Fig. 5. Prophylactic hypothermia and delayed propofol independently prevent the stimulation of d-aspartate efflux caused by organic peroxide. Astrocytes were preloaded with d-[3H]aspartate (10 μm) overnight. Subsequently, beginning at time zero of efflux, they were incubated for 30 min with tert-butyl hydroperoxide (t-BOOH; 1 mm) or aqueous vehicle at 28, 33, or 37°C. Finally, they were incubated with propofol (1 μm) or Intralipid vehicle for an additional 90 min at the same temperatures. (A ) Cumulative efflux rates after 60 min for three experiments. * P less than 0.05 compared with the 37°C vehicle control that did not receive t-BOOH. (B ) Transient protective effect of hypothermia against t-BOOH during the 20-min efflux period in the same experiments. * P less than 0.05 compared with the 37°C treatment.