Distribution of [H-3]GR65630 binding in human brain postmortem

We investigated the distribution of serotonin (5-HT) receptors of type 3 (5 -HT3) in human brain areas, by means of the the specific binding of [H-3]GR 65630. The brains were obtained during autoptic sessions from 6 subjects. H uman brain membranes and the binding of [H-3]GR65630 were carried out accor ding to standardized methods. The highest density (Bmax +/- SD, fmol/mg pro tein) of [H-3]GR65630 binding sites was found in area postrema (13.1 +/- 9. 7), followed at a statistically lower level, by nucleus tractus solitarius (6.7 +/- 3.4), nervus vagus (5.5 +/- 2.1), striatum (4.8 +/- 2.4) with a pr ogressive decrease in amygdala, olivar nuclei, hippocampus, olfactory bulbu s and prefrontal cortex, and then by the other cortical areas and the cereb ellum, where no binding was detected. These observations extend previous fi ndings on the distribution of 5-HT3 receptors and confirm interspecies vari ations that might explain the heterogeneous properties of 5-HT3 receptors i n different animals.