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Arachidonic acid-induced activation of large-conductance potassium channels and membrane hyperpolarization in mouse B cells
Cited 9 time in
Web of Science
Cited 8 time in Scopus
- Authors
- Issue Date
- 2008-01-25
- Publisher
- Springer Verlag
- Citation
- Pflugers Arch. 456(5):867-881
- Keywords
- Animals ; Arachidonic Acid/metabolism/*pharmacology ; Calcium/metabolism ; Calcium Signaling/physiology ; Cell Line ; Membrane Potentials/*drug effects/physiology ; Mice ; Patch-Clamp Techniques ; Potassium Channels/*metabolism ; B-Lymphocytes/drug effects/metabolism
- Abstract
- Lymphocytes express voltage-gated (Kv) and Ca(2+)-activated (IKCa1) K(+) channels. Recently, we found that WEHI-231, an immature B cell line, expresses voltage-independent K(+) channels called large-conductance background K( + ) channels (LK(bg)). Arachidonic acid (AA) has attracted attention because of its potential regulatory roles in the apoptosis of immature B cells. To elucidate the functional targets of AA, we investigated the effects of AA on membrane currents, voltages, and cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) of WEHI-231 and Bal-17 cells that represent immature and mature mouse B cells, respectively. In whole-cell patch clamp, both Kv and IKCa1 were inhibited by AA. On the other hand, AA activated LK(bg) current and non-selective cationic (NSC) current in WEHI-231 while only NSC current in Bal-17. Inside-out patch clamp study showed that AA directly activates LK(bg). AA induced hyperpolarization of WEHI-231 and depolarization of Bal-17 cells, respectively. The selective functional expression of LK(bg) and their activation by AA were also confirmed in the immature B cells (B220(+)/AA4.1(+)) freshly isolated from mouse spleen. In fura-2 spectrofluorimetry, AA induced persistent increase in [Ca(2+)](c) of WEHI-231 cells, which was attenuated by KCl-induced depolarization. In Bal-17 cell, however, AA induced only a transient increase of [Ca(2+)](c). In summary, the novel type of background K(+) channels (LK(bg)) in immature B cells is strongly activated while the other K(+) channels (Kv and IKCa1) commonly expressed in lymphocytes are inhibited by AA. The hyperpolarization and augmentation of Ca(2+) influx by LK(bg) activation might play a role in the response of immature B cells to AA.
- ISSN
- 0031-6768 (Print)
- Language
- English
- URI
- http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=18214524
http://www.springerlink.com/content/at03t94mq9271081/fulltext.pdf
https://hdl.handle.net/10371/68188
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