circulation

Question 1

selection of drugs to treat hypertension: why not use drugs which donate ‘ready-to-use’ exogenous nitric oxide

Answer 1

too short-acting to be useful; still used to relieve angina

Question 2

selection of drugs to treat hypertension: why not use drugs which impede phosphodiesterase enzyme to prevent degradation of nitric oxide

Answer 2

unwanted side effects such as erections (marketed as viagra)

Question 3

selection of drugs to treat hypertension: why not use drugs which inhibit ACh

Answer 3

too many side effects as widely used neurotransmitter

Question 4

selection of drugs to treat hypertension: why are drugs which act as Ca2+ channel blocker used

Answer 4

prevent IP3 causing Ca2+ influx, impeding cross-bridge cycling causing contraction and vasoconstriction

Question 5

how do ACE inhibitors and angiotensin receptor blockers treat hypertension

Answer 5

prevent angiotensin I being converted to angiotensin II, preventing downstream vacular smooth muscle contraction

Question 6

when is COX-1 used

Answer 6

widely

Question 7

when is COX-2 used

Answer 7

upregulated during physiological insult

Question 8

effect of aspirin acetylation on COX-1

Answer 8

irreversible inactivation

Question 9

effect of aspirin acetylation on COX-2

Answer 9

irreversibly switches function to generate protective lipids (COX-2-specific inhibitors cause reverse inhibition of COX-2 isoforms only)

Question 10

why does protacyclin levels remain the same but prostaglandin and thromboxane synthesis decrease in proportion with low dose aspirin

Answer 10

nucleus in endothelial cells able to build more COX so not affected by aspirin (platelets have no nucleus so cannot do this)