PHARM; Lecture 1, 2 and 3 - Intro to ANS, Mechanism of Drug action (I & II) Flashcards Preview

Y2 LCRS 1 - Pharm, Endo, Reproduction > PHARM; Lecture 1, 2 and 3 - Intro to ANS, Mechanism of Drug action (I & II) > Flashcards

Flashcards in PHARM; Lecture 1, 2 and 3 - Intro to ANS, Mechanism of Drug action (I & II) Deck (95)
Loading flashcards...
1
Q

What are the principal target organs of the sympathetic NS?

A

Eye, Salivary glands, trachea/bronchioles, skin, heart, GI, Liver, adipose, kidney, ureters and bladder, blood vessels

2
Q

What are the principal target organs of the Parasympathetic NS?

A

Eye, Salivary glands, trachea/bronchioles, heart, GI, ureters and bladder

3
Q

FITB for the action of ANS on target organs

A

x

4
Q

What transmitters are released from pre and post ganglionic fibres in sympathetic NS?

A

x

5
Q

What transmitters are released from pre and post ganglionic fibres in parasympathetic NS?

A

x

6
Q

What is the difference between the PSNS and SNS in terms of response?

A

SNS is very coordinated with a lot of divergence due to short pre-ganglionic fibres VS PSNS is discrete, localised and with little divergence

7
Q

What is the difference in the innervation of the somatic NS compared to the ANS?

A

Somatic has a motor neurone which releases ACh then leads onto the effector skeletal muscle

8
Q

What are the membrane bound receptors for ACh?

A

Muscarinic and Nicotinic

9
Q

What kind of receptor are the nicotinic ones?

A

Ionotropic, and is stimulated by nicotine/acetylcholine

10
Q

Where are nicotinic receptor situated?

A

All autonomic ganglia

11
Q

What are muscarinic receptors and where are they situated?

A

G-protein coupled and located at all effector organs innervated by post-ganglionic PSNS fibres

12
Q

What are muscarinic receptors stimulated by?

A

Muscarine and ACh

13
Q

Which of the following effects would be observed after blockade of nicotinic acetylcholine receptors in an individual at rest? 1) Bronchoconstriction 2) Increased sweat production 3) Constipation 4) Increased urinary frequency 5) Short-sightedness

A

Constipation

14
Q

What are the types of muscarinic receptors?

A

M1, M2, M3, M4, M5

15
Q

What is the function of M1 receptor?

A

Neural - forebrain; learning and memory

16
Q

What is the function of M2 receptor?

A

Cardiac - brain; inhibitory autoreceptors

17
Q

What is the function of M3 receptor?

A

Exocrine and smooth muscle - Hypothalamus; food intake

18
Q

What is the function of M4, M5?

A

M4: periphery; prejunctional nerve endings (inhibitory). M5: Striatal DA release

19
Q

What are the different types of muscarinic?

A

x

20
Q

What are the types of adrenoceptors?

A

Alpha 1, 2 and beta 1, 2

21
Q

Where are adrenoceptors located?

A

All effector organs innervated by postganglionic sympathetic fibres

22
Q

What are adrenoceptors and what stimulates them?

A

G-protein coupled and stimulated by NA/Adrenaline

23
Q

Blockade of which of the following receptor sub-types would induce both an increased heart rate and a reduction in sweat production during exercise? 1) Muscarinic receptors 2) α1 adrenoceptors 3) α2 adrenoceptors 4) β1 adrenoceptors 5) β2 adrenoceptors

A

Muscarinic receptor

24
Q

How is ACh synthesised, released and metabolised?

A

1) Binding of Acetyl CoA + Choline to form ACh. 2) ACh is placed in vesicles. 3) Ca2+ moves in via VSCC, so vesicle moves to membrane 4) ACh is exocytosed into the synaptic space. 5&6) ACh moves in synapse and attaches with receptor. 7) Acetylcholine esterase breaks down ACh into choline and acetate. 8) Choline is taken up and is used back up.

25
Q

How is NA synthesised, released and metabolised?

A

x

26
Q

Blockade of which of the following targets would cause the most significant rise in synaptic noradrenaline concentrations? 1) Tyrosine hydroxylase 2) DOPA decarboxylase 3) Uptake 1 transport protein 4) Monoamine oxidase 5) Cathecol-O-methyl transferase

A

Uptake 1 transport protein

27
Q

What is pharmacokinetics?

A

What the body does to the drugs

28
Q

What is pharmacodynamics?

A

What the drugs do to the body

29
Q

What is a drug?

A

A chemical substance that interacts with a biological system to produce a physiological effect

30
Q

What are the 4 drug target sites?

A

Receptors, ion channels, transport systems, enzymes - NB: ALL ARE PROTEINS

31
Q

What are the receptors for drug target sites and what are they activated by?

A

Proteins within cell membranes, 4 types -> activated by NT/hormones

32
Q

What is an agonist?

A

A molecule that stimulates the receptor causing the original action

33
Q

What is an antagonist?

A

A molecule that blocks the receptor

34
Q

How do ion channels allow drugs to target?

A

Has selective pores and allows transfer of ions down electrochemical gradients

35
Q

How many types of ion channels and what are they?

A

2 -> Voltage sensitive (VSCC) and receptor-linked (nAChR)

36
Q

What are some examples of receptor drugs?

A

ACh (agonist), atropine (antagonist)

37
Q

What are some examples of ion channels drugs?

A

Local anaesthetics, Ca channel blockers

38
Q

What are the transport system drug targets?

A

Transport against conc grad; with specificity for certain species

39
Q

What are some examples for transport system receptors?

A

Na/K ATPase and Na uptake 1

40
Q

What are some drug examples for transport systems?

A

Tricyclic anti-depressants, cardiac glycosides

41
Q

What are enzymes that are acted upon by drugs and how do they interact with drugs?

A

Catalytic proteins interacting by: enzyme inhibitors, false substrates (form false substrates), prodrugs

42
Q

What is an example of an enzyme inhibitor drug?

A

Anticholinesterases

43
Q

What is an example of a false substrate drug?

A

Methyldopa -> Produces fake NA which causes a decreased interaction

44
Q

What is an example of a prodrug drug?

A

Chloralhydrate -> triichloroethanol

45
Q

What is an example of an unwanted effect from paracetamol?

A

It saturates metabolising enzymes, so is metabolised via other pathways producing toxic metabolites

46
Q

What kind of drugs aren’t part of the 4 drug target sites?

A

Non-specific drugs

47
Q

How do non-specific drugs work?

A

Changing their physiochemical properties, e.g. by changing their active site

48
Q

Give an example of a non-specific drug?

A

Antacids (neutralise acids not targeting the active site of the cells) and osmotic purgatives

49
Q

What are the different drug-receptor interactions?

A

Agonist, antagonist, potency, full and partial agonist, selectivity and structure-activity relationship

50
Q

What is an example of an agonist?

A

ACh, nicotine

51
Q

What is an example antagonist?

A

Atropine, hexamethonium

52
Q

What does the potency of a drug depend on?

A

Efficacy and affinity

53
Q

What is the efficacy of the drug?

A

Ability to produce a change in the receptor -> the intrinsic activity/ conformational change of receptor

54
Q

What is the affinity of a drug?

A

How the drug seeks to bind to the receptor

55
Q

What is a full agonist?

A

The drug causes the maximum response

56
Q

What is a partial agonist?

A

The drug can’t cause the maximum response due to less than max efficacy -> antagonist activity

57
Q

How can the activity/selectivity of a drug change?

A

By changing the structure of the drug

58
Q

What are the different types of structure-activity relationship?

A

Lock and key; agonist-> antagonist; pharmacokinetics

59
Q

How does an agonist interact with the receptor?

A

x

60
Q

What does the dose-response curve look like for a full agonist vs a partial agonist (log vs non-log)?

A

x

61
Q

What is the affinity/efficacy of antagonists?

A

They have affinity but no efficacy

62
Q

What are the 2 types of receptor antagonists?

A

Competitive and irreversible

63
Q

What are competitive antagonists?

A

Act on the same site as the agonist; is surmountable by increasing the concentration of the agonist; shifts the D-R curve to the right

64
Q

Give some examples of competitive antagonists.

A

Atropine, propanolol

65
Q

What are irreversible antagonists?

A

Bind tightly to same site OR to different site than agonist; it is insurmountable -> forms tight covalent bonds or e.g. in ion channels

66
Q

Give an example of an irreversible antagonist

A

Hexamethonium

67
Q

How does the log D-R curve shift with competitive and irreversible agonists?

A

x

68
Q
A

C

69
Q
A

D

70
Q

What are the different types of drug antagonism?

A

Receptor blockade, physiological antagonism, chemical antagonism, pharmacokinetic antagonism

71
Q

What is receptor blockade antagonism?

A

Either competitive or irreversible -> has a use-dependency

72
Q

What is a use-dependency and give an example of such drugs?

A

Of ion channel blockers -> i.e. the more active the cell the faster the drug will block the ion channels. Eg: local anaesthetics

73
Q

What is physiological antagonism?

A

Each drug acts on a different receptor causing opposite effects on the same tissue

74
Q

Give an example of physiological antagonism

A

Noradrenaline causes vasoconstriction, increasing TPR and BP BUT Histamine increases dilatation which decreases TPR and BP -> Antagonise but act on different receptors

75
Q

What is chemical antagonism?

A

The rarest form of antagonism, occurs during interaction in solution

76
Q

Give an example of chemical antagonism

A

Dimercaprol -> attaches to heavy metals and forms complexes which can be toxic; acts as a chelating agent

77
Q

What is pharmacokinetic antagonism?

A

Works as an antagonist, decresing the concentration of active drug at site of action

78
Q

Give an example of a pharmacokinetic antagonist

A

Barbiturates affect other drugs by decreasing their absorption, increasing their metabolism and excretion (NB: clinically important reaction)

79
Q

What is drug tolerance?

A

A gradual decrease in responsiveness to drug with repeated administration

80
Q

What is the main drug that is tolerated quickly?

A

Benzodiazepines

81
Q

What are some reasons for increased drug tolerance?

A

Pharmacokinetic factors, loss of receptors, change in receptors, exhaustion of mediator stores, physiological adaptation

82
Q

How do pharmacokinetic factors affect drug tolerance and give an example?

A

Can increase rate of metabolism of drugs -> barbiturates, alcohol

83
Q

How does loss of receptors affect drug tolerance and give an example?

A

Receptors are lost from cell surface via endocytosis -> down-regulated due to over stimulation. E.g. beta-adrenoceptors

84
Q

How does a change in receptors affect drug tolerance and give an example?

A

Receptors become desensitised due to a conformational change -> drug will still have affinity to receptor but the efficacy has lowered. E.g. nAChR at NMJ

85
Q

How does the exhaustion of mediator stores affect drug tolerance and give an example?

A

For example, when amphetamine is used, it causes enhanced release of NA and after a few doses of Amph, the NA stores become depleted and the response is no longer the same

86
Q

How does physiological adaptation affect drug tolerance?

A

Homeostatic responses in the body change -> the tolerance is to the drug side effects

87
Q

How many types of receptor families are there and what is each family?

A

1) Ion channel-linked. 2) G-protein coupled. 3) Kinase-linked. 4) Intracellular steroid type

88
Q

What are the characteristics of ion channel-linked receptors and give an example?

A

Fast responses (milliseconds) -> nAChR, GABAa

89
Q

What are the characteristics of G-protein coupled receptors and give an example?

A

Slower responses (seconds) -> beta1 adrenoceptors in heart

90
Q

What are the characteristics of kinase-linked type and give an example?

A

Quite slower respones (mins) -> insulin/growth factors

91
Q

What are the characteristics of intracellular steroid type receptors and give an example?

A

Very slow (hrs) as they regulate DNA transcription -> steroids, thyroid hormones

92
Q

Summarise the location, effector, coupling and examples of the 4 main types of receptors

A

x

93
Q

Where are the binding domains for each of the 4 types of receptors?

A

x

94
Q
A

C

95
Q

x

A

E

Decks in Y2 LCRS 1 - Pharm, Endo, Reproduction Class (19):