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Forschungsdatenbank PMU-SQQUID

Further characterization of volume regulatory decrease in cultured renal epitheloid (MDCK) cells.
Ritter, M; Paulmichl, M; Lang, F;
Pflugers Arch. 1991; 418(1-2): 35-39.
Originalarbeiten (Zeitschrift)

PMU-Autor/inn/en

Paulmichl Markus
Ritter Markus

Abstract

In Madin Darby canine kidney (MDCK) cells volume regulatory decrease (VRD) is paralleled by a variable, transient hyperpolarization followed by a sustained depolarization of the cell membrane. In the depolarized cells, the cell membrane selectivity is decreased for potassium and increased for chloride. Without knowledge of the cell membrane resistance (Rm), these changes of cell membrane selectivity cannot be translated into conductances, i.e. the observed alterations of ion selectivity could have been due to inhibition of potassium conductance or activation of anion conductance. In the present study Rm has been determined by cellular cable analysis. To this end, three microelectrodes were impaled into three different cells of a cell cluster, current (up to 3 nA) was injected into one cell and the corresponding voltage deflections determined in the other two cells. As a result, exposure of the cells to hypotonic perfusates leads to a marked, sustained reduction of Rm. In the absence of chloride and in the absence of bicarbonate and chloride, the decrease of Rm is only transient. The data indicate that cell swelling leads to a transient increase of potassium conductance followed by a sustained increase of anion conductance. As evident from BCECF fluorescence, exposure of MDCK cells to hypotonic perfusates leads to a significant decrease of intracellular pH, which may in part be due to loss of bicarbonate through the anion conductive pathway.


Useful keywords (using NLM MeSH Indexing)

Animals

Cell Line

Cell Membrane/physiology

Chlorides/metabolism

Dogs

Epithelium/physiology

Fluoresceins

Hydrogen-Ion Concentration

Kidney/cytology

Kidney/physiology*

Membrane Potentials

Potassium/metabolism


Find related publications in this database (Keywords)

MDCK CELLS
CELL MEMBRANE RESISTANCE
POTASSIUM CONDUCTANCE
ANION CONDUCTANCE
CELL VOLUME REGULATION
INTRACELLULAR PH