Drugs of Abuse 1: for nonscience majors

1. Drugs of Abuse

2. Objectives:
• Be able to define the
following terms:
▫ Pharmacology
▫ Drug
▫ Stimulant
▫ Depressant
▫ Hallucinogen
• Drugs of abuse:
▫ Pharmacology
▫ Physiological effects
▫ Toxicity

3. Important definitions:
• Pharmacology:
▫ The scientific study of the effect of drugs on biological
system
• Drug:
▫ Any chemical substance, other than food, that alters the
mental state or biological function of living organisms
▫ Medically, a drug is any chemical substance used in the
treatment, cure, prevention, or diagnosis of disease.

4. Types of Drugs
• Stimulants:
▫ Substances that stimulate or speed up the functions of
the nervous system
 Enhances alertness, wakefulness, and locomotion
• Depressants:
▫ Substances that depress or decrease the functions of the
nervous system
 Enhances relaxation and calmness
• Hallucinogens:
▫ Substances that cause changes in perception, thought,
emotion, and consciousness

5. How Drugs Affect the Body
• The effect produced by a drug is an alteration of
a natural physiological function or process.
• Drugs bind to a target to either activate, partially
activate, or inactivate it.
• Most common drug targets include
▫ Transporters
▫ Ion Channels
▫ Receptors
▫ Enzymes

6. How Drugs Affect the Body
• Most common drug targets include
Enzyme: Biological molecule that cause a specific biochemical reaction

7. Drug Actions at the Synapse

8. Drugs of Abuse
http://learn.genetics.utah.edu/content/addiction/mouse/

9. Drugs of Abuse
• Heroin
• Alcohol
• Cocaine
• Methamphetamine
• Ecstasy (MDMA)
• LSD
• Marijuana
• Nicotine
• Caffeine

10. Heroin
• Synthetic opioid drug that is highly addictive. It is processed from
morphine, a naturally occurring substance in poppy plants

11. Heroin Pharmacology
• Main site of action:
▫ Opiate receptors in the
 Brain and spinal cord
 Thalamus
 Hypothalamus
 Nucleus accumbens
 Medulla
 Sensory nerves in
peripheral nervous
system (PNS)
• Decreases the release of
neurotransmitters into
the synaptic cleft

12. Heroin Pharmacology
• Binds to opiate receptors in
▫ Reward/pleasure centers of the brain (image above) to induce eupohoria
▫ Brain, spinal cord, and periphery to reduce pain sensation

13. Heroin Pharmacology
• Binds to opiate receptors in:
▫ Reward/pleasure areas of the
brain to induce euphoria
▫ Brain, spinal cord, and
periphery to reduce pain
sensation

14. Physiological Effects of Heroin
• Effects last 3-5 hrs
▫ Pain relief
▫ Suppressed cough
▫ Constipation
▫ Drowsiness & confusion
▫ Impaired coordination
▫ Reduced heart rate,
blood pressure, and
breathing
▫ Constricted pupils
(“pinpoint pupils”)
▫ Euphoria & pleasure
▫ Hypothermia

15. Toxicity of Heroin
 Acute Toxicity
 Heroin depress the medulla, leading to decreased
heart/breathing rates
 Toxic effects are additive in the presence of alcohol or
other depressants
 Physical symptoms of heroin overdose: slow heart rate
and breathing, blue lips and nails, seizures, muscle
spasms, coma, death

16. Alcohol
• One of the oldest recreational drugs still used by humans

17. Alcohol
• Metabolism of Alcohol
▫ Absorption into the bloodstream
 Primarily in small intestines
 Some in stomach
▫ Metabolized (degraded) by the liver
▫ Excreted
 Urine
 Breath (5% excreted in breath)
 Sweat (“drunk smell”)

18. Alcohol Pharmacology
• CNS depressant
• Affects various neurotransmitter systems
▫ GABA, glutamate, dopamine, opioid
▫ Know for exam: Enhances the inhibitory effects of
GABA on its receptor (GABAA Receptor)

19. Physiological Effects of Alcohol
• Frontal Lobe: Judgement &
reasoning altered
• Midbrain: Pleasure, loss of
emotional control
• Cerebellum: Loss of
coordination & balance
• Pons, Medulla: respiration &
heart rate reduced
• Hippocampus: alters long term
memory formation

20. Alcohol Toxicity
• Symptoms of Alcohol Poisoning
▫ Can’t communicate
▫ Irregular/slow heart rate
▫ Hypothermia (low body temp)
▫ Respiratory depression (slowed breathing)
▫ Coma
▫ Death
• Dangerous in combination with other drugs
▫ Especially with other depressants

21. Cocaine
• Crystalline alkaloid obtained from the coca plant
▫ Not to be confused with the cocoa (chocolate) plant

22. Cocaine Pharmacology
• Main site of action:
▫ Monoamine reuptake
transporters
 Inhibits transporter function
 Monoamines:
 Dopamine
 Seratonin
 Norepinephrine
• Increases the concentration of
monoamines in the synaptic
cleft

23. Cocaine Pharmacology
• Cocaine inhibits the actions of monoamine reuptake transporters
▫ Increases the time that monoamines can bind their receptors

24. Physiological Effects of Cocaine
• Effects last 1-2 hrs
▫ Increased energy & motor activity
▫ Increased heart rate & blood pressure
▫ Euphoria
▫ Decreased appetite
▫ Mental alertness
▫ Increased body temp
▫ Dilated (large) pupils

25. Cocaine Toxicity
• Heavy use can cause:
▫ Rapid heart beat
▫ Hallucinations
▫ Paranoid delusions
▫ Tremors and convulsions
▫ Respiratory failure
▫ Heart attack or heart failure
▫ Stroke

26. Methamphetamine
• Synthetic (man-made), crystal-like, addictive stimulant
produced from pseudoephedrine or ephedrine found in cold
medicines

27. Methamphetamine Pharmacology
• Mechanisms of Action
▫ Inhibits the
monoamine reuptake
transporters (1)
▫ Induces release of
monoamines into the
synapse (2)
▫ Binds MAO & blocks
degradation of
monoamines (3)
▫ Causes the
monoamine reuptake
transporters to act in
reverse (4)

28. Methamphetamine Pharmacology
• Medicinal uses of amphetamines
▫ Treat narcolepsy & ADHD

29. Physiological Effects of Methamphetamine
• Effects last 8-12 hrs
▫ Effects similar to cocaine use
▫ Irritability and aggression
▫ Anxiety and/or paranoia/nervousness
▫ Increased wakefulness
▫ Tremors/convulsions
▫ Decreased appetite
▫ Insomnia
▫ High blood pressure & increased heart rate

30. Methamphetamine Toxicity
• Neurotoxic (induces neuron cell death)
▫ Serotonergic neurons
▫ Dopaminergic neurons
• Permanent psychosis (paranoia, hallucinations
or repetitive motor activity)
• Hyperthermia (high body temp)
• Kidney failure
• Coma
• Stroke
• Heart attack

32. Review
• What is the definition of each of the following terms:
• Pharmacology
• Drug
• Stimulant
• Depressant
• Hallucinogen
• Drugs of abuse: Heroin, alcohol, cocaine, and methamphetamine
▫ Know the drug target(s) for each
▫ Know the regions of the brain (if discussed) that each drug acts to elicit its
effects
▫ Know the physiological effects of the drugs

33. Questions