From Physiological Systems To Molecular Drug Targets I Flashcards Preview

PM2C Autumn Amy L > From Physiological Systems To Molecular Drug Targets I > Flashcards

Flashcards in From Physiological Systems To Molecular Drug Targets I Deck (61):
1

Name the 4 major sites of action of drugs

  1. Enzymes
  2. Transporters
  3. Ion channels
  4. Receptors

2

What does PNS stand for?

Peripheral Nervous System

3

What is the role of the PNS?

To regulate the body's internal environment

4

What does the PNS represent?

The output of the CNS

5

What 2 systems does the PNS consist of?

  1. ANS = autonomic nervous system
  2. SNS = somatic (motor) nervous system

6

How is the ANS controlled?

The ANS is usually outside of voluntary control

7

How is the SNS controlled?

The SNS is under concious control

8

Name the 2 nerves that make up the SNS

Efferent and Afferent

9

What is the role of the efferent nerves?

Control movement by innervating skeletal muscle

10

What is the role of afferent nerves?

Respond to external stimuli e.g. pain-sensing (nociceptive) fibres

11

What is the CNS made up of?

The brain and the spinal cord

12

List 5 processes that the ANS regulates

  1. Heart beat
  2. Smooth muscle contraction and relaxation
  3. All exocrine function
  4. Some endocrine function
  5. Some steps in intermediate metabolism

13

Name the 3 major systems/divisions of the ANS

  1. PNS = Parasympathetic Nervous System
  2. SNS = Sympathetic Nervous System
  3. ENS = Enteric Nervous System

14

What effect does blocking the noradrenaline receptors have?

Activates the sympathetic system

15

What effect does blocking the muscarinic ACh receptors have?

Blocks the parasympathetic system

16

What effect does activating the muscarinic ACh receptors have?

Activates the parasympathetic system

17

Describe the SNS

The SNS evokes a 'fight or flight' response

18

Describe the PNS

The PNS mediates a 'rest and digest' state

19

Define: Endocrine gland

A gland which secretes hormones directly into the bloodstream

20

Define: Exocrine gland

A gland which secretes hormones via ducts onto an epithelium rather than directly to the blood

21

List 3 actions of the SNS

  1. Pupil dilation (wide)
  2. Blood flow directed to the skeletal muscle
  3. Bronchodilation (more O2)

22

List 3 actions of the PNS

  1. Pupil constriction
  2. Blood flow directed to the viscera (organs)
  3. Bronchoconstriction

23

What is the role of ACh-esterase?

Convert ACh ---> acetate + choline

24

What are ACh-esterase inhibitors also known as?

Anti-cholinesterases

25

What does blocking ACh-esterase do?

Increase the amount of ACh in the synaptic cleft

26

Where is ACh broken down by ACh-esterase?

The synaptic cleft

27

Which receptor does atropine block?

Muscarinic ACh receptor (mAChR)

Antagonist

28

Which receptor does succinylcholine block?

Nicotinic ACh receptor (nAChR)

29

Name the substance that blocks the muscarinic ACh receptor

Atropine

30

Name the substances that block the nicotinic ACh receptor

Succinylcholine and Tubocurarine

31

Which receptor does tubocurarine block?

Nicotinic ACh receptor

32

What effect does tubocurarine have on the body?

Paralyses muscles

By blocking the nicotinic ACh receptor

33

Name a condition that anticholinesterases are used to treat

Alzheimer's Disease

34

What effect does ACh have on the blood pressure?

ACh decreases the blood pressure

More ACh = greater decrease in BP

35

What substance does atropine block the effects of?

ACh

36

What substance blocks the effects of ACh?

Atropine

37

How does atropine block the effects of ACh?

By blocking (antagonist) the muscarinic ACh receptor

38

Name the receptor that causes an increase in BP when bound to ACh (as atropine has blocked the muscarinic receptor)

Nicotinic receptor

39

How many subtypes of muscarinic receptor exist?

5: M1, M2, M3, M4, M5

40

What type of receptor do muscarinic receptors exist as?

G protein-coupled receptors

41

What response do M1, M3 and M5 (odd numbers) cause?

They cause an increase in IP3

42

What type of G protein are M1, M3 and M5?

q

43

What type of G protein are M2 and M4?

i/o

44

What response do M2 and M4 (even numbers) cause?

Decrease in cAMP

45

Why is it not recommended to target agonist drugs at the mAChR subtypes?

The agonists are non-selective - could target any/all of the subtype receptors = unpredictable effects

46

Why is it preferable to target mAChR subtype receptors with antagonist drugs

Drugs that are antagonists are more selective so they have a more predictable effect, only targeted at 1 receptor

47

What are the benefits of having a more selective drug?

  • More likely to be safe
  • More likely to be potent/efficacious

48

What is the role of Gαq? (M1/M3/M5)

Activates phospholipase C (which converts PIP2 into IP3 + DAG)

49

What is the role of phospholipase C?

It converts PIP2 into IP3 + DAG

50

What effect does IP3 + DAG have on the cell?

Increases intracellular calcium:

  • Secretion
  • Contraction
  • Vasodilation

51

List 3 effects of an increase in intracellular calcium

  1. Secretion
  2. Contraction
  3. Vasodilation

52

Name the enzyme that is inhibited by Gαi/o (M2/M4)

Adenylate cyclase (so ATP can't be converted to cAMP)

53

What enzyme do M2/M4 inhibit?

Adenylate cyclase (so ATP can't be converted to cAMP)

54

What is the role of adenylate cyclase?

Convert ATP to cAMP

55

Name a physiological effect of a reduction in cAMP

Bradycardia = reduced heart rate

56

Define: Cholinergic

Relating to nerve cells in which ACh acts as a neurotransmitter

57

The actions of mAChRs mimic which nervous system?

Parasympathetic nervous system

58

List 4 parasympathetic effects caused by the actions of mAChRs

  1. Bradycardia
  2. Vasoconstriction
  3. Increased secretion
  4. Increased gut motility

59

List 4 physiological effects of the actions of atropine (blocking mAChRs)

  1. Tachycardia (increased heart rate)
  2. Pupillary dilation
  3. Block secretion
  4. Inhibits gut motility

60

Name 3 indications of atropine

  1. Smooth muscle relaxants (e.g. IBS)
  2. Cardiovascular (e.g. to treat bradycardia after heart attack)
  3. Anaesthesia (to prevent vagal inhibition of the heart)

61

What is the mechanism of action of atropine?

  • Antagonist
  • Blocks at muscarinic ACh receptors
  • Non-selective
  • Doesn't block nicotinic receptors