Figure 4. The myosin inhibitor blebbistatin protected against TRAP effects in the impedance assays, but shows no effect on macromolecular permeability.

HMECs were treated with blebbistatin (10 μM) for 30 min and subsequently with TRAP (50 μM). Representative experiments indicate time-dependent changes of CI (A) or impedance levels (B), both normalized to untreated cells (control). The bar graphs summarize the statistical analysis of all experiments, normalized to control cells, for CI (A) or impedance measurement (B) at time points indicated with black arrows (1: TRAP addition; 2: maximum effect of TRAP; 3: after 3.5 h) in the corresponding experiment. (C) Macromolecular permeability of FITC-dextran (40 kDa) across an HMEC cell layer was measured with a Transwell^® two-compartment system. Samples were taken from the lower compartment at indicated time points. The results are depicted as normalized FITC-dextran concentrations or as absolute permeability (reference time point was 60 min in each case). All experiments were performed independently at least three times. Data are expressed as mean ± SEM. *P ≤ 0.05 (one-way ANOVA followed by Newman-Keuls post-hoc test).