Effects of chromanol 293B on transient outward and ultra-rapid delayed rectifier potassium currents in human atrial myocytes
| Autor: | Chu-Pak Lau, Gui-Rong Li, Xin-Ling Du, Hung-Fat Tse, Uwe Gerlach, Shui-Wah Chiu |
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| Rok vydání: | 2003 |
| Předmět: |
Adult
medicine.medical_specialty Chromanol 293B Patch-Clamp Techniques Potassium Channels Potassium Analytical chemistry chemistry.chemical_element Slow component Membrane Potentials Potassium Channels Tandem Pore Domain Internal medicine Potassium Channel Blockers medicine Humans Repolarization Myocytes Cardiac Heart Atria Atrial myocytes Chromans Molecular Biology Cells Cultured Ion channel Aged Sulfonamides Depolarization Middle Aged Delayed rectifier chemistry Potassium Channels Voltage-Gated Cardiology Cardiology and Cardiovascular Medicine Delayed Rectifier Potassium Channels |
| Zdroj: | Journal of Molecular and Cellular Cardiology. 35:293-300 |
| ISSN: | 0022-2828 |
| DOI: | 10.1016/s0022-2828(03)00007-5 |
| Popis: | It is unclear whether chromanol 293B, a selective inhibitor of slow component of delayed rectifier K + current (I K s ), may affect other K + currents in human atrium. With whole-cell patch configuration, we evaluated effects of 293B on transient outward K + current (I t o 1 ) and ultra-rapid delayed rectifier K + current (I K u r ) in isolated human atrial myocytes. It was found that 293B inhibited I t o 1 and I K u r in a concentration-dependent manner. At 10 μM 293B suppressed I t o 1 to 3.4 ′ 0.4 from 5.1 ′ 0.3 pA/pF (P < 0.01), and I K u r to 1.5 ′ 0.2 from 2.1 ′ 0.3 pA/pF (P < 0.01) at +50 mV. The inhibition of I t o 1 and I K u r was independent of depolarizing voltage, and the concentration of 50% inhibition was 31.2 μM for I t o 1 , and 30.9 μM for I K u r . 293B blocked I t o 1 and I K u r with the same concentration range, and the significant effect was observed from the concentration of I pM. The maximum inhibitive effect was 88% for I t o 1 and 96% for I K u r at 250 pM. Voltage dependence of activation and inactivation, and time-dependent recovery from inactivation of I t o 1 were not altered by 293B; however, time to peak and time-dependent inactivation of I t o 1 was significantly accelerated. The results indicate that 293B significantly inhibits the major repolarization K + currents I t o 1 and I K u r in human atrial myocytes. |
| Databáze: | OpenAIRE |
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