Cellular volume regulation in salinity stressed molluscs: The response ofNoetia ponderosa (Arcidae) red blood cells to osmotic variation

1980 ◽  
Vol 138 (4) ◽  
pp. 283-289 ◽  
Author(s):  
Lynn M. Amende ◽  
Sidney K. Pierce
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Volume Regulation ◽  
Cellular Volume

Minimal volume regulation after shrinkage of red blood cells from five species of reptiles

2008 ◽  
Vol 150 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Karina Kristensen ◽  
Michael Berenbrink ◽  
Pia Koldkjær ◽  
Augusto Abe ◽  
Tobias Wang
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Volume Regulation ◽  
Minimal Volume

scholarly journals Volume regulation by flounder red blood cells in anisotonic media

1977 ◽  
Vol 69 (5) ◽  
pp. 537-552 ◽  
Author(s):  
PM Cala
Keyword(s):  
Red Blood Cells ◽  
Cell Volume ◽  
Water Flow ◽  
Blood Cells ◽  
Volume Regulation ◽  
Control Cell ◽  
Regulatory Volume Decrease ◽  
Electrochemical Gradient ◽  
Osmotic Swelling ◽  
Inorganic Cation

The nucleated high K, low Na red blood cells of the winter flounder demonstrated a volume regulatory response subsequent to osmotic swelling or shrinkage. During volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation the net water flow was secondary to net inorganic cation flux. Volume regulation after osmotic swelling is referred to as regulatory volume decrease (RVD) and was characterized by net K and water loss. Since the electrochemical gradient for K is directed out of the cell there is no need to invoke active processes to explain RVD. When osmotically shrunken, the flounder erythrocyte demonstrated a regulatory volume increase (RVI) back toward control cell volume. The water movements characteristic of RVI were a consequence of net cellular NaCl and KCl uptake with Na accounting for 75 percent of the increase in intracellular cation content. Since the Na electrochemical gradient is directed into the cell, net Na uptake was the result of Na flux via dissipative pathways. The addition of 10(-4)M ouabain to suspensions of flounder erythrocytes was without effect upon net water movements during volume regulation. The presence of ouabain did however lead to a decreased ration of intracellular K:Na. Analysis of net Na and K fluxes in the presence and absence of ouabain led to the conclusion that Na and K fluxes via both conservative and dissipative pathways are increased in response to osmotic swelling or shrinkage. In addition, the Na and K flux rate through both pump and leak pathways decreased in a parallel fashion as cell volume was regulated. Taken as a whole, the Na and K movements through the flounder erythrocyte membrane demonstrated a functional dependence during volume regulation.

Active and passive Ca movements in dog red blood cells and resealed ghosts

1979 ◽  
Vol 237 (1) ◽  
pp. C10-C16 ◽  
Author(s):  
J. C. Parker
Keyword(s):  
Body Temperature ◽  
Red Blood Cells ◽  
Cell Volume ◽  
Blood Cells ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Low Ph ◽  
Coupling Ratio ◽  
Cell Shrinkage ◽  
Resealed Ghosts

Dog red blood cells accumulate Ca rapidly when deprived of substrate or cooled to 5 degrees C. The latter effect is reversible as the cells are rewarmed to body temperature. Resealed ghosts extrude Ca, provided ATP is incorporated in them. Passive fluxes of Ca are stimulated by Na on the opposite side of the membrane, consistent with a model for Ca-Na countertransport. Quinidine, cell shrinkage, and low pH--all known to suppress net Ca influx--have no accelerating effect on Ca efflux, thus validating earlier conclusions about the variability of the coupling ratio for Ca-Na exchange. The significance of these findings for cell volume regulation is discussed.

Several cation transporters and volume regulation in high-K dog red blood cells

1991 ◽  
Vol 260 (3) ◽  
pp. C589-C597 ◽  
Author(s):  
H. Fujise ◽  
I. Yamada ◽  
M. Masuda ◽  
Y. Miyazawa ◽  
E. Ogawa ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Volume Regulation ◽  
Cation Composition ◽  
Influx Rate ◽  
Physiological Conditions ◽  
High K ◽  
Dependent Transport ◽  
Low K ◽  
K Transport

Normal dog red blood cells lack the Na-K pump, and their cation composition is low K and high Na (LK). Recently, a dog was found with red blood cells containing high K and low Na concentrations (HK) due to the existence of the Na-K pump. In the present study, cation transport and volume regulation in HK cells were compared with those of LK cells. HK cells showed not only Rb influx through a Na-K pump, but also Rb influx through a Cl-dependent K transporter. The Rb influx rate through the Na-K pump was 0.65-1.44 mmol.l cells-1.h-1 in Cl and 1.75-2.24 mmol.l cells-1.h-1 in NO3, in HK cells, but only trace activities are found in LK cells. In HK cells, the Rb influx rate through Cl-dependent K transport was 0.36-0.96 mmol.l cells-1.h-1, and it was enhanced in swollen cells but vanished in shrunken cells. In LK cells, the transport was evident only in swollen cells. The original volume of swollen HK cells was restored by water extrusion promoted by Cl-dependent transport. The Na-Ca exchange transporter, which works as a volume regulator in LK cells, functioned in HK cells only when they were loaded with Na. Hence, the exchange transporter is latent in HK cells under physiological conditions. Moreover, the exchange transporter could restore the cell volume in swollen and Na-loaded HK cells. However, the volume in HK cells was still larger than that in LK cells, while the Na-Ca exchange transporter was working.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Volume regulation by Amphiuma red blood cells. The membrane potential and its implications regarding the nature of the ion-flux pathways.

1980 ◽  
Vol 76 (6) ◽  
pp. 683-708 ◽  
Author(s):  
P M Cala
Keyword(s):  
Membrane Potential ◽  
Alkali Metal ◽  
Red Blood Cells ◽  
Cell Volume ◽  
Blood Cells ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Ion Flux ◽  
Regulatory Response

After osmotic perturbation, the red blood cells of Amphiuma exhibited a volume-regulatory response that returned cell volume back to or toward control values. After osmotic swelling, cell-volume regulation (regulatory volume decrease; RVD) resulted from net cellular loss of K, Cl, and osmotically obliged H2O. In contrast, the volume-regulatory response to osmotic shrinkage (regulatory volume increase; RVI) was characterized by net cellular uptake of Na, Cl, and H2O. The net K and Na fluxes characteristic of RVD and RVI are increased by 1-2 orders of magnitude above those observed in studies of volume-static control cells. The cell membrane potential of volume-regulating and volume-static cells was measured by impalement with glass microelectrodes. The information gained from the electrical and ion-flux studies led to the conclusion that the ion fluxes responsible for cell-volume regulation proceed via electrically silent pathways. Furthermore, it was observed that Na fluxes during RVI were profoundly sensitive to medium [HCO3] and that during RVI the medium becomes more acid, whereas alkaline shifts in the suspension medium accompany RVD. The experimental observations are explained by a model featuring obligatorily coupled alkali metal-H and Cl-HCO3 exchangers. The anion- and cation-exchange pathways are separate and distinct yet functionally coupled via the net flux of H. As a result of the operation of such pathways, net alkali metal, Cl, and H2O fluxes proceed in the same direction, whereas H and HCO3 fluxes are cyclic. Data also are presented that suggest that the ion-flux pathways responsible for cell-volume regulation are not activated by changes in cell volume per se but by some event associated with osmotic perturbation, such as changes in intracellular pH.

scholarly journals Evidence of Coordinated and Adjustable Osmolytes Movements Following Hyposmotic Swelling in Rainbow Trout Red Blood Cells

2021 ◽  
Vol 55 (S1) ◽  
pp. 185-195
Author(s):  
Valérie Maxime ◽  
Keyword(s):  
Red Blood Cells ◽  
Cell Volume ◽  
Blood Cells ◽  
Volume Regulation ◽  
Rapid Change ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Gravimetric Method ◽  
Ph Control ◽  
Na Uptake

BACKGROUND/AIMS: The osmolytes involved in the volume regulation of hyposmotically-swollen fish cells are well identified. However, if a coordination and adjustments of their fluxes are obvious, few studies have clearly illustrated these aspects. METHODS: Trout red blood cells volume variations were estimated from water contents obtained by a gravimetric method. Intracellular K+ and Na+ contents, and Cl- content of haemolysed cells were determined by photometry and colorimetry, respectively. The taurine contribution to cell volume regulation was calculated from the net changes of water, K+, Cl- and Na+ contents. The intracellular pH was calculated from the chloride distribution across the cells membranes according to the Donnan equilibrium. RESULTS: Cells responses to a rapid change (from 296 to 176 mOsm.kg-1)
of the saline osmolality were examined in three conditions designed to not impact (Hypo. I)
or to reduce the K+ (Hypo. II) and Cl- (Hypo. III) contributions to the volume regulation. Hypo. I condition caused an immediate increase in water content, followed by a 90 min. full regulation, concomitant with gradual lowering of K+ and Cl- contents and a surprising increase in Na+ content. Hypo. II and III conditions showed a partial and complete volume regulation, respectively. This was made possible by an increase in the taurine involvement. These experiments allowed to confirm that K+ and Cl- were released via KCl cotransport and by separate channels. The comparison of Hypo. I and III conditions led to the observation that the partially amiloride-sensitive Na+ influx is proportional to the taurine efflux; the latter being sustained mainly by a Na+/taurine cotransport. The Hypo. II condition was suitable for the (Na+/K+)ATPase activity inhibition. This effect could explain the observed lack of Na+ uptake, the consecutive depletion of intracellular taurine stock and the incomplete volume regulation. Finally, the results support the importance of taurine in pH control under Hypo. I (physiologic) condition. The alkalosis observed in Hypo. II and III conditions were the consequences of changes in the salines compositions, not of physiologic adjustments. CONCLUSION: The regulatory volume decrease process of trout RBCs is complex and adjustable through coordinated osmolytes movements. The obliged decrease in K+ and/or Cl- contributions stimulates taurine and Na+ pathways. This study highlights the importance of taurine as a compensatory variable in cell volume regulation and explains for the first time the significance of the Na+ uptake during this process

Ion Transport and Volume Regulation in Red Blood Cells

1986 ◽  
Vol 488 (1 Membrane Path) ◽  
pp. 174-186 ◽  
Author(s):  
MARK A. MILANICK ◽  
JOSEPH F. HOFFMAN
Keyword(s):  
Ion Transport ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Volume Regulation
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