Figure 1.

Effects of pertussis toxin (PTx) and YM-254890 on substance P (SP)-induced degranulation and Ca²⁺ mobilization in RBL-2H3 cells stably expressing MRGPRX2, (RBL-MRGPRX2). (A) Cells were cultured overnight in the absence or presence of PTx (100 ng/mL, 16 h), washed and incubated with or without YM-254890 (10 μM) for 5 min. Cells were then exposed to a buffer (control) or different concentrations of SP for 30 min, and β-hexosaminidase release was determined. All data points are the mean ± SEM of at least three experiments performed in triplicate. (B) Cells were cultured overnight in the absence or presence of PTx (100 ng/mL, 16 h), then loaded with Fura-2 and intracellular Ca²⁺ mobilizations in response to SP (1 μM) were determined. To determine the effect of Gαq, cells were incubated with YM-254890 (10 μM) for 5 min before stimulating with SP. Data shown are representative of three independent experiments. Statistical significance was determined by the nonparametric t-test and two-way ANOVA. * p ≤ 0.05, ** p ≤ 0.01, *** p ≤ 0.001, and **** p ≤ 0.0001.