BACKGROUND: Regulation of cell volume is one of the major physiologic functions in living cells. Intracellular calcium ion and cytoskeletal component of cell membrane play pivotal roles in cell volume regulation. The significance of astroglial cell swelling is in its relation to delayed and permanent neuronal death. The aim of the current study is therefore to elucidate the effect of propofol on the cell volume, [Ca2+]i and actin filaments in astroglial cells. METHODS: Astroglial cell line U1242MG astrocytoma cells were used in vitro. To investigate the alterations of cell volume and [Ca2+]i by propofol, flow cytometry system was used. Actin filaments were determined by tetramethylrhodamine isothiocyanate (TRITC)-phalloidin staining. RESULTS: Treatment with propofol 10 microgram/ml for 15 min or 2 h perfusion reduced significantly both cell volume and [Ca2+]i. Cell volume was reduced 3-4% in either duration of perfusion with propofol. Decreases in [Ca2+]i level in the presence of propofol was duration-dependent. Fifteen min perfusion with propofol caused 5% decrease in [Ca2+]i, but 2 h perfusion decreased [Ca2+]i further to 10%. The changes of actin filaments after propofol treatment for 30 min were apparently observed under fluorescent microscope. CONCLUSIONS: Changes of cell volume, [Ca2+]i and actin filaments are occurred by propofol in astroglial cells. Rearrangement of actin filaments may be associated with volume changes by propofol in astroglial cells.