When snorted, smoked, or injected, cocaine induces intense feelings of euphoria. Over time, however, the body alters its own natural patterns in terms of production and reuptake of the neurotransmitters. Tolerance to the drug develops and more and more cocaine is needed to achieve the desired effect. Cocaine acts on the reward centers of the brain by increasing the effects of naturally occurring neurotransmitters (such as serotonin and dopamine) that make a person feel good. Cocaine, also known as coke, is a powerful stimulant derived from the coca plant.