Reserpine/

Biologieal

Reserpine is an indole alkaloid antipsychotic and antihypertensive drug that has been used for the control of high blood pressure and for the relief of psychotic symptoms, although because of the development of better drugs for these purposes and because of its numerous side-effects, it is rarely used today. Reserpine acts by blocking the vesicular monoamine transporter VMAT, which normally transports free norepinephrine, serotonin, and dopamine from the cytoplasm of the presynaptic nerve into vesicles for subsequent release into the synaptic cleft. The unprotected neurotransmitters are then metabolized by MAO and therefore never reach the synapse. [1]

Reference

[1] http://en.wikipedia.org/wiki/Reserpine