THE PHARMACOLOGY AND PHYSIOLOGY OF DRUGSGoldberg Chapter 5

SOC 204 Drugs & Society

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 day

B. A month

C. A trillion seconds

D. 32,000 years All day

A month

A trilli

on seco

nds

32,000 years

12%

19%

50%

19%

Nervous System

• Somatic Nervous System• Autonomic Nervous System• Central Nervous System

The Brain

Action Potential

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

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, movement

3. 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

memory

7. 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. True

B. FalseTru

eFa

lse

0%

100%

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

A. GABA

B. Dopamine

C. Serotonin

D. Norepinephrine

GABA

Dopamine

Seroto

nin

Norepinephrin

e

12%

81%

4%4%

This neurotransmitter is the brain’s major inhibitory neurotransmitter

A. Serotonin

B. GABA

C. Endorphins

D. AcetylcholineSero

tonin

GABA

Endorphins

Acety

lcholin

e

23%

0%8%

69%

This neurotransmitter has a huge influence on mood

A. Endorphins

B. Glutamate

C. Serotonin

D. Acetylcholine

Endorphins

Glutamate

Seroto

nin

Acety

lcholin

e

8% 8%

85%

0%

This neurotransmitter is responsible for feelings of pleasure/reward.A. Glutamate

B. Serotonin

C. Dopamine

D. GABAGlutamate

Seroto

nin

DopamineGABA

0% 0%

100%

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

Synaptic Gap

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

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. True

B. False

True

False

4%

96%

I’m ready for the exam Friday!A. Completely

B. Not yet, but I will be

C. NOOOOOOOOOO

D. I’m going to be gone and need to take it Thursday

Completely

Not yet, b

ut I w

ill be

NOOOOOOOOOO

I’m going t

o be gone an...

13%17%

29%

42%

Drug Effects

• Nonspecific effects• Set• Setting

• Specific effects

• Placebo effects • https://www.youtube.com/watch?v=EGDMXvdwN5c • https://www.youtube.com/watch?v=v_feOG94IAs

Placebos are drugs that mimic other drugs.

A. True

B. False

True

False

63%

38%

Double-blind procedure

Double-blind procedures are important because:A. Drugs can have more than

one effect

B. Drugs might be ineffective

C. Drug effects are influenced by expectations

D. Drug effects aren’t measurable in single-blind studies

Drugs c

an have m

ore th

..

Drugs m

ight b

e ineffecti

ve

Drug effects

are in

fluenc..

Drug effects

aren’t

meas...

8%13%

58%

21%

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

A threshold is:A. What you carry a

bride over

B. The maximum effective dose

C. The dose at which a response is first observed

What y

ou carry

a bride over

The maxim

um effective ...

The dose at w

hich a re

sp...

0%

100%

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

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

A. True

B. False

True

False

96%

4%

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

Safety margin is:A. Space you leave between

you and the next car while driving on the highway

B. Difference between therapeutic dose and dose that causes toxic side effects

C. Measuring the potency of drugs

Space you le

ave betw

ee...

Differe

nce betw

een the...

Measu

ring th

e potency

o...

0% 0%

100%

Effective dose is the same as the threshold

A. True

B. False

True

False

92%

8%

Drug Interactions

• Interactions can be hazardous• Drug-drug• Drug-food

• Effects can be• Additive• Antagonistic• Synergistic

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

A. True

B. FalseTru

eFa

lse

96%

4%

Routes of Administration

Forms and methods

of taking drugs

oral ingestion

inhalation

injection

topical application

Distribution

Mechanisms

• Transport in the blood• Blood-brain barrier• Effects on all neurons• Effects on neurotransmitters• Enzyme induction• Deactivation

Tolerance

• Pharmacological• Behavioral• Cross-tolerance• Reverse tolerance

When a ‘shroom user develops tolerance to LSD

92%

8%

0% A. Reverse tolerance

B. Behavioral tolerance

C. Cross tolerance