Effect of magnesium on serum melatonin in a rat model of Parkinson' s Disease

Abstract

Objective To explore the relationship between magnesium (Mg) and melatonin (MLT) by observation serum MLT levels in advanced Parkinson' s disease (PD) rats,and to clarify the effect of magnesium on serum melatonin in PD model.Methods PD rat model was established by a unilateral injection of 6-OHDA into the right substantia nigra pars compacta (SNc) and the right medial forebrain bundle (MFB).Rats of control group received saline injection.Twenty animals were divided into four groups.PD model (PD/H2O) and control/H2O groups were vehicle-treated rats,and received drinking water (magnesium sulphate vehicle) daily.Magnesium sulphate (MgSO40.36 g/kg/day dissolved in drinking water) was administered in rats of PD/Mg and control/Mg groups for four weeks.Then apomorphine-induced rotational behaviour,serum MLT levels and histological changes were tested.Results The level of MLT in PD groups was ( 153.4 ±29.8) pg/L,which distinctly higher than those in the controls (77.2 ±13.7) pg/L,while the levels of MLT in PD model and control rats receiving Mg were decreased to ( 126.8 ± 15.9) pg/L and (53.4 ± 18.1 ) pg/L respectively.MLT levels appeared to correlate well with the frequency of apomorphine-induced rotations.The frequency of rotations in PD/Mg group decreased compared with those in PD/H2O group.Conclusion The rotational behaviour in advanced PD rat might ameliorated by magnesium,and magnesium may partly inhibit compensatory increased MLT. Key words: Parkinson's disease; Melatonin; Magnesium sulphate