11C-labeling of indolealkylamine alkaloids and the comparative study of their tissue distributions.

Five indolealkylamines—N,N-dimethyltryptamine, N-methyltryptamine, bufotenine, O-methylbufotenine, and N,N,N-trimethyltryptamine iodide—were labeled with carbon-11 using 11CH3I. The labeled compounds were synthesized with radiochemical yields of 2–50% in 20–35 minutes and purities above 92%. In rats, all compounds accumulated highly in the liver, lung, and small intestine. [11C]DMT and [11C]OMB also showed substantial and retained accumulation in the brain, while brain uptake of the other three was low. [11C]DMT is recommended for studying serotonin action in the brain due to its highest radiochemical yield and brain uptake.

Study at a glance

Abstract

Five indolealkylamines (N,N-dimethyltryptamine, N-methyltryptamine, bufotenine, O-methylbufotenine, N,N,N-trimethyltryptamine iodide) were labeled with 11C by use of 11CH3I. The labeled compounds were synthesized with a radiochemical yield of 2-50% (based on trapped 11CH3I) in 20-35 min with radiochemical purities of more than 92%. The tissue distributions of these labeled compounds were investigated in rats. In all cases, the accumulations in the liver, lung and small intestine were high. [11C]DMT and [11C]OMB also accumulated to a large extent in the brain, where their accumulation was retained. Brain uptake of three other radiopharmaceuticals was low. [11C]DMT is the radiopharmaceutical of choice for the study of the serotonin action mechanism in the brain, because it has the highest radiochemical yield and the highest brain uptake of these 11C-labeled compounds.