Lovett, R. One hundred cups of coffee would probably kill a person.
Nicotine is highly addictive, and the use of tobacco products is associated with increased risks of heart disease, stroke, and a variety of cancers. Substances of abuse also affect the nucleus accumbens by increasing the release of the neurotransmitter dopamine, which helps to regulate the feelings of pleasure euphoria and satisfaction.
Need Help? Stimulants also reduce food intake, reduce sleep time, and may increase socialization activities. The chemical compositions of the hallucinogens are similar to the neurotransmitters serotonin and epinephrine, and they act primarily as agonists by mimicking the action of serotonin at the synapses.
Bushman, B. Too little dopamine in certain areas of the brain results in the tremors and paralysis of Parkinson's disease. Besides providing quick energy, stimulants increase the heart rate and dopamine levels in the brain.