Pharmacology

Question 1

What is a type of drug that affects Na/K ATPase and how does it work?

Answer 1

Cardiac Glycoside (Digitalis)

It enhances myocardial contractility by prolonging the amount of intracellular calcium because the Na/K pump isn’t working so there is a high intracellular Na conc so the Ca/Na exchanger has no gradient to go off so can’t pump Ca out

Question 2

Which pharmacological agents increase myocardial contractility? (also called positive inotropy)

(3 and say how)

Answer 2

Digitalis (cardiac glycoside) by blocking Na/K pump so NCX pump can’t pump Ca out of cell

Increase in symp activity (Activation of B1 adrenoreceptors causes increase in intracellular Ca)

B agonists (mimic natural sympathetic activation) e.g. Dobutamine

Question 3

Which pharmacological agents decrease myocardial contractility? (also called negative inotropy)

1 Example and 3 names

Answer 3

B blockers (propanolol, atenolol, metoprolol)

Question 4

B1 adrenergic receptors at the SA node..

What does it do?

Activation of B1 receptors activates ____ which makses ___, which activates _____, which activates ____ channels

cAMP directly activates ____ HCN channels (also called ___ channels or ____ channels)

Answer 4

Increased HR (sympathetic stimulation, parasymp slows it)

adenylate cyclase which makes cAMP which activates protein kinase A which activates voltage gated calcium channels

leaky sodium channels or If channels

Question 5

Antiarrhythmic drugs… what do they do?

Class 1=

Class 2=

Class 3=

Class 4=

Answer 5

Slow HR, prolong AP

Class 1: Na channel blockers

Class 2: B adrenergic antagonists

Class 3: K channel blockers

Class 4: Ca channel blockers