Sarah Chevalier, Mélina Decourt, Maureen Francheteau, François Nicol, Anaïs Balbous, Pierre-Olivier Fernagut, Marianne Benoit-Marand
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引用次数: 0
Abstract
Parkinson’s disease is characterized by the degeneration of substantia nigra pars compacta (SNc) dopaminergic neurons, leading to motor and cognitive symptoms. Numerous cellular and molecular adaptations following neurodegeneration or dopamine replacement therapy (DRT) have been described in motor networks but little is known regarding associative basal ganglia loops. This study investigated the contributions of nigrostriatal degeneration and pramipexole (PPX) on neuronal activity in the orbitofrontal cortex (OFC), frontostriatal plasticity, and markers of synaptic plasticity. Bilateral nigrostriatal degeneration was induced by viral-mediated expression of human mutated alpha-synuclein in the SNc. Juxtacellular recordings were performed in anesthetized rats to evaluate neuronal activity in the OFC. Recordings in the dorsomedial striatum (DMS) were performed, and spike probability in response to OFC stimulation was measured before and after high-frequency stimulation (HFS). Post-mortem analysis included stereological assessment of nigral neurodegeneration, BDNF and TrkB protein levels. Nigrostriatal neurodegeneration led to altered firing patterns of OFC neurons that were restored by PPX. HFS of the OFC led to an increased spike probability in the DMS, while dopaminergic loss had the opposite effect. PPX led to a decreased spike probability following HFS in control rats and failed to counteract the effect of dopaminergic neurodegeneration. These alterations were associated with decreased levels of BDNF and TrkB in the DMS. This study demonstrates that nigral dopaminergic loss and PPX both contribute to alter frontostriatal transmission, precluding adequate information processing in associative basal ganglia loops as a gateway for the development of non-motor symptoms or non-motor side effects of DRT.
期刊介绍:
npj Parkinson's Disease is a comprehensive open access journal that covers a wide range of research areas related to Parkinson's disease. It publishes original studies in basic science, translational research, and clinical investigations. The journal is dedicated to advancing our understanding of Parkinson's disease by exploring various aspects such as anatomy, etiology, genetics, cellular and molecular physiology, neurophysiology, epidemiology, and therapeutic development. By providing free and immediate access to the scientific and Parkinson's disease community, npj Parkinson's Disease promotes collaboration and knowledge sharing among researchers and healthcare professionals.