Cardiovascular

Question 1

Anti-anginals are used to improve the balance between myocardial oxygen supply and demand. For acute symptoms short acting nitrates (GTN spray/sl tabs, isosorbide dinitrate) can be used. What THREE classes of drug are used in the prevention of angina?

Answer 1

• Beta-blockers; first line - avoid abrupt withdrawal as it can lead to increased myocardial ischaemia, risk of infarction or SUDDEN DEATH!! (Withdraw gradually over 2 weeks, 4-6 weeks if treated for many years)
• Calcium Channel Blockers; second line (if beta-blockers contraindicated), Verapamil and diltiazem in particular.
• Long-acting nitrates; third line.
• Others: ivabradine, nicorandil, perhexiline

Question 2

Beta -blockers should be used with caution in diabetics because they can mask acute signs of hypoglycaemia (tachycardia, tremor). What are some contraindications for beta-blockers?

Answer 2

• Shock
• Bradycardia, second/third degree AV block, sick sinus syndrome, severe hypotension, uncontrolled HF
• Severe or poorly controlled asthma

Be careful in PAD, especially Raynaud’s as they may impair peripheral circulation.

Question 3

What are the four major catecholamines?

Answer 3

DNA-I

Dopamine - precursor of noradrenaline, also a transmitter and neuromodulator in its own right
Noradrenaline - neurotransmitter, precursor to adrenaline
Adrenaline - Hormone
Isoprenaline - synthetic derivative of noradrenaline, not produced in the body

Question 4

Alpha-1 receptors activate phospholipase C leading to increased inositol triphosphate, diacylglycerol and Calcium. They are most responsive to NA. 
How do they act on:
Smooth Muscle - 6
Sphincters - 2 
Liver - 1 
Salivary gland - 1

Answer 4

SM - constrict: bronchi, blood vessels, iris (radial muscle), seminal vesicle, uterus Relax: GIT
Sphincters - Contracts bladder and GI sphincters
Liver - promotes glycogenolysis
Salivary Gland - K release

Question 5

Alpha-2 receptors decrease cAMP, Ca channels and increase K channels. They are most sensitive to adrenaline.
How do they act on:
Smooth muscle - 2
Pancreatic islets - 1
Nerve terminals - Adrenergic and Cholinergic
Platelets - 1
Brain stem - 1

Answer 5

Smooth muscle - constrict/dilate blood vessels, relax GIT
Pancreatic islets - Decrease insulin secretion
Nerve terminals - Adrenergic and Cholinergic - decrease release
Platelets - cause aggregation
Brain stem - inhibit sympathetic out flow

Question 6

ß-1 receptors are most sensitive to isoprenaline and then NA, they increase cAMP within cells.
How do they act on the
Heart - 2
Salivary gland - 1

Answer 6

Heart - increase rate and force of contraction

Salivary gland - Amylase secretion

Question 7

ß-2 receptors are most sensitive to isoprenaline and then adrenaline and also work by increasing cAMP.
How do they act on
Smooth muscle - 7
Heart - 2 
Skeletal Muscle - 3
Liver - 1
Adrenergic nerve terminals - 1 
Mast cells - 1

Answer 7

Smooth muscle - Dilate blood vessels and bronchi, Relax GIT, uterus, bladder detrusor, seminal tract, ciliary muscle
Heart - increase rate of contraction and force (very minor)
Skeletal Muscle - Tremor, increased muscle mass & speed of contraction, glycogenolysis
Liver - glycogenolysis
Adrenergic nerve terminals - increased release
Mast cells - inhibition of histamine release

Question 8

All adrenoceptors are G-protein coupled receptors and all ß receptors increase cAMP. ß-3 receptors are equi-sensitive to A and NA.
How do they act on
Skeletal muscle -1
Fat - 2

Answer 8

Skeletal muscle - thermogenesis

Fat - Lipolysis, thermogenesis