Increased expression of synaptophysin and stathmin mRNAs after methamphetamine administration in rat brain

The rearrangement of neural networks associated with the behavioral sensitization induced by psychostimulants is poorly understood. We have investigated the effect of methamphetamine (METH) administration on the mRNA levels of three different classes of plasticity-related genes in the rat brain. The expression of synaptophysin mRNA increased 20-40% in the nucleus accumbens, prefrontal and temporal cortices, 1-24 h after acute METH administration, and that of stathmin mRNA increased about 20% in the prefrontal cortex 1 h later. They did not change after subchronic administration. The level of alpha-tubulin mRNA was constant. Therefore, synaptophysin and stathmin play an important role in the neural plastic changes involved in the early induction process of METH-induced sensitization, but not in the later maintenance process.