THE PHARMACOLOGY AND PHYSIOLOGY OF DRUGSGoldberg Chapter 5SOC 204 Drugs & Society

Attendance: How is your brain?A. Ready to goB. Still on weekend

modeC. Why do you ask?

Ready to

go

Still o

n weeke

nd mode

Why d

o you ask?

28%

11%

61%

Pharmacology

• Different drugs produce different effects within the psyche and soma

• The interaction between drugs and living organisms is called pharmacology

• Drug pharmacology relates to the way it is administered, absorbed, distributed, metabolized, and excreted

• Drugs that act quickly and produce intense effects are more likely to be abused than are drugs that act slowly

Drug Actions

• Drugs affect various organs, including the nervous system.

• The nervous system consists of the central nervous system (CNS), the autonomic nervous system (ANS), and the peripheral nervous system (PNS)

• The CNS consists of the brain and spinal cord, and is composed of nerve cells (neurons)

• Information is transmitted electrically within the neuron, and chemically between neurons

Nervous System

• Homeostasis• Neurons• Glial Cells

You have approximately 100 billion neurons and 100 trillion synapses in your brain. How long would it take to count to a trillion?

A. All dayB. A monthC. A trillion secondsD. 32,000 years All d

ay

A month

A trilli

on seco

nds

32,000 years

6%

33%

17%

44%

Nervous System

• Somatic Nervous System• Sensory Information

• Autonomic Nervous System• Sympathetic Branch –

Fight/Flight/Freeze• Parasympathetic Branch –

regulate body functions

• Central Nervous System• Brain & Spinal Cord

The Brain

Action Potential

https://www.youtube.com/watch?v=HnKMB11ih2o

Synaptic Gap

https://www.youtube.com/watch?v=XGINQ7xhPkM

Your neurotransmitter

• What it does• What happens if you have too much?• What happens if you have too little?

Chemical Pathways

1. Dopamine (excitatory)• Found in basal ganglia and

other regions – behavior & emotions, including pleasure

• Nigrostriatal dopamine pathway• Related to muscle rigidity

• Mesolimbic dopamine pathway• Related to psychotic behavior• Possible component of the

“reward” properties of drugs

Chemical Pathways

2. Acetylcholine (excitatory)• Found in the cerebral cortex & basal ganglia• Involved in Alzheimer’s disease, learning, memory

storage, movement3. Norepinephrine (excitatory & inhibitory)• Regulates level of arousal and attentiveness, memory• May play a role in initiation of food intake (appetite)

Chemical Pathways

4. Serotonin (inhibitory or excitatory)• Found in the brain stem raphe nuclei• May have a role in impulsivity, aggression, depression,

control of food, and alcohol intake• Hallucinogenic drugs influence serotonin pathways5. GABA (Gamma-amino butyric acid) (inhibitory)• Found in most regions of the brain• Inhibitory neurotransmitter, sleep, anxiety

Chemical Pathways

6. Glutamate (excitatory)• Found in most regions of the brain• Excitatory neurotransmitter, involved in long-term

memory7. Endorphins (inhibitory)• Opioid-like chemical occurring naturally in the brain• Play a role in pain relief

People who engage in strenuous exercise actually emit a neurotransmitter that contributes to a “high” feeling.

A. TrueB. False

TrueFa

lse

0%

100%

The neurotransmitter responsible for control of alertness and the fight-or-flight response is:

A. GABAB. DopamineC. SerotoninD. Norepinephrine

GABA

Dopamine

Serotonin

Norepinephrine

7%

78%

15%

0%

This neurotransmitter is the brain’s major inhibitory neurotransmitter

A. SerotoninB. GABAC. EndorphinsD. Acetylcholine

SerotoninGABA

Endorphins

Acetylcholin

e

11%19%

15%

56%

This neurotransmitter has a huge influence on moodA. EndorphinsB. GlutamateC. SerotoninD. Acetylcholine

Endorphins

Glutamate

Serotonin

Acetylcholin

e

10%0%

79%

10%

This neurotransmitter is responsible for feelings of pleasure/reward.A. GlutamateB. SerotoninC. DopamineD. GABA

Glutamate

Serotonin

DopamineGABA

3% 0%

97%

0%

Lifecycle of a Neurotransmitter

1. Neurotransmitter precursors are found circulating in the blood supply

2. Uptake: Selected precursors are taken up by cells, a process requiring energy

3. Synthesis: Precursors are changed (synthesized) into neurotransmitters through the action of enzymes

4. Storage: Neurotransmitters are stored in small vesicles

Lifecycle of a Neurotransmitter

5. When the action potential arrives, neurotransmitters are released into the synapse

6. Released neurotransmitters bind with receptors on the membrane of the next neuron

7. Neurotransmitters may have excitatory or inhibitory effects

8. Once a signal has been sent, neurotransmitters are removed from the synapse; may return or be metabolized

Drug Actions

• Alter neurotransmitter availability• Agonists - Mimic neurotransmitters• Antagonists = Occupy neurotransmitter and prevent

its activation• Interference with reuptake• Video: https://

www.youtube.com/watch?v=uXREQnFGHGA

Names of Drugs

• Chemical name: Complete chemical description of the molecule

• Example: N'-[2-[[5-(dimethylaminomethyl)-2-furyl] methylsulfanyl]ethyl]-N-methyl-2-nitro-ethene-1,1-diamine

• Generic name: Official (legal) name, listed in the United States Pharmacopoeia (USP)

• Example: ranitidine

• Brand name: Specific drug or formulation trademarked by manufacturer; can be patented for 20 years

• Example: Zantac®

Classifications

One’s mood while taking a psychoactive drug will affect the experience derived from the drug.A. TrueB. False

TrueFa

lse

8%

92%

Drug Effects

• Nonspecific effects • SET• SETTING

• Specific effects

• Placebo effects

Double-blind procedure

Dose-Response

• Dose-response relationship = correlation between the response and the quantity of drug administered

• Threshold = the dose at which an effect is first observed

Older men are more affected by a drug’s effects than are older women.

A. TrueB. False

TrueFa

lse

0%0%

Dose

• Effective dose = the dose of a drug that produces a meaningful effect in some percentage of test subjects• ED50 refers to the effective dose for half the animal

subjects in a drug test• Lethal dose = the dose of a drug that has a lethal

effect in some percentage of test subjects• LD50 refers to the lethal dose for half the animal subjects in

a drug test • Therapeutic index = LD50/ED50

• Always greater than one

If a drug has a lethal dose that is close to its effective dose, that drug is more dangerous than if the LD is far from the ED.

A. TrueB. False

TrueFa

lse

0%0%

Mixing medications with wine causes more potential health problems than mixing medications with beer.

A. TrueB. False

TrueFa

lse

0%0%

Dose

• Potency = measured by the amount of a drug required to produce a given effect

• Toxicity = capacity of a drug to do damage or cause adverse side effects

• Safety margin = difference between: • Dose that produces the desired therapeutic effect in most

patients• Lowest dose that produces an unacceptable toxic reaction

• Most drugs have an LD1 well above the ED95

Women are less likely today than they were 30 years ago to use medicines while pregnant.

A. TrueB. False

TrueFa

lse

0%0%

Routes of Administration

Forms and methods

of taking drugs

oral ingestion

inhalation

injection

topical application

Distribution

Tolerance

• Pharmacological• Behavioral• Cross-tolerance• Reverse tolerance

Video: https://www.youtube.com/watch?v=8-Qtd6RhfVA