Figure 7.

Ca²⁺ imaging of praziquantel (PZQ) action in mesenteric artery smooth muscle cells (MASMCs). A: ex vivo analysis of intracellular Ca²⁺ dynamics in mesenteric vessels by 2-photon microscopy. Left: bright-field image of isolated mouse mesenteric artery strip, together with baseline fluorescence (Fluo-8H) at chosen 2-photon imaging plane (right). Boxed region containing smooth muscle cells is enlarged in B. Scale bar, 150 μm. B: an example of fluorescence signals recorded in smooth muscle cells during addition of racemic PZQ [(±)-PZQ, 100 µM; black] or ATP (10 µM; red). Scale bar, 20 s (horizontal), F/F₀ = 1 (fluorescence/fluorescence at time = 0, F/F₀, vertical). C: representative images of intracellular Ca²⁺ dynamics in smooth muscle cells before (left) and after (right) addition of (±)-PZQ (100 µM). Scale bar, 85 μm. D: statistical analyses summarizing differences in peak amplitude of fluorescent transient in the individual SMCs (n ≥ 10 cells from at least 3 different vessels. E: representative images of isolated primary mouse MASMCs loaded with the fluorescent Ca²⁺ indicator Fluo-4 NW before and after treatment with (±)-PZQ (100 µM) or 5-hydroxytryptamine (5-HT; 1 µM). Scale bar, 100 μm. F and G: fluorescence traces over time detailing responses to (±)-PZQ (100 µM), 5-HT (1 µM), and ATP (100 µM). H: cumulative measurements of peak fluorescence ratio (F/F₀) from Ca²⁺ imaging experiments from primary MASMCs. Plot shows individual data points, together with mean (line) and SD (shaded bar) for PZQ (green), 5-HT (orange), and ATP (red) from 3 independent experiments.