ABSTRACT
We know generally the ways many drugs affect the user. However, the pharmacological mechanisms through which some drugs exert their effects are only partially understood. Researchers have identified locations and substances in the brain that are closely associated with the effects of drugs and their reinforcement properties. Although the process is complex, the neurotransmitter dopamine appears to play an important role in determining the effects of drugs such as cocaine and heroin. Cocaine acts on the pleasure center of the brain to the extent that in some people, particularly those with personality disorders already in place, cocaine becomes more important and pleasurable than some of the most basic human needs such as food, sex, or exercise. Normally, dopamine is released by nerve centers and is then withdrawn. In the case of cocaine, dopamine continues to be transmitted, significantly raising the blood pressure and increasing the heart rate.
