Act Nerv Super Rediviva 2010; 52(4): 269–271 SHORT REPORT Activitas Nervosa Superior Rediviva Volume 52 No. 4 2010 Methamphetamine does not influence the metabolic activity of CYP 1A2, 2C6 and 2D2 isoenzymes in the animal study Ondřej Zendulka 2 , Jan Juřica 1,2 , Michaela Sabová 2 , Alexandra Šulcová 1,2 1 Central European Institute of Technology (CEITEC), Masaryk University, Brno 2 Faculty of Medicine, Department of Pharmacology, Masaryk University, Brno, Czech Republic. Correspondence to: PharmDr. Jan Juřica, Ph.D., Department of Pharmacology, Faculty of Medicine, Masaryk University Brno, Czech Republic, tel: +420549494531 fax: +420549492364. email: jurica@med.muni.cz Submitted: 2010-11-12 Accepted: 2010-12-01 Published online: 2011-01-25 Key words: methamphetamine; cytochrome P450; isolated perfused rat liver Act Nerv Super Rediviva 2010; 52(4): 269–271 ANSR520410A09 © 2010 Act Nerv Super Rediviva Introduction Methamphetamine (MET) belongs to the amphet- amine group of sympathomimetic drugs. It is approved by the FDA for the treatment of ADHD and exogenous obesity, but it is frequently illegally used for its psycho- stimulatory, euphorizing and anorectic activities. The abuse as well as the pharmacotherapy with MET brings out the problem of drug-drug interactions, when MET is co-administered/abused with other medications. On the pharmacokinetic level the interactions can be based on biotransformation of MET by CYP450 enzymes (Lin et al 1995). MET abusers, who are exten- sive metabolizers are more sensitive to neurocognitive impairment caused by MET’s metabolites (Cherner et al 2010). The only study (Dostalek et al 2007) avail- able according to the literature aimed on the influ- ence of MET on the rat CYP enzymes indicates that MET acts as an inducer. Thus the knowledge whether MET modulates the activity of CYP is important for safe pharmacotherapy with MET, and perhaps also for the prediction of cognitive disorders in abusers. The aim of the present study was to investigate MET influ- ence on the activity of selected CYP isoenzymes in the model of isolated perfused rat liver. Methods and materials Animals Male Wistar albino rats (Biotest, Konarovice, CZ) weighing 220 ± 20g were divided into 2 groups of 10 animals. For 10 days the Group I was administered intraperitoneally with MET (Sigma Chemical Co., St. Louis, USA) dissolved in saline at increasing doses in bolus injections as follows: 1 st day – 2.5 mg/kg/day; 2 nd day – 5 mg/kg/day; 3 rd day – 7.5 mg/kg/day; 4 th –10 th days – 10 mg/kg/day. The group II (control animals) was administered in the same manner with saline. All experimental procedures were approved by the Czech Central Commission for Animal Welfare. Model of isolated perfused rat liver Model of perfused rat liver was used for the determi- nation of CYP 1A2, 2C6 and 2D2 isoenzyme activ- ity. Rats were anesthetized with the combination of ketamine (100 mg/kg) and xylasine (16 mg/kg). The liver isolation was performed as described elsewhere (Zendulka et al 2009). Liver was then placed into the modified Miller’s (Miller et al 1951) perfusion appara- tus and was perfused with Williams’ medium E (Sigma Chemical Co., St. Louis, USA). Marker substances phenacetin (PHE)-CYP 1A2, diclofenac (DCL)-2C6 and dextromethorphan (DEM)-2D2 (all Sigma Chemical Co., St. Louis, USA) were added as a bolus into perfusion medium after 20 minutes of pre-perfusion. Perfusion medium samples were collected in the 30 th ; 60 th and 120 th minute of perfusion. Quantitative analysis of markers and metabolites Levels of markers and their specific metabolites paracetamol (PAR)-1A2; 4-hydroxydiclofenac (HDCL)-2C6 and dextrorphan (DEX)-2D2 were ana- lyzed after extraction from perfusion medium using validated HPLC method.