The Brain's Response to Opiates
If you've ever seen "The Wizard of Oz," then you've seen the poppy plant -- the source of a type of drug called opiates. When Dorothy lies down in a field of poppies, she falls into a deep sleep.
No wonder the Latin name of this plant -- Papaver somniferum -- means "the poppy that makes you sleepy."
Opiates are made from opium, a white liquid in the poppy plant. They're also referred to as narcotics. Maybe you've heard of drugs called heroin, morphine or codeine. These are examples of opiates.
Opiates can produce a quick, intense feeling of pleasure followed by a sense of well-being and a calm drowsiness. But they can also become an addiction. If someone uses opiates again and again, his or her brain is likely to become dependent on them.
Nerve Cells Experience Addiction and Withdrawal
What happens to make a person and his or her brain become addicted to an opiate? Long term opiate use changes the way nerve cells in the brain work. These cells grow so used to having the opiate around that they actually need it to work normally.
If opiates are taken away from dependent nerve cells, many cells become overactive. Eventually, these cells will work normally again, but in the meantime, they cause a wide range of symptoms in the brain and body. These are known as withdrawal symptoms.
Have you ever had the flu? You probably experienced symptoms such as aching, fever, sweating, shaking or chills. These are similar to withdrawal symptoms, but withdrawal symptoms are much worse. Yuck!
Here's one way to illustrate how hard it is for brain cells to function without a drug they depend on: Grab a sheet of paper and try drawing any picture in a magazine without using the hand you usually use.
How Nerve Cells Respond to Opiate
Within the limbic system, brainstem and spinal cord, there are places on certain nerve cells that recognize opiates. When stimulated by opiates, these sites -- called opiate receptors -- trigger responses in the brain and body.
Scientists have identified three types of opiate receptors: delta, mu and kappa (named after letters in the Greek alphabet). Each of these receptors is involved in different brain functions. For example, mu is responsible for the pain-relieving effects of the drug morphine.
Opiates Act On Many Places In The Brain And Nervous system
The limbic system controls emotions. Opiates change the limbic system to produce increased feelings of pleasure, relaxation and contentment. (red)
The brainstem controls things your body does automatically, like breathing or coughing. Opiates can act on the brainstem to stop coughing or slow breathing. (blue)
The spinal cord transmits pain signals from the body. By acting here, opiates block pain messages and allow people to bear even serious injuries. (yellow)
After years of experiments, scientists have discovered how to copy ("clone") the genes that control the production of
opiate receptors. Now it will be easier for researchers to make opiate receptors and study how opiates affect nerve cells..
This discovery may lead to other exciting developments, such as better treatments for opiate addiction.
Opiates Stop Pain
Did you know that some opiates can have important medical uses? They're powerful pain killers, and doctors sometimes prescribe them to control severe diarrhea. If you look on a cough medicine label, you might find that codeine is one of the ingredients.
When used properly for medical purposes, opiates don't produce an intense feeling of pleasure, and patients have very little chance of becoming addicted.
Your brain produces its own versions of opiates, called endogenous opioids. These chemicals act just like opiates, binding to opiate receptors.
Endogenous opioids are your body's way of controlling pain. If you've ever felt pleasantly relaxed after exercising a lot, that feeling was probably caused by the release of this natural chemical in your brain.
The Search Continues
There's still a lot that scientists don't know about the effects of opiates on the brain. Maybe someday you will make the next big discovery.
References: (1) Mind over Matter: Opiates (NIDA 2004)
If you are interested in more information concerning opioids, then continue on with us, but I wanted to take the time to explain it at a level we all could understand it. It can become very complicated and without some medical knowledge it can be difficult to understand.
I hope all of you following along are learning because it is very crucial you understand the basics behind addiction. If you find yourself having any trouble understanding the material, then, please take the time to send a message to the address below and let me know what you are having a problem comprehending. It would be my pleasure to take the time to help you understand. I can be reached at the address below:
Editor: Deborah Shrira Updated: 20 February 2008
Asst.Editor: Dee Black Last Update: May 2012