Hippocampal Substrates of Methamphetamine Reinforcement

Drug abuse and addiction are major problems in the United States. In particular methamphetamine (METH) use has increased dramatically. A greater understanding of how METH acts on the brain to induce addiction may lead to a therapeutic treatment for this problem. The hippocampus is recognized as an important structure in learning and memory, not usually associated with reinforcement and reward processes. Here the focus is on the hippocampus which has been largely ignored in the addiction literature when compared to the nucleus accumbens (NAc), ventral tegmental area (VTA), and prefrontal cortex (PFC). The results show that METH administered unilaterally via a microdialysis probe to rats' right dorsal hippocampus will induce a positive conditioned place preference (CPP) and also that rats will self administer METH into their hippocampus. Furthermore, both of these responses are dependent on local dopamine (DA) D1-like receptor activation, as they are blocked by a selective D1-like receptor antagonist (SCH 23390).