Five healthy male volunteers free of neurologic or psychiatric diseases, with no past or current history of cigarette smoking, were intravenously injected with a saline solution of 10.9 mCi (s.d. ¼ 1.0 mCi) of [11C]-harmine at a specific radioactivity of 1,124 Ci/mmol (s.d. ¼ 203 Ci/mmol) as a bolus and immediately flushed with 10 mL saline. Radioactivity in the brain was measured by Positron Emission Tomography PET in a series of sequential frames of increasing duration (from 1 to 5 mins).

Human HepG2 cells were cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum at 37 deg-C in a 5% CO2 atmosphere. Harmine was dissolved in dimethyl sulfoxide and diluted to appropriate concentrations with culture medium. The CCK-8 test was used to monitor cell proliferation. Cells were plated at a density of 5000 cells per well in 96 well plates. After 24 hours, the cultures were treated with harmine at concentrations of 0, 0.625, 1.25, 2.5, 5, 10, or 20 μg/mL for 48 hours. After addition of test compounds, 10 μL CCK-8 was added to each well. Harmine inhibited the growth of HepG2 cells in a dose-dependent manner, with an IC50 of 9.80 μg/mL.