Background: Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, increases the activity of NF-kappa B (NF-kappa B) and then induces the expression of intercellular adhesion molecule-1 (ICAM-1). However, the mechanisms regulating ADMA-induced NF-kappa B activation are unknown. This study investigated the function of actin cytoskeleton for ADMA-induced NF-kappa B activation and ICAM-1 expression in endothelial cells. Material/Methods: Human umbilical vein endothelial cells (HUVEC) were cultured and left untreated or challenged for 24h with 100 mu M ADMA in the absence and presence of 5 mu M cytochalasin D (Cyt D), or 1 mu M Jasplakinolide (Jas). The form of actin cytoskeleton, the translocation of NF-kappa B, NF-kappa B DNA binding activity, and the expression of ICAM-1 were determined. Results: ADMA increased the formation of stress fiber in endothelial cells, and Cyt D clearly induced destabilization of the actin filaments. Either stabilizing or destabilizing the actin cytoskeleton prevented ADMA-induced NF-kappa B activation. It also showed that the inhibition of NF-kappa B activity was due to the impaired NF-kappa B nuclear translocation. Further, stabilizing or destabilizing the actin cytoskeleton inhibited the expression of the NF-kappa B target protein, ICAM-1. Conclusions: Actin cytoskeleton may be engaged in modulated ADMA-induced NF-kappa B activation and thereby ICAM-1 expression in endothelial cells.