Workshop 4: Interactions with drugs

Question 1

Psychopharmacology

Answer 1

Study of drugs that affect the nervous system and behaviour

Question 2

Drugs of abuse

Answer 2

CNS depressants (e.g. alcohol)

CNS stimulants (e.g. caffine)

Opiates and opioids (narcotics)
—-> can be synthetically made, or painkillers

Hallucinogens (e.g. LSD, psilocybin, mushrooms)

Marijuana
—-> can be a hallucinogen but can be different for individuals

(some have dual roles - e.g. alcohol depresses some systems but stimulates others)

Question 3

Categories for psychotherapeutic drugs

Answer 3

Categorised for their mechanism for action, physiological effect and chemical structure of the drug

	▪ The Anatomical Therapeutic Chemical (ATC) Classification System
	▪ International Pharmacopeia (WHO)
	▪ European Pharmacopeia ▪ United States Pharmacopeia (USP)

Question 4

ATC classification system (Anatomical therapeutic chemical)

Answer 4

• 5 levels
• organ system or pharmacological classification (class A)
• therapeutic subgroup (class A10)
• pharmacological subgroup (class A10B)
• chemical subgroup (class A10BA)
• chemical substance (class A10BA02)

(see slides for deets)

Question 5

4 main factors to psychopharmacology

Answer 5

Dose - response

Tolerance

Sensitivity

Withdrawal

Question 6

Dose - reaction

Answer 6

§ How much do we need to give to get a certain response
§ Individual differences
Drug strength

There is a dose range of no effect, where increasing dosage means increased effects, and a maximum effect range

Question 7

Tolerance

Answer 7

§ Repeated exposure
How does it change to adapt to drug

Question 8

Sensitivity

Answer 8

As exposure goes up, sensitivity goes down (usually)

Question 9

Withdrawal

Answer 9

§ With increased tolerance & dependence on a drug, the reduction of that drug typically causes an opposite effect to the drug itself
§ Withdrawal effects vary from drug to drug, and can last varying amounts of time
§ Internal systems perpetuate homeostasis by using counterregulatory methods to create a new state of balance based on the presence of the drug in the system
§ Adaptions include levels of NTS, hormones, and other substances to adjust for the addition of the drug to the body
Withdrawal means the body is no longer naturally producing the neurotransmitter it was before the drug use

Question 10

NTs task: Number stages 1-5

Answer 10

1) NTs is synthesised in cell body or terminal

2) NTs is packaged into vesicle

3) NTs is released when vesicles fuse

4) NTs binds to and activates postsynaptic receptors

5) NTs is metabolised and transported back into terminal

Question 11

Drugs: Agonists examples

Answer 11

• Benzodiazepine (activates GABA receptors)
• Morphine
• SSRIs (Indirect agonist)
• LSD
• THC

Question 12

Drugs: Antagonist

Answer 12

Caffeine

Question 13

Tolerance definition

Answer 13

the diminished response to drugs over the course of repeated or prolonged exposure

Accounted for by adapting physiological processes that achieve stability in a constantly changing environment (NIH, 2024)

Acute tolerance = reaction to initial surge of drug (short term effects - from 15-30 mins lessened)

Rapid tolerance = 24hrs for humans (4 for flies)

Chronic tolerance = repeated exposure over 24 hrs

Question 14

Types of tolerance (4 types)

Answer 14

• acute
• pharmacodynamic
• pharmacokinetic
• behavioural

Question 15

Acute tolerance

Answer 15

Tachyphylaxis!

Instant short-term effect of drug on NTs and synaptic junction

Question 16

Pharmacodynamic tolerance

Answer 16

Dispositional!

Reduction in cellular response to drug (e.g. desensitisation of receptor, reduction in receptors)

Question 17

Pharmacokinetic tolerance

Answer 17

Metabolic!

Absorption, distribution, metabolism and excretion of drugs (ADME)

= reduced amount of drug reaching site of action

(metabolism to drug - changes over time depending on how much drug consumed, sensitisation to drug changes)

Question 18

Behavioural tolerance

Answer 18

Conditioned!

Tolerance to a behavioural effect of drug.

Occurs through drug-independent learning or as a form of pharmacodynamic tolerance in the brain

• learned effect to drug
• physiological effect - reward feeling associated with drug

Question 19

Sensitivity

Answer 19

• drug intolerance▪ An increased response to a drug with repeated administration.▪ Amplified effects, including therapeutic benefits and side effects.▪ Mechanisms behind sensitization are not fully understood but thought to involve neuroadaptive changes.

▪ Understanding tolerance and sensitization is crucial for optimizing drug therapy as they impact dosing, effectiveness, and potential side effects

(see graph that shifts left when sensitised, and right when tolerance)

Question 20

Withdrawal

Answer 20

With increased tolerance and dependence on a drug, the reduction of that drug typically causes an opposite effect to the drug itself. (vary from drug to drug)

Withdrawal means the body is no longer naturally producing the NTS it was before the drug use

▪ Internal systems perpetuate homeostasis by using counterregulatory methods to create a new state of balance based on the presence of the drug in the system.

▪ Adaptions include levels of neurotransmitters, hormones, and other substances to adjust for the addition of the drug to the body.

Question 20

The release of what ions leads to the exocytosis of neurotransmitters from the terminal buttons?

Answer 20

calcium

Question 21

What does an antagonist do?

Answer 21

Prevents storage of neurotransmitters in vesicles

Question 22

On what receptors do psilocin work?

Answer 22

Serotonin

Question 23

What type of tolerance is represented by a decrease in sensitivity of the receptor?

Answer 23

Pharmacodynamic

Question 24

What is used to block opioid receptors and prevent overdose?

Answer 24

Naloxone

Question 25

According to the Centre of Disease control and Prevention, how many times stronger is fentanyl than heroin?

Answer 25

50 x