Substances and the Brain

1. Substances and the Brain Presented by Paige Hays August 28, 2006

2. Brief History Lesson Late 19th century Paul Ehrlich found when using dyes to study anatomy that the dye would stain all the body tissues except the spinal cord and brain.

3. Brief History Lesson 1913- Edwin Goldmann tried the opposite experiment, putting the dye directly into the spinal cord. The result was that only the spinal cord and brain became dyed. These two experiments lead to the conclusion that there was some kind of blood-brain barrier. 1960s- Using new electron microscopes, the barrier could finally be seen.

4. The Blood-Brain Barrier Blood in carried in the brain by arteries and capillaries. Capillaries deliver oxygen and other necessary substances to the neurons in the brain.

5. The Blood-Brain Barrier There are 100 billion capillaries in the brain (400 miles), and virtually every neuron (brain cell) has its own capillary. Capillaries are made with endothelial cells that have small spaces between them, allowing some substances to pass in and out. In the brain, these spaces are very small creating the blood-brain barrier.

6. The Blood-Brain Barrier What the purpose? Protection! The brain needs a constant environment. Many substances would harm the brain if they could get in, such as infections, poisons, or hormones use elsewhere in the body. Why do we care? The blood-brain barrier is not always perfect. There are substances that will cross the barrier that can be dangerous to the brain both in the short-term and long-term. Drug abuse and addiction

7. What Can Cross the Blood-Brain Barrier? Oxygen, nutrients, glucose (sugar) Poisons (Ever heard of a �Mad Hatter�? Hat makers who worked with mercury has brain damage from the poison.) Caffeine Nicotine Alcohol Drugs Medications Illegal substances

8. Drugs and the Brain Cross the blood-brain barrier Many drugs work because the have a similar size and shape as neurotransmitters. Neurotransmitters are chemical that allow neurons (brain cells) to communicate. Drugs lock into receptors causing unnatural reactions or preventing normal brain functioning.

9. Caffeine and the Brain Stimulant- prevents the brain from calming down Other effects: reduce fine motor coordination cause insomnia cause headaches, nervousness and dizziness Caffeine interferes with adenosine, a neurotransmitter. Adenosine plays an important role in sleep and waking.

10. Nicotine and the Brain Increases the level of dopamine, which affects the areas that control pleasure. Can create a sensation of pleasure Nicotine is shaped like a neurotransmitter called acetylcholine. Acetylcholine and its receptors involved with muscle movement, breathing, heart rate, learning, and memory. Addiction to nicotine results in withdrawal symptoms For example, when chronic smokers were deprived of cigarettes for 24 hours, they had increased anger, hostility, and aggression, and loss of social cooperation.

11. Medications and the Brain Treating illnesses that are found in the brain (depression, cancers, Alzheimer�s Disease,etc.) is very difficult Most potential drugs are too big to cross the blood-brain barrier The most progress have been made on medications for mood disorders and schizophrenia Often there are side effects because it effects the whole central nervous system Side effects often go away as the brain gets used to the new substances Many can become addictive and dangerous (such as interactions with other medications) if not used as prescribed

12. Alcohol and the Brain Depressant- relaxes In low-medium doses, alcohol produces: reduces tension lowers inhibitions impairs concentration slows reflexes/impairs reaction time reduces coordination slur speech cause drowsiness alter emotions In high doses, alcohol produces: vomiting breathing difficulties unconsciousness coma Because if its small size and how it combines with water and lipids, it easily crosses the blood brain barrier Affects the spinal cord, cerebellum and cerebral cortex, and on many neurotransmitters, such as norepinephrine, dopamine, acetylcholine, and endorphins.

13. Alcohol and the Brain Chronic alcohol use can: Damage the frontal lobes and decreases brain size Korsakoff's syndrome and "Wernicke's Encephalopathy" Caused by a deficiency in vitamin B-1 Impaired memory, confusion, apathy, disorientation, and lack of coordination Dependence on alcohol and withdrawal symptoms such as shaking, sleep problems, nausea, hallucinations, and seizures.

14. Alcohol and the Brain

15. Marijuana and the Brain Marijuana acts on neurons at cannabinoid sites. Cannabinoid receptors are found in the parts of the brain that influence pleasure, memory, thought, concentration, sensory perception, and movement. The short-term effects: memory and learning problems, distorted perception, difficulty in thinking and problem solving, and a loss of coordination Long-term affects: Impairments in short-term memory, verbal skills, and judgment and distort perception. Depression, anxiety, and personality disturbances have been associated with chronic marijuana use. 

16. Methamphetamines and the Brain Stimulant- strongly activates certain systems in the brain. Releases high levels of the neurotransmitter dopamine Effects include irritability, insomnia, confusion, tremors, convulsions, anxiety, paranoia, and even death

17. Methamphetamines and the Brain

18. LSD, Ecstasy, and the Brain Hallucinogens- distortions in a person�s perception. Effects serotonin Serotonin is involved in the control of behavior, mood, hunger, body temperature, and sensory perception. Confusion, depression, sleep problems, anxiety, and flashbacks can occur weeks after use. Some users develop mental illness, but the relationship is unclear. Long-term memory and thinking problems

19. LSD, Ecstasy, and the Brain Research with primates shows that it damages neurons in areas related to mood, thinking, and judgment

20. PCP and the Brain PCP is a "dissociative drug," meaning that it distorts perceptions of sight and sound and produces feelings of detachment (dissociation) from the environment and self. Change the distribution glutamate. Glutamate is involved in a person's perception of pain, responses to the environment, and memory.

21. Addiction and the Brain Addiction has many components Many drugs that are abused (such as nicotine, cocaine, and marijuana) affect the brain's limbic system. The limbic system responds to pleasurable experiences by releasing the dopamine, which creates feelings of pleasure or reward. The brain changes as a result of the unnatural flood of neurotransmitters caused by drug use. Reduce the number of dopamine receptors Neurons may also make less dopamine The result is less dopamine in the brain The brain has to retrain/adjust once the drug is not longer being used Withdrawal Long-term recovery

22. Images taken from the following websites: http://www.pbs.org/wnet/brain/ http://www.chemistryexplained.com/Di-Fa/Ehrlich-Paul.html http://www.brainexplorer.org/glossary/cns.shtml http://www.armagen.com/images/gif/emoxau2.jpg http://www.ohsu.edu/bbb/forprof_program.html http://en.wikipedia.org/wiki/Caffeine http://faculty.washington.edu/chudler/alco.html http://www.nida.nih.gov/ResearchReports/MDMA/MDMA2.html http://www.loni.ucla.edu/~thompson/MEDIA/METH/PR.html http://www.memorylossonline.com/glossary/neurotransmitter.html

23. Information taken from the following websites: http://faculty.washington.edu/chudler/neurok.html www.armagen.com/about-bbb.php http://en.wikipedia.org/wiki/Blood-brain_barrier http://users.ahsc.arizona.edu/davis/bbb.htm http://www.nida.nih.gov/index.html http://teens.drugabuse.gov/facts/index.asp