ID 111358
Author
Sörensen, Mads V Aarhus University
Leipziger, Jens Aarhus University
Keywords
K+ channel
ion secretion
colon
epithelium
Content Type
Others
Description
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.
Journal Title
The Journal of Medical Investigation
ISSN
13496867
13431420
NCID
AA11166929
AA12022913
Publisher
Faculty of Medicine Tokushima University
Volume
56
Issue
Supplement
Start Page
301
End Page
301
Sort Key
301
Published Date
2009-12
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Publisher