Quantitative radioluminography of serotonin uptake sites in the porcine brain

The regional density of serotonin uptake sites in porcine brain was determi ned by quantitative radioluminography. Brain cryostat sections 30 mum thick were cut in the sagittal plane and were incubated with [H-3]citalopram for selective labeling of serotonin uptake sites. The autoradiograms were quan tified using tritium-sensitive radioluminography. The apparent affinity (K- D) of [H-3]citalopram for its binding sites in various brain regions ranged from 2.3-5.6 nM. The density of serotonin uptake sites was highest (200-30 0 fmol/mg tissue) in the amygdala, superior colliculus, and substantia nigr a. Intermediate binding (100 fmol/mg tissue) was present in the dorsomedial thalamus, basal ganglia, and entorhinal cortex. Traces of specific binding (10 finol/mg tissue) were detected in the neocortex and cerebellar cortex. The findings show that the anatomic distribution of serotonin uptake sites in the porcine brain is similar to that reported in other mammals. The den sity was close to that reported in human brain and in rat brain. Synapse 39 :351-355, 2001. (C) 2001 Wiley-Liss, Inc.