Fig. 5. DNase1-mediated actin depolymerization can enhance, and phalloidin and jasplakinolide stabilization can inhibit, resealing of RGM1 cells. (a) The total amount of ATP released by cells upon syringe injury was measured in a chemiluminesence assay as a function of phalloidin (Pha-2; 2 µg/ml; or Pha-20; 20 µg/ml) or DNase1 (DN-2; 2 µg/ml; or DN-20; 20 µg/ml) loading by a first syringing event. Control (Cont) cells were subject to the loading procedure (syringing) carried out in PBS with no additives. Total cell population content of ATP was measured after lysis initiated by the addition of a kit-supplied cell lysis reagent (All). Values plotted represent mean and s.d. of three experiments, and differed significantly from the control (Cont) condition (P<0.05, Kruskal-Wallis test). (b) The total amount of ATP released upon no injury (NW), and upon syringe injury of cells pre-incubated for 20 minutes in plain PBS (Cont), jasplakinolide (Jasp; 3 µg/ml) or cytochalasin B (CyB; 3 µg/ml). Values represent the mean and s.d. of three experiments. Comparison of the control and jasplakinolide samples yields P<0.05 (Kruskal-Wallis test). Plasma membrane disruptions were induced in an automated syringe-loading device designed to inflict a reproducible level of mechanical stress on cells (Clarke and McNeil, 1992).