Fig. 1.

PMCA activity is inhibited by RES. Cells were monitored for changes in [Ca²⁺]_i for 15 min using Fura-2. Graphs depict changes in [Ca²⁺]_i as measured by 340 nm/380 nm ratio signal intensity. PMCA inhibition with LaCl₃ (A) (arrows mark addition of 5 µM TG and 1 mM LaCl₃ at 1 min and 6 min, respectively). LaCl₃ induced an increase in [Ca²⁺]_i in PDF (blue) and MDA (black) cell types as compared to vehicle only treatment in the respective cell types (PDF cells represented by green, MDA cells represented by red), indicative of PMCA inhibition. To ensure there were no calcium independent effects, BAPTA and Fura-2 were co-loaded into cells (B) (arrows mark addition of 5 µM TG and 50 µM RES at 1 min and 6 min, respectively). PMCA inhibition by RES (C), (arrows mark addition of 5 µM TG and 100 µM RES at 1 min and 6 min, respectively) in both PDF (blue) and MDA (black) cells. RES induced a statistically significant rise in [Ca²⁺]_i as compared to a vehicle only treatment (* signifies a statistically significant difference from respective vehicle controls at p<0.01) in the respective cell types (PDF cell vehicle treatment represented by green, MDA cell vehicle treatment represented by red). RES dose-dependent PMCA inhibition (D). Arrows mark addition of 5 µM TG and followed by either 1 (red), 10 (green), 20 (blue), 50 (yellow), or 100 µM (black) RES at 1 min and 6 min, respectively. RES induced statistically significant increases in [Ca²⁺]_i (* signifies a statistically significant increase from vehicle control (violet) at p<0.01) in 50 µM and 100 µM RES treatments.