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  • Ginsenoside Re enhances small-conductance Ca(2+)-activated K(+) current in human coronary artery endothelial cells.

Ginsenoside Re enhances small-conductance Ca(2+)-activated K(+) current in human coronary artery endothelial cells.

Life sciences (2014-09-23)
Suporn Sukrittanon, Wattana B Watanapa, Katesirin Ruamyod
ABSTRACT

Ginsenosides, active components in ginseng, have been shown to increase nitric oxide (NO) production in aortic endothelial cells. This effect was reversed by tetraethylammonium (TEA) inhibition of endothelial Ca(2+)-activated K(+) (KCa) channels. The objectives of this study, therefore, were to test 1) whether vasorelaxing ginsenoside Re could affect KCa current, an important regulator of NO production, in human coronary artery endothelial cells (HCAECs); and 2) whether small-conductance KCa (SKCa) channel was the channel subtype involved. Ionic currents of cultured HCAECs were studied using whole-cell patch clamp technique. Ginsenoside Re dose-dependently increased endothelial outward currents, with an EC50 of 408.90±1.59nM, and a maximum increase of 36.20±5.62% (mean±SEM; p<0.05). Apamin, an SKCa channel inhibitor, could block this effect, while La(3+), a nonselective cation channel (NSC) blocker, could not. When NSC channel, inward-rectifier K(+) channel, intermediate-, and large-conductance KCa channels were simultaneously blocked, ginsenoside Re could still increase outward currents significantly (35.49±4.22%; p<0.05); this effect was again abolished by apamin. Repeating the experiments when Cl(-) channel was additionally blocked gave similar results. Finally, we demonstrated that ginsenoside Re could hyperpolarize HCAECs; this effect was reversed by apamin. These data clearly indicate that ginsenoside Re increased HCAEC outward current via SKCa channel activation, and NSC channel was not involved. This is the first report to demonstrate that ginsenoside Re could increase SKCa channel activity in HCAECs. This can be a mechanism mediating ginseng's beneficial actions on coronary vessels.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hydrocortisone, γ-irradiated, powder, BioXtra, suitable for cell culture
Sigma-Aldrich
Hydrocortisone, ≥98% (HPLC)
Sigma-Aldrich
Hydrocortisone, BioReagent, suitable for cell culture
Supelco
Hydrocortisone, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Hydrocortisone, meets USP testing specifications
Hydrocortisone, British Pharmacopoeia (BP) Assay Standard
USP
Hydrocortisone, United States Pharmacopeia (USP) Reference Standard
Hydrocortisone, European Pharmacopoeia (EP) Reference Standard
Supelco
Ginsenoside Re, analytical standard
Sigma-Aldrich
Lanthanum, pieces
Sigma-Aldrich
Lanthanum, powder, −40 mesh, under oil, 99.9% trace rare earth metals basis
Sigma-Aldrich
Apamin, synthetic, ≥97% (HPLC)
Sigma-Aldrich
Apamin, from bee venom, ≥95% (HPLC)
Sigma-Aldrich
β-D-Allose, rare aldohexose sugar
Ginsenoside Re, primary reference standard
Lanthanum, rod, 50mm, diameter 6.35mm, cast, 99%
Hydrocortisone for peak identification, European Pharmacopoeia (EP) Reference Standard
Lanthanum, foil, 100x100mm, thickness 0.1mm, as rolled, 99%
Lanthanum, foil, 50x50mm, thickness 0.1mm, as rolled, 99%
Lanthanum, foil, 50x50mm, thickness 0.125mm, as rolled, 99%
Lanthanum, foil, not light tested, 100x100mm, thickness 0.025mm, as rolled, 99%
Lanthanum, foil, not light tested, 25x25mm, thickness 0.025mm, as rolled, 99%
Lanthanum, foil, 100x100mm, thickness 0.125mm, as rolled, 99%
Lanthanum, foil, not light tested, 50x50mm, thickness 0.025mm, as rolled, 99%
Lanthanum, rod, 100mm, diameter 6.35mm, cast, 99%
Lanthanum, foil, 25x25mm, thickness 0.125mm, as rolled, 99%
Lanthanum, foil, 25x25mm, thickness 0.1mm, as rolled, 99%