Proteins of the vesicular cycle as a marker of neuroplasticity of dopaminergic neurons in the substantia nigra of the brain

Nigrostriatal dopaminergic neurons (DNs) involved in the regulation of motor function, are characterized by high plasticity. Indeed, at the death of up to 50% of DNs in Parkinson’s disease, the survived neurons provide normal regulation. This study was aimed to determine whether proteins of the vesicular cycle, syntaxin Ia (Syn Ia), synaptotagmin I (Syt I), Rab5a and complexins I and II (Cmpx I and II), are involved in the mechanisms of neuroplasticity in the substantia nigra, which mainly contains cell bodies and processes of the DNs. In neurotoxic models of Parkinson’s disease in mice, it was shown that at the degeneration of up to 50% of DNs, the content of Syt I, Syn Ia, Cmpх I and II involved in vesicle exocytosis does not change in the substantia nigra as whole, while this is compensatory increased in individual survived DNs. Thus, the data obtained in this study suggest that the impairment of motor behavior that occurs at the death of half of nigrostriatal DNs is not caused by the impairment of the production of vesicular cycle proteins in surviving DNs.