Involvement of pertussis toxin-sensitive G-proteins in the mGluR5-mediated effects. (A) BV-2 cells were pretreated for 6 hours with 100 ng/mL pertussis toxin (PTX) prior to loading with the fluorochrome Fluo-4 AM and the addition of 100 μM MPEP. Intracellular Ca2+ concentrations were determined by detecting the fluorescence intensity of Fluo-4 AM. Relative changes of the Ca2+ concentrations were analyzed after 15 minutes. Results are expressed as ΔF/F (in %), with F being the baseline fluorescence and ΔF the variation of fluorescence. (B) BV-2 cells were pretreated for 6 hours with 100 ng/mL PTX, followed by treatment with 100 μM MPEP for 2 hours. Phospholipase C (PLC) activity was adjusted to total protein content (mU/μg total protein). Results represent mean ± SD of three independent experiments and significance was analyzed by one-way ANOVA followed by Tukey’s test. *P <0.05, ***P <0.005. MPEP, 2-methyl-6-(phenylethynyl)-pyridine.