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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1
|
| pubmed:dateCreated |
1995-9-26
|
| pubmed:abstractText |
1. Single cell photometry and whole-cell patch clamp recording were used to study caffeine-induced intracellular Ca2+ signals and membrane currents, respectively, in endothelial cells freshly dissociated from rabbit aorta. 2. Caffeine (5 mM) evoked a transient increase in [Ca2+]i in fura-2-loaded endothelial cells. Pretreatment of cells with 10 microM ryanodine did not alter resting [Ca2+]i but irreversibly inhibited the caffeine-induced rise in [Ca2+]i. The caffeine-induced increase in [Ca2+]i was not attenuated by the removal of extracellular Ca2+ and did not stimulate the rate of Mn2+ quench of fura-2 fluorescence. 3. Bath application of caffeine evoked a dose- and voltage-dependent outward current. The rate of onset and amplitude of the caffeine-evoked outward current increased with higher caffeine concentrations and membrane depolarization. The relationship between caffeine-evoked current amplitude and membrane potential was non linear, suggesting that the channels underlying the current are voltage-sensitive. 4. In the absence of extracellular Ca2+, the amplitude of the caffeine-evoked outward current was reduced by approximately 50% but the duration of the current was prolonged compared to that observed in the presence of external Ca2+. Ca(2+)-free external solutions produced an unexpected increase in both the frequency and amplitude of spontaneous transient outward currents (STOCs). 5. Inclusion of heparin (10 micrograms ml-1) in the patch pipette abolished the acetylcholine (ACh)-induced outward current but failed to inhibit either STOCs or the caffeine-evoked outward current in native endothelial cells. In the absence of extracellular Ca2+, heparin did not affect either STOCs or the caffeine-induced outward current. 6. Externally applied tetraethylammonium ions (TEA, 3-10mM) reversibly inhibited unitary Ca2+-activated K+ currents and STOCs in endothelial cells but failed to inhibit completely the outward current evoked by 20 mM caffeine.7. Bath application of 0.1 mM zinc ion (Zn2+), a chloride channel blocker, did not affect unitary currents or STOCs but reduced the amplitude of the caffeine-evoked current by >75% compared to control. Replacement of extracellular NaCl with Na gluconate also reduced the amplitude of the caffeine-induced outward current. Bath application of 0.1 mM Zn2+ and 10 mM TEA completely blocked the caffeine-evoked outward current in endothelial cells.8. Caffeine-induced Ca2+ release from intracellular stores evokes a transient rise in [Ca2+1, which is correlated with a large, transient outward current. The ionic dependence and inhibition of the caffeine sensitive current by TEA and Zn2+ suggests that Ca2+-activated K+ and Cl- conductances contribute to the caffeine response in rabbit aortic endothelial cells.
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| pubmed:grant | |
| pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1291681,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1318033,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1382265,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1484364,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1697946,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1720891,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-1904293,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2177344,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2348402,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2385008,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2442353,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2452017,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2453021,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2585296,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-2798038,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-3064851,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-3110148,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-3136153,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-3136667,
http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-3194169,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-3838314,
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http://linkedlifedata.com/resource/pubmed/commentcorrection/7647967-8383430
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
May
|
| pubmed:issn |
0007-1188
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
115
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
133-41
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| pubmed:dateRevised |
2009-11-18
|
| pubmed:meshHeading |
pubmed-meshheading:7647967-Animals,
pubmed-meshheading:7647967-Aorta,
pubmed-meshheading:7647967-Caffeine,
pubmed-meshheading:7647967-Calcium,
pubmed-meshheading:7647967-Cell Membrane,
pubmed-meshheading:7647967-Endothelium, Vascular,
pubmed-meshheading:7647967-Fluorometry,
pubmed-meshheading:7647967-Heparin,
pubmed-meshheading:7647967-Membrane Potentials,
pubmed-meshheading:7647967-Rabbits,
pubmed-meshheading:7647967-Ryanodine
|
| pubmed:year |
1995
|
| pubmed:articleTitle |
Caffeine-evoked, calcium-sensitive membrane currents in rabbit aortic endothelial cells.
|
| pubmed:affiliation |
Department of Molecular & Cellular Pharmacology, University of Miami School of Medicine, FL 33101, USA.
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| pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
|