Decrease of serotonin-S2 receptors in temporal cortex of patients with Parkinson's disease and progressive supranuclear palsy.

The number of serotonin-S2 receptors was decreased in the temporal cortex of patients with Parkinson's disease and progressive supranuclear palsy (PSP). There was no significant modification of these receptors in the frontal cortex or in the hippocampus and putamen in both diseases. The decrease in number of receptors in PSP was unexpected, because the cerebral cortex is thought to be spared in this disease. There was no correlation between the decrease in number of serotonin-S2 receptors and the degree of dementia in Parkinson's disease, suggesting that these receptors are not directly involved in the deterioration of cognitive functions.