|MadSci Network: Neuroscience|
Alcohol affects the brain (and cerebellum) by interfering with chemicals, called neurotransmitters, which are responsible for transferring information in the brain. The action of one chemical, glutamate (an amino acid) excites or makes active other brain cells. Alcohol inhibits the ability of glutamate to excite brain cells. This causes people to be drowsy and not be able to think as fast. This also decreases the ability of the cerebellum to work as well as it usually does, causing problems with coordination.
Alcohol also increases the ability of another chemical, called gamma amino butyric acid (also called GABA) to inhibit brain cells. Inhibition is the opposite of excitation, and inhibition causes brain cells to be less active. This also causes poor coordination, impaired judgement and drowsiness.
Together, these actions on the brain cause one to feel really tired, make you feel like you do not want to do anything, make it hard for you to concentrate, and slow down your reaction time. They also impair your judgement, allowing you to do stupid things you normally would not do. If taken in very dangerous concentration, they can stop your breathing or cause convulsions and seizures.
There are many ways other drugs affect the brain. Many drugs work to either decrease excitation or increase inhibition. Central nervous system depressants, like Phenobarbital, pentobarbital and valium all work this way. Chemicals like gasoline, kerosene, the solvent in glue and paint also work this way. This makes sniffing or inhaling these chemicals really dangerous. In addition, these chemicals also affect the electrical conduction in the heart, making these dangerous.
Drugs that are stimulants (like cocaine, methylphenidate (Ritalin) and amphetamines) increase the amount of chemical called norepinephrine (related to adrenaline) in the brain. This causes increased alertness, stomach aches, decreased appetite, keep you from sleeping, make you feel real mad, scared or suicidal, make you paranoid (make you think everyone is after you, your friends do not like you, or that people are picking on you), make you see or hear things that do not exist (hallucinations), make you hyper, make your body shake all over, make your heart beat too fast (and cause part of your heart to die from lack of blood flow [a heart attack]) and cause seizures and convulsions.
Another important group of drugs are the opiates, like heroin and many prescription pain killers, such as morphine, meperidine (Demerol) and methadone. This drugs all act to stop pain. But, like alcohol and Valium, they also cause drowsiness and in too high dose can stop breathing. They also cause physical addiction. When they are stopped they cause symptoms like vomiting and diarrhea, shaking and chills.
One thing that I did not do, on purpose, was separate drugs used to treat illnesses from those that are used recreationally. This is because, whether they are prescribed by a physician or not, they work the same. And if used improperly, can be very dangerous.
I found one internet site that might interest you. Both of these sites were made to give teenagers information about drugs and drug abuse. This site is made by the US Drug Enforcement Agency, and, obviously, carries an anti-drug message. Unfortunately, I have found no sites that give information about how drugs work in the brain.
What do drugs do the brain anyway?
Try the links in the MadSci Library for more information on Neuroscience.