Figure 4. The alpha2-antagonistic effect of atipamezole given intrathecally 10 min before administration of clonidine (CLON), MK-801 (MK), mixture of clonidine and MK-801 (CLON + MK), or their vehicle (SALINE). Each column represents the mean %MPE and SEM. * Statistically significant different from the effect of agent without atipamezole (P < 0.05).