Memantine is a useful drug to prevent the spatial and non-spatial memory deficits induced by methamphetamine in rats

Methamphetamine (METH) is a street drug that is abused by young people. In previous studies, we demonstrated the effectiveness of alpha-7 nicotinic receptor antagonists in preventing the neurotoxicity induced by this amphetamine derivative. The present study seeks to determine whether pre-treatment with memantine (MEM) (an antagonist of both NMDA and alpha-7 nicotinic receptors) counteracts the memory impairment induced by METH administration in male Long Evans rats. Non-spatial memory was tested in the object recognition test and spatial learning memory was tested in the Morris water maze. In our experimental conditions, rats that received the MEM (5 mg/kg, intraperitoneally) pre-treatment recovered the ability to discriminate between a familiar and a novel object. This ability had been abolished by METH (10 mg/kg, subcutaneously) at 72 h and 1 week after treatment. Moreover, MEM pre-treatment also inhibited the thigmotaxis behaviour induced by METH. Rats treated with METH showed impaired learning in the Morris water maze. The results of the probe trial demonstrated that METH-treated rats did not remember the location of the platform, but this memory impairment was also prevented by MEM pre-treatment. Moreover, MEM by itself improved the learning of the task. Finally, MEM significantly improved the learning and memory impairment induced by METH. Therefore, MEM constitutes the first successful approach to prevent the cognitive deficits induced by amphetamine derivatives which are frequently abused in western countries.