Figure 6.

Contribution of intracellular stores to cytosolic Ca²⁺ increase. A. PL-induced Ca²⁺ release was dramatically reduced in the presence of thapsigargin, 2-APB, U73122, caffeine (30 min pre-incubation for each drug). PL was added at 20%. Data are means ± s.e.m. of [Ca²⁺]i traces recorded in different cells. Number of cells: PL 20% alone: 20 cells from 3 experiments; PL 20% + thapsigargin 5 µM: 40 cells from 3 experiments; PL 20% + 2-APB 50 µM: 45 cells from 3 experiments; PL 20% + U73122 10 µM: 50 cells from 3 experiments; PL 20% + caffeine 10 mM. B. Mean ± s.e.m. of the Ca²⁺ response to 20% PL recorded at the peak and at the plateau under the designated treatments. Data are means ± s.e.m. of [Ca²⁺]_i measured by confocal imaging at peak maxima. Number of cells: PL 20% alone: 20 cells from 3 experiments; PL 20% + thapsigargin 5 µM: 40 cells from 3 experiments; PL 20% + 2-APB 50 µM: 45 cells from 3 experiments; PL 20% + U73122 10 µM: 50 cells from 3 experiments; PL 20% + caffeine 10 mM. Asterisks on bars indicate statistical differences determined by two-way ANOVA with Bonferroni’s correction (p < 0.001).