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Pharmacology Y2 > Sympathetic Nervous System > Flashcards

Sympathetic Nervous System Flashcards

1
Q

Define the word ‘gating’ in terms of activation on an agonist

A

This is the reaction where the complex of the agonist and receptor become active

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2
Q

When does affinity occur in the activation of a drug?

A

This is when the agonist and receptor bind to each other

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3
Q

When does efficacy occur in the activation of a drug?

A

This is when the complex of the agonist and receptor become activated

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4
Q

Do modulators act at the same binding site as the agonist?

A

No, they act at an allosteric binding site

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5
Q

What is the function of modulators?

A

They can either increase or decrease the effect of the agonist, so a lower concentration of the drug is required to achieve the drug result

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6
Q

What is a reversible competitive antagonist?

A

When bound to the receptor it prevents the agonist from binding to the receptor

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7
Q

What happens if you increase the concentration of the agonist to a reversible competitive antagonist?

A

It can overcome the effect of the antagonist as the bonds formed by the antagonist are not permanent

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8
Q

What is an irreversible competitive antagonist?

A

When bound to the receptor it prevents the agonist binding, but bonds covalently so limits the maximum efficacy that can be reached

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9
Q

What is a non competitive antagonist?

A

When bound to receptor covalently it prevents the agonist from binding, however binds to an allosteric site on the receptor

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10
Q

What does selective mean in terms of antagonists/agonists?

A

Means that the drug affects that specific receptor in a specific cell population, and will have a stronger effect there rather than other sites

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11
Q

What does non selective mean in terms of antagonists/agonists?

A

Means that the drug will nit distinguish between drug sites and the receptor it binds to, will affects multiple sites in the body

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12
Q

Which adrenoreceptors are excitatory?

A

Alpha 1
Beta 1
Beta 2

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13
Q

Which adrenoreceptors are inhibitory?

A

Alpha 2
Beta 3

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14
Q

Name 2 non selective alpha receptor antagonists

A

Phenoxybenzamine
Phentolamine

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15
Q

Is phenoxybenzamine competitive or non competitive?

A

It is a non competitive antagonist

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16
Q

Is phentolamine competitive or non competitive?

A

Competitive, reversible

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17
Q

Which receptors does phenoxybenzamine and phentolamine affect?

A

Alpha 1
Alpha 2

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18
Q

What happens to blood pressure when adrenaline is added?

A

Initially increases due to activation of alpha 1+ beta 1 receptors, then decreases back to normal due to baroreceptor reflex

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19
Q

What happens to blood pressure when phentolamine is added?

A

Initially decreases due to inhibition on alpha 1 + beta 1 receptors, then increases back to normal due to baroreceptor reflex

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20
Q

What happens to blood pressure when adrenaline is added in the presence of phentolamine?

A

Blood pressure decreases -> adrenaline is much lower due to the competitive antagonism -> low levels of adrenaline activate beta 2 instead of alpha 1 -> beta 2 receptors cause vasodilation, so blood pressure decreases

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21
Q

Name 3 selective alpha 1 antagonists

A

Prazosin
Doxazosin
Tamulosin

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22
Q

Name 3 selective alpha 2 antagonists

A

Yohimbine
Idazoxan
Atipamezole

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23
Q

How do alpha 2 antagonists result in antidepressant effects?

A

Blocking alpha 2 prevents noradrenaline reuptake form the synapse -> more neurotransmitter in the synapse can result in antidepressant effects

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24
Q

How do alpha 1 antaognists result in postural hypotension(venous pooling)?

A

Blocked baroreceptor reflex -> sympathetic nervous system is not able to increase heart rate fast enough through vasoconstriction or sympathetic drive when standing up -> results in venous pooling

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25
Q

How do alpha 1 antagonists result in nasal stuffiness?

A

Causes dilation of blood vessels in nasal passage -> narrows the airways

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26
Q

How do alpha 1 antagonists result in miosis (constriction of the pupil)?

A

Radial muscle in eye dilates with alpha 1 activation -> antagonist for alpha 1 will result in constriction of the pupil

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27
Q

What is the baroreceptor reflex response to the blood pressure falling due to alpha 1 antagonists?

A

Baroreceptor reflex can only affect sympathetic drive not vasculature -> activates beta 1 -> tachycardia -> increases release of renin for RAAS -> increased reabsorption of sodium and water -> oedema/weight gain

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28
Q

How are alpha adrenoreceptor antagonists used to treat hypertension?

A

Alpha 1 antagonists prevent noradrenaline or adrenaline from binding to alpha 1 receptors on vasculature -> vasodilation -> lowered blood pressure

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29
Q

How are alpha adrenoreceptor antagonists used to treat benign prostatic hyperplasia?

A

Alpha 1 antagonists prevents noradrenaline or adrenaline from binding to the smooth muscle of the prostate ->
dilation of the smooth muscle -> allows urethra to open to empty bladder

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30
Q

Which selective alpha 1 antagonist has a high affinity to alpha 1 receptors on the prostate?

A

Tamulosin

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31
Q

If an antagonist has a high affinity for the receptor, does it require a high or low dosage?

A

High affinity drugs require a lower dosage for the wanted drug result

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32
Q

If an antagonist has a low affinity for the receptor, does it require a high or low dosage?

A

Low affinity drugs require a higher dosage for the wanted drug result

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33
Q

Which selective alpha 1 antagonist has a low affinity to alpha 1 receptors on the prostate?

A

Prazosin

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34
Q

What contra indication could occur with a high dosage of a alpha 1 antagonist?

A

Blood pressure could also lower which could be dangerous

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35
Q

Name 3 selective beta 1 antagonists

A

Atenolol
Bisoprolol
Metoprolol

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36
Q

Name 2 non selective beta 1 antagonists

A

Propanolol
Sotalol

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37
Q

Propanolol also blocks beta 2 receptors aswell as beta 1. What are the contraindications of this?

A

Blocking beta 2 receptors will also prevent bronchodilation of the smooth muscle in trachea, therefore can be dangerous for people with asthma.

38
Q

Define intrinsic sympathomimetic activity

A

Beta blockers that can stimulater agonistic and antagonist effects of adrenaline and noradrenaline

39
Q

Do beta blockers with intrinsic sympathomimetic activity have agonistic effects at low concentrations?

A

No, only at high concentrations, therefore is not a partial agonist

40
Q

Outline where a beta blocker with intrinsic sympathomimetic activity would be used

A

The beta blocker could be used to cause vasodilation and bradycardia, but if you wanted to also stimulate the heart the intrinsic sympathomimetic activity would work to do this

41
Q

Name 2 beta blockers with intrinsic sympathomimetic activity

A

Pindolol
Oxyprenolol

42
Q

What receptors can a vasodilation beta blocker act on?

A

Beta receptors
Alpha 1 receptors

43
Q

Name 2 vasodilation beta blockers that act on beta and alpha 1 receptors

A

Carvedilol
Labetalol

43
Q

Name 2 vasodilation beta blockers that act on beta and alpha 1 receptors

A

Carvedilol
Labetalol

44
Q

What is the effect of carvedilol binding to beta receptors?

A

Reduced heart rate and contractility

45
Q

What is the effect of carvedilol binding to alpha 1 receptors?

A

Reduced peripheral resistance
Decreased blood pressure

46
Q

Does the baroreceptor reflex occur when carvedilol is given?

A

No - the response of baroreceptor reflex to vasodilation is to increase heart rate, however it cannot dp this as carvedilol also acts of the beta 1 receptors of the heart, so no compensation occurs

47
Q

Name a drug that uses nitric oxide to cause vasodilation?

A

Nebivolol

48
Q

How does nevibolol cause vasodilation?

A

Activates beta 3
Inactivates beta 1

49
Q

How does activating beta 3 receptors result in vasodilation?

A

Beta 3 stimulation of the myocardium releases NO from the endothelium of the myocardium.
NO causes vasodilation, reducing fibrosis and hypertrophy.

50
Q

List 5 conditions that beta adrenoreceptor antagonists are a therapeutic use against

A

Congestive heart failure
Angina
Hypertension
Myocardial infarction
Arrhythmias

51
Q

How do beta adrenoreceptor antagonists help angina?

A

Reduces heart workload
Reduced pain

52
Q

How do beta adrenoreceptor antagonists help hypertension?

A

Reduced cardiac output
Reduced renin release (reduced angiotensin 2 release)
Reduced water retention
Reduced blood pressure

53
Q

How do beta adrenoreceptor antagonists help myocardial infarction?

A

Reduced sympathetic stimulation from the brain
Reduced blood pressure

53
Q

How do beta adrenoreceptor antagonists help myocardial infarction?

A

Reduced sympathetic stimulation from the brain
Reduced blood pressure

54
Q

How can beta adrenoreceptor antagonists help thyrotoxicosis?

A

Decreased thyroid hormone release
Decreased sympathetic stimulation

55
Q

How can beta adrenoreceptor antagonists help glaucoma?

A

Blocks beta 2 receptors on the ciliary body which reduces production of aqueous fluid, therefore reducing the intraocular pressure

56
Q

Lipid soluble drugs have a _______ half life

A

Shorter

57
Q

_____ soluble drugs have a longer half life

A

Water

58
Q

Lipid soluble drugs are metabolised by the _____

A

Liver

59
Q

_____ soluble drugs are excreted by the kidney

A

Water

60
Q

What does it mean is a beta blocker has ‘spontaneous activity’?

A

Nothing needs to be bound to it in order to activate it, it can be activated on its own without an agonist

61
Q

Can a neutral, normal antagonist block the receptor even when an agonist is not present?

A

No, the agonist has to be present for the antagonist to block the action of the receptor

62
Q

What type of beta blocker can prevent spontaneous activity from occurring even when an agonist is not present?

A

Inverse agonist

62
Q

What type of beta blocker can prevent spontaneous activity from occurring even when an agonist is not present?

A

Inverse agonist

63
Q

Describe the action of inverse agonists

A

Antagonists that, when bound, prevent the agonist from binding but also stop the receptor from spontaneously going into the active state when the agonist is not present

64
Q

Name an inverse agonist

A

Metaprolol

65
Q

List 5 unwanted side effects of beta blockers

A

Fatigue
Bradycardia
Cold extremities
Hypoglycaemia
Sleep disturbance/nightmares

66
Q

How can beta blockers cause hypoglycaemia?

A

Beta 2 receptors on the liver stimulate the release of glucose, so when these receptors are blocked the body cannot increase the blood glucose levels fast enough for the bodys need

67
Q

What disease can be caused by prolonged hypoglycaemia?

A

Insulin resistance and type 2 diabetes

68
Q

How can hypoglycaemia caused by beta blockers lead to diabetes?

A

Reaction to hypoglycaemia is to increase beta stimulation to release more glucose from the liver, however this will exacerbate the hypoglycaemia

69
Q

What affect do beta blockers have on blood triglycerides and HDL?

A

They increase the blood triglycerides and decrease levels of HDL (good thing)

70
Q

What affect do alpha 1 antagonists have on blood triglycerides and HDL?

A

They reduce blood triglycerides and increase levels of HDL (and decrease LDL, bad thing)

71
Q

Name 2 beta blockers that all have an alpha 1 antagonistic effect?

A

Carvedilol
Labetalol

71
Q

Name 2 beta blockers that all have an alpha 1 antagonistic effect?

A

Carvedilol
Labetalol

72
Q

Only when the Gs receptor is ______________, it allows arresting to bind

A

Phosphorylated

73
Q

What happens when arrestin is bound to a Gs receptor?

A

It results in desensitisation and inactivation of the Gs receptor

74
Q

Name 2 beta blockers that stimulate the phosphorylation and arrestin pathway of blocking receptors

A

Carvedilol
Nebivolol

75
Q

Why would the arrestin pathway be favoured over blocking the receptor sites for adrenaline and noradrenaline?

A

It reduces the levels of cAMP and Ca2+ influxes during heart failure

76
Q

Blockage of adrenoreceptors can be caused by inhibition of s________ and s______ of neurotransmitter

A

Synthesis
Storage

77
Q

Name 3 drugs that are used in the blockage of synthesis of adrenaline and noradrenaline

A

Alpha methyltyrosine
Alpha methyl DOPA
Disulfiram

77
Q

Name 3 drugs that are used in the blockage of synthesis of adrenaline and noradrenaline

A

Alpha methyltyrosine
Alpha methyl DOPA
Disulfiram

78
Q

What is the mechanism of alpha methyl tyrosine?

A

It blocks the tyrosine hydroxylase enzyme in the pathway that forms adrenaline and noradrenaline

79
Q

What is the mechanism of alpha methyl DOPA?

A

It is an analogue of L-DOPA, so is substitutes into the pathway and eventually forms alpha methyl noradrenaline

80
Q

How does alpha methyl noradrenaline reduce sympathetic outflow?

A

It is selective for alpha 2, so does not cause vasoconstriction, and activation of more alpha 2 receptors reduces sympathetic outflow from brain stem

81
Q

Which enzyme in production of adrenaline and noradrenaline does disulfiram block?

A

It blocks dopamine beta hydroxylase so prevents dopamine becoming noradrenaline or adrenaline

82
Q

Name a drug used to prevent noradrenaline reuptake into the presynaptic vesicle

A

Reserpine

83
Q

Which receptor on the pre synaptic vesicles does reserpine block?

A

VMAT2

84
Q

Why is reserpine effective?

A

Prevents noradrenaline coming back to pre synaptic knob so I cannot be released again into the synapse

85
Q

How does blockage of alpha 2 receptors affect noradrenaline release from the presynaptic membrane?

A

Blocking the alpha 2 receptors means that there is no detection of noradrenaline in the synapse, therefore more noradrenaline is released from the presynaptic membrane

86
Q

Are the blood vessels in the nasal passage determined by alpha 1 or beta 2?

A

Their vasoconstriction/vasodilation relies on the stimulation of alpha 1 receptors

87
Q

Which receptors are involved in angina?

A

Angina is to do with the constriction of coronary blood vessels, which is caused by alpha 1 receptors

Pharmacology Y2 (9 decks)

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