Figure 4. The effect of dexmedetomidine on norepinephrine turnover in desipramine-treated rats. Desipramine, 10 mg/kg given subcutaneously twice daily, was administered for 3 weeks. Thirty minutes after administration of 30 [micro sign]g/kg dexmedetomidine, the animals were killed, and the ratio of MHPG to norepinephrine in the locus coeruleus was determined.