two-day pretreatment with a combination of desipramine ( dmi ) ( 10 mg/kg , ip ) and methadone ( 15 mg/kg , po ) enhanced the development of dispositional tolerance to methadone analgesia which was evidenced by a greater decrease in the brain concentration of methadone and a greater increase in methadone metabolism as compared to those changes in rats pretreated with only methadone .
C0006104
brain
C0086045
concentration