Fig. 3. Concentration-dependent effect of the Rho-kinase inhibitor Y-27632 on the morphology of colchicine-stimulated neutrophils. Neutrophils were preincubated for 30 minutes without or with increasing amounts of Y-27632, as indicated, at 37°C. The incubation was continued for another 30 minutes either in medium or in 10 µM colchicine. Cells were fixed with glutaraldehyde and examined using Nomarski optics. The percentage of spherical cells (circles), cells with front-tail polarity (triangles) and non-polar cells (squares) was determined for 100 cells per sample. In the absence of colchicine and Y-27632, 96±4% of the cells were spherical, 3±3% polarized and 2±1% non-polar. Mean±s.e.m. of five experiments.