Adrenergic (2)

Question 1

Which receptor types do ergot alkaloids bind to?

Answer 1

Alpha-adrenoceptors
5-HT receptors
Dopamine receptors

Question 2

What is the physiological effect of ergotamine and what is it used to treat?

Answer 2

Vasoconstrictor

Treats migraines

Question 3

What is the physiological effect of ergometrine and what is it used to treat?

Answer 3

Uterine smooth muscle contraction

Treats post-partum haemhorrage

Question 4

Bromocriptine is an agonist of which receptor type, and what is it used to treat?

Answer 4

D2 receptors

Treats Parkinsonism

Question 5

What are the physiological effects of alpha-adrenoceptor blockade?

Answer 5

Decreased blood pressure - reflex tachycardia
Inability to vasoconstrict - postural hypotension and nasal congestion
Renin release - Na+ and water retention

Question 6

Is prazosin an agonist or antagonist? Of which receptor type? What is its physiological effect?

Answer 6

Alpha1-adrenoceptor antagonist

Causes vasodilation - decreases blood pressure

Question 7

What are the clinical uses of alpha-adrenoceptor antagonists?

Answer 7

Hypertension

Benign prostatic hyperplasia

Question 8

Name a cardioselective beta1-adrenoceptor antagonist

Answer 8

Atenolol

Question 9

Name a non-selective beta-adrenoceptor antagonist

Answer 9

Propranolol

Question 10

What are the clinical uses of beta-adrenoceptor antagonists?

Answer 10

Angina
Hypertension
Glaucoma
Anxiety
Arrhythmias

Question 11

What are the contraindications of beta-adrenoceptor antagonists?

Answer 11

Asthma

Peripheral vascular disease

Question 12

What are the side effects of beta-adrenoceptor antagonists?

Answer 12

Bradycardia
Breathlessness
Cold extremities

Question 13

What are the six stages where drugs can interfere with sympathetic transmission?

Answer 13

Ganglia
Synthesis
Storage
Release
Uptake
Metabolism

Question 14

What is hexamethonium and what does it do?

Answer 14

nAChR antagonist

Blocks ganglion - prevents post-ganglionic neurotransmitter release

Question 15

What does disulfiram do?

Answer 15

Inhibits dopamine-beta-hydroxylase - prevents NA synthesis

Question 16

What does reserpine do?

Answer 16

Binds irreversibly to VMAT - inhibits vesicular NA uptake - depletes vesicular NA storage

Question 17

What is guanethidine and what does it do?

Answer 17

Pumped into vesicles - displaces NA
Pre-junctional alpha2-adrenoceptor agonist
Also blocks Na+ channels in neuron terminal
Blocks adrenergic neuron release

Question 18

What does desmethylimipramine do?

Answer 18

Prevents NA reuptake

Question 19

What does phenelzine do?

Answer 19

Inhibits MAO (MAOI)

Question 20

What is the rate-limiting step in NA synthesis and which enzyme does it require?

Answer 20

L-tyrosine to L-dopa

Requires tyrosine hydroxylase

Question 21

Which drug inhibits tyrosine hydroxylase?

Answer 21

Alpha-methyltyrosine

Question 22

What is the final step of NA synthesis and which enzyme does it require?

Answer 22

Dopamine to NA

Requires dopamine-beta-hydroxylase

Question 23

Name 2 examples of uptake1 inhibitors and describe their effect

Answer 23

Cocaine, tricyclic antidepressants

Prevent NA reuptake into pre-junctional neuron - more sympathetic effects

Question 24

Tyramine binds to which type of receptors?

Answer 24

Post-junctional alpha-adrenoceptors

Question 25

What are the physiological effects of tyramine if it is not broken down?

Answer 25

Vasoconstriction - increased peripheral resistance - increased risk of subarachnoid haemorrhage