Memantine improves memory impairment and depressive-like behavior induced by amphetamine withdrawal in rats

Amphetamine (AMPH) induces deficits in cognition, and depressive-like behavior following withdrawal. The aim of the present study was to investigate whether pre-treatment with memantine (5mg/kg, i.p.), a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, attenuates memory impairment induced by withdrawal from a 1 day binge regimen of AMPH (2mg/kg, four times every 2h, i.p.), in the novel object recognition test in rats. Herein, the influence of scopolamine (0.1mg/kg), an antagonist of the muscarinic cholinergic receptors, and the impact of MK-801 (0.1mg/kg), an antagonist of the NMDA receptors, on the memantine effect, were ascertained. Furthermore, the impact of memantine (5; 10; 20mg/kg, i.p.) was measured on depression-like effects of abstinence, 14 days after the last AMPH treatment (2mg/kg×1×14 days), in the forced swim test. In this test, the efficacy of memantine was compared to that of tricyclic antidepressant imipramine (10; 20; 30mg/kg, i.p.). Our study indicated that withdrawal from a binge regimen of AMPH impaired recognition memory. This effect was attenuated by administration of memantine at both 72h and 7 days of withdrawal. Moreover, prior administration of scopolamine, but not MK-801, decreased the memantine-induced recognition memory improvement. In addition, memantine reversed the AMPH-induced depressive-like behavior in the forced swim test in rats. The antidepressant-like effects of memantine were stronger than those of imipramine. Our study indicates that memantine constitutes a useful approach towards preventing cognitive deficits induced by withdrawal from an AMPH binge regimen and by depressive-like behavior during AMPH abstinence.

Memory impairment induced by amphetamine derivatives in laboratory animals and in humans: a review

The 20th century brought with it the so-called club drugs (the most notorious being amphetamine derivatives), which are used by young adults at all-night dance parties. Methamphet­amine and 3,4-methylenedioxymethamphetamine (MDMA or ecstasy) are synthetic drugs with stimulant and psychoactive properties that belong to the amphetamine family. Here, we have reviewed the literature about the cognitive impairment induced by these two amphetamine derivatives and the preclinical and clinical outcomes. Although there is controversial evidence about the effect of methamphetamine and MDMA on learning and memory in laboratory animals, results from published papers demonstrate that amphetamines cause long-term impairment of cognitive functions. A large number of pharmacological receptors have been studied and screened as targets of amphetamine-induced cognitive dysfunction, and extensive research efforts have been invested to provide evidence about the molecular mechanisms behind these cognitive deficits. In humans, there is a considerable body of evidence indicating that methamphetamine and MDMA seriously disrupt memory and learning processes. Although an association between the impairments of memory performance and a history of recreational amphetamine ingestion has also been corroborated, a number of methodological difficulties continue to hamper research in this field, the most important being the concomitant use of other illicit drugs.