FIGURE 2.

Li⁺ blocks agonist-mediated oscillations in [Ca²⁺]_i. A, cytoplasmic Ca²⁺ oscillations evoked by 160 nm LTC₄ are compared between a control cell and one pre-exposed to 10 mm LiCl for ∼90 min. B, graph comparing cytoplasmic Ca²⁺ oscillations evoked by LTC₄ between control cells and cells exposed to different concentrations of LiCl prior to stimulation. C, graph plotting the number of cytoplasmic Ca²⁺ oscillations evoked by LTC₄ over 800 s of stimulation in the presence of different LiCl concentrations. The number of oscillations is normalized to the number of oscillations observed in control cells. Values were fitted with a Hill-type equation, yielding an IC₅₀ value of 15 mm. D, thapsigargin-evoked Ca²⁺ release and Ca²⁺ influx are compared between control cells and cells pre-exposed to 50 mm LiCl for 90 min. Error bars (mean ± S.E.) are within the symbols. E, comparison of ionomycin-induced Ca²⁺ release in control cells and cells pretreated with 15 mm of LiCl for 90 min. F, data from three independent experiments as in E. ns, not significant. G, cytoplasmic Ca²⁺ oscillations in Ca²⁺-free external solution following stimulation with 160 nm LTC₄ are compared between a control cell and one pretreated with 15 mm LiCl for 90 min. H, aggregate data from three experiments measuring the total number of cytoplasmic Ca²⁺ oscillations over an 800-s stimulation period with LTC₄ are compared. Cells were stimulated either in the presence or absence of external Ca²⁺. The LiCl groups refer to pretreatment with 15 mm LiCl for 90 min. The data represent >52 cells from four independent experiments for each condition. ****, p < 0.0001. I, aggregate data showing the number of cytoplasmic Ca²⁺ oscillations evoked by LTC₄ in 50 mm LiCl in an external solution containing either 155 or 105 mm NaCl, both with 2 mm Ca²⁺. Each bin number represents a period of 200 s. Each data point is >25 cells.