title: Voltage-dependent slowly activating anion current regulated by temperature and extracellular pH in mouse B cells.
abstract: 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.
authors.affiliation: Department of Physiology and Biophysics, Seoul National University College of Medicine, Seoul 110-799, South Korea.
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Nam
authors.forename: Hai Feng
authors.initials: HF
authors.lastname: Zheng
authors.forename: Ki Hyun
authors.initials: KH
authors.lastname: Earm
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Ko
authors.forename: Ik-Jae
authors.initials: IJ
authors.lastname: Lee
authors.forename: Tong Mook
authors.initials: TM
authors.lastname: Kang
authors.forename: Tae Jin
authors.initials: TJ
authors.lastname: Kim
authors.forename: Yung
authors.initials: Y
authors.lastname: E Earm
authors.forename: Sung Joon
authors.initials: SJ
authors.lastname: Kim
mesh_terms: 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
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D007473:Ion Channels; D009544:Niflumic Acid; D000255:Adenosine Triphosphate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid