EFFECT OF CHRONIC ADMINISTRATION OF MAGNESIUM-SULFATE ON METHYL-4-PHENYL-1,2,3,6-TETRAHYDROPYRIDINE-INDUCED NEUROTOXICITY IN MICE

This investigation was aimed to study the effect of magnesium on 1-met hyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity i n mice. Four groups of mice were given magnesium sulfate (MgSO4 . 7H(2 )O) in drinking water at four different concentrations of 0.0 g/l (con trol), 2.5 g/l (low), 5.0 g/l (medium) and 10.0 g/l thigh) respectivel y for a period of 16 weeks: these animals also received MPTP (30 mg/kg , intraperitoneally daily) during the last five days of Mg treatment. Other four groups of mice were given similar dose regimen of MgSO4 but received injections of saline instead of MPTP. Seventy-two hr after t he last dose of MPTP, neurobehavioural studies including locomotor act ivity, pole climbing test and heat nociception test were performed and striata were collected for the analysis of dopamine. The results of t his study show that treatment of mice with MgSO4 or MPTP individually has no effect on their behaviour. Concomitant administration of low do se of MgSO4 (2.5 g/l) along with MPTP produced increase in motor activ ity and latency to heat stimuli; whereas medium and high doses of MgSO 4 in combination with MPTP produced opposite las compared to low dose) effects resulting in a decrease in motor activity and latency to heat stimuli and increase in pole climbing time. However, MgSO4 dose-depen dently exacerbated MPTP-induced depletion of striatal dopamine. The mo rtality was drastically increased (30-55%) in the animals receiving co mbined treatments of MPTP and MgSO, as compared to the mice treated wi th MPTP alone (12%). This study clearly points towards the ability of MgSO4 to modify MPTP-induced neurotoxicity.