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1

Statins are used to treat atherosclerosis. Which of the following is the major molecular target of statins in the liver?
A. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG CoA) reductase
B. Low density lipoprotein (LDL) receptor
C. SRE-binding protein (SREBP)
D. SREBP cleavage activating protein (SCAP)
E. Sterol response element (SRE)

A. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG CoA) reductase

2

Hypertension is a major risk factor for myocardial infarction.Which of the following factors is beneficial strategy to treat hypertension?
A. Increase cardiac afterload
B. Increase cardiac preload
C. Increase renal Na+ excretion
D. Increase renal water reabsorption
E. Increase vascular resistance

C. Increase renal Na+ excretion

3

A new antidysrhythmic agent, CV307, has been developed. Its mechanism of action has been compared to other available antidysrhythmic agents.CV307 rapidly blocks voltage-gated Na+ channels in a use-dependent manner and preferentially binds to the inactive state of voltage-gated Na+ channels. Which current antidysrhythmic agent is most similar in action to CV307?
A. Amiodarone
B. Atenolol
C. Flecainide
D. Lidocaine
E. Quinidine

D. Lidocaine

4

Which of the following is a beneficial strategy in the treatment of angina pectoris?
A. Increasing cardiac afterload
B. Increasing excretion of Na+
C. A positive chronotropic effect
D. Inhibition of the late inward Na+ current
E. Inhibition of T-type Ca2+ channels

D. Inhibition of the late inward Na+ current

5

Pain in angina is caused by myocardial ischaemia. Which of the following factors is least likely to predispose those with stable angina to pain?
A. Positive chronotropy
B. Increasing circulating volume
C. Reduced time in diastole
D. Positive inotropy
E. Reduced cardiac efficiency

D. Positive inotropy

6

Hypercholesterolaemia is well known to contribute to cardiovascular disease. Which of the following mechanisms may be useful in preventing the generation of atherosclerotic plaques?
A. Transfer of cholesterol from peripheral tissues to the blood in the form of HDL
B. Antagonism of peroxisome proliferator-activated receptors (PPARs)
C. Agonism of HMG CoA reductase to increase the hepatic concentration of mevalonate
D. Antagonising lipoprotein lipase (releasing triglycerides from lipoproteins)
E. Increasing uptake of sterols from the gut

D. Antagonising lipoprotein lipase (releasing triglycerides from lipoproteins)

7

Which of the following conditions is not a cause of secondary (not essential) hypertension?
A. Phaeochromocytoma
B. Liddle's syndrome
C. Kidney failure
D. Myasthenia gravis
E. Hyperaldosteronism (Conn's Syndrome)

D. Myasthenia gravis

8

Regarding drugs that can act on steroid receptors
A. Fludrocortisone can be used to treat postural hypotension
B. Spironolactone is an agonist at the mineralocorticoid receptor
C. Tamoxifen is an anti-cancer drug that agonises oestrogen at the oestrogen receptor
D. Norethisterone is a contraceptive that antagonises the progesterone receptor
E. Hydrocortisone can cause postural hypotension

A. Fludrocortisone can be used to treat postural hypotension

9

In a radioligand binding assay, the alpha 1 adrenoceptor antagonist prazosin was used to displace the specific binding of 100 nM [3H]phenylephrine.The affinity constants for prazosin and [3H]phenylephrine were 1.1x108 M-1 and 0.5x108 M-1 respectively. What is the IC50 for prazosin displacement of [3H]phenylephrine?
A. 54 pM
B. 0.54 nM
C. 54 nM
D. 54 μM
E. 0.54 mM

C. 54 nM

10

Pertussis toxin is a useful substance for studying G protein-coupled receptor (GPCR) signalling.Which of the following best describes the action of pertussis toxin?
A. ADP-ribosylation of αi
B. ADP-ribosylation of αq
C. ADP-ribosylation of αs
D. ADP-ribosylation of β
E.ADP-ribosylation of γ

A. ADP-ribosylation of αi

11

Receptor desensitisation commonly occurs following prolonged exposure to an agonist. Which of the following best describes a mechanism of homologous desensitisation in β adrenoceptors?
A. β adrenoceptor kinase (βARK) phosphorylates sites at the N-terminal
B. Phosphorylation enhances affinity for β-arrestin
C. Phosphorylation enhances G protein coupling
D. Phosphorylation occurs at low agonist concentrations
E. Protein kinase A (PKA) phosphorylates sites at the C-terminal

B. Phosphorylation enhances affinity for β-arrestin

12

Drug-receptor interactions can be described with regards to both affinity and efficacy. Which of the following best describes what is meant by effective concentration 50 (EC50)?
A. The concentration of a drug that displaces 50% of agonist binding
B. The concentration of a drug that inhibits 50% of a full agonist response
C. The concentration of a drug that occupies 50% of the receptors
D. The concentration of a drug that produces 50% of the maximal response
E. The concentration of a drug that produces 50% of the maximum specific binding

D. The concentration of a drug that produces 50% of the maximal response

13

Local anaesthetics have a variety of clinical uses. Under experimental circumstances how can quaternary local anaesthetics most effectively produce anaesthesia?
A. Application of a depolarising pre-pulse
B. Intracellular application
C. Lowering of the extracellular solution pH
D. Lowering of the stimulation rate
E. Raising of the intracellular solution pH

B. Intracellular application

14

Nicotinic acetylcholine receptors (nAChR) mediate fast neurotransmission. Which of the following best describes the structure of nAChRs?
A. Dimeric ion channels
B. Hexameric ion channels
C. Pentameric ion channels
D. Tetrameric ion channels
E. Trimeric ion channels

C. Pentameric ion channels

15

Adrenoceptors mediate the biological effects of the catecholamines. Which of the following best describes the signalling events associated with stimulation of adrenoceptors?
A. α1-adrenoceptor stimulation leads to activation of adenylyl cyclases
B. α2-adrenoceptor stimulation leads to inhibition of phospholipase C
C. β1-adrenoceptor stimulation leads to production of cAMP
D. β2-adrenoceptor stimulation reduces the level of cAMP
E. β3-adrenoceptor stimulation leads to increase in cytosolic free Ca2+ concentration

C. β1-adrenoceptor stimulation leads to production of cAMP

16

Reduced salivation was required for a patient in preparation for an oral surgical procedure. Which of the following strategies will be the best in reducing salivation?
A. Activation of muscarinic receptors in the salivary glands
B. Activation of nicotinic receptors in the salivary glands
C. Blockade of adrenoceptors in the salivary glands
D. Blockade of muscarinic receptors in the salivary glands
E. Blockade of nicotinic receptors in the salivary glands

D. Blockade of muscarinic receptors in the salivary glands

17

Atropa belladonna is a plant that is enriched in atropine. Which of the following drugs will be the most suitable in treating poisoning with belladonna?
A. Hemicholinium
B. Ipratropium
C. Malathion
D. Physostigmine
E. Propranolol

D. Physostigmine

18

Sarin is an organophosphate, which is also known as a nerve gas. Which of the following could best serve as an antidote to sarin poisoning?
A. Atropine
B. Carbachol
C. Nicotine
D. Physostigmine
E. Pilocarpine

A. Atropine

19

A blood vessel ring is mounted in an organ bath and its contraction is monitored. Noradrenaline was found to trigger contraction.Which drug is most likely to block this effect
A. Phenylephrine
B. Physostigmine
C. Pirenzipine
D. Prazosin
E. Propranolol

D. Prazosin

20

Noradrenaline is synthesised from tyrosine.Which of the following drugs will most effectively block the rate-limiting step in this pathway?
A. α-methyldopa
B. α-methyltyrosine
C. Carbidopa
D. Disulfiram
E. Tyramine

B. α-methyltyrosine

21

Reperfusion of a vessel following thrombosis can be improved by clot lysis. Which statement best describes the action of streptokinase to improve clot lysis?
A. It inhibits factor XIIIa
B. It activates plasminogen
C. It inhibits platelet P2Y12
D. It activates protein C
E. It inhibits thrombin activity

B. It activates plasminogen

22

Excessive platelet activation can result in thrombosis.Which statement best describes the action of clopidogrel as an anti-thrombotic?
A. It inhibits COX-1
B. It inhibits GPIIb/IIIa
C. It inhibits P2Y12
D. It inhibits PAR-1
E. It inhibits thrombin

C. It inhibits P2Y12

23

Cardiac glycosides have a positive inotropic effect. Which of the following best describes the mechanism of action of these drugs?
A. They inhibit delayed rectifying K+ channel Kv11.1
B. They inhibit phosphodiesterase III
C. They inhibit the Na+/K+-ATPase
D. They inhibit the plasma membrane Ca2+ ATPase (PMCA)
E. They inhibit the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA)

C. They inhibit the Na+/K+-ATPase

24

Thiazide diuretics may be used to reduce extracellular fluid volume. What is their principal mechanism of action
A. Inhibition of aldosterone receptors
B. Inhibition of carbonic anhydrase
C. Inhibition of epithelial Na+ channels
D. Inhibition of Na+/Cl- cotransporter
E. Inhibition of Na+/2Cl-/K+ cotransporter

D. Inhibition of Na+/Cl- cotransporter

25

Hypokalaemia is a problematic side effect of loop diuretics. What is the main reason this occurs?
A. Loop diuretics activate apical K+ channels
B. Loop diuretics activate basolateral Na+/K+ ATPase activity
C. Loop diuretics inhibit K+ reabsorption in the loop of Henle
D. Loop diuretics increase Na+ load in the distal tubule
E. Loop diuretics inhibit the basolateral K+/Cl- exchanger in the distal tubule

D. Loop diuretics increase Na+ load in the distal tubule

26

Cardiac action potentials consist of inward and outward currents.Which of the following channels is chiefly responsible for a sustained outward current in ventricular myocytes during the action potential?
A. Delayed rectifier K+ channels
B. Inward rectifier K+ channels
C. L-type Ca2+ channels
D. Na+ channels
E. T-type Ca2+ channels

A. Delayed rectifier K+ channels

27

Inodilators increase the force of cardiac contraction and cause vasodilatation. What is the principle mechanism by which they have these two effects?
A. Activation of adenylyl cyclase
B. Activation of β-adrenoceptors
C. Activation of K+ channels
D. Inhibition of the Na+/K+ ATPase
E. Inhibition of phosphodiesterases

E. Inhibition of phosphodiesterases

28

Ion channels play an essential role in the cardiac action potential. The effects of a new ion channel blocker on the ventricular action potential are investigated. Rapid depolarisation is blocked, but a slower depolarisation and plateau phase are seen.Which is the most likely target of this blocker?
A. Delayed rectifier K+ channels
B. L-type voltage-gated Ca2+ channels
C. Na+/K+ ATPase
D. T-type voltage-gated Ca2+ channels
E. Voltage-gated Na+ channels

E. Voltage-gated Na+ channels

29

Spirolonolactone is a diuretic with a relatively slow rate of onset. What best accounts for this slow rate?
A. Its effects depend on increasing protein synthesis
B. Its effects depend on protein turnover
C. Its effects depend on the rate of aldosterone synthesis
D. It is metabolised in the liver
E. Its target tissue is poorly perfused

B. Its effects depend on protein turnover

30

Reperfusion of a vessel following thrombosis is necessary for the affected tissue to recover. Which statement best describes the action of plasmin in reperfusion?
A. It activates protein C
B. It degrades fibrin
C. It inhibits platelet aggregation
D. It inhibits thrombin generation
E. It inhibits thrombin activity

B. It degrades fibrin