Class Test 1 Flashcards Preview

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Flashcards in Class Test 1 Deck (76):
1

How do you calculate Kd?

[H] x [R] / [HR]

2

In what ways can drugs be classified by the components involved?

Receptors
Ion channels
Carrier molecule
Enzymes

3

What are cells, tissues and organs controlled by?

Nervous system
Humoral agents
Local factors

4

In what ways can a drug be classified?

By nature
By action
Which cell components are involved
Which of the body systems does the drug affect
How does the drug help in the disease state

5

What is strength of signal replayed by the receptor dependent on?

Concentration of hormone-receptor complex

6

Where can other drugs block signal transduction?

Inside the membrane
Intracellular signal reception points

7

Common features of receptors?

Saturable
Activated by binding of an endogenous ligand

8

What does the fraction of total membrane receptors occupied by Ligands determine?

Size of transmembrane signal transduction

9

What is affinity of a drug?

Ability of a drug to bind to a receptor

10

What do drugs participate in?

Intracellular communication via chemical signals

11

What happens upon recognition of an appropriate chemical signalling molecule (ligand)?

Receptor proteins transmit the signal into a biochemical change in the target cell

12

What are the important steps of hormone initiated signal transduction?

Biosynthesis of hormone
Storage and secretion of hormone
Transport of hormone to target cell
Recognition by the hormone receptor protein
Relay and amplification of the signal that leads to defined biochemical reactions within the target cell
Removal of hormone

13

What properties do receptors have

Recognition
Transduction

14

What does the signalling cascade allow?

Signal to be amplified to produce multiple responses

15

Examples of responses produced by signal transduction?

Modulation of gene translation
Hormone secretion
Energy production
Cell division
Cell motion

16

Examples of intracellular second messenger signalling molecules

Cyclic nucleotides (cAMP, cGMP)
Calcium ions
IP3 and DAG

17

What do second messengers regulate?

Function of specific cellular effectors

18

Other examples of ligand-gated ion channels

GABA A receptor
Iontropic glutamate receptor
5-HT3 receptor

19

What type of receptors are on ligand gated ion channels

Multimeric transmembrane receptors

20

What does gaba a receptors do and used for?

Opens Cl- channel
Used as tranquillisers and anticonvulsant

21

What's the composition of GPCRs?

2 highly conserved cysteine residues in extracellular loops that form an intramolecular disulphide bond to stabilise the receptor structure

22

What are the physiological roles of GPCRs

Sensation
Immune system and inflammation
Metabolism
Behaviour
Autonomic nervous system

23

What do nuclear receptors affect

Gene transcription
Directly bind to DNA

24

What kind of responses are consequence of this increase in membrane permeability?

Postsynaptic excitatory or inhibitory responses

25

What is a second messenger?

Intracellular substance that mediates cell activity by relaying a signal from an extracellular molecule

26

Types of responses GPCRs allow?

Amplification
Diversity

27

What is efficacy?

Effect of a drug
More effect more efficacious the drug

28

What is potency?

Refers to the concentration of the drug
Less concentration required more potent the drug

29

What are nuclear receptors

Ligand activated transcription factors

30

What do GPCRs do?

Activate signal transduction inside the cell
E.g. cAMP

31

What does tyrosine receptor kinases do?

Act as an enzyme
Activated by hormones and growth factors

32

What is the structure and function of RTKs?

For cell growth differentiation
Contain tyrosine (intracellular)
Carry out messages through signal transduction

33

What is a kinase?

Something that has the ability to transfer phosphorus molecules, usually from a high energy substance like ATP

34

What are the types of heterotrimeric G-proteins

Gi- activated Cyclase to increase cAMP
Gs- inhibits adenylate cyclase to decrease cAMP
Gq- activates phospholipase C to produce IP3 and DAG

35

What do beta- adrenoceptors do?

Activate adenylate Cyclades

36

What are the effects of increased cAMP?

Heart (beta 1)- increased heart rate
Lungs- relaxes bronchial smooth muscle

37

Effects of agonists in the lung?

Dilates bronchial smooth muscle
Eases respiration

38

Effects of antagonists in the heart

Slows heart rate and reduces force of beat

39

What activates alpha alpha1-adrenoceptor?

Epinephrine
Expressed in smooth muscle

40

How does alpha-adrenoceptor increase intracellular Ca2+ concentration?

Release from SR (IP3)
Through membrane channels (DAG)
Ca2+ stimulates smooth muscle contraction

41

What is hypertension

High blood pressure

42

What is hypotension

Low blood pressure

43

What other cell responses are regulated by Gq inositol-phospholipid signalling

Liver- vasopressin- glycogen breakdown
Pancreas- acetylcholine- amylase secretion
Smooth muscle- acetylcholine- contraction
Blood platelets- thrombin- aggregation

44

What is dimerisation?

Coupling by an agonist binding to 2 receptors

45

Examples of drugs that inhibit RTK signalling

Imatinib (Gleevec)- for leukaemia
Lapatinib (Tykerb)- EGF receptor inhibitor for breast cancer
Trastuzumab- antibody against EGF for breast cancer

46

What is thioureylene?

Converts T4 to T3

47

What do thyroid hormones promote the synthesis of?

Adrenoceptors

48

What is hypothyroidism for Hashimoto's thyroidtis?

Lack of hormone
Treated by giving T4

49

What does TSH act on?

Receptors on the membrane of the thyroid follicle cells through the mechanism that involves cAMP

50

What do thyroid hormones do?

Increase basal metabolic rate
Increase heat production
Increase glucose uptake

51

How can hyperthyroidism be treated

With beta adrenoceptors antagonists

52

Zones of adrenal cortex

Glomerulosa- aldosterone
Fasiculata and reticularis- adrenal androgens and cortisol

53

Adrenal medulla secretes

Catecholamines
E.g. Epinephrine and norepinephrine
Adrenaline in response to sympathetic nervous system

54

What are adrenocortical hormones?

Steroid hormones

55

What does failure of adrenal medulla cause?
What does tumour of adrenal medulla cause?

Failure- hypotension
Tumour- hypertension
E.g. Phrenocheomocytoma, neuroblastoma

56

What are glucocorticoids

Cortisol
Actions
Metabolic
Negative feedback on AP and H
Anti inflammatory and immunosuppressive effects

57

What are mineralcorticoids

Aldosterone

58

What are sex hormones

Testosterone

59

What are HREs?

Short segments of DNA able to bind a specific hormone receptor complex affecting transcription

60

What are oestrogen receptor antagonists for?

Prevention and treatment of breast cancer (tamoxifen)

61

What is the composition of a typical ligand

Lipophillic hormones with steroid hormones and dedicates of vitamin A and D

62

When is a mineralcorticoid receptor antagonist used?

Liver cirrhosis and heart failure

63

What are oestrogen receptor agonists used for?

Hormone replacement therapy in postmenopausal women

64

Adverse effects of glucocorticoids

Osteoporosis
Cushing's syndrome
Metabolic effects
Suppression of infection
Suppression endogenous glucocorticoid synthesis

65

What is glucocorticoid receptor agonist for?

Inflammation

66

What are the actions of adrenalin in tissues

Increase cyclic AMP

67

What do anti-inflammatory and immunosuppressive activity reduce?

Blood vessel dilation and leakage
Glucocorticoids inhibit phospholipase A2- blocks production of arachidonic acid, pstoglanduns and leukotrienes from cell membrane phospholipid

68

What are androgen receptor antagonists used for?

Prostate cancer treatment

69

How do ADR and Na maintain blood pressure

Iontropic effects on heart and vasoconstrictor
I.e. Increases heart rate and contracts blood vessels

70

Dose vs concentration?

Dose- amount of drug (micro grams, nanomoles)
Concentration- amount of drug per unit volume (micromolar, nanomolar)

71

What are drug receptor controls?

Selectivity of drug effect
Magnitude of response
Mechanisms to prevent/mimic physiological function

72

What is magnitude of response?

Hyperbolic
[AR] = [A]
[RT] Kd + [A]

73

What is EC50?

Concentration required to get half the maximum response

74

How do allosteric Ligands produce effects

By increasing/decreasing potency
Causing an increase/decrease in efficacy

75

What is implied by receptors ability to spontaneously adopt an active site

Level of constitutive activity

76

What is an inverse agonist?

Ligand that binds to the receptor and limits constitutive activity