Acidic Extracellular Ph-activated Outwardly Rectifying Chloride Current in Mammalian Cardiac Myocytes.
From: Department of Physiology, Saga University Faculty of Medicine, Saga, Japan. yamamot3@cc.saga-u.ac.jp
American journal of physiology. Heart and circulatory physiology
- Publish Date: May 2006
- ISSN: 0363-6135
- Volume: 290
- Issue: 5
- Pages: H1905-14
- Medium: Print
- Language: English
- Citation (JAMA): Yamamoto Shintaro, Ehara Tsuguhisa, et al. Acidic Extracellular Ph-activated Outwardly Rectifying Chloride Current in Mammalian Cardiac Myocytes.. Am. J. Physiol. Heart Circ. Physiol. May 2006;290:H1905-14
Abstract
Extracellular acidic pH was found to induce an outwardly rectifying Cl- current (I(Cl,acid)) in mouse ventricular cells, with a half-maximal activation at pH 5.9. The current showed the permeability sequence for anions to be SCN- > Br- > I- > Cl- > F- > aspartate, while it exhibited a time-dependent activation at large positive potentials. Similar currents were also observed in mouse atrial cells and in atrial and ventricular cells from guinea pig. Some Cl- channel blockers (DIDS, niflumic acid, and glibenclamide) inhibited ICl,acid, whereas tamoxifen had little effect on it. Unlike volume-regulated Cl- current (ICl,vol) and CFTR Cl- current (ICl,CFTR), ICl,acid was independent of the presence of intracellular ATP. Activation of ICl,acid appeared to be also independent of intracellular Ca2+ and G protein. ICl,acid and ICl,vol could develop in an additive fashion in acidic hypotonic solutions. Isoprenaline-induced ICl,CFTR was inhibited by acidification in a pH-dependent manner in guinea pig ventricular cells. Our results support the view that ICl,acid and ICl,vol stem from two distinct populations of anion channels and that the ICl,acid channels are present in cardiac cells. ICl,acid may play a role in the control of action potential duration or cell volume under pathological conditions, such as ischemia-related cardiac acidosis.
Mesh Headings (Keywords): Animals, Cells, Cultured, Chloride Channels, Chlorine, Extracellular Fluid, Guinea Pigs, Hydrogen-Ion Concentration, Ion Channel Gating, Membrane Potentials, Mice, Mice, Inbred C57BL, Myocytes, Cardiac, Water-Electrolyte Balance
Check for Full Text / PubMed Unique Identifier (PMID): 16339831
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.