RESUMO
BACKGOUND: Cell volume regulation is especially important in the brain because the brain is confined within a non-compliant vault and cannot tolerate significant perturbations in cell size. Cerebral cell volume regulation mechanisms are activated by sustained disturbances in plasma osmolality. The constancy of cell volume under physiological conditions is generally thought to reflex a balance between influx and efflux of solute and is therefore critically dependent on the properties of the plasma membrane. Cell volume regulation have not been described under isoosmotic solution. The object of the study was to know the effects of thiopental on cell volume change in isoosmotic condition. METHODS: We made isoosmotic solution without thiopental (Group 1) and isoosmotic solution with 22.9 mM (Group 2), 16.8 mM (Group 3), 13.3 mM (Group 4) thiopental, separately, in order to study changes in cell volume under isoosmotic solution. We put cultured human brain astrocytoma cells into isoosmotic solution for each group and calculated cell volume using Coulter Counter after 30 minutes. RESULTS: Cell volume was shown to be 5084+/-8580 (micrometer3)in Group 1, 501+/-854 (micrometer3) in Group 2, 1183+/-3839 (micrometer3) in Group 3, and 624+/-1100 (micrometer3) in Group 4. We discovered that cells in Group 2,3,4 were shrunk relative to cells in Group 1 (p<0.01). And there were significant differences in cell volume among thiopental groups. CONCLUSIONS: Thiopental may has an effect on cell membrane properties and decrease cell volume under isoosmotic solution in brain astrocytoma cell.