Which substance is considered a depressant and derived from opium?

Codeine is recognized as a depressant and is derived from opium, which is a crucial point in understanding its classification and effects. Opium is obtained from the latex of the opium poppy, Papaver somniferum, and contains various alkaloids, including morphine and codeine.

As a depressant, codeine operates primarily by binding to specific opioid receptors in the brain, leading to a reduction in neural activity, which results in pain relief, sedation, and a sense of euphoria. This mechanism is consistent with the effects of other opiates, which tend to slow down the body's functions and can induce relaxation and drowsiness—common characteristics of depressant substances.

The other substances listed do not fall into the category of opiate-derived depressants. For instance, atropine is an alkaloid derived from plants like belladonna and functions primarily as an anticholinergic, affecting the autonomic nervous system. Reserpine is an antihypertensive and tranquilizing drug derived from the plant Rauvolfia serpentina, which can have sedative effects but is not derived from opium. Camptothecine, extracted from the Camptotheca acuminata tree, is used in