Arecoline increases actin stress fiber formation in HA22T/VGH cells. HA22T/VGH cells were treated with 0, 10, 30, 60, or 100 μg/ml of arecoline for 24 h, then were fixed with paraformaldehyde for actin labeling and observation by fluorescence microscopy (A) or flow cytometry (B). In A, panel AC is untreated cells incubated with second antibody alone, and C is the untreated control group incubated with primary and secondary antibodies. The values shown in B are the percentage of actin staining-cells and are the mean ± S.D. for three independent experiments. The green filled area is the untreated control and those delimited by the black lines the treated groups. *: p < 0.05 as compared to the untreated control.