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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-4-18
pubmed:abstractText
We investigated effects of external acidosis on HERG current expressed in Xenopus oocytes. HERG current was rapidly and reversibly suppressed by external acidosis in a voltage-independent manner. The slope conductance was decreased from 143 +/- 11 to 93.4 +/- 6.8 microS by changing external pH (pH(o)) from 7.6 to 6.0 (P<0.05). Steady-state activation was shifted by about 20 mV in a depolarized direction with a change from pH(o) 7.6 to 6.0, while steady-state inactivation was not significantly changed. Activation time constants were increased, deactivation and recovery time constants were decreased, while those of inactivation showed no significant change. When external K(+) concentration ([K(+)](o)) was increased from 2 mM to 10 mM, a ratio of slope conductance at pH(o) 6.0 to pH(o) 7.6 was significantly smaller in 2 mM (pH(o) 6.0/pH(o) 7.6 = 0.65 +/- 0.04) than in 10 mM[K(+)](o) (0.83 +/- 0.06, P<0.05). The changes in activation, deactivation and recovery from inactivation were not affected by change in [K(+)](o). The results indicated that external acidosis suppressed HERG current mainly by shifting the voltage-dependence of the activation and deactivation kinetics, and partly by decreasing slope conductance. Moreover, the reduction of HERG current could be partly antagonized with increasing [K(+)](o).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2828
pubmed:author
pubmed:copyrightInfo
Copyright 2000 Academic Press.
pubmed:issnType
Print
pubmed:volume
32
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11-21
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Effects of external acidosis on HERG current expressed in Xenopus oocytes.
pubmed:affiliation
Department of 1st Internal Medicine, School of Medicine, Tokyo, 113-8510, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't