Activity of ion channels during volume regulation by clonal N1E115 neuroblastoma cells.
When exposed to a hypotonic bathing solution, clonal N1E115 neuroblastoma cells initially swell and then undergo a regulatory volume decrease (RVD). Using cell-attached patch-clamp recording, we have found that the activity of a stretch-sensitive, nonselective cation [C+(SA)] channel increases shortly after the onset of osmotically induced cell swelling; this depolarizes the cells as much as 30 mV. Shortly thereafter, and roughly coincident with the onset of RVD, two types of voltage-dependent channels open at the new resting potential; these are (i) a delayed-rectifier type K+ [K+(DR)] channel and (ii) a large-conductance anion channel. We suggest that opening of the C+(SA) channel may contribute to the volume "sensor" mechanism, while the depolarization-induced opening of the K+(DR) and anion channels may constitute a significant K+ salt exit pathway, operating in RVD.
Falke
L C
LC
Department of Internal Medicine, Jewish Hospital of Saint Louis, MO 63110.
Misler
S
S
D000818:Animals; D000838:Anions / Q000502:physiology; D002118:Calcium / Q000502:physiology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials; D009447:Neuroblastoma / Q000473:pathology / Q000503:physiopathology*; D009994:Osmolar Concentration; D011188:Potassium / Q000502:physiology; D013997:Time Factors; D014407:Tumor Cells, Cultured; D014882:Water-Electrolyte Balance
D000838:Anions; D007473:Ion Channels; D011188:Potassium; D002118:Calcium