with DIDS and isoproterenol.

Cell volume regulation in hemoglobin CC and AA erythrocytes

1987 ◽  
Vol 252 (3) ◽  
pp. C300-C306 ◽  
Author(s):  
L. R. Berkowitz ◽  
E. P. Orringer
Keyword(s):  
Cell Volume ◽  
Incubation Medium ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Loop Diuretics ◽  
Red Cells ◽  
Regulatory Pathway ◽  
Intracellular Chloride ◽  
Original Cell

Swelling hemoglobin CC erythrocytes stimulates a ouabain-insensitive K flux that restores original cell volume. This volume regulatory pathway was characterized for its anion dependence, sensitivity to loop diuretics, and requirement for Na. The swelling-induced K flux was eliminated if intracellular chloride was replaced by nitrate and both swelling-activated K influx and efflux were partially inhibited by 1 mM furosemide or bumetanide. K influx in swollen hemoglobin CC cells was not diminished when Na in the incubation medium was replaced with choline, indicating Na independence of the swelling-induced flux. Identical experiments with hemoglobin AA cells also demonstrated a swelling-induced increase in K flux, but the magnitude and duration of this increase were considerably less than that seen with hemoglobin CC cells. The increased K flux in hemoglobin AA cells was likewise sensitive to anion replacement and to loop diuretics and did not require the presence of Na. These data indicate that a volume-activated K pathway with similar transport characteristics exists in both hemoglobin CC and AA red cells.

scholarly journals Sodium Movement in High Sodium Feline Red Cells

1971 ◽  
Vol 57 (6) ◽  
pp. 684-696 ◽  
Author(s):  
R. I. Sha'afi ◽  
J. J. Hajjar
Keyword(s):  
Cell Volume ◽  
Red Cells ◽  
Unusual Behavior ◽  
Experimental Conditions ◽  
High Sodium ◽  
Medium Osmolarity ◽  
A Cell ◽  
Increasing Temperature ◽  
Temperature Errors ◽  
Human Red Cells

The transport of Na in the cat red cells has been studied under various experimental conditions. The unidirectional radioactive Na influx increased with increasing temperature until it reached a maximum value at 37°C ± 2°C and then decreased with a further increase in temperature. Errors stated in this paper represent 1.0 standard errors of the mean. The apparent activation energy was calculated in the region between 25 and 37°C and was found to be 4.9 ± 0.5 kcal/mole. Copper at a concentration of 0.04 mM inhibited this influx by 65%. When cells were suspended in isosmotic KCl buffer, cell volume was found to decrease initially with time. This unusual behavior is discussed in terms of Na to K preference of the cell membrane. In cat red cells, Na influx was found to increase about 13-fold when cell volume was decreased from 1.16 normal to 0.87. This effect could not be reproduced when the medium osmolarity was changed only by the addition of urea, a permeating molecule. On the other hand, K influx was found to decrease from 0.24 ± 0.03 mEq/liters RBC, hr at a relative cellular volume equal to 1.0 to 0.11 ± 0.01 mEq/liters RBC, hr at a cell volume of 0.75. Na influx in human red cells did not show any significant dependence on cell volume. The properties of Na movement in the cat red cells are compared to those of human red cells.

Regulation of cytosolic free Ca2+ concentration in acinar cells of rat pancreas

1983 ◽  
Vol 245 (3) ◽  
pp. G347-G357 ◽  
Author(s):  
H. Streb ◽  
I. Schulz
Keyword(s):  
Steady State ◽  
Incubation Medium ◽  
Minimal Medium ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Atpase Inhibitor ◽  
Rat Pancreas ◽  
Mitochondrial Inhibitors ◽  
Pancreatic Cells ◽  
State Concentration

Ca2+ uptake into isolated exocrine pancreatic cells with highly permeable plasma membrane was determined by measuring the decrease in free Ca2+ concentration of the surrounding incubation medium with a Ca2+-specific electrode. In the presence of Mg-ATP and respiratory substrates the free Ca2+ concentration of the incubation medium decreased rapidly after addition of leaky cells until a stable medium free Ca2+ concentration of 4.2 +/- 0.1 X 10(-7) mol/l was obtained. Changes in the medium free Ca2+ concentration at steady state by addition of Ca2+ or EGTA were buffered by cellular uptake or release, respectively, until the steady-state free Ca2+ concentration was reestablished. When nonmitochondrial Ca2+ uptake was determined in the presence of a combination of mitochondrial inhibitors (10(-5) mol/l antimycin, 5 X 10(-6) mol/l oligomycin, and 10(-2) mol/l azide), the rate of uptake was considerably reduced, while the steady-state concentration was unaltered. In contrast, mitochondrial uptake that could be observed in the presence of the ATPase inhibitor vanadate (2 X 10(-3) mol/l) proceeded at the same rate as the control, but the minimal medium free Ca2+ concentration reached was 2.4 +/- 0.1 X 10(-7) mol/l higher than the control. Addition of secretagogues at steady-state free Ca2+ concentration resulted in a Ca2+ release of 0.73 +/- 0.08 nmol/mg protein. The increase in medium free Ca2+ concentration was entirely transient and followed by reuptake to the prestimulation level. The data indicate that a cytosolic free Ca2+ concentration of 4 X 10(-7) mol/l can be regulated in pancreatic acinar cells by a nonmitochondrial Mg2+-dependent Ca2+ pool.

Noradrenaline-induced calorigenesis in warm- or cold-acclimated rats. In vivo estimation of adrenoceptor concentration of noradrenaline effecting half-maximal response

1980 ◽  
Vol 58 (9) ◽  
pp. 1072-1077 ◽  
Author(s):  
Florent Depocas ◽  
Gloria Zaror-Behrens ◽  
Suzanne Lacelle
Keyword(s):  
Adipose Tissue ◽  
Steady State ◽  
Brown Adipose Tissue ◽  
Maximal Response ◽  
Brown Adipose ◽  
Acclimation Group ◽  
Arterial Plasma ◽  
State Concentration ◽  
Na Uptake

Desmethylimipramine (DMI, 1 mg DMI∙HCl kg−1) and normetanephrine (NMN, 1 μg min−1 g−0.74) were used to inhibit, respectively, neuronal and extraneuronal uptakes of noradrenaline (NA) during calorigenesis induced in barbital-sedated warm-acclimated (WA) or cold-acclimated (CA) rats by infusion of NA, a procedure which mimics the effects of NA released within calorigenic tissues in response to cold exposure. The doses of the inhibitors were selected for maximal effectiveness in potentiating calorigenic response and for minimal side effects. For rats of either acclimation group treated with DMI and NMN, with DMI only, or with neither inhibitor the doses of NA required to evoke approximately half-maximal calorigenic responses were, respectively, 0.5, 1.0, and 3.5 ng min−1 g−0.74. The corresponding steady-state concentrations of NA in arterial plasma averaged 14.3, 21.7, and 43.2 nM in the three groups of WA rats and 10.0, 14.8, and 31.9 nM in the three groups of CA rats. Reduction by NA uptake inhibitors of the circulating levels of NA necessary to stimulate calorigenesis, half-maximally, presumably in brown adipose tissue, indicates a reduction in the steepness of the NA concentration gradient between capillary plasma and synaptic clefts in that tissue. The steady-state concentration of NA in blood plasma of rats treated with DMI and NMN and infused with NA at a dose of 0.5 ng min−1 g−0.74 (~1 × 10−8 M) is a good estimate of the NA concentration required at calorigenic adrenoceptors to effect half-maximal activation. Presumably, this concentration is also an estimate of that resulting from NA released at nerve endings during cold-induced activation of nonshivering thermogenesis at half-maximal rates in brown adipose tissue.

Measurement of circulating red cell volume using biotin-labeled red cells: validation against 51Cr-labeled red cells

Transfusion ◽  
1999 ◽  
Vol 39 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Donald Mock ◽  
Gary L. Lankford ◽  
John A. Widness ◽  
Leon F. Burmeister ◽  
Daniel Kahn ◽  
...  
Keyword(s):  
Cell Volume ◽  
Red Cells ◽  
Red Cell ◽  
Red Cell Volume

Semiparametric approach to pharmacokinetic-pharmacodynamic data

1989 ◽  
Vol 256 (4) ◽  
pp. R1005-R1010
Author(s):  
D. Verotta ◽  
S. L. Beal ◽  
L. B. Sheiner
Keyword(s):  
Steady State ◽  
Rate Constant ◽  
Drug Concentration ◽  
Venous Blood ◽  
Time Lag ◽  
Elimination Rate ◽  
Hysteresis Loops ◽  
Real Data ◽  
Elimination Rate Constant ◽  
Arterial Blood

A semiparametric model for analysis of pharmacokinetic (PK) and pharmacodynamic (PD) data arising from non-steady-state experiments is presented. The model describes time lag between drug concentration in a sampling compartment, e.g., venous blood (Cv), and drug effect (E). If drug concentration at the effect site (Ce) equilibrates with arterial blood concentration (Ca) slower than with Cv, a non-steady-state experiment yields E vs. Cv data describing a counterclockwise hysteresis loop. If Ce equilibrates with Ca faster than with Cv, clockwise hysteresis is observed. To model hysteresis, a parametric model is proposed linking (unobserved) Ca to Cv with elimination rate constant kappa ov and also linking Ca to Ce with elimination rate constant kappa oe. When kappa oe is greater than (or less than) kappa ov clockwise (or counterclockwise) hysteresis occurs. Given kappa oe and kappa ov, numerical (constrained) deconvolution is used to obtain the disposition function of the arterial compartment (Ha), and convolution is used to calculate Ce given Ha. The values of kappa oe and kappa ov are chosen to collapse the hysteresis loops to single curves representing the Ce-E (steady-state) concentration-response curve. Simulations, and an application to real data, are reported.

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