Drugs and PNS

Question 1

3 components of PNS?

Efferent or afferent

Answer 1

Autonomic (E), somatic (E), sensory (A)

Question 2

How does sympathetic NS affect

a) pupils
b) respiratory rate
c) heart rate
d) blood flow to visceral organs
e) salivary secretions

Answer 2

a) dilate
b) increase
c) increase
d) increase
e) decrease

Question 3

How does parasympathetic NS affect

a) pupils
b) respiratory rate
c) heart rate
d) blood flow to visceral organs
e) salivary secretions

Answer 3

a) constrict
b) decrease
c) decrease
d) decrease
e) increase

Question 4

Describe sympathetic fibres?

Answer 4

Short preganglionic fibre - Ach as NT

Long post-ganglionic fibre - NA as NT

Question 5

Describe parasympathetic fibres?

Answer 5

Long pre-ganglionic fibre - Ach as NT

short post-ganglionic fibres - Ach as NT

Question 6

Describe somatic fibres?

Answer 6

Single fibre terminating at NMJ, Ach as NT

Question 7

How do sweat glands and adrenal glands show exceptions to these rules?

Answer 7

Both sympathetic fibres but
Sweat glands = Ach at synapse to target not NT
Adrenal glands = single fibre using Ach

Question 8

How is acetyl choline made?

Answer 8

Choline transported into fibre

Choline to Ach via cholineacyetyl transferase (CAT)

Question 9

How is Ach stored and released?

Answer 9

Vesicles exocytosis

Question 10

What type of receptor does Ach interact with?

Answer 10

Muscarinic or nicotinic

Question 11

How is Ach terminated?

Answer 11

Acetylcholinesterase (breaks down into choline and acetate)

Question 12

Name muscarinic receptor subtypes?

Answer 12

M1 2 3

Question 13

Where are muscarinic receptors found?

Answer 13

Post-ganglionic parasympathetic synapses

Question 14

What type of receptors are muscarinic?

Answer 14

G coupled

Question 15

What are nicotinic receptor subtypes?

Answer 15

Neuronal and muscular

Question 16

Where are neuronal nicotinic receptors?

Answer 16

Preganglionic sympathetic and parasympathetic synapses

Question 17

Where are muscular nicotinic receptors found?

Answer 17

NMJ (somatic)

Question 18

What type of receptor is nicotinic?

Answer 18

Ligand gated ion channel

Question 19

Action of muscarinic antagonists?

Answer 19

Activate parasympathetic nervous system

Question 20

2 uses of muscarinic agonist and name the drug?

Answer 20

Pilocarpine
Treat glaucoma - pupil contraction
Treat xerostomia - increase saliva flow

Question 21

Use of the muscarinic antagonists

a) Atropine
b) Tropicamide
c) Ipratroprium
d) Hyoscine

Answer 21

a) Treats bradycardia by inhibiting decrease in heart rate
b) Pupil dilation in surgery
c) treat asthma
d) decrease gastric motility and motion sickness

Question 22

Effect of nicotinic agonist at NMJ?

Example

Answer 22

Suxemethonium
Initial depolarisation and muscle fibre contraction (twitch)
Because agonist is not metabolised rapidly by acetylcholinesterase the fibre is constantly depolarised = depolarising block
Paralysis and muscle contraction for surgery

Question 23

Effect of nicotinic antagonist at NMJ?

Example

Answer 23

Tubocurarine
Hyperpolarisation
Inhibition of depolarisation
Non-depolarising block 
Paralysis for surgery

Question 24

What is the main use for nicotinic antagonists and agonists?

Answer 24

Paralysis for surgery

Question 25

Name 4 muscarinic antagonists and their uses?

Answer 25

Atropine - treat bradycardia
Tropicamide - pupil dilation during surgery
ipratroprium - treat asthma
Hyoscine - treat motion sickness (decrease gastric motility)

Question 26

Name the type of drug g that inhibits acetylcholinesterase

Answer 26

anticholinesterases

Question 27

How do anticholinesterases effect autonomic nervous system?

Answer 27

Increased transmission at parasympathetic post-ganglionic synapses = increase parasympathetic effects

Question 28

How do anticholinesterases effect NMJ?

Answer 28

Increased muscle tension and twitching (depolarising block at large doses)

Question 29

Name an anti cholinesterase and its use?

Answer 29

Neostigmine
Myastheia gravis
Induce paralysis for surgery