cocaine effect on brain.

Miscommunication in the Brain

Cocaine and amphetamines change the way the brain works by changing the way nerve cells communicate. Nerve cells, called neurons, send messages to each other by releasing special chemicals called neurotransmitters. Neurotransmitters are able to work by attaching to key sites on neurons called receptors.

One of the neurotransmitters affected by cocaine is called dopamine. Dopamine is released by neurons in the limbic system -- the part of the brain that controls feelings of pleasure.

Normally, once dopamine has attached to a nerve cell's receptor and caused a change in the cell, it's pumped back to the neuron that released it. But cocaine blocks the pump, called the dopamine transporter. Dopamine then builds up in the gap synapse between neurons.

The result: dopamine keeps affecting a nerve cell after it should have stopped. That's why someone who uses cocaine feels an extra sense of pleasure for a short time.

Cocaine Can Damage the Way the Brain Works

Although cocaine may make someone feel pleasure for a while, later it can damage the ability to feel pleasure. Research suggests that long-term cocaine use may reduce the amount of dopamine or the number of dopamine receptors in the brain.

When this happens, nerve cells must have cocaine to communicate properly. Without the drug, the brain can't send enough dopamine into the receptors to create a feeling of pleasure.

If a long-term user of cocaine or crack stops taking the drug, the person feels an extremely strong craving for it, because without it he or she can't feel nearly as much pleasure.

Scientists Discover Answers

Fortunately, scientists have figured out how to copy the gene that controls the dopamine transporter. This process is called cloning.

By studying copies of the transporter, scientists may learn more about how cocaine affects it -- and how to prevent those effects. These studies may even lead to the discovery of a treatment for cocaine dependency.

Scientists are already working to create fake cocaine for use as a treatment. This chemical would attach to the dopamine transporter just like real cocaine does, but it wouldn't block dopamine's normal movement back into neurons. By attaching to the transporter, the substitute would block the effects of real cocaine.