Lecture 29 - Introduction to Drugs

Question 1

What is the definition of a drug?

What isn’t a drug?

Answer 1

A chemical compound of known structure that produces a biological effect.

It is no herbal remedies, or dietary requirements

Question 2

Which neurotransmitters act on the cardivascular system?

Which receptors?

Answer 2

NA and Ad

alpha and beta adrenoceptors

Question 3

What is the scientific basis of the action of drugs?

Answer 3

Molecular pharmacology
Cell and tissue physiology
Organ pharmacology
Whole body
Population

Question 4

Give an example of the scientific basis of drugs

Answer 4

Thiazide diuretics

1. Blocks Na+/Cl- transporter
2. Decrease in Na+/Cl- reabsorption
3. Increased excretion from kidney
4. Lower blood volume and BP
5. K+ loss, hyperglycaemia, gout

Question 5

What is pharmacodynamics?

Answer 5

Effect of a drug on the body

Question 6

What is pharmacokinetics?

Answer 6

What the body does to the drug

Question 7

What are the generalised targets of drugs?

Answer 7

• Receptors
• Enzymes
• Ion channels / transporters
• Gene transcription / translation

Question 8

Where are the generalised location of receptors?

Answer 8

• Cell surface
• Cytosol
• Nucleus

Question 9

What are the types of cell surface receptors?

Answer 9

• GPCR
• Ion channels
• Tyrosine-Kinase linked

Question 10

What are the two ways that two cells can interact?

Give examples of each

Answer 10

1/ Release of molecules
- hormones

2/ Membrane bound molecules
- immune system

Question 11

How can such a small molecule bring about a response in a cell?

Answer 11

Amplification

Question 12

Describe the generalised process of amplification

Answer 12

1. One ligand binds to one receptor
2. Receptor activates many second messengers
   and so on

Question 13

Describe a drug-receptor interaction that takes in the order of milliseconds to elicit a response

Answer 13

ACh - nAChR

At motor endplate

Question 14

Describe a drug-receptor interaction that takes in the order of seconds to elicit a response

Answer 14

NA - Adrenoceptors

Question 15

Describe a drug-receptor interaction that takes in the order of minutes to elicit a response

Answer 15

Insulin - IR

Question 16

Describe a drug-receptor interaction that takes in the order of hours to elicit a response

Answer 16

Cortisol - Glucocorticoid receptor

Question 17

What type of receptor is the nAChR?

Answer 17

Ion channel

Question 18

What type of receptor is the mAChR?

Answer 18

GPCR

Question 19

What type of receptor is the insulin receptor?

Answer 19

Receptor tyrosine kinase

Question 20

What type of receptor are adrenoceptors?

Answer 20

GPCR

Question 21

What is the effect of d-Turbocurarine?

Answer 21

Blocks Na+ channels

No action potential conductance

Question 22

What is the structure of GPCR?

Answer 22

Receptor: 7TM (heptahelical)
Binding domain extracellularly
Linked to G-protein:
alpha, beta gamma subunits
GDP

Question 23

What is a drug that targets AChE?

What does it then do?

Answer 23

Physostigmine

It is an antagonists - prevents the breakdown of ACh

Question 24

What is a drug that targets cyclo-oxygenase?

Describe what happens when it is taken

Answer 24

Aspirin

Inhibits the production of inflammatory prostaglandins

Question 25

What is a drug that targets the bcr-abl fusion protein? What does the drug do?

Answer 25

Imatinib Blocks the kinsase action of the fusion protein

Question 26

Describe the function of receptor tyrosine kinases

Answer 26

1. Ligands bind 2. Subunits dimerise 3. Auto-phosphorylation 4. Tyrosine residue is phosphorylated 5. Kinase property of the receptor is activated

Question 27

Give an example of a nuclear hormone receptor target

Answer 27

Cortisol - GR

Question 28

Describe the action of cortisol

Answer 28

1. Diffuses through membrane 2. Binds to GR in cytoplasm, chaperon dissociates 3. GR + cortisol move to the nucleus 4. Binds to DNA 5. Change in gene expression

Question 29

What type of hormone is cortisol?

Answer 29

Steroid

Question 30

How is chemical signalling controlled? | Give an example of each

Answer 30

``` 1/ Breakdown - ACh 2/ Reuptake - NA 3/ Metabolism, Negative feedback - Insulin - Cortisol ```

Question 31

Describe the regulation of NA

Answer 31

Once it has acted on the receptors, it is taken back up by the pre-synaptic cell

Question 32

What is the mechanism of action of cocaine in the body?

Answer 32

Blocks the reuptake of noradrenaline and dopamine

Question 33

Describe the regulation of insulin in the body

Answer 33

Controlled by negative feedback 1. Glucose in the blood 2. Increased ATP in cells 3. K+ channels blocked 4. Depolarisation 5. Release of insulin

Question 34

Describe the regulation of cortisol

Answer 34

1. Hypothalamus release CRF 2. CRF leads to release of ACTH from the pituitary 3. ACTH releases cortisol from the adrenal gland 4. Cortisol feeds back negatively on the hypothalamus

Question 35

What is ACTH?

Answer 35

Adrenocorticotrophic hormone

Question 36

What is CRF?

Answer 36

Corticotropin releasing factor