Effect of latrunculin B and blebbistatin on leukocyte interstitial migration behavior. In vivo transillumination microscopy image of interstitially migrating leukocytes in the mouse cremaster muscle upon perivenular microinjection of PAF (injected together with green fluorescence–labeled microspheres for identification of the site of microinjection); the migration track of a single leukocyte is shown in blue (scale bar: 25 µm; also see supplemental Video 3). (A) Representative plots of migration tracks of transmigrated leukocytes in the cremasteric interstitial tissue of animals treated with latrunculin B, blebbistatin, or vehicle. Leukocyte interstitial migration behavior was analyzed after perivenular microinjection of PAF or CCL3, as detailed in the “Methods” section. Panels show results for directionality (B-C), velocity (D-E), and accumulated distance (F-G) of interstitially migrating leukocytes in animals treated with latrunculin B, blebbistatin, or vehicle (mean ± SEM for n = 4 per group; *P < .05 vs vehicle).