Melatonin in Parkinson's disease and its therapeutic potential

Abstract

Although the etiology of Parkinson's disease (PD) is not known, most patients with PD experience sleep-related problems like difficulty in initiating and maintaining sleep, excessive daytime sleepiness, sleep fragmentation, and reductions in non-REM or REM sleep. Since melatonin and its analogues have sleep-promoting and sleep-wake rhythm-regulating actions, interest has been focused on the role of melatonin in PD. Interestingly use of melatonin in animal models of PD has shown that melatonin has been useful in improving the neurotoxic effects of administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, or maneb and paraquat. Being an antioxidant melatonin counteracted the MPTP-induced lipid per oxidation. The finding of reduced expression of MT1 and MT2 melatonin receptors in amygdale and substantia nigra of patients with PD supports the involvement of melatonergic system in the possible etiology of PD. Use of melatonin or its analogues may be beneficial in treating patients with PD for improving the sleep quality and also for enhancing the neuroprotection against oxidative stress seen in PD.