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

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

Drug BasicsAlcohol

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 BasicsAlcohol

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 BasicsCaffeine

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 BasicsCaffeine

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 BasicsEnactogens

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 BasicsEnactogens

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 BasicsHallucinogens

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 BasicsHallucinogens

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 BasicsInhalants

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 BasicsInhalants

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 BasicsMarijuana

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 judegement; overdose is virtually impossible

Drug BasicsMarijuana

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 BasicsNicotine

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 BasicsNicotine

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 BasicsOpiates

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 BasicsOpiates

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 BasicsSteroids

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 BasicsSteroids

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 BasicsStimulantsDrug 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 BasicsStimulants

Getting In: Ingestion; inhalation; absorption by mucus membranes

Getting Out: Liver breaks down drugs (cocaine/crack~1-2 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 BasicsReference

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.