Linked Life Data

17285302

Source:http://linkedlifedata.com/resource/pubmed/id/17285302

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-3-30
pubmed:abstractText
Employing microfluorometric system and patch clamp technique in rabbit basilar arterial myocytes, regulation mechanisms of vascular excitability were investigated by applying intracellular pH (pH(i)) changers such as sodium acetate (SA) and NH(4)Cl. Applications of caffeine produced transient phasic contractions in a reversible manner. These caffeine-induced contractions were significantly enhanced by SA and suppressed by NH(4)Cl. Intracellular Ca(2+) concentration ([Ca(2+)](i)) was monitored in a single isolated myocyte and based the ratio of fluorescence using Fura-2 AM (R (340/380)). SA (20 mM) increased and NH(4)Cl (20 mM) decreased R (340/380) by 0.2 +/- 0.03 and 0.1 +/- 0.02, respectively, in a reversible manner. Caffeine (10 mM) transiently increased R (340/380) by 0.9 +/- 0.07, and the ratio increment was significantly enhanced by SA and suppressed by NH(4)Cl, implying that SA and NH(4)Cl may affect [Ca(2+)](i) (p < 0.05). Accordingly, we studied the effects of SA and NH(4)Cl on Ca(2+)-activated K(+) current (IK(Ca)) under patch clamp technique. Caffeine produced transient outward current at holding potential (V (h)) of 0 mV, caffeine induced transient outward K(+) current, and the spontaneous transient outward currents were significantly enhanced by SA and suppressed by NH(4)Cl. In addition, IK(Ca) was significantly increased by acidotic condition when pH(i) was lowered by altering the NH(4)Cl gradient across the cell membrane. Finally, the effects of SA and NH(4)Cl on the membrane excitability and basal tension were studied: Under current clamp mode, resting membrane potential (RMP) was -28 +/- 2.3 mV in a single cell level and was depolarized by 13 +/- 2.4 mV with 2 mM tetraethylammonium (TEA). SA hyperpolarized and NH(4)Cl depolarized RMP by 10 +/- 1.9 and 16 +/- 4.7 mV, respectively. SA-induced hyperpolarization and relaxation of basal tension was significantly inhibited by TEA. These results suggest that SA and NH(4)Cl might regulate vascular tone by altering membrane excitability through modulation of [Ca(2+)](i) and Ca(2+)-activated K channels in rabbit basilar artery.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
454
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
307-19
pubmed:meshHeading
pubmed-meshheading:17285302-Ammonium Chloride, pubmed-meshheading:17285302-Animals, pubmed-meshheading:17285302-Basilar Artery, pubmed-meshheading:17285302-Caffeine, pubmed-meshheading:17285302-Calcium, pubmed-meshheading:17285302-Calcium Channel Blockers, pubmed-meshheading:17285302-Calcium Signaling, pubmed-meshheading:17285302-Cytoplasm, pubmed-meshheading:17285302-Dose-Response Relationship, Drug, pubmed-meshheading:17285302-Electric Stimulation, pubmed-meshheading:17285302-Electrophysiology, pubmed-meshheading:17285302-Hydrogen-Ion Concentration, pubmed-meshheading:17285302-Isometric Contraction, pubmed-meshheading:17285302-Large-Conductance Calcium-Activated Potassium Channels, pubmed-meshheading:17285302-Membrane Potentials, pubmed-meshheading:17285302-Myocytes, Smooth Muscle, pubmed-meshheading:17285302-Nicardipine, pubmed-meshheading:17285302-Rabbits, pubmed-meshheading:17285302-Sodium Acetate, pubmed-meshheading:17285302-Tetraethylammonium
pubmed:year
2007
pubmed:articleTitle
Regulation of membrane excitability by intracellular pH (pHi) changers through Ca2+-activated K+ current (BK channel) in single smooth muscle cells from rabbit basilar artery.
pubmed:affiliation
Department of Anesthesiology and Pain Medicine, College of Medicine, Cheju National University, 66 Jejudaehakno, Jeju, Jeju Special Self-Governing Province 690-756, South Korea.
pubmed:publicationType
Journal Article