nicotinic cholinergic synapse Flashcards

1
Q

what is the role of vesamicol?

A

blocks transfer of ACh into vesicles

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2
Q

what is the role of batulinum toxin?

A

blocks the release of Ach from nerve ending

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3
Q

what is the role of anticholinesterases?

A

prevent the hydrolysis of ACh by enzyme acetylcholinesterases

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4
Q

what is the role of hemicholinium?

A

blocks uptake of choline by neuromuscular junction

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5
Q

n bmkx,,what is noradrenaline?

A

neurotransmitter that plays a key role in the bodys sympathetic nervous system

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6
Q

where is noradrenaline synthesised and what is the rate limiting step

A

occurs in noradgrenic nerves, tyrosine hydroxylase is rate limiting step

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7
Q

where does noradrenaline act on?

A

adrenergic alpha and beta adrenoceptors

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8
Q

give 3 actions that happens when noradrernaline acts upon adrenergic receptors

A

increased heart rate + blood pressure
vasoconstriction
bronchodilation

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9
Q

what is the role of disulfram? (synthesis)

A

inhibits dopamine beta-hydroxylate, casuing depletion of NA stores

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10
Q

what is the role of reserpine? (storage)

A

blocks mechanism that transports NA into vesicles

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11
Q

what is the role of tyramine (amphetamine)? (release)

A

increase release of NA from vesicles

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12
Q

what is the role of nimodipine? (release)

A

reduces release by blockage of Ca2+ channels in nerve terminals

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13
Q

give 4 effects of alpha 1-adrenoceptors

A
  • contraction of smooth muscle (blood vessel)
  • relaxation of gut smooth muscle
  • salivary secretion
  • hepatic glycogenolysis
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14
Q

give 4 effects of alpha 2-adrenoceptors

A
  • inhibition of transmitter release
  • platelet aggregation
  • contraction of vascular smooth muscle
  • decreased insulin release
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15
Q

what is the effect of beta 1-adrenoceptor

A

increased heart rate

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16
Q

what is the 4 effects of beta 2-adrenocpetor?

A
  • bronchodilation
  • vasodilation
  • muscle tremor
  • relaxation of gut smooth muscle
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17
Q

what is the effect of beta 3-adrenocpetor

A

lipolysios

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18
Q

which adrenoceptors is adrenaline an agonists of? (epinephrine)

A

a1, a2, b1, b2

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19
Q

which adrenoceptors is noradrenaline an agonists of? (norepinephrine)

A

a1, a2, b1

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20
Q

which adrenoceptors is isoprenaline an agonists of? (isoproterenol)

A

b1, b2

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21
Q

give an agonist of alpha 1

A

phenylephrine

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22
Q

give an agonist of alpha 2

A

clonidine

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22
Q

give a b1-agonist

A

dobutamine (heart failure)

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23
Q

give a b2-agonists

A

salbutamol

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23
Q

give a non selective a-antagonist

A

phentolamine

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23
Q

give an a2-antagonist

A

yohimbine

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24
Q

give an a1-antagonist

A

prazosin

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25
Q

give a b1-antagonists

A

atenolol

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26
Q

give a non-selectibe b-antagonist

A

propranolol

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27
Q

give a b2-antagonist

A

butaxamine

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28
Q

what is the PNS split into

A

somatic (effernt) system and autonomic system

29
Q

what is the role of the somatic nervous system and is it voluntary or involuntary?

A

innervates skeletal muscle
- voluntary

30
Q

what is the role of the autonomic nervous system and it is voluntary or unvolntary ?

A

innervates smooth muscle (blood vessel)
- involuntary

31
Q

what is the autonomic system split into

A
  • sympathetic (fight or flight)
  • parasympathetic (rest and digestion)
32
Q

where in the PNS is ACh found?

A

somatic and parasympathetic nerves

33
Q

where in the PNS is NA found

A

postganglionic sympathetic nerves

34
Q

in the somatic nervous system where does ACh act?

A

on nicotinic receptors to cause contraction

35
Q

in the parasympathetic system where does ACh act?

A
  • long preganglionic nerves release ACh to activate nicotinic receptors
  • postganglionic nerves release Ach to activate muscarnic receptors
36
Q

in the sympathetic system where does NA act?

A

postganglionic nerves release NA and act on adrenergic receptors

36
Q

in the sympathetic system where does ACh act?

A
  • preganglionic nerves release Ach to activate nicotinic receptors
37
Q

what 3 agonists stimulate nicotinic receptors and what do they do

A
  • nicotine
  • acetylcholine
  • carbachol
    contract muscles
38
Q

give 2 nicotinic receptor antagonists and what do they do?

A
  • tubocurarine
  • panctonium
    prevent muscle action
39
Q

give 3 parasympathetic target organs that contain muscarinic receptors

A
  • heart
  • lungs
  • glands
40
Q

give a muscarinic receptor agonist and what does it do?

A
  • bethanechol
    increase secretion and decrease heart rate
41
Q

give a muscarinic receptor antagonist and what does it do?

A
  • atropine
    increasing heart rate or relaxing airways
42
Q

give the 7 types of drug binding

A
  1. covalent
  2. ion-ion
  3. ion-dipole
  4. dipole-dipole
  5. hydrogen bonding
  6. van der waals
  7. hydrophobic bonding
43
Q

give the 2 pharmacological options for enhancing cholinergic effects at the NMJ to treat myasthenia gravis

A
  • increasing ACh in NMJ to stregnthen muscle contraction
  • mimic the effect of ACh at the NMJ
44
Q

what is the role of anticholinesterases

A

increase ACh at nicotinic and muscarinic receptors

45
Q

what is the role of nicotinic agonists

A

mimic the effet of ACh

46
Q

true or false skeltal muscles favour the quaternary ammonium group of Ach

A

TRUE

47
Q

true or false muscarinic receptors are more sensitive to changes in ester group

A

TRUE

48
Q

What does more potent mean

A

achieves biological response at a lower concentratiom

49
Q

what does less potent mean

A

requires a higher concentration to achieve the same effect

50
Q

what does equipotemt molar ratios show

A

hoe effective different variants of ACh are at NIC and MUS receptors

51
Q

what does higher EMR show

A

less potency

52
Q

what is the role of the ethylene bridge in ACh

A
  • connects ammoinium group to ester group
  • maintains structural integrity
    -conformational flexibility
  • provides optimal distance between group and binding site
53
Q

what happens if you shorten the ethylene bridge

A

reduces receptor affinity

54
Q

what happens if you rigidify the ethylene bridge

A

can improve receptor selectivity by locking acetylcholine conformations

55
Q

what are rigid analogues

A

molecules designed to mimic ACh’s key functional features while constrainig its conformational flexibility

56
Q

what is a pharmacophores

A

molecular structure that is required for a compound to inteact with a specific receptor

57
Q

why do NIC and MUS pharmacophores differ

A

they belong to different families

58
Q

what types of receptor is NIC

A

ligand gated ionotropic reeptor at extracellular domain

59
Q

what types of receptor is MUS

A

G-protein coupled metabotropic receptor with transmembrane region

60
Q

give the characrteristic of a nicotinic antagonist

A

biquaternary ammomium compounds (competitive antagonist)

61
Q

give 2 applications of neuromuscular blocking agents

A
  • relax skeletal muscles during surgery
  • reduce patient movement and facilitate intubation
62
Q

give an application of ganglionic blockage

A

used for managing hypertension by reducing autonomic activity

63
Q

give the number chain length with maximum potency and the name of the ganglionic blocker

A
  • 6 carbons
  • hexamethonium
64
Q

how does the ganglionic blocker work

A

blocks signal transmission between preganglionic and postganglionic neurons

65
Q

give the number chain length with maximum potency and the name of the neuromuscular blockers

A
  • 10 carbons
  • decamethonium
66
Q

why do neuromuscular blockers have a longer chain length

A
  • 2 ammonium groups
  • NMJ required longer space between ammonium groups
67
Q

what is the function of acetylcholinesterases

A

regulate ACh by hydrolysing it

68
Q

what is the function of anticholinesterases

A

enhance acetylcholine activity by inhibiting acetylcholinesterase

69
Q

give the 3 groups of anticholinesterases and their reversibility

A
  1. reversible (short acting): edrophonium
  2. time dependent irreversible: neostigmine
  3. irreversible (organophosphorus): dyflos
70
Q

how many subunits do NIC receptors have

A

5

71
Q

briefly explain the 2 sites in acetylcholinesterases

A
  1. anionic site: cation pi-interactions
  2. esteric site: mediates catalysis via covalent bonding and breakdown