pharmacology of the ANS

Question 1

describe a parasympathetic nerve in terms of length and neurotransmitters

Answer 1

long pre-ganglionic nerve,
first NT: aCh - nicotinic receptor
second NT: aCh - muscarinic receptor

Question 2

describe a sympathetic nerve in terms of length and neurotransmitters

Answer 2

shorter preganglionic neurons, 1st synapse aCh(n), second synapse NA alpha and beta receptors for organ targets.

for systemic release, first neurone goes to adrenal gland so second neurotransmitter can be adrenaline or noradrenaline

Question 3

IN the para sympathetic NS, what is ALWAYS the ganglionic neurotransmitter and receptor

Answer 3

ACh(n)

Question 4

LIst the secondary SYMPATHETIC NTs and receptors for
* straight tohearts and vessels
* sweat glands and vessels
* renal vessels
* via adrenals

Answer 4

• Noradrenaline alpha and beta NA receptors
• Ach(m2)
• Dopamine (d1 dopaminergic)
• adrenaline goes into blood then alpha and beta receptors on hearts and vessels

Question 5

where do you get varicosities. What does it do?

Answer 5

post ganglionic neurones of the ANS (both SNS and PNS). Spread neurotransmitters throught the tissue in a network of varicosities rather than having to have loads of separate axons

Question 6

what is NANC

Answer 6

non-adrenergic non- cholinergic neurotransmitter, common in airways, smooth muscle

can be Nitrous Oxide, Vasoactive Intestinal Peptide, neuropeptide Y, 5HT, ATP

often co-transmitted with ACH or Noradrenaline. Work as inhibitors (I think)

Question 7

what are the characteristics of nicotinic receptors

Answer 7

pentameric sodium ion channel
usually heteromeric (2 alpha, 2 beta)
different alpha types:
* 3: autonomic ganglia
* 1: NMJ
* 4&7: CNS

Question 8

why are ACh(N) receptors heteromeric

Answer 8

more affinity

Question 9

what plant products mimic ACh action on receptors

Answer 9

nicotine for Ach(n) and muscarine (dangerous poison in Fly Agaric mushrooms)

Question 10

what drug treats Glaucoma and why

Answer 10

Carbachol - nicotinic agonist but, like Ach works at both N and M Ach receptors - parasympathomimetic
causes pupillary contraction and increased aqueous humour

Question 11

where does nicotine select for

Answer 11

CNS, ganglia, not NMJ

Question 12

where does succinylcholine select for

Answer 12

NMJ (think paralysis

Question 13

name 2 nicotinic antagonists. what do they do

Answer 13

tubocurarine
pancuronium

block receptors so Ach can’t bind. neuromuscular block - paralysis

Question 13

name 2 nicotinic antagonists. what do they do

Answer 13

tubocurarine
pancuronium

block receptors so Ach can’t bind. neuromuscular block - paralysis

Question 14

what does activation of the IP3/DAG pathway lead to

Answer 14

smooth muscle contraction

Question 15

what are the functions of the different Muscarinic receptors

Answer 15

1,3,5 excitatory, 2&4 inhibitory

Question 16

what is a muscarinic recpetor

Answer 16

GPCR

Question 17

what type of receptor is a nicotinic receptor

Answer 17

Ligand gated ion channel

Question 18

why are some muscarinic actions inhibitory and some excitatory

Answer 18

heart rate needs to go down but gastric secretions etc need to go up

Question 19

which areas have M1, M2, M3 receptors

Answer 19

M1 CNS, gastric parietal cells (excitatory
M2 heart (inhibitory)
M3 all other organs (think Vagus nerve) (excitatory)

Question 20

what’s the problem with carbachol

Answer 20

non-selective - works on M and N receptors

Question 21

how would you diagnose Adie pupil

Answer 21

pupil is tonic whether bright or dim light
one drop of pilocarpine produces significant consrtiction
Therefore likely aetiology of tonicity is denervated post-ganglionic iris - Adie pupil

Question 22

what drug would you use to achieve increased bladder contraction

Answer 22

bethanechol, selective muscarinic receptor agonist. M3 receptors on bladder are excitatory

Question 23

what does a muscarinic antagonist do

Answer 23

blocks Ach binding, stops parasympathetic action

Question 24

name some effects of atropine and what it does

Answer 24

non-selective muscarinic antagonist
bronchodilation
pupil dilation
treats bradycardia
antidote fro organophosphate poisoning

Question 25

what is a drug for asthma which is a muscarinic antagonist? how does it work

Answer 25

ipratropium - blocks ACHMR, prevents bronchoconstriction - encourages bronchodilation

Question 26

what is scopolamine

Answer 26

ACHMR GI antispasmodic

Question 27

what would a M1 antagonist in the gut do. Name one

Answer 27

reduce gastric secretions. Pirenzepine

Question 28

what would a M2 antagonist in the heart do. Name one

Answer 28

cause tachycardia - gallamine

Question 29

name a M3 antagonist. What does it treat

Answer 29

solifenacin - overactive bladder

Question 30

how could you increase ach function

Answer 30

use a cholinesterase inhibitor

Question 31

what drug is used for Myasthenia Gravis and what is it

Answer 31

neostigmine or pyridostigmine- cholinesterase inhibitor

Question 32

is Botox reversible and what does it do

Answer 32

cleaves snare proteins so vesicles can’t bind so no Ach is released

Question 33

what is the molecule that breaks down dopamine

Answer 33

COMT

Question 34

what does dopamine start as

Answer 34

tyrosine

Question 35

how does tyrosine become adrenalin

Answer 35

in the kidneys monoamine oxidases degrade it to L-dopa -> dopamine->noradrenaline
then adrenal medulla PNMT enzyme converts it to adrenaline

Question 36

what is the interaction between warfarin and phenytoin

Answer 36

both bind to albumin - competitive binding. If one drug is ceased, the other will bind to the available receptors, making it less effective (potentially leading to stroke or epilepsy)

Question 37

what drugs are contraindicated in asthmatics who use salbutamol

Answer 37

beta blockers