Higher levels of cerebrospinal fluid nitrite and nitrate in levodopa-induced dyskinesias in parkinson’s disease

Introduction Levodopa-induced dyskinesias (LID) in Parkinson’s disease (PD) are frequent complications, and nitric oxide has a role on its pathophysiology. The present work aims to investigate CSF levels of nitric oxide metabolites nitrite and nitrate (NOx) in patients with PD and LID. Methods We measured CSF NOx levels in patients with PD with and without LID, and in healthy controls. The levels of CSF NOx levels were measured by ozone-based chemiluminescence. Results 67 participants were enrolled. CSF NOx levels were higher in patients with PD with LID than in healthy controls (Kruskal-Wallis statistics = 7.24, p = 0.02). CSF NOx levels did not correlate with other clinical variables. Conclusion We reported higher levels of nitric oxide in the CSF of patients with PD and LID. Highlights ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported by the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP; 159688/2015-9) and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq; 2012/17626-7). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ribeirao Preto Medical School Ethics Committee (Number 3.036.243) All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.