The effects of piracetam on heroin-induced CPP and neuronal apoptosis in rats

• A new drug epidemic phenomenon in China is described and explained.
• Piracetam enhanced on heroin-induced conditioned place preference (CPP) expression in rats.
• Piracetam play a role of protection in heroin-induced neuronal apoptosis in rats.
• Piracetam normalized the levels of β-EP within the corticolimbic system, which were disrupted by heroin.

BackgroundPiracetam is a positive allosteric modulator of the AMPA receptor that has been used in the treatment of cognitive disorders for decades. Recent surveys and drug analyses have demonstrated that a heroin mixture adulterated with piracetam has spread rapidly in heroin addicts in China, but its addictive properties and the damage it causes to the central neural system are currently unknown.MethodsThe effect of piracetam on the reward properties of heroin was assessed by conditioned place preference (CPP). Electron microscopy and radioimmunoassay were used to compare the effects of heroin mixed with equivalent piracetam (HP) and heroin alone on neuronal apoptosis and the levels of beta-endorphin (β-EP) in different brain subregions within the corticolimbic system, respectively.ResultsPiracetam significantly enhanced heroin-induced CPP expression while piracetam itself didn’t induce CPP. Morphological observations showed that HP-treated rats had less neuronal apoptosis than heroin-treated group. Interestingly, HP normalized the levels of β-EP in the medial prefrontal cortex (mPFC) and core of the nucleus accumbens (AcbC) subregions, in where heroin-treated rats showed decreased levels of β-EP.ConclusionsThese results indicate that piracetam potentiate the heroin-induced CPP and protect neurons from heroin-induced apoptosis. The protective role of HP might be related to the restoration of β-EP levels by piracetam. Our findings may provide a potential interpretation for the growing trend of HP abuse in addicts in China.