Glutamate Signaling in Patients With Parkinson Disease With REM Sleep Behavior Disorder
Christopher E. J. Doppler, Aline Seger, Ezequiel Farrher, Cláudia Régio Brambilla, Lukas Hensel, Christian Filß, Martin Hellmich, Ana Gogishvili, N. Jon Shah, Christoph Lerche, Bernd Neumaier, Karl‐Josef Langen, Gereon R. Fink, Michael Sommerauer
Abstract
BACKGROUND AND OBJECTIVES: Clinical heterogeneity of patients with Parkinson disease (PD) is well recognized. PD with REM sleep behavior disorder (RBD) is a more malignant phenotype with faster motor progression and higher nonmotor symptom burden. However, the neural mechanisms underlying this clinical divergence concerning imbalances in neurotransmitter systems remain elusive. METHODS: C]ABP688 were estimated with metabolite-corrected plasma concentrations during steady-state conditions between 45 and 60 minutes of the scan following a bolus-infusion protocol. Glutamate, glutamine, and glutathione levels were investigated with single-voxel stimulated echo acquisition mode MR spectroscopy of the left basal ganglia. RESULTS: = 0.022). DISCUSSION: C]ABP688 despite unaffected glutamate levels. The imbalance of glutamate receptors and MR spectroscopy glutamate metabolite levels indicates a novel mechanism contributing to the heterogeneity of PD and warrants further investigation of drugs targeting mGluR5.