Intraventricular methotrexate: Motor deficit in male Wistar rats

Objective: To investigate the effect of intraventricular methotrexate on locomotor and exploratory activity in the male rats. Methods: Male Wistar rats aged 4 months were administered with 2 mg/kg and 3 mg/kg dose of methotrexate for 3 alternate days into the lateral ventricle through a cannula (implanted using stereotaxic apparatus). After a week, the locomotor and exploratory activity was assessed by open field test and dark/bright arena test including control groups. The dopamine level in the brainstem and frontal cortex was estimated by high pressure liquid chromatography. Results: Methotrexate at 2 mg/kg and 3 mg/kg dose altered locomotor and exploratory activity in both the test models used, along with a decrease in dopamine level in brainstem and frontal cortex. Conclusion: Intraventricular methotrexate produced motor deficit which is due to altered dopamine level in the brain. The severity of the effects depended on dose.