Fig 5.

Cereulide-driven efflux of K⁺ from human keratinocytes (HaCaT) and PBMC. Washed HaCaT cells (6 × 10⁶ ml⁻¹) or PBMC (15 × 10⁶ ml⁻¹) in 1 ml of K⁺-free medium were placed in a measurement chamber, and the extracellular [K⁺] was recorded in real time with a K⁺-selective electrode, with one reading per second. The effects of cereulide using 60 ng (panels A and C), 45 and 90 ng (traces 1 and 2, respectively, in panel B), and 30 ng (panel D) on the efflux of K⁺ are shown. The “control” trace indicates data for vehicle only (methanol). The inset in panel C shows that the exposure to cereulide transiently initiated the influx of K⁺, followed by a massive efflux of K⁺. At the end of each run, the electrode response was verified by adding KCl to increase the concentration in the cuvette by 100 μM.