Ion channels activated by osmotic and mechanical stress in membranes of opossum kidney cells.
For patch-clamp measurements cultured kidney (OK) cells were exposed to osmotic and mechanical stress. Superfusion of a cell in whole cell configuration with hypotonic media (190 mOsm) evokes strong depolarization, which is reversible by returning to the isotonic bath medium. In the cell-attached configuration the exposure to hypotonic media evokes up to six ion channels of homogeneous single-channel properties in the membrane patch. Subsequently, the channels became activated after a time lag of a few seconds. At an applied membrane potential of 0 mV, the corresponding membrane current is directed inward and shows a transient behavior in the time range of minutes. In the same membrane patch these ion channels can be activated by application of negative hydrostatic pressure. The channel has a single-channel conductance of about 22 pS and is permeable to Na+ and K+ as well as to C1-. It is suggested that volume regulation involves mechanoreceptor-operated ion channels.
Ubl
J
J
Faculty of Biology, University of Konstanz, Federal Republic of Germany.
Murer
H
H
Kolb
H A
HA
D000818:Animals; D002478:Cells, Cultured; D006706:Homeostasis; D007038:Hypotonic Solutions; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D007668:Kidney / Q000166:cytology / Q000648:ultrastructure*; D009893:Opossums / Q000502:physiology*; D009997:Osmotic Pressure; D011189:Potassium Chloride / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013314:Stress, Mechanical
D007038:Hypotonic Solutions; D007473:Ion Channels; D012965:Sodium Chloride; D011189:Potassium Chloride