TY - JOUR T1 - Unraveling the mechanisms underlying irregularities in inspiratory rhythm generation in a mouse model of Parkinson's disease JF - The Journal of Neuroscience JO - J. Neurosci. DO - 10.1523/JNEUROSCI.2114-20.2021 SP - JN-RM-2114-20 AU - Luiz M. Oliveira AU - Nathan A. Baertsch AU - Thiago S. Moreira AU - Jan-Marino Ramirez AU - Ana C. Takakura Y1 - 2021/04/16 UR - http://www.jneurosci.org/content/early/2021/04/13/JNEUROSCI.2114-20.2021.abstract N2 - Parkinson’s disease (PD) is a neurodegenerative disorder anatomically characterized by a progressive loss of dopaminergic neurons in the substantia nigra compacta (SNpc). Much less known, yet clinically very important, are the detrimental effects on breathing associated with this disease. Consistent with the human pathophysiology, the 6-hydroxydopamine (6-OHDA) rodent model of PD shows reduced respiratory frequency (fR) and NK1r-immunoreactivity in the pre-Bötzinger complex (preBötC) and PHOX2B+ neurons in the retrotrapezoid nucleus (RTN). To unravel mechanisms that underlie bradypnea in PD, we employed a transgenic approach to label or stimulate specific neuron populations in various respiratory-related brainstem regions. PD mice were characterized by a pronounced decreased number of putatively rhythmically active excitatory neurons in the preBötC and adjacent ventral respiratory column (VRC). Specifically, the number of Dbx1 and Vglut2 neurons were reduced by 47.6 and 17.3%, respectively. By contrast, inhibitory Vgat+ neurons in the VRC, as well as neurons in other respiratory-related brainstem regions, showed relatively minimal or no signs of neuronal loss. Consistent with these anatomical observations, optogenetic experiments identified deficits in respiratory function that were specific to manipulations of excitatory (Dbx1/Vglut2) neurons in the preBötC. We conclude that the decreased number of this critical population of respiratory neurons is an important contributor to the development of irregularities in inspiratory rhythm generation in this mouse model of PD.SIGNIFICANCE STATEMENT:We found a decreased number of a specific population of medullary neurons which contributes to breathing abnormalities in a mouse model of Parkinson’s disease (PD). ER -