Enhancement of psychostimulant effect and development of behavioural sensitisation to methamphetamine in mice by combined treatment with piracetam

The present study evaluated in mice the possible modification of psychostimulant methamphetamine (MET) effects by co-administration of piracetam (PIR) and the development of behavioural sensitisation to the psychostimulant in the case of combined treatment. On the Day 1 mice were randomly allocated into 4 groups and control open field test was performed. On the Day 7, after 5 days without treatment, mice were intraperitoneally adiministered: a) saline; b) MET 2.5 mg/kg/day; c) PIR 300 mg/kg/day; d) MET+PIR. These doses were repeated for 6 following days. On the Day 14 the acute “challenge” dose of MET 2.5 mg/kg was given to all groups and locomotor activity was measured. On the Day 21, after 6 days of withdrawal, MET challenge was repeated. Data were analysed using two-way ANOVA and Bonferroni post-test. Significant increase in locomotion was recorded in mice treated with acute doses of MET+PIR compared with animals treated with MET (p<0.05). The increased locomotor responses to MET challenge doses (a sign of behavioural sensitisation) after the repeated treatment were more pronounced in animals pre-treated with MET+PIR than in those pre-treated with just PIR or MET (p<0.01 and p<0.001). Piracetam in our experiment enhanced acute effects of methamphetamine as well as development of sensitisation to its stimulatory effects. Background of these pharmacological drug-drug interactions remains unclear. Although clinically piracetam itself shows minimal adverse effects and toxicity, its combination with methamphetamine could worsen the negative drug abuse consequences.