Binding of the Novel Serotonin Agonist 8‐Hydroxy‐2‐(Di‐n‐Propylamino) Tetralin in Normal and Alzheimer Brain

Abstract

Binding of [3H]8-hydroxy-2-(di-n-propylamino)tetralin, a putative ligand for the 5-hydroxytryptamine (5-HT, serotonin) IA recognition site, was measured in neocortex from the postmorten human brain. The substance was found to bind to a saturable site with a KD value and pharmacological profile similar to that of rat. Binding to membranes from normal human temporal cortex was found to significantly correlate (inversely) with age. A significant reduction in binding, reflecting decreased density of recognition sites, was observed in the frontal cortex of patients with Alzheimer''s disease (48% loss). This region in the dement brains showed unaltered presynaptic 5-HT function (5-HT and 5-hydroxyindoleacetic acid content) whereas 5-HT concentration was reduced in the temporal cortex.