Potent inhibitor of vesicular monoamine uptake; depletes stores of dopamine, serotonin and noradrenalin. Binds with high affinity (IC50= 3.2 nM) to vesicular monoamine transporter (VMAT) in chromaffin granule membranes and displays higher affinity for VMAT2 than VMAT1. Also reported to block dopamine receptors. Causes behavioral depression; inhibits locomotor activity and produces hypothermia upon systemic administration in rats and mice.