Linked Life Data

15653752

Source:http://linkedlifedata.com/resource/pubmed/id/15653752

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2005-5-17
pubmed:abstractText
Despite the important roles played by ventricular fibroblasts and myofibroblasts in the formation and maintenance of the extracellular matrix, neither the ionic basis for membrane potential nor the effect of modulating membrane potential on function has been analyzed in detail. In this study, whole cell patch-clamp experiments were done using ventricular fibroblasts and myofibroblasts. Time- and voltage-dependent outward K(+) currents were recorded at depolarized potentials, and an inwardly rectifying K(+) (Kir) current was recorded near the resting membrane potential (RMP) and at more hyperpolarized potentials. The apparent reversal potential of Kir currents shifted to more positive potentials as the external K(+) concentration ([K(+)](o)) was raised, and this Kir current was blocked by 100-300 muM Ba(2+). RT-PCR measurements showed that mRNA for Kir2.1 was expressed. Accordingly, we conclude that Kir current is a primary determinant of RMP in both fibroblasts and myofibroblasts. Changes in [K(+)](o) influenced fibroblast membrane potential as well as proliferation and contractile functions. Recordings made with a voltage-sensitive dye, DiBAC(3)(4), showed that 1.5 mM [K(+)](o) resulted in a hyperpolarization, whereas 20 mM [K(+)](o) produced a depolarization. Low [K(+)](o) (1.5 mM) enhanced myofibroblast number relative to control (5.4 mM [K(+)](o)). In contrast, 20 mM [K(+)](o) resulted in a significant reduction in myofibroblast number. In separate assays, 20 mM [K(+)](o) significantly enhanced contraction of collagen I gels seeded with myofibroblasts compared with control mechanical activity in 5.4 mM [K(+)](o). In combination, these results show that ventricular fibroblasts and myofibroblasts express a variety of K(+) channel alpha-subunits and demonstrate that Kir current can modulate RMP and alter essential physiological functions.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0363-6135
pubmed:author
pubmed:issnType
Print
pubmed:volume
288
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H2931-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
K+ currents regulate the resting membrane potential, proliferation, and contractile responses in ventricular fibroblasts and myofibroblasts.
pubmed:affiliation
Dept. of Bioengineering, Univ. of California-San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0412, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't