Cation conductance regulated by ambient Cl- in cultured rat mesangial cells.
Several functions of mesangial cells, such as contraction and release of nitric oxide, are dependent on the ambient Cl- concentration. Herein we describe a direct effect of Cl- on mesangial cell membrane conductance. Rat mesangial cells were isolated, cultured, and were patch-clamped in the whole-cell configuration. The external concentration - ([Cl-]o) - of standard Ringer's solutions was changed isotonically from standard of 160 mM to 35 mM while cell membrane conductance was continuously recorded. Results indicated that control I-V curves of the steady state current had a linear slope conductance of 0.95 nS (n = 10, r = 0.9). In low [Cl-]o, conductance outwardly rectified and increased to 4.1 nS between -120 and 0 mV and to 16.8 nS between 0 and 40 mV (n = 10, r = 0.9; p<0.01). The increase in conductance occurred within a few seconds and was reversible. Our results show that a large mesangial cell membrane conductance for cations is activated upon exposure to low [Cl-]o.
Huang
C J
CJ
Department of Biomedical Engineering, Rutgers University, Piscataway, NJ 08854, USA.
Palant
C E
CE
Craelius
W
W
D000818:Animals; D002412:Cations / Q000378:metabolism*; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism / Q000503:physiopathology*; D006706:Homeostasis / Q000502:physiology; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley
D002412:Cations; D002712:Chlorides