drugs acting in the Sympathetic system

Question 1

Name 6 things the sympathetic nervous system does

think HR, bronchi and mucus, sweating, gut muscles and secretion, adrenaline and detrusor muscle

Answer 1

• increased heart rate
• bronchodilation and inhibiton of mucus secretion
• increased sweating
• Decreased motility of gut muscles and inhibition of secretion
• release of adrenaline
• relaxation of detrusor muscle  contraction of sphincter  decreased micturition

Question 2

What neurotransmitter is produced from the postganglionic neurons and effects adrenergic receptors in the sympathetic nervous system

Answer 2

noradrenaline

Question 3

What neurotransmitter is produced from the preganglionic neuron and effects nicotinic acetylcholine receptors in the Sympathetic nervous system

Answer 3

ACh

Question 4

what receptors are does Ach from the preganglionic neurone bind to to allow the eventual release of Noradrenaline

Answer 4

nicotinic acetylcholine receptors

Question 5

What are the 2 outlier target organs that are stimulated by ACh rather than adrenaline/noradrenaline

Answer 5

• adrenal medulla
• sweat glands

Question 6

What is the main neurotransmitter that works in the airways alongside noradrenaline

Answer 6

adrenaline

Question 7

What is the relative potency ranking list in a-adrenergic receptors

Answer 7

adrenaline > noradrenaline > isoprenaline

Question 8

What are the 2 two subtypes of a-adrenergic receptors

Answer 8

• a1-adrenergic receptors
• a2-adrenergic receptors

Question 9

What is the relative potency in B-adrenergic receptors

Answer 9

isoprenaline > adrenaline > noradrenaline

Question 10

What are the 2 subtypes of B-adrenergic receptors and state if adrenaline or noradrenaline is more potent at each receptor subtype

Answer 10

• B1 adrenergic receptors (adrenaline and noradrenaline potency is equal)
• B2 adrenergic receptors ( adrenaline is more potent then noradrenaline )

Question 11

where are B2 receptors

Answer 11

• lungs
• blood vessels

Question 12

where are B1 receptors found?

Answer 12

• heart
• gut

Question 13

What G protein are B1 receptors couple to in the heart and what does this do in heart

Answer 13

• Gs G protein
• increase heart rate and force of contraction of cardiac muscle.

Question 14

Via what molecule do Gs G proteins signal

Answer 14

cAMP

Question 15

Outline how adrenaline/noradrenaline increases heart rate

Answer 15

1. Adrenaline/noradrenaline binds to B1 receptor
2. a-GTP subunit of Gs protein binds to adenylyl cyclase, converting ATP to cAMP
3. cAMP binds to sodium ion channels, opening them and allowing influx of sodium ions
4. depolarizes cardiac cell membrane, increasing HR

Question 16

Outline how adrenaline/noradrenaline increase force of contraction

Answer 16

1. Adrenaline/noradrenaline binds to B1 receptor
2. a-GTP subunit of Gs protein binds to adenylyl cyclase, converting ATP to cAMP
3. cAMP activates Protein Kinase A (PKA)
4. PKA binds to calcium ion channels, opening them and allowing influx of Ca2+
5. this depolarizes cardiac cell membrane, increasing force of contraction

Question 17

Outline how adrenaline/noradrenaline causes bronchodilation

Answer 17

1. Adrenaline/noradrenaline binds to B2 receptor
2. a-GTP subunit of Gs protein binds to adenylyl cyclase, converting ATP to cAMP
3. cAMP activates PKA
4. PKA phosphorylates myosin light chain kinase, which effects the myosin muscle system, causing relaxation of smooth muscle

Question 18

what 2 reasons does salbutamol work longer and thus a better alternative to adrenaline in treating asthma with inhalers

Answer 18

• more resistant to metabolism by COMT on the HO- side of the molecule
• more resistant to metabolism by MAO on the CH3 end

Question 19

What drug is better for treating asthma than salbutamol and how long does it last

Answer 19

• salmeterol
• 12 hours

Question 20

How is Noradrenaline (NA) reuptaken into the postganglionic neuron

Answer 20

Noradrenaline transporter (called NET)

Question 21

Name 2 uptake inhibitors of noradrenaline

Answer 21

• cocaine
• amphetamine

Question 22

What are unwanted cardiovascular effects of cocaine and amphetamine

Answer 22

• In Heart: increased rate and force of contraction

– In blood vessels: blood vessels constricting

• in Kidneys: release of renin, increasing fluid volume.

this is all due to increase noradrenaline in the synaptic cleft

Question 23

What are unwanted urinary bladder effects of cocaine and amphetamine

Answer 23

relaxtion of detrustor muscle and contraction of sphincter muscles leading to urinary retention (cant go to the toilet) due to increased Noradrenaline in the cleft.