Spared caudal brainstem SERT binding in early Parkinson's disease.

Postmortem data indicate loss of serotoninergic neurons in Parkinson's disease (PD). We used the serotonin transporter (SERT) radioligand 3-amino-4-(2-dimethylaminomethyl-phenylsulfaryl)-benzonitril (DASB) and positron emission tomography to examine SERT distribution and changes in early PD subjects. We studied five PD subjects (H&Y 1 to 2.5) and eight normal controls. There is reduced SERT binding in PD. The magnitude of DASB binding reductions was greater in the forebrain than in the brainstem regions. There was no asymmetry of diminished SERT binding. DASB binding in the medulla was relatively spared, inconsistent with the description of early prominent pathologic study in these caudal brainstem nuclei.