Regulatory volume decrease in Trypanosoma cruzi involves amino acid efflux and changes in intracellular calcium

2003 ◽  
Vol 126 (2) ◽  
pp. 219-230 ◽  
Author(s):  
Peter Rohloff ◽  
Claudia O. Rodrigues ◽  
R. Docampo
Keyword(s):  
Amino Acid ◽  
Trypanosoma Cruzi ◽  
Intracellular Calcium ◽  
Regulatory Volume Decrease ◽  
Amino Acid Efflux ◽  
Volume Decrease

scholarly journals Regulatory volume decrease in cultured kidney cells (A6): role of amino acids.

1995 ◽  
Vol 106 (3) ◽  
pp. 525-542 ◽  
Author(s):  
P De Smet ◽  
J Simaels ◽  
P E Declercq ◽  
W Van Driessche
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Acid Concentration ◽  
Short Circuit ◽  
Regulatory Volume Decrease ◽  
Short Circuit Current ◽  
Amino Acid Concentration ◽  
Cell Content ◽  
Volume Decrease

Volume regulation was studied in A6 epithelia grown on permeable supports by measuring cell thickness (Tc) while simultaneously recording short circuit current (ISC) and transepithelial conductance (Gt). Lowering the tonicity of the basolateral solution (pi b) from 250 or 215 to 140 mOsm/kg elicited a rapid rise in Tc followed by a regulation of the cell volume towards control. This decrease in Tc displays the characteristics of the regulatory volume decrease (RVD). Upon restoring the isoosmotic conditions, Tc decreased rapidly below its control value. A post RVD regulatory volume increase (RVI) as described for other cell types was not observed. The subsequent reduction of the basolateral osmolality increased Tc to the level recorded at the end of the first hypoosmotic pulse. Because cell content was not altered during the isoosmotic period the second hypoosmotic challenge was isotonic with the cell and did therefore not evoke an RVD. However, the cell did not lose its ability to volume regulate since an RVD could be elicited by further reduction of pi b from 140 to 100 mOsm/kg. The possibility of an involvement of amino acids in the RVD was tested. The amount of amino acids in the cell as well as excreted in the bath was determined by amino acid analysis. Millimolar concentrations of threonine, serine, alanine, glutamate, glycine and aspartate were found in the cell extract. The cellular amino acid concentration was 28.8 +/- 0.4 mM. The amounts of glycine, aspartate and glutamate excreted from the cell during the hypotonic treatment were significantly larger than in control conditions. The excretion of these amino acids during hypotonicity decreased the cellular amino acid concentration by 8.4 +/- 0.2 mM. This quantity cannot completely account for the RVD during the first hypotonic challenge. The addition of glycine, aspartate and glutamate to the bathing solutions, although used at concentrations higher than intracellularly, did not reduce RVD. On the contrary, this maneuver increased the amplitude of the RVD following both hypoosmotic pulses. This result suggests a stimulatory role of the amino acids on the processes responsible for the RVD.

Amino Acid Correction of Regulatory Volume Decrease Evoked by Hypotonic Stress in Mouse Oocytes In Vitro

2015 ◽  
Vol 159 (1) ◽  
pp. 35-37 ◽  
Author(s):  
M. A. Pogorelova ◽  
V. A. Golichenkov ◽  
V. N. Pogorelova ◽  
A. I. Panait ◽  
A. A. Smirnov ◽  
...  
Keyword(s):  
Amino Acid ◽  
Regulatory Volume Decrease ◽  
Hypotonic Stress ◽  
Mouse Oocytes ◽  
Volume Decrease

Amino Acid Osmolytes in Regulatory Volume Decrease and Isovolumetric Regulation in Brain Cells: Contribution and Mechanisms

2000 ◽  
Vol 10 (5-6) ◽  
pp. 361-370 ◽  
Author(s):  
Herminia Pasantes-Morales ◽  
Rodrigo Franco ◽  
M. Eugenia Torres-Marquez ◽  
Karla Hernández-Fonseca ◽  
Arturo Ortega
Keyword(s):  
Amino Acid ◽  
Regulatory Volume Decrease ◽  
Brain Cells ◽  
Volume Decrease

Human Platelets Exposed to Mechanical Stresses Express a Potent Lipoxygenase Product

1992 ◽  
Vol 68 (05) ◽  
pp. 589-594 ◽  
Author(s):  
Alon Margalit ◽  
Avinoam A Livne
Keyword(s):  
Regulatory Volume Decrease ◽  
Human Platelets ◽  
Mechanical Stresses ◽  
Arterial Stenosis ◽  
Platelet Suspension ◽  
Suspension Flows ◽  
Lipoxygenase Product ◽  
Pathological Conditions ◽  
K Permeability ◽  
Volume Decrease

SummaryHuman platelets exposed to hypotonicity undergo regulatory volume decrease (RVD), controlled by a potent, yet labile, lipoxygenase product (LP). LP is synthesized and excreted during RVD affecting selectively K+ permeability. LP is assayed by its capacity to reconstitute RVD when lipoxygenase is blocked. Centrifugation for preparing washed platelets (1,550 × g, 10 min) is sufficient to express LP activity, with declining potency in repeated centrifugations, indicating that it is not readily replenish-able. When platelet suspension flows in a vinyl tubing (1 mm i.d.), at physiological velocity, controlled at 90–254 cm/s, LP formation increases as a function of velocity but declines as result of increasing the tubing length. Stirring the platelets in an aggregometer cuvette for 30 s, yields no LP unless the stirring is intermittent. No associated platelet lysis or aggregation are observed following the mechanical stress applications. These results demonstrate that although mechanical stresses result in LP production, the mode of its application plays a major role. These results may indicate that LP is synthesized under pathological conditions and could be of relevance to platelets behavior related to arterial stenosis.

LRRC8A is essential for swelling‐activated chloride current and for regulatory volume decrease in astrocytes

2018 ◽  
Vol 33 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Francesco Formaggio ◽  
Emanuela Saracino ◽  
Maria Grazia Mola ◽  
Shreyas Balachandra Rao ◽  
Mahmood Amiry-Moghaddam ◽  
...  
Keyword(s):  
Regulatory Volume Decrease ◽  
Chloride Current ◽  
Volume Decrease

Extracellular pH alkalinization by Cl−/HCO3− exchanger is crucial for TASK2 activation by hypotonic shock in proximal cell lines from mouse kidney

2007 ◽  
Vol 292 (2) ◽  
pp. F628-F638 ◽  
Author(s):  
S. L'Hoste ◽  
H. Barriere ◽  
R. Belfodil ◽  
I. Rubera ◽  
C. Duranton ◽  
...  
Keyword(s):  
Cell Lines ◽  
Regulatory Volume Decrease ◽  
Inhibitory Effect ◽  
Buffering Capacity ◽  
Mouse Kidney ◽  
Wild Type ◽  
Cytosolic Ph ◽  
Hypotonic Shock ◽  
External Ph ◽  
Volume Decrease

We have previously shown that K+-selective TASK2 channels and swelling-activated Cl− currents are involved in a regulatory volume decrease (RVD; Barriere H, Belfodil R, Rubera I, Tauc M, Lesage F, Poujeol C, Guy N, Barhanin J, Poujeol P. J Gen Physiol 122: 177–190, 2003; Belfodil R, Barriere H, Rubera I, Tauc M, Poujeol C, Bidet M, Poujeol P. Am J Physiol Renal Physiol 284: F812–F828, 2003). The aim of this study was to determine the mechanism responsible for the activation of TASK2 channels during RVD in proximal cell lines from mouse kidney. For this purpose, the patch-clamp whole-cell technique was used to test the effect of pH and the buffering capacity of external bath on Cl− and K+ currents during hypotonic shock. In the presence of a high buffer concentration (30 mM HEPES), the cells did not undergo RVD and did not develop outward K+ currents (TASK2). Interestingly, the hypotonic shock reduced the cytosolic pH (pHi) and increased the external pH (pHe) in wild-type but not in cftr −/− cells. The inhibitory effect of DIDS suggests that the acidification of pHi and the alkalinization of pHe induced by hypotonicity in wild-type cells could be due to an exit of HCO3−. In conclusion, these results indicate that Cl− influx will be the driving force for HCO3− exit through the activation of the Cl−/HCO3− exchanger. This efflux of HCO3− then alkalinizes pHe, which in turn activates TASK2 channels.

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