Platelet serotonin uptake sites increased in drinkers ofayahuasca

Abstract

The binding of [³H]citalopram to the platelet 5-hydroxytryptamine (5-HT) transporter was measured in a group of healthy male drinkers ofayahuasca, a psychoactive sacrament indigenous to Amazonia, and a group healthy male controls. An increased number of binding sites (B_max) in the platelets of ayahuasca drinkers was found, while the dissociation constant (K_d) remained the same for both groups. If indicative of neuronal 5-HT uptake activity, these results would suggest a decreased concentration of extracellular 5-HT, or a response to increased production and release of 5-HT. Such changes in 5-HT synaptic activity, in this case, should not be misinterpreted as an indication of developing neurological or psychiatric illness.