Serotonin uptake in the blood platelets of Alzheimer's disease patients.
We determined serotonin (5-HT) uptake in the blood platelets of Alzheimer's disease (AD) patients and comparable age-matched normal controls. The maximum number of 5-HT uptake sites (Vmax) was significantly increased in mild and moderate AD patients, and a trend toward decreased V max was observed in severe AD patients as compared with normal controls. The Km of 5-HT uptake was negatively correlated with the Face-Hand Test (FHT) score of severely ill AD patients, whereas Vmax was correlated with the FHT score and the Mental Status Questionnaire score in the entire AD sample.