ISSN:
1432-2013
Keywords:
MDCK Cells
;
Cell membrane resistance
;
Potassium conductance
;
Anion conductance
;
Cell volume regulation
;
Intracellular pH
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
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 (R m), 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 R m 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 R m. In the absence of chloride and in the absence of bicarbonate and chloride, the decrease of R m 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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00370449
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