Nicotinamide attenuates methamphetamine-induced striatal dopamine depletion in rats.

The aim of the present study was to examine the effects of nicotinamide, a co-factor in the electron transport chain, on the relationship between methamphetamine (MA)-induced striatal dopamine (DA) depletion and energy metabolism change. Four injections of MA (10 mg/kg, i.p.) at 2 h intervals resulted in decreases of 51% and 23%, respectively, in striatal DA and adenosine 5'-triphosphate (ATP) levels 5 days later. Nicotinamide (500 mg/kg, i.p.) treatment prior to each MA injection attenuated the reductions of striatal DA and ATP contents. Nicotinamide had no long-term effects on striatal DA and ATP levels. These findings suggest that energy impairment might play a role in MA-induced DAergic neurotoxicity in the striatum.