ID 111358
著者
Sörensen, Mads V Aarhus University
Leipziger, Jens Aarhus University
キーワード
K+ channel
ion secretion
colon
epithelium
資料タイプ
その他
抄録
Distal colonic K+ excretion is determined by the balance of K+ absorption and K+ secretion of the enterocytes. K+ secretion occurs via active basolateral K+ uptake mostly via the NKCC1 co-transporter followed by K+ exit via a luminal K+ channel. The specific focus here is directed towards the luminal secretory K+ channel (1). Several recent observations highlight the pivotal role of the large conductance, Ca2+-activated KCa1.1 (BK, KCNMA) channel as the only functionally relevant luminal K+ efflux pathway in mouse distal colon (2, 3). This conclusion was based on defining results from BK knock-out mice. The following key observations were made : 1. BK channels mediate the resting distal colonic K+ secretion (2, 4), 2. They are acutely stimulated by activation of luminal nucleotide receptor and elevations of intracellular Ca2+ (2, 4, 5), 3. Colonic BK channels are up-regulated by increases of plasma aldosterone (3), 4. In addition, the cAMP-stimulated distal colonic K+ secretion is apparently mediated via BK channels, 5. Finally, aldosterone was found to up-regulate specifically the ZERO (e.g. cAMP activated) C-terminal splice variant of the BK channel. In summary, we suggest that the sole exit pathway for transcellular K+ secretion in mammalian distal colon is the BK channel, which is the target for short term intracellular Ca2+ and cAMP activation and long term aldosterone regulation.
掲載誌名
The Journal of Medical Investigation
ISSN
13496867
13431420
cat書誌ID
AA11166929
AA12022913
出版者
Faculty of Medicine Tokushima University
56
Supplement
開始ページ
301
終了ページ
301
並び順
301
発行日
2009-12
出版社版DOI
出版社版URL
フルテキストファイル
言語
eng
著者版フラグ
出版社版