Abstract
We developed a method to quantitatively evaluate the potency of Na+/Ca2+ exchanger (NCX) inhibitors with fluorescence microscopy in NCX1-transfected HEK 293 cells. The reverse mode and forward mode NCX activities were measured as the ascending slope of the early phase increase in cytoplasmic Ca2+ concentration after change to low Na+ extracellular solution and the descending rate (inverse of the exponential time constant) on return to normal solution, respectively. Both modes of NCX were inhibited by SEA0400 (2-[4-[(2,5-difluorophenyl)methoxy]phenoxy]-5-ethoxyaniline) and KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate), and the concentration-inhibition relationships for both inhibitors were in good agreement with those previously reported in voltage clamped cardiomyocytes.
MeSH terms
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Aniline Compounds / pharmacology
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Animals
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Calcium / metabolism
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Cattle
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Cell Line
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Fluorescence*
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Green Fluorescent Proteins / chemistry
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Green Fluorescent Proteins / genetics
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Green Fluorescent Proteins / metabolism
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Humans
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Ion Transport / drug effects
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Kinetics
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Phenyl Ethers / pharmacology
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Sodium / pharmacology
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Sodium-Calcium Exchanger / antagonists & inhibitors*
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Sodium-Calcium Exchanger / genetics
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Sodium-Calcium Exchanger / metabolism*
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Thiourea / analogs & derivatives
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Thiourea / pharmacology
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Transfection / methods
Substances
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2-(2-(4-(4-nitrobenzyloxy)phenyl)ethyl)isothiourea methanesulfonate
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Aniline Compounds
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Phenyl Ethers
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Recombinant Fusion Proteins
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SEA 0400
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Sodium-Calcium Exchanger
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Green Fluorescent Proteins
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Sodium
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Thiourea
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Calcium