Methylphenidate and Modafinil Mitigate Scopolamine-Induced Behavioral Alterations

This study investigated the effects of modafinil and methylphenidate in a rat model of dementia induced by scopolamine. The degeneration of cholinergic neurons in dementia is linked to cognitive and motor deficits, and dopaminergic mechanisms play a crucial role in modulating cholinergic transmission. Given this, the study explored the potential role of psychostimulants in treating these disruptions. Both psychostimulants were administered orally in therapeutic doses: methylphenidate (10 mg/kg/day) and modafinil (75 mg/kg/day). The study assessed fine motor skills using the stationary rod test, cognitive function through tasks such as the maze and passive avoidance tests, and locomotor activity in both familiar and novel environments. Scopolamine injections (SC. 1 mg/kg) caused reduced locomotion, impaired motor skills, and memory dysfunction, all of which were improved with psychostimulant treatment. Behavioral sensitization was observed in the second week of treatment. Both methylphenidate and modafinil improved motor coordination and cognitive function. Methylphenidate showed more significant improvements, particularly in cognitive functions, while modafinil had a greater effect on increasing motor activity. However, the overall therapeutic efficacy was similar for both treatments. Notably, modafinil-induced locomotor sensitization, which requires further study to understand its implications. These findings highlight the potential of psychostimulants in treating dementia-related cognitive and motor deficits, suggesting their possible role in developing therapies for neurodegenerative disorders. However, the risks of long-term use, such as psychosis and addiction, should be carefully considered.