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|Meth and Your Brain
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How Meth Effects the Brain and the Body
How Does Methamphetamine Cause its Effects?
No matter how methamphetamine is used, it eventually ends up in the can
affect lots of brain structures, but the ones it affects the most are the can
affect lots of brain structures, but the ones it affects the most are the ones
that contain a chemical called dopamine. The reason for this is that the
shape, size, and chemical structure of methamphetamine and dopamine
are similar. Before I tell you more about dopamine and methamphetamine,
I'd better tell you how nerve cells work.
methamphetamine, I'd better tell you how nerve cells work.
Your brain is made up of billions of nerve cells (or neurons). Neurons
come in all shapes and sizes, but most have three important parts: a cell
body that contains the nucleus and directs the activities of the neuron;
dendrites, short fibers that receive messages from other neurons and
relay them to the cell body; and an axon, a long single fiber that carries
messages from the cell body to dendrites of other neurons.
Axons of one neuron and the dendrites of a neighboring neuron are
located very close to each other, but they don't actually touch. Therefore,
to communicate with each other they use chemical messengers known as
neurotransmitters. When one neuron wants to send a message to another
neuron it releases a neurotransmitter from its axon into the small space
that separates the two neurons. This space is called a synapse. The
neurotransmitter crosses the synapse and attaches to specific places on
the dendrites of the neighboring neuron called receptors. Once the
neurotransmitter has relayed its message, it is either destroyed or taken
back up into the first neuron where it is recycled for use again.
There are many different neurotransmitters, but the one that is most
affected by methamphetamine is dopamine. Dopamine is sometimes
called the pleasure neurotransmitter because it helps you feel good from
things like playing soccer, eating a big piece of chocolate cake, or riding a
roller coaster. When something pleasurable happens, certain axons
release lots of dopamine. The dopamine attaches to receptors on
dendrites of neighboring neurons and passes on the pleasure message.
This process is stopped when dopamine is released from the receptors
and pumped back into the neuron that released it where it is stored for
Usually neurons recycle dopamine. But methamphetamine is able to fool
neurons into taking it up just like they would dopamine. Once inside a
neuron, methamphetamine causes that neuron to release lots of
dopamine. All this dopamine causes the person to feel an extra sense of
pleasure that can last all day. But eventually these pleasurable effects
stop. They are followed by unpleasant feelings called a "crash" that often
lead a person to use more of the drug. If a person continues to use
methamphetamine, they will have a difficult time feeling pleasure from
anything. Imagine no longer enjoying your favorite food or an afternoon
with your friends.
Methamphetamine has lots of other effects
Because it is similar to dopamine, methamphetamine can change the
function of any neuron that contains dopamine. And if this weren't
enough, methamphetamine can also affect neurons that contain two other
neurotransmitters called serotonin and norepinephrine. All of this means
that methamphetamine can change how lots of things in the brain and the
body work. Even small amounts of methamphetamine can cause a person
to be more awake and active, lose their appetite, and become irritable and
aggressive. Methamphetamine also causes a person's blood pressure to
increase and their heart to beat faster.
Long Term Effects of Meth
Scientists are using brain imaging techniques, like positron emission
tomography (called PET for short), to study the brains of human
methamphetamine users. They have discovered that even three years
after long-time methamphetamine users had quit using the drug, their
dopamine neurons were still damaged. Scientists don't know yet whether
this damage is permanent, but this research shows that changes in the
brain from methamphetamine use can last a long time. Research with
animals has shown that the drug methamphetamine can also damage
neurons that contain serotonin. This damage also continues long after the
drug use is stopped.
These changes in dopamine and serotonin neurons may explain some of
the effects of methamphetamine. If a person uses methamphetamine for a
long time, they may become paranoid. They may also hear and see things
that aren't there. These are called hallucinations. Because
methamphetamine causes big increases in blood pressure, someone
using it for a long time may also have permanent damage to blood vessels
in the brain. This can lead to strokes caused by bleeding in the brain.
The Search Continues
Researchers are only beginning to understand how methamphetamine
acts in the brain and body. When they learn more about how
methamphetamine causes its effects, they may be able to develop
treatments that prevent or reverse the damage this drug can cause.
Maybe someday you'll make the next major breakthrough.
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Mind Over Matter is produced by the National Institute on Drug
Abuse, National Institutes of Health. These materials are in the
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