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Flashcards in Pharmacology Deck (147)
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1

Adrenaline activates B2 adrenoceptors in the heart to cause increased heart rate. True/False?

False
Acts on B1 adrenoceptors

2

Which muscarinic receptor does ACh act on in the heart to cause decreased heart rate?

M2 receptors

3

What does adenylyl cyclase do?

Increases production of cAMP

4

Which channels, when blocked, decrease the slope of the SA node action potential?

HCN channels

5

Name a drug that is a selective blocker of HCN channels and for what heart condition it is mainly used

Ivabradine
Used for angina

6

Sympathetic stimulation decreases AV nodal delay. True/False?

True

7

Sympathetic stimulation causes increased automaticity. What is this?

Increased tendency for non-nodal regions to acquire spontaneous conduction activity

8

Sympathetic stimulation causes a decrease in the duration of systole. True/False?

True

9

What factors increase venous return?

Increased skeletal muscle activity
Adrenergic effects on blood vessels
Increased depth + frequency of respiration

10

What is the function of ryanodine receptors with regards to calcium action + action potentials?

Enable release of Ca++ from sarcoplasmic reticulum through the process of calcium-induced calcium release

11

What is the function of SERCA with regards to calcium action + action potentials?

Removes Ca++ from the cytoplasm to bring about relaxation

12

What happens when phosphalamban is phosphorylated with regards to calcium action + action potentials?

This increases Ca++ storage in the SR and also activates SERCA to promote relaxation

13

What happens when troponin I is phosphorylated with regards to calcium action + action potentials?

Decreases affinity of troponin C for calcium, thus accelerating relaxation

14

Name a B1 agonist drug used sometimes in heart failure

Dobutamine

15

Propranolol is a selective B2 receptor antagonist. True/False?

False
It is non-selective

16

Name a selective B1 antagonist drug

Atenolol
Metoprolol

17

Give some clinical uses of B-blockers

Arrhythmias
Hypertension
Angina
Heart failure (low-dose)

18

Give some adverse effects of B-blockers

Aggravate asthma
Aggravate heart failure
Cold extremities
Bradycardia
Fatigue

19

Which class of drug is atropine?

Non-selective muscarinic antagonist

20

Name the main clinical use of atropine

Reverse bradycardia modestly

21

What are the dangers of digoxin?

It has a low therapeutic ratio and is thus toxic, especially in hypokalaemia
Can cause heart block

22

What is an indirect effect of digoxin?

Slows AV node conduction to increase refractory period

23

What does Levosimendan do?

Binds to troponin C to increase its affinity for Ca++

24

In the smooth muscle cell, calcium binds with _____, which undergoes a conformation change. The __-__ complex then interacts with _____ to activate it. The active ____ then phosphorylates ___-__ which, when phosphorylated, ultimately causes contraction.

In the smooth muscle cell, calcium binds with calmodulin, which undergoes a conformation change. The Ca-CaM complex then interacts with MLCK to activate it. The active MLCK then phosphorylates myosin-LC which, when phosphorylated, ultimately causes contraction.

25

In the endothelial cell, Ca-CaM complex activates ___ which binds _-____ and __ to form NO, which rapidly diffuses into the smooth muscle cell (to ultimately cause relaxation).

In the endothelial cell, Ca-CaM complex activates eNOS which binds l-arginine and O2 to form NO, which rapidly diffuses into the smooth muscle cell (to ultimately cause relaxation).

26

In the smooth muscle cell, NO does 2 things:
1] activates ___ ____ which synthesises cGMP from ___. cGMP activates protein kinase _ which ultimately causes relaxation.
2] keeps Ca-dependent _ channel open, allowing _ to efflux, leaving _ve charge in the cell which causes membrane potential to ______ so we get relaxation.

In the smooth muscle cell, NO does 2 things:
1] activates guanylate cyclase which synthesises cGMP from GTP. cGMP activates protein kinase A which ultimately causes relaxation.
2] keeps Ca-dependent K channel open, allowing K to efflux, leaving -ve charge in the cell which causes membrane potential to hyperpolarise so we get relaxation.

27

How do organic nitrates (GTN) work in the smooth muscle cell?

Combines with SH groups to liberate NO, which then acts like endogenous NO in signalling pathways

28

Nitrates cause arteriolar dilation at low doses. True/False?

False
Mainly cause venorelaxation, but can cause arteriolar dilation at high doses

29

How do nitrates help in angina?

Decrease preload + afterload
Improve perfusion to ischaemic zone (dilates collateral vessels)

30

Name 2 examples of organic nitrates used clinically

GTN tablet/spray
Isosorbide mononitrate