ISSN:
1432-1424
Keywords:
Ca2+-activated K+ channels
;
Cell volume
;
Regulatory volume decrease
;
Tetraethylammonium
;
Lacrimal acinar cells
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract The volumes of acinar cells isolated from rat lacrimal gland were measured on computer by video-imaging. Cells were found to swell on exposure to hypotonic solutions; they subsequently exhibited a regulatory volume decrease (RVD). RVD was inhibited in the absence of extracellular Ca2+, and by the K+ channel blocker tetraethylammonium chloride (2 mm TEA+). The possible involvement of K+ channels in RVD was further investigated in cell-attached patches. Exposing the cells to a hypotonic solution activated channels with a conductance of 141±6 pS (n=11). These channels were partially blocked by 0.5 mm TEA+, and channel activation was not observed in the absence of extracellular Ca2+. Experiments in the inside-out patch configuration demonstrated that the channels activated by hypotonie stress were “maxi” Ca2+-activated K+ channels. It is concluded that the opening of these channels plays an important role in RVD, by facilitating K+ loss from the cell.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00238253
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