Dextromethorphan alters methamphetamine self-administration in the rat.

Various lines of evidence indicate that methamphetamine (METH) self-administration in rats is under dopaminergic control, and NMDA receptors have been shown to control the release of dopamine at its synapse. Consequently, the aim of this study was to observe the effects of dextromethorphan (DM), a non-competitive NMDA antagonist, in rats self-administering METH. The hypothesis was that acute pretreatment of DM (25 mg/kg) would alter response to METH. DM significantly altered self-administration by reducing the number of correct responses for three METH self-administration doses (0.05, 0.1, 0.25 mg/kg). The same pretreatment did not affect responding for food reward. These findings show that the DM was able to selectively alter METH self-administration.