Tehran University of Medical Sciences Current Journal of Neurology 2717-011X 14 4 2016 03 03 195 203 EN Javad Hami Department of Anatomy, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran Mehran Hosseini Research Centre of Experimental Medicine AND Department of Public Health, Deputy of Research and Technology, Birjand University of Medical Sciences, Birjand, Iran Sekineh Shahi Department of Biology, School of Sciences, Payame Noor University, Tehran, Iran Nassim Lotfi Department of Anatomy, School of Medicine, Birjand University of Medical Sciences, Birjand AND Department of Anatomy and Cell Biology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran Abolfazl Talebi School of Medicine, Birjand University of Medical Sciences, Birjand, Iran Mohammad Afshar Department of Anatomy, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran 2015 10 11 Background: Parkinson’s disease (PD) is a common neurodegenerative disease resulting from the degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). Increasing evidence demonstrated that mice treated intranasally with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) suffered impairments in motor functions associated with disruption of DA neurons in SNc conceivably analogous to those observed in PD. L-arginine has been proposed as a novel neuroprotective agent that plays protective roles in several models of neuronal cellular damage. This study aimed to evaluate the effects of L-arginine on the numerical density of dark neurons (DNs) in the SNc of Balb/c mice subjected to MPTP administration. Methods: In the present study, we demonstrated that repeated treatment with L-arginine (300 mg/kg, i.p.) during 7 consecutive days attenuated the production of DNs in SNc of adult male Balb/c mice infused with a single intranasal administration of MPTP (1 mg/nostril). Results: Pre-treatment with L-arginine significantly decreased the numerical density of DNs in SNc of mice 21 days after intranasal MPTP administration. Conclusion: This investigation provides new insights in experimental models of PD, indicating that L-arginine represents a potential neuroprotective agent for the prevention of DA neuron degeneration in SNc observed in PD patients. https://ijnl.tums.ac.ir/index.php/ijnl/article/view/291 https://ijnl.tums.ac.ir/index.php/ijnl/article/download/291/18