reserpine

Reserpine (also known by trade names Raudixin, Serpalan, Serpasil) 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. The antihypertensive actions of reserpine are a result of its ability to deplete catecholamines (among other monoamine neurotransmitters) from peripheral sympathetic nerve endings. These substances are normally involved in controlling heart rate, force of cardiac contraction and peripheral vascular resistance.
Reserpine-mediated depletion of monoamine neurotransmitters in the synapses is often cited as evidence to the theory that depletion of the monoamine neurotransmitters causes subsequent depression in humans (c.f. monoamine hypothesis). However, this claim is not without controversy. The reserpine-induced depression is considered by some researchers to be a myth, while others claim that teas made out of the plant roots containing reserpine have a calming, sedative action that can actually be considered antidepressant. Notably, reserpine was the first compound shown to be an effective antidepressant in a randomized placebo-controlled trial.
Moreover, reserpine has a peripheral action in many parts of the body, resulting in a preponderance of the effects of the cholinergic part of the autonomous nervous system on the GI tract, smooth muscles, blood vessels, etc.