Figure 3.

Histidine reduces the Ca²⁺ influx in CAP-treated melanoma cells, nitric oxide (NO) scavenging does not alter the CAP effect. (A–D) Fluorescence spectroscopic analysis of CAP-induced species production in pbECS (#4; 7 × 20 µL). The fluorescence dyes DHR 123 (A), reactive oxygen (ROS)-indicator), Singlet Oxygen Sensor Green Reagent (C) and 4,5-diaminofluorescein (DAF-2) (D), NO-indicator) were solved in pbECS (#4) at a concentration of 10 µM and exposed to different CAP-doses. (B) H₂O₂ concentration was determined in duplicates using the Fluorimetic Hydrogen Peroxide Assay Kit. (E–H). Investigation of the effect of the NO scavenger 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) (250 µM) and the ROS scavenger histidine (3 µM) on 30 s CAP-induced Ca²⁺ influx in Mel Im ((E,G), n = 234–470) and Mel Juso ((F,H), n = 84–307) cells. The latter traces are identical to Figure 1 in [26].