Cocaine clogs the brain's delicate message system

Cocaine interferes with the brain's normal handling of dopamine, a brain chemical, or neurotransmitter, involved with feelings of pleasure.

Like all neurotransmitters, dopamine travels from one brain cell, or neuron, to another by crossing a synapse, or gap, between cells. It then sends its message by binding to a dopamine receptor on the next cell. When finished, it returns into the synapse, where a transporter carries it back to the first brain cell for reuse.

Cocaine binds to and blocks dopamine transporters, preventing them from picking up dopamine for recycling. "The transporter is like a pump in a swimming pool that recycles water to keep the water at a certain level," explains NIDA's Dr. Grant. "Cocaine clogs the pump, allowing dopamine levels to rise to abnormally high levels, just like a clogged water pump will make a swimming pool overflow and produce a flood."

Scientists believe that this dopamine "flood" is behind the cocaine high. And just like a literal flood, it can cause a lot of damage. With repeated exposure to cocaine, the brain becomes unable to process dopamine normally. "Many cocaine users report that they have less ability to experience pleasure in life," says Dr. David Gorelick of NIDA. To try to feel good, they return to the drug, again and again, while the joys of real life pass them by.

How Dangerous Is Cocaine?

You might remember Chris Farley. The Saturday Night Live comedian was found dead in his luxury New York City apartment on December 18, 1997. He was only 33 years old. The cause of death was a morphine-and-cocaine-induced heart attack.

Cocaine played a role in the death of this talented comic, and the drug has had a hand in many other deaths. Cocaine can trigger fatal heart attacks and strokes—even in healthy young people.

Here's how cocaine can cause a heart attack: "Cocaine increases the amount of oxygen needed by the heart because it stimulates the heart to beat faster and stronger," explains NIDA's Dr. Gorelick. "At the same time, cocaine is decreasing the amount of blood flowing to the heart muscle, or blocking blood flow completely." This is because the drug constricts blood vessels.

Dr. Gorelick also explained how cocaine induces strokes. "In one type of stroke, blood flow is stopped because the blood vessel is constricted and or blocked," he says. "In another type, the blood vessel leaks or bursts, and blood no longer flows beyond the point of damage."

In 2001, there were 193,034 hospital emergency-department cases involving cocaine nationwide, or 10 percent more than in 2000 (according to the Drug Abuse Warning Network, 2002). The irony is that some young people try cocaine for thrills and excitement. How exciting is it to end up in the emergency room . . . or dead?

From Scholastic and the Scientists of the National Institute on Drug Abuse, National Institutes of Health, U.S. Department of Health and Human Services