Cocaine in the Brain

Biology 202
2000 First Web Report
On Serendip

Cocaine in the Brain

Melissa Hoegler

During the 1980s, Partnership for a Drug Free America began airing commercials that seem to either frighten or educate people about the use of illegal drugs. One of these commercials avowed, "No one ever says, 'I want to be a junkie when I grow up'." The comment is obvious, but very true. Probably very few people aspire to be drug addicts. But it happens, everyday. Why? What is so good about a drug that can potentially destroy a person's body? How does it work? What are its effects on the brain? Why is it so hard to quit?

Cocaine (C17H21NO4) comes from the leaf of an Erythroxylon coca bush. It is a drug that effects the central nervous system. It causes feelings of euphoria, pleasure, increased energy and alertness. People under the influence of cocaine often do not feel the need for food or sleep. They also feel energetic and may talk a lot. However, depending on factors such as environment, dosage, and the manner in which the drug is taken, cocaine can have adverse effects such as violent, erratic behavior, dizziness, paranoia, insomnia, convulsions, and heart failure to name a few. Long- term effects of cocaine include, but are not limited to strokes, heart attacks, seizures, loss of memory, and decrease in learning capability (1).

People may not always know the exact consequences of the drug they are taking, however, chances are that they do know that the drug is unhealthy for them. Schools across the country educate about the dangers of drug use and abuse through programs like D.A.R.E., television stations show anti-drug advertisements as a public service, and even city buses blazon anti-drug propaganda. People are aware that very rarely does anything good come from drug use, and still, everyday people fall victim to drugs. Why do people succumb to the urge to try drugs? It feels good...why else?

When a person takes cocaine, it causes a rush. There is between one or two minutes of intense pleasure. This is followed by five to 8 minutes of euphoria, then as the high comes down, an overwhelming urge for more, which may last for a day. (3) When a user is between cocaine doses or halts usage, the opposite effects occur. The user is depressed and tired (2).

Cocaine is attractive to users because it triggers dopamine. Dopamine is a neurotransmitter that is present in many regions of the brain. In normal mice, the introduction of cocaine increases dopamine by 150 percent. Dopamine regulates movement, emotion, motivation, and the feeling of pleasure. In a normal brain, dopamine is released by a neuron into a synapse and then it moves to dopamine receptors on other neurons. It is then moved back to the neuron that transmitted the dopamine initially.

When cocaine enters the area of the brain where the dopamine is located, it blocks the reuptake pumps that remove the dopamine from the synapse of the nerve cell. Thus, more dopamine gathers at the synapse and feelings of intense pleasure result. This feeling continues until cocaine is naturally removed from the system (2). Research findings by the National Institute of Drug Addiction (NIDA) demonstrate that cocaine not only effects the level of dopamine in the brain, but also the level of seratonin. In a study using mice without dopamine transporters, the mice were given cocaine and they still experienced rewarding effects. This was obvious because the animals kept on attempting to get or self-administer more. These researchers speculate that more than one neurotransmitter is responsible for the pleasurable feeling cocaine yields (2). Although main hypothesis as to why cocaine is so pleasurable, is that it alters levels of dopamine, norepinephrine, and seratonin, some scientists report that cocaine effects approximately 90 different parts of the brain, not just the two main regions of the amygdala and the nucleus accumbens. However, it is interesting that it is these two regions of the brain that remain active after the cocaine has left the system, and the powerful, uncontrollable desire for the drug has set in. (3)

The first time people use cocaine and its effects fade, they want more. Such is the nature of the drug. The main reason cocaine use continues is the need to experience the "high" and the development of dependence. Dependence is, "the need to maintain a level of the drug in the brain to both satisfy the need and stimulate the reward center, and avoid physical withdrawal symptoms" (5). There is continual research occurring about dependence and how it can be streamlined.

It was recently discovered through newer imaging techniques that cocaine hinders blood flow. This is why is it can cause brain damage or defects. Recent research demonstrates that if a cocaine user even thinks about cocaine, the blood flow is altered . This suggests that the addictive nature of the drug is stronger than we think, because simply thinking about it produces similar results in addicts' brains' (4). This is likely to be a result of the way in which cocaine changes the structure of an abuser's brain. For example n experiments done with lab rats, scientists reported that after repeated exposure to cocaine, the rats' dendrites changed by becoming bigger and denser. This means that an increase in synaptic connectivity results from cocaine use which triggers people and animals to work harder to attain the drug (6).

Scientists are working furiously for a way to combat cocaine addiction. They specifically are examining the genetic factors that contribute to the addiction (5). However, even if scientists do identify all of the factors that cause addiction, they are still faced with the dilemma of how exactly to stop the addiction. New hope to end cocaine addiction lies in experimental drugs, such as one that is used to treat epilepsy and holistic approaches such as acupuncture.

Although it may seem like science knows a great deal about addiction and the effects of cocaine, scientific knowledge still cannot make the cocaine problem disappear. There is no sure cure for cocaine addiction. Once you try the drug, addiction strikes randomly, like a bullet in a game of Russian roulette. There is no cure for the addiction. Before trying the drug, really think, is a moment of pleasure worth a lifetime of pain?

WWW Sources

2)Cocaine's Pleasurable Effects May Involve Multiple Chemical Sites, This site is a part of NIDA notes. It explains theories about the way cocaine effects the brain. There is a picture of how cocaine effects the neurotransmitter .

3) Intricate Effects of Cocaine on the Brain Seen In Scans , Some older (3 years), but more controversial research about cocaine use. It shows cool pictures of brain scans.

4) Researches see how cocaine Affects the Brain, Highlights an experiment involving images of butterflies and cocaine. Interesting results.

5) New Targets in the Brain's Reward CenterThis article concentrates on the genetic causes of coke addiction.

6) Repeated Exposure To Cocaine Alters Brain Structure", Talks about the long term effect of coke on the brain and nerves.