Fig. 3.

The changes of membrane potential using voltage sensitive dye, bis (1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC₄(3)) with various K⁺ concentrations, K⁺ channel blockers, and quercetin. Fluorescence-activated cell sorting (FACS) assay results from 253J cells loaded with DiBAC₄(3) (100 nM) are shown. (A) As graded increase of KCl concentration mean fluorescence intensity (MFI) was increased (the peak shifted right) (B) Treatment with quercetin (30 µM) decreased DiBAC₄(3) MFI (the peak shifted left). The application of TEA (5 mM, dotted line) in quercetin-free solution augmented MFI more than control (shaded bar), whereas co-treatment with TEA (5 mM) and quercetin (thick solid line) prevented quercetin-induced hyperpolarization (thin solid line).