Functional neuroimaging of the 6-OHDA lesion rat model of Parkinson's disease

Abstract

We characterized the unilaterally 6-hydroxydopamine (6-OHDA)-lesioned rat, a well-known acute model of Parkinson's disease (PD), with [18F]-fluoro-2-deoxy-d-glucose (FDG) small-animal positron emission tomography (PET), which we compared with a drug-induced rotation behavioral test. In the 6-OHDA model, significant glucose hypometabolism was present in the primary motor cortex, substantia nigra, and pedunculopontine tegmental nucleus on the ipsilateral side. In contrast, neuronal activations were observed in the primary somatosensory cortex and ventral caudate–putamen area after lesioning. Correlation analysis revealed a significant relationship between the behavioral results and the degree of glucose metabolism impairment in the primary motor cortex, substantia nigra, and pedunculopontine tegmental nucleus. In addition, the pedunculopontine tegmental nucleus correlated significantly with the primary somatosensory cortex, the ventral caudate–putamen, the substantia nigra, and the primary motor cortex. Furthermore, the primary motor cortex also showed significant correlations with the substantia nigra. In conclusion, In vivo cerebral mapping of the 6-OHDA-lesioned rats using [18F]-FDG PET showed correspondence at the functional levels to the cortico–subcortical network impairment observed in PD patients.