Transcript Your Brain on Drugs?!

Your Brain on Drugs?!
Drug Basics
•A drug is any chemical put into the
body that changes mental state or bodily
function.
•How a drug is taken can make a huge a
difference in its effect.
•The length of time a drug effects the
CNS can vary tremendously.
•The effects of drugs can change with
time, as our bodies adapt to the drug.
This is called tolerance.
Drug Basics
Drug
Basics
Drugs work by binding to receptors on
the surface of cells.
•Drugs that activate receptors when
bound are called agonists.
•Drugs that deactivate
receptors when bound
are called antagonists.
Drug Basics
Drug
Basics
How do drugs get into the body?
•Cutaneous absorption
•Mucus membranes
•Ingestion
•Inhalation
•Injection
Drug Basics
Drug
Basics
Where do drugs go in the body?
•Once in circulation, drugs go to all
tissues easily.
•Only psychoactive drugs can effect the
brain.
•Drugs that are not removed from the
body are stored in fat tissue.
•The liver is the organ that breaks down
drugs for removal from the body.
Drug Basics
Drug
Basics
Pathways to drug tolerance:
•Increased enzyme production by
liver (alcohol)
•Removal of receptors to balance
stimulation (nasal decongestants)
•Body preemptively counteracts
drug by unconscious expectation
(heroin)
Drug Basics
Drug
Basics
Addiction vs. Dependence
•Addiction is the repetitive, compulsive
use of a substance despite negative
consequences to the user. (AKA
Psychological Dependence; Dopamine)
•Physical dependence results from a
change in cell function such that organs
cannot function without the drug. (ex:
seizures during alcohol withdrawl)
Drug
Basics
Alcohol
Drug Class:
Sedative hypnotic
Individual Drugs:
beer, wine, liquor
The Buzz: Pleasure and
relaxation during
first ~30min,
followed by
sedation
The BuzzKill: Alcohol poisoning; chronic abuse can lead to
psoriasis of the liver, stomach ulcers, increased risk of heart
disease and cancer, brain shrinkage (decrease in memory,
problem solving, concentration); diuretic (hangover)
Drug
Basics
Alcohol
Getting In: Absorbed by blood vessels in stomach and
small intestines (greater alcohol content=faster
absorption)
Getting Out: Primarily metabolized by liver (alcohol
dehydrogenase); products are excreted in urine;
intermediate product, acetaldehyde, causes nausea
Brain Effects: Activates GABA
receptors (inhibitory); deactivates
glutamate receptors (excitatory);
Increases release of dopamine
(addictive)
Drug
Basics
Caffeine
Drug Class:
Stimulant
Individual Drugs:
coffee, soft drinks
The Buzz: Low-moderate
doses=increased alertness
and ability to concentrate;
high doses=nervousness,
agitation
The BuzzKill: diuretic; caffeine poisoning (tremors,
nausea, rapid heart rate, confusion; fatal overdose is
rare)
Drug
Basics
Caffeine
Getting In: Absorbed by blood vessels in stomach and
(primarily) small intestines
Getting Out: Metabolized by liver; products are excreted
in urine
Brain Effects: Inhibits adenosine (inhibitory)
Effects on Other Organs:
Irregular heart beat; raise
cholesterol (unfiltered coffee);
activate kidneys; irritate
stomach; increase breathing
rate, relax bronchioles
Drug Basics
Enactogens
Drug Class:
Enactogen
Individual Drugs:
ecstasy
The Buzz: Produce a
sense of energy and
alertness like
amphetamines; experience good feelings for all those
around them and strong empathy
The BuzzKill: Jitteriness and teeth-clinching; increased heart
rate, blood pressure, and body temperature can lead to
death when combined with physical activity or stimulants;
chronic abuse damages neurons
Drug Basics
Enactogens
Getting In: Absorbed by blood vessels in gastrointestinal
tract; usually taken orally
Getting Out: Metabolized by liver
in 3-6 hours
Brain Effects: Floods synapses
with dopamine (addicitive),
norepinephrine (excitatory),
serotonin (hallucination); chronic
use leads to irreparable
brain damage
Drug Basics
Hallucinogens
Drug Class: Hallucinogens
Individual Drugs: LSD, mushrooms (psilocybin),
peyote (mescaline), PCP (phencyclidine), Special K
(ketamine)
The Buzz: Indivdual experience vary widely; low
doses=feelings of detachment from surroundings,
mood swings, altered sense of space and time; high
doses=hallucinations, out of body experience
The BuzzKill: LSD, mushrooms, and peyote=bad trip
can produce extreme anxiety, lack of awareness of
surroundings can lead to injury or death; PCP and
Special K=death by overdose
Drug Basics
Hallucinogens
Getting In: Absorbed by blood vessels in gastrointestinal
tract; usually taken orally; inhalation
Getting Out: Liver breaks down drugs; could take 1 hour
to several hours, depending on the drug
Brain Effects: All=floods
synapses with serotonin
(hallucination); PCP and
Special K=blocks
glutamate receptors
(excitatory); PCP also
has amphetamine
effects
Drug
Basics
Inhalants
Drug Class: mixed
Individual Drugs: nitrites,
whippets (nitrous oxide),
paints, fuels
The Buzz: mild euphoria; smooth muscle relaxation;
reduction of pain; hallucinations (solvents)
The BuzzKill: muscular incoordination; nausea,
vomiting; heart palpations; loss of consciousness;
suppression of breathing; death-for real!
Drug
Basics
Inhalants
Getting In: Inhalation: absorbed by capillaries in
the lungs
Getting Out: Liver breaks down some drugs;
others are inert and lose their effect shortly after
exhalation
Brain Effects: Details about brain effects are
unknown; inhibit ability of nerves to conduct
impulses; neurotransmitter, GABA, involved
Drug
Basics
Marijuana
Drug Class: marijuana
Individual Drugs: marijuana, hash
The Buzz: experiences vary: relaxation, mood
elevation, hillarity,
contemplative silence,
sedation
The BuzzKill: anxiety; increase
heart rate; impair judgement;
overdose is virtually impossible
Drug
Basics
Marijuana
Getting In: Inhalation: absorbed by capillaries in
the lungs; ingestion
Getting Out: Liver breaks down THC slowly; THC
stored in fat tissue for weeks, metabolic products
are also mildly psychoactive
Brain Effects: THC binds to cannabinoid
receptors in hippocampus (anandamine); leads
to deficits in memory formation
Effects on Other Organs: depress immune
system; anti-nausea/appetite stimulant;
decreased lung capacity; reproductive effects
Drug
Basics
Nicotine
Drug Class: stimulant
Individual Drugs: tobacco
The Buzz: increases
attention and concentration;
calming effect
The BuzzKill: dizziness;
weakness; nausea; chronic
use is implicated in increased
incidence of depression
overdose is rare
Drug
Basics
Nicotine
Getting In: Inhalation; absorption in mucus
membranes
Getting Out: Liver breaks down nicotine into
cotinine and nicotine-N-oxide, which are
excereted in the urine after ~30 min
Brain Effects: Excites neurons; increases cell-cell
signaling; acetylcholine agonist (memory)
Effects on Other Organs: strongly associated
with lung disease, atherosclerosis, heart attack
Drug
Basics
Opiates
Drug Class: opiate analgesic
Individual Drugs: opium, heroin, morphine,
codeine, hydrocodone
The Buzz: rush of euphoria;
dreamy, pleasant state; little
sensitivity to pain
The BuzzKill: constipation;
post-high crash; risk of lethal
overdose is real;
Drug
Basics
Opiates
Getting In: Inhalation; ingestion; absorption in
mucus membranes; intravenous injection
Getting Out: Liver breaks down opiate in ~2-6
hours; opiate antagonist naxolone
Brain Effects: Opiates bind to
endorphin-receptors, which
would not naturally be so
stimulated; building tolerance
is common
Effects on Other Organs:
negatively effects reproductive
system
Drug
Basics
Steroids
Drug Class: anabolic steroids
Individual Drugs: testosterone
The Buzz: rush of euphoria
(hours after taking);
increased energy and
combativeness
The BuzzKill: chronic use
can lead to heart attack,
stroke
Drug
Basics
Steroids
Getting In: Ingestion;
intravenous injection
Getting Out: Liver
breaks down steroids
Brain Effects: Significant
brain effects are
unknown
Effects on Other Organs:
leads to increased muscle mass; general increase in
male traits; shrunken testicles
Drug
Basics
Stimulants
Drug Class: stimulants
Individual Drugs:
cocaine, crack,
methamphetamine,
Ritalin, ephedrine,
bath salts
The Buzz: rush of
energy; alertness;
talkativeness; general
sense of well-being
The BuzzKill: increased heart rate, blood pressure,
breathing rate; seizures; cardiac arrest; lethal
overdose
Drug
Basics
Stimulants
Getting In: Ingestion; inhalation; absorption by mucus
membranes
Getting Out: Liver breaks down drugs (cocaine/crack~12 hrs; Meth/ephedrine~2-4 hrs)
Brain Effects: Inhibit reuptake of monoamine
neurotransimtters (users feel compelled to engage in
repetitve activity); increase epinephrine/norepinephrine
(fight or flight); release of dopamine (addictive); release
serotonin (decrease appetite, release hormones, raise
body temperature)
Effects on Other Organs: Cocaine is used as a local
anesthetic. All produce fight-or-flight response
Drug
Basics
Reference
Kuhn, Swartzwelder, and Wilson. Buzzed: The
Straight Facts about the Most Used and Abused
Drugs, from Alcohol to Ecstacy. New York: W.W.
Norton & Company, Inc., 1998.