Fig. 4. The glucocorticoid receptor agonist dexamethasone (DEX; 4 μg intrathecal), with coadministration of morphine (MS; 10 μg intrathecal) given twice daily for 4 days, significantly diminished morphine antinociception when examined on day 5. * P < 0.05 as compared with the morphine-plus-vehicle group; + P < 0.05 as compared with morphine-alone and vehicle groups. %MPAE = percent of maximal possible antinociceptive effect; VEH = vehicle.