Figure 5.

2-Deoxy-[³H]glucose transport and metabolism is accelerated in cultured astrocytes exposed to norepinephrine. Astrocyte cultures were superfused with medium containing 2.5 mM of glucose in the absence (control; white bars) or presence of 100 μ M norepinephrine (NE; blacks bar). The cultures were superfused for 15, 30, 45, or 60 min (n = 3–4) and during the last 15 min tracer amounts of 2-deoxy-[³H]glucose (2DG) were added to the superfusion medium. The astrocytes were extracted with ethanol and the extent of 2DG uptake was determined by measuring radioactivity in cell extracts (counts per minute; CPM). The 2DG uptake reflects both glucose transport and subsequent metabolism. The presence of NE gave rise to an increase in 2DG uptake in all time periods compared to controls. No significant differences were observed between time periods within controls. However, in astrocytes exposed to NE, the 2DG uptake was significantly higher from 30 to 45 min compared to all other time periods during NE exposed conditions. ^* and ^# indicate statistically significant differences between control and NE exposed astrocytes, and amongst NE exposed astrocytes, respectively (One-Way ANOVA followed by Bonferroni post hoc test, P < 0.05).