Voltage-dependent slowly activating anion current regulated by temperature and extracellular pH in mouse B cells.
Voltage-dependent, outwardly rectifying anion channels have been described in various cells including lymphocytes. In this study, we found that murine B cells express the voltage-dependent slowly activating anion channels (VSACs). Using a whole-cell configuration, I (VSAC) in Bal-17 was induced by a sustained depolarization (>0 mV) which was remarkably facilitated at 35 degrees C (Q (10)=23 at 30 mV of clamp voltage). Substitution of extracellular Cl(-) with gluconate shifted the reversal potential to the right (35.7 mV). Gd(3+) (IC(50)=0.11 microM) significantly attenuated I (VSAC), but DIDS partially blocked I (VSAC). In addition, extracellular acidification suppressed I (VSAC) whereas alkalinization facilitated the channel activation. I (VSAC) was decreased by 90% at pH 6.35 and increased by 180% at pH 8.0. In cell-attached and inside-out patch clamps, depolarization slowly activated the anion channels of large conductance (approximately 270 pS) with multiple levels of subconductances. The single channel currents were also blocked by Gd(3+) and acidic pH. Furthermore, I (VSAC) was also observed in WEHI-231 (an immature B cell line) and freshly isolated splenic B cells of mice. In summary, murine B cells express unique voltage-dependent anion channels that show a strong sensitivity to both temperature and extracellular pH. Further investigation is required to understand the physiological roles of VSAC and its molecular identity.
Nam
Joo Hyun
JH
Department of Physiology and Biophysics, Seoul National University College of Medicine, Seoul 110-799, South Korea.
Zheng
Hai Feng
HF
Earm
Ki Hyun
KH
Ko
Jae Hong
JH
Lee
Ik-Jae
IJ
Kang
Tong Mook
TM
Kim
Tae Jin
TJ
E Earm
Yung
Y
Kim
Sung Joon
SJ
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001402:B-Lymphocytes / Q000502:physiology*; D002460:Cell Line; D004594:Electrophysiology; D006863:Hydrogen-Ion Concentration; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D009544:Niflumic Acid / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D013696:Temperature
D000894:Anti-Inflammatory Agents, Non-Steroidal; D007473:Ion Channels; D009544:Niflumic Acid; D000255:Adenosine Triphosphate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid