M&R 10.2

Question 1

What is an example of a non-depolarising blocking agent?

Answer 1

tubocurarine

Question 2

What is an example of a depolarising blocking agent?

Answer 2

suxamethonium

Question 3

What is an example of anticholinesterase / AChE inhibitors?

When are they used?

Answer 3

neostigmine
pyridostigmine
donepezil

used in myasthenia gravis - prolong ACh time in synaptic cleft

Question 4

How is NA synthesised? Where is it synthesised? name the enzymes and significance

Answer 4

Tyrosine - tyrosine hydroxylase-> DOPA - DOPA decarboxylase-> Dopamine - dopamine ß-hydroxylase (in vesicle) -> NA

DOPA decarboxylase targeted during Parkinson’s

Question 5

How is NA terminated?

Answer 5

uptake 1: high affinity Na+ dependent, takes NA back into pre-synaptic
uptake 2: low affinity, non-neuronal, takes any NA not captured by uptake 1 (escaped cleft)

rest of NA not taken up will be metabolised by MAO/COMT

Question 6

What are significance of MAO/COMT?

Answer 6

targetted in Parkinsons

Question 7

How do indirect acting sympathomimetic agents work? Examples?

Answer 7

taken into Na synaptic vesicle, and causes NA to leak from synapse without Ca2+ driven exocytosis
e.g. amphetamine, tyramine, ephedrine

Question 8

What are uptake 1 inhibitors? examples?

Answer 8

they act in the CNS, have side effects in the PNS, increase NA stimulation (inhibit uptake 1)
e.g. amitriptyline, imipramine

Question 9

What is trimethaphan used for? What is it?

Answer 9

ganglion blocking drug

treat emergency hypertension, gives controlled hypotension

Question 10

What is tolterodine used for?

Answer 10

treat overactive bladder

Question 11

What are the side effects of non-selective mAChR agonists?

Answer 11

increase HR & CO (M2)
cause bronchoconstriction (M3)
increase sweat & salivary secretion (M1/M3)

Question 12

example of non-selective mAChR agonist? what is it used to treat?

Answer 12

pilocarpine, treat glaucoma (cause pipillary muscle to contract prevent it always dilating)

Question 13

eamples of mAChR antagonists? what is it used to treat?

Answer 13

ipatropium / tiotropium

treat COPD

Question 14

What is used to treat over active bladder? which receptor does it utilise?

Answer 14

oxybutynin - M3

Question 15

What is an example of ß2-agonist? what does it treat?

Answer 15

salbutamol
treat asthma
reverse / oppose bronchoconstriction

Question 16

What is an example of a1-adrenoceptor-selective antagonist? what does it treat?

Answer 16

doxazosin

treat hypertension - inhibit a1, causing decrease in vasoconstriction

Question 17

What are examples of ß1-adrenoceptor selective antagonist?

Answer 17

atenolol, bisoprolol, metoprolol

treat hypertension

Question 18

What is an example of a mixed ß1/ß2/a1 adrenoceptor antagonist?

Answer 18

carvedilo

Question 19

how do you prevent NA release?

Answer 19

stimulate a2-adrenoceptor

Gi, adenyly cyclase decrease, ßgamma inhibits some VOCC (L-type?), preventing influx of Ca2+ lead exocytosis of NA

Question 20

How do post ganglionic sympathetic neurones work?

Answer 20

they have highly branched axonal network called varicosities

each is a specialised site for Ca2+ independent NA release