Transcript Addiction, Drugs, and the Endocrine System

Drugs and the Nervous System
1. Why study drugs?
combat…drug abuse
combat…anxiety, sleeplessness, depression, schizophrenia
2. “Good Drugs” versus “Bad Drugs”?
motivation…appropriate or not? Abuse?
help us understand mechanisms of the brain and how it works
on a physiological level
Sources of drugs
1. Plant
Tobacco (nicotine)
Coffee (caffeine)
Poppy (opiates)
Coca (cocaine)
Cannibis (marajuana)
2. Fungus
LSD
3. Specialized Labs
Produced in labs
Methamphetamine (crystal ice)
Ecstacy
Many pharmaceutical drugs
Many are “designer” drugs
The chemistry of drugs
Effect neurotransmitters such as:
acetylcholine: learning and memory, muscle contractions
norepinephrine: energy, (+) emotion, sympathetic pathway
serotonin: biological rhythms, sleep, emotion, mood, pain
dopamine: desire and pleasure
TERMS:
Agonist: mimics or increases the effect of the neurotransmitter
Antagonist: blocks or takes away from the effects of a neurotransmitter
Affinity: ability of a drug to bind to a receptor
Efficacy: degree to which a drug activates the receptor, once bound
Mixed Agonist / Antagonist: depends on dose or amount
effectiveness and side effects vary from one person to
another…the receptors are controlled by genes of the individual.
“Pleasure
chemical”
• Neurotransmitter and hormone
• Released by hypothalamus
• Pleasure center for the brain
• Services sympathetic responses
• Excess dopamine can lead to psychosis (schizophrenia)
• Reinforces, motivates, and increases arousal and desire
• Food, sex, drugs, (addiction)
In midbrain (substantia nigra): controlled muscle movements (Parkinsons)
In frontal lobe: attention, creativity, problem solving. (ADD)
• Neurotransmitter. Receptors found along the brainstem (pons)
• Regulates anger, aggression, mood, sleep, appetite, temp. regulation
• Imbalance can lead to emotional disorders such as
• depression, suicide, impulsive behaviors, aggression
To treat depression:
• block the re-uptake of serotonin
• more serotonin floating around in the synapse…better mood!!
* May lead to SIDS: low levels in the brainstem…breathing, heart rate, blood pressure
• Neurotransmitter and hormone
• Sympathetic pathway chemical
• arousal, excitement, increase heart rate, blood pressure
• Adrenaline (“fight or flight”)
• Neurotransmitter.
• Acts in the somatic nervous system to help with muscle contraction
• it is broken down by an enzyme naturally in the body. People with
Myasthenia Gravis have muscle weakness and fatigue. The enzyme can
be blocked with medication, allowing acetylcholine to work longer,
consequently increasing muscle strength.
• Acts in the autonomic nervous system to help with learning and memory.
• found in short amounts in Alzheimer's patients.
• agonists are used to help treat
(gamma-amino butyric acid)
• Amino acid that functions as a neurotransmitter.
• Inhibits neural activity…slows things down.
• With glutamate (metabolism), it is more widely present that all other chemicals
combined. * Found in 90% of all synapses!!
• Because it’s so widely present, it’s the reason why there are so many side effects
to drugs.
• Amino acid that functions as a neurotransmitter.
• Major excitatory neurotransmitter in the brain…involved in brain plasticity, such as
learning and memory
• Plays a central role in metabolism
• With GABA, it is more widely present that all other chemicals combined. * Found
in 90% of all synapses!!
• Because it’s so widely present, it’s the reason why there are so many side effects
to drugs.
• Effects “neural plasticity”…strengthen the connection between neurons (memory)
• Neural plasticity leads to addiction….why?
Electrical stimulation
Nucleus accumbens: rich in dopamine receptors.
Amygdala: emotion
Hippocampus: memory
VTA: pleasure
Locus Coeruleus: addiction motivation (increase
adrenaline secretion)
Substantia nigra: movement
More specifically, drugs can:
Stop the chemical reactions that create neurotransmitters.
Empty neurotransmitters from the vesicles where they're
normally stored and protected from breakdown by enzymes.
Block neurotransmitters from entering or leaving vesicles.
Bind to receptors in place of neurotransmitters.
Prevent neurotransmitters from returning to their sending
neuron (the reuptake system).
Interfere with second messengers, the chemical and electrical
changes that take place in a receiving neuron
Stimulants
Increase the activity of the CNS.
Mimic the stimulation of the Sympathetic NS
Increase behavioral arousal
Increase activity at dopamine receptors
Cocaine
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Crack
Cocaine (Charlie, Snow, Coke) comes in the form of a white powder made from coca shrub that
can be eaten, smoked, sniffed or injected
Crack (Rock, Stone and Wash) is derived from cocaine hydrochloride, it too is white but in the
form of crystals or rocks the size of raisins that are smoked.
Increase the release of norepinephrine…energy, mood, and (+) emotion
Bind to the transporters usually reserved for dopamine and norepinephrine. This causes
increased levels of these neurotransmitters in the synapses.
Effects
feeling of invincibility, strength, and confidence due to a powerful buzz.
intense talking and feelings of well being
high last about 10-15 minutes, disappearing after 1 hour…consequently repeated
doses are needed to stay “high”…constant need for more (expensive to maintain)
Anxiety, restlessness, weight loss, feelings of persecution, tiredness, hunger,
sickness, depression
Dopamine re-uptake system
Dopamine is reabsorbed by membrane transporters.
dopamine
Neuron
This frees up the synapse for more normal everyday
functioning of the nervous system, such as muscle
movement and metabolism.
Membrane transporters
Dopamine is re-absorbed into the
cell
Mechanism of cocaine
cocaine
Neuron
Membrane Transporters
dopamine
Cocaine is blocking the re-uptake of dopamine.
Therefore, dopamine remains in the synapse and
over-stimulates.
dopamine
Ecstasy
Common names:
“E”, Esky, Snowballs, Doves, New Yorkers,
Burgers, soap, love-drug.
Active chemical: MDMA (methylenedioxy methanptanine)
Ecstasy is a pill taken orally, but can be snorted, and rarely injected
Takes effect after 30 minutes and can last for several hours…considered a “hallucinogenic stimulant”
Originally used as anger management and marriage counseling medication!
Effects:
Tingling body feeling and overall feeling of joy and ecstasy…can be accompanied by hallucinations
Urge to dance and overly affectionate with people
Aches, pains, dizziness, panic attacks, depression, paranoia, insomnia, dehydration and heat stroke.
Respiratory problems and seizures
Linked to deaths in young people….also ,regular use can lead to depleted serotonin which can lead
to chronic depression (serotonin = mood)
Mechanism of Ecstasy
Serotonin is contained in vesicles in the cell.
Ecstasy mimics serotonin is easily absorbed by the
transporters.
Serotonin
Neuron
It then confuses the cell and causes it to push
serotonin OUT of the cell.
Serotonin is now in excess in the synapse and overstimulates the cell.
Membrane transporters
Ecstasy
Amphetamines
Common names: Adderoll
Bennies, Black beauties, Dexies, Jollies,
Speed, Uppers, Ups, Wake ups.
The drug comes in the form of colored or off-white powder and is packaged in a 'wrap' made from an
envelope of folded paper. It can be taken by snorting or, swallowing, drunk e.g. with juice or by
injecting.
Effects:
Person feels more confident, talkative and cheerful…elevated mood
Used to stay awake, energy, focus, enhanced motivation (dance stimulant)
Need to eat or sleep is diminished
Causes excessive release of nor epinephrine from storage sites in PNS, and causes an increase in
dopamine release. Mimic the effects of norepinephrine…increase mood and + emotion
Methamphetamine (Ice)
• Use as alternative to cocaine. Found as a crystalline salt and a has appearance of sheet-like
crystal. Similar effect as cocaine, but last for hours. 90% of users become addicted!!
• Inhibits the re-uptake of dopamine and epinephrine, therefore increasing the time those
chemicals spend in the system.
Nicotine
Consumed in the form of cigarettes, cigars, pipes,
chewing, or sniffed in the form of snuff.
Approximately 30% of people aged 16 or over regularly smoke. Most Tobacco is smoked in the form of
cigarettes
Cigarette smoke contains various substances such as nicotine, tar, carbon monoxide and other gases.
Some of these substances are absorbed by the lungs. Nicotine is the active addictive of cigarette smoking
as it builds up in the body. The effects decline soon after stopping. As a consequence the user may be left
wanting more after only a short time
Effects:
Heart disease, Lung cancer, Heart attack, Emphysema
Highly addictive
Withdrawal symptoms include irritability, restlessness, depression
Increased risk of miscarriage or fetal defect if pregnant mother smokes
Attaches to nicotinic receptors and increases dopamine release in nucleus
accumbens.
Anabolic Steroids
Pharmaceutical examples: Durabolin, Stanozol, Dianabol
Derived from hormones which occur naturally in the human body and are responsible for the
development and function of the reproductive organs. Most synthetic anabolic steroids on the
market are derived from human testosterone, however some are intended for use on animals and
should not be used on humans.
Effects:
Users report that steroids help them recover more easily from strenuous exercise. It has also
controversially been claimed that steroids enhance athletic performance
Aggression
Shunted growth in young people
Increased blood pressure
Abnormalities in body development
Caffeine
Found in coffee, tea, chocolate, sports drinks, coke
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The action of caffeine is to block the neurotransmitter adenosine (caffeine acts as an antagonist)
Antagonism of adenosine receptors by caffeine would appear to promote neurotransmitter
release of epinephrine, thus explaining the stimulatory effects of caffeine
Effects:
Constricts blood vessels in brain
abstention results in headache and
restlessness due to increased
blood flow
Long term effects or damage are inconclusive
Depressants
• Suppresses the activity of the central
nervous system
• Activates the neurotransmitter GABA
which is responsible for calming the CNS
and promoting sleep
• dangerous because it slows breathing,
heart rate and other vital functions.
Heroin
Common names: “H”, Smack, Junk, Gear, Brown,
Lady, white girl, horse, black tar, brown sugar,
goods, Harry
Opiate family: Morphine, Oxycontin, Vicodan, Percocet, Codeine
Methadone, Demerol, Fentanyl
• Can be sniffed, smoked (chasing the dragon), or the powder can be
dissolved in water and injected.
• Injection is most effective and quickest (few seconds) high, but also most
dangerous overdose potential. Also, risk of disease (HIV/Hepatitis) and
infection is high.
• Heroin depresses the brain activity including reflexes like coughing,
breathing, and heart rate (overdose can lead to cessation of vital reflexes =
death.
Effects of Heroin
Stimulate the release of natural endorphins in the brain
Heroin also blocks the release of Substance P from the brain stem and spinal cord.
Substance P is responsible for transmitting pain signals.
Inhibits the release of neurotransmitter GABA, which limits dopamine release.
Since GABA can no longer regulate it, dopamine is released in huge quantities.
It takes a long time for the body to replenish the dopamine, so the “high” is
replaced by a tremendous “low” due to depleted dopamine levels.
Over time, an addict can damage dopamine releasing cells, causing extreme lows
and chronic depression.
• slowed and slurred speech, slow gait, constricted pupils, droopy eyelids,
impaired night vision,
• warm flushing of the skin, a dry mouth, and heavy extremities sweating, Regular
use tends to lead to poor health due to bad diet and chaotic lifestyle. Women user's
menstrual cycle may be disrupted
• drug craving, restlessness, muscle and bone pain, insomnia, diarrhea and
vomiting, cold flashes with goose bumps ("cold turkey"), kicking movements, jitters,
cramps, constipation, collapsed blood vessels.
• Brain disintegration in chronic users
Dopamine Inhibitors
Dopmaine
Neuron
Dopamine inhibitors attach to receptors
and block dopamine release.
This allows the cell to function normally.
Dopamine inhibitors
(GABA)
Neuron
Mechanism of Heroin
Heroin blocks the inhibitors
Dopmaine
Neuron
Inhibitors cannot get out and
inhibit dopamine release
Dopamine is now free to flow into the
synapse.
Dopamine inhibitors
Heroin
http://www.thirteen.org/closetohome/science/html/animations.html
Barbiturate
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Barbiturates (Barbs, Downers, Quaaludes) calm people down and in higher doses act
as sleeping pills.
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binds to receptors in medulla…interfere with breathing. Heart-rate. Overdose= death.
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They come in a wide variety of different colored tablets and capsules of various
shapes and sizes, bearing various trade names and markings. They are usually taken
orally, but may be injected. Only prescribed for treating severe insomnia.
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A small dose makes the user feel relaxed and a larger dose puts the user to sleep.
The effects are exaggerated by taking alcohol and results in intoxication
Categories: Anti-anxiety. Anti-depressant, Tranquilizers, (reduces emotional tension)
Xanax, Ativan, Valium, Prozac, Paxil, Zoloft
Inhibit the re-uptake of serotonin (sleep, mood, emotion) so the chemical is more readily
available at the synapse
Alcohol
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Alcoholic drinks consist of ethyl or ethanol alcohol and water. Alcohol is produced by the
fermentation of grains or vegetables. Beer contains about 1 part alcohol to 20 parts water, wine is
2-4 times as strong as beer and spirits are even stronger.
Beer and wine drinking almost certainly predate recorded history and are an integral part of
everyday life
Alcohol is absorbed into the bloodstream and starts to take effect within five to ten minutes.
Effects GABA (inhibitory) and GLUTAMATE (excitatory) neurotransmitters.
Activates the dopamine driven “pleasure pathway”.
De-activates connections to the frontal lobe…causes disinhibition.
alcohol affects the pituitary gland that controls the flow of water released by the body as
urine…results in dehydration and leads to a hangover
Alcohol is packed with calories one gin and tonic contains the same amount as a bowl of ice
cream so consistent use can lead to noticeable weight gain.
gastric and liver damage
$116 billion industry in the USA ($3 billion in marketing alone!!)
Average consumption is 20 gallons per year
GABA is the body’s primary inhibitory
neurotransmitter
It prevents a neuron from firing by clogging up
the transporters.
GABA
ALCOHOL helps GABA with it’s inhibitory effects
Therefore further preventing a neuron from
firing.
Neuron
Alcohol
That’s why it is a depressant.
GLUTAMATE is the body’s primary excitatory
neurotransmitter.
It causes a neuron to fire.
ALCOHOL prevents glutamate from exciting the
cell, and consequently has sedative effects.
It causes a neuron NOT to fire…and another
reason why alcohol is a depressant!
Alcohol
Hallucinogens
• Distort perception
• Crossing over…”hearing” colors and
“seeing” sounds.
• Alters conscious, and causes psychosis
(lose contact with reality)
• One of the oldest drugs used by man.
Cannabis
Common Names: marijuana, dope, grass, blow, puff, hash, ganja, Buddha,
wacky tobacky, chronic, Mary Jane, skunk
Active ingredient: THC tetrahydrocannabinol
Cannabinoid receptors in brain areas that influence pleasure, memory, thought, concentration,
sensory and time perception, and coordinated movement
THC attaches to cannabinoids receptors in the hippocampus and consequently disrupts memory,
motivation, mood, and learning. It also interferes with the limbic system…causes emotional
changes ranging from uncontrollable laughter to paranoia.
Considered a hallucinogenic stimulant and also has sedative effects.
Users may feel more talkative, more relaxed, experience a sense of well being and
being ‘stoned’ (heightened perception) often mentally distancing them from their
surroundings. Mild hallucinations and strong feelings of affection may occur. Skunk
is a new strain of Cannabis that is extremely potent causing very strong
hallucinogenic experiences
paranoia, panic attacks, mood swings, sleeping problems, short term memory loss
and reduced concentration
No receptors in the brainstem – no effect on heartbeat
“Gateway” drug
LSD
Chemical name: Lysergic Acid Diethylamide
Common name: Acid, Trips, Tabs, Blotter, Doses
Most common psychedelic drug.
Derived from a fungus infecting rye
Often LSD is added to absorbent paper, such as blotter paper, and divided into small, decorated
squares, with each square representing one dose
Used during the Cold War as “truth serum” during CIA interrogations
Beatles song “Lucy in the Sky with Diamonds”
Mimics serotonin because LSD resembles serotonin in chemical structure
users experience severe, terrifying thoughts and feelings, fear of losing control, fear of insanity and
death, and despair while using LSD. Some fatal accidents have occurred during states of LSD
intoxication.
Sensations may seem to "cross over," giving the user the feeling of hearing colors and seeing
sounds. These changes can be frightening and can cause panic.
Highs can last as long as 12 hours…addiction to LSD does not occur.
User may have “flashbacks” and “bad trips” where depression, schizophrenia, and psychosis have
been recorded
Mushrooms
Common names: shrooms, magic mushrooms, mushies
Chemical name: Psilocybe Semilanceata (Psilocybin)
Look like dried mushrooms and are usually eaten. Can be brewed and consumed as
tea and sometimes cooked.
Agonists to neurotransmitters GABA and glutamic acid and effect hippocampus,
cerebral cortex, and cerebellum
Effects:
Nausea is a common effect. Causes distorted perceptions of touch, sight, sound and taste.
Other effects can include nervousness and paranoia. Effects can be different during each use
due to varying potency, the amount ingested, and the user's expectations, mood, surroundings,
and frame of mind.
On some trips, users experience sensations that are enjoyable. Others can include terrifying
thoughts, and anxiety, fears of insanity, death, or losing control.
Poisoning can result in vomiting, diarrhea, stomach cramps, loss of consciousness and
convulsions and death
PCP
Chemical name: Phencyclidine
Common Name: angel dust, ozone, wack, rocket fuel
Act by altering distribution of the neurotransmitter glutamate throughout the brain.
Glutamate is involved in a person's perception of pain, responses to the environment,
and memory.
Effects:
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
Intoxicated individuals may act in an unpredictable fashion, driven by their delusions
or hallucinations. Included in the portfolio of behavioral disturbances are acts of selfinjury including suicide, and attacks on others or destruction of property
Summary
Stimulants:
Depressants:
Hallucinogens
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1. Pineal Body: Melatonin – patterns of wake and sleep
2. Pituitary: “Master gland. Stimulates other glands
Oxytocin: uterine contractions during labor, birth, breastfeeding
Prolactin: stimulates milk production after birth in females
Vasopressin: water retention, constrict blood vessels
3. Thyroid: Controlled by pituitary and hypothalamus. Determines how quickly
energy is burned by body
Thyroxin: controls rate of metabolism
4. Thymus: Immune system stimulant
5. Adrenal: Sympathetic response
Adrenaline (epinephrine):stimulates fight or flight
6. Pancreas: aids in digestion of food
Pancreatic juice contains many digestive enzymes
7. Ovaries: female reprodcutive organ
Estrogen: sex characteristics, regulates menstration
Progesterone: maintains uterus during pregnancy
8. Testes: Male reproductive organ
testosterone: male sex characteristics & produce sperm
5 signs of dependence
1. Time thinking about it
2. Doing more each time
3. Desire to stop
4. Withdrawal symptoms
5. Tolerance