Final answer:
The nucleus accumbens is influenced by neurotransmitters such as dopamine, serotonin, and norepinephrine, as well as other substances like glycine, glutamate, and GABA. Cocaine and nicotine, particular stimulants that prolong dopamine activity, are known to stimulate the pleasure centers of the brain, leading to their addictive qualities.
Step-by-step explanation:
Various substances act on the nucleus accumbens, a region in the brain associated with reward and pleasure. Neurotransmitters like dopamine, serotonin, and norepinephrine play a crucial role in the functioning of the nucleus accumbens. Dopamine in particular is known for its involvement in the reward system and is influenced heavily by drugs such as nicotine and cocaine. Cocaine, for instance, acts as a stimulant by blocking the reuptake of dopamine, leading to elevated levels that stimulate the pleasure centers, contributing to its addictive properties. Other neuroactive substances like glycine, glutamate, aspartate, and gamma aminobutyric acid (GABA) also impact the nucleus accumbens, as do neuropeptides like Substance P and endorphins. Stimulants increase overall neural activity, often by acting as agonists of the dopamine system, while other drugs affect neurotransmitter systems like GABA, acetylcholine, the opioid system, and various others depending on their mechanism of action.