ICPP Review Flashcards

1
Q

Drug action/ligands are dependent on the

A

Concentration of drug molecules around receptors

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2
Q

What is a ligand

A

• A ligand is a substance that can interact with target protein- or receptor
• Ligands usually bind to a specific site on the signalling protein(s)
• Can be endogenous signalling molecules

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3
Q

What is an agonist

A

Substance that binds to a receptor and produces a measurable biological response

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4
Q

What is an antagonist

A

Ligands that have affinity for a receptor or target protein but do not produce a biological response

Blocks the effect of agonist

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5
Q

What is affinity

A

How tightly a molecule is bound to its receptor- strength or avidity

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6
Q

What is the measure to define affinity

A

Kd = dissociation constant

Conc of ligand at which 50% of all available receptors are bound

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7
Q

Lower Kd =

A

Greater affinity

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8
Q

Intrinsic efficacy is a term used to describe the ability of a ligand to

A

Generate the active form of the receptor R

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9
Q

What is ligand efficacy

A

Cause a measurable biological response

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10
Q

How do we define agonist potency

A

Conc of a drug that evokes 50% of its maximal response Emax = EC50

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11
Q

What is a partial agonist

A

Ligands that evoke responses that are lower than the mammal response of a full agonist (have a lower Emax)

Lower intrinsic activity

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12
Q

Compared to a full agonist, a partial agonist has

A

Lower intrinsic efficacy (full agonist generates confirmation of receptor which is really good at activating downstream signals, partial agonist is less good at this)

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13
Q

Which drug has the highest intrinsic activity in a graph

A
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14
Q

Which drug has highest potency and affinity in graph

A
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15
Q

Pharmacodynamic principles reflected in Kd and EC50

A

Signal amplification and spare receptors

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16
Q

Which pharmacodynamic principle explains a higher Kd than EC50

A

Spare receptors

17
Q

3 types of drug antagonism

A

• Reversible competitive antagonism (the same binding site as the endogenous ligand, interaction is relatively weak)
• Irreversible competitive antagonism (the same binding site as the endogenous ligand, interaction is irreversible and reflects high affinity with very slow dissociation, maybe covalent binding)
• Non competitive antagonism (generally allosteric- can ever work post-receptor)

18
Q

Which organs are most likely to be affected by the major adverse side effects of atenolol (beta blocker for hypertension)

A

brain, kidneys, GI tract

most severe side effects

19
Q

efficacy definition

A

E Max = maximal response achievable from a drug within particular system or tissue in body

20
Q

intrinsic efficacy definition

A

a measure of how effective a drug is in inducing the active conformation of the target protein

21
Q

What is potency

A

the dose of drug required to produce a specific effect of given intensity (usually EC50)

22
Q

greatest potency and highest affinity will have

A

lowest efficacy and Kd

23
Q

what does a bioavailability of 0.2 tell you

A

not much of the oral medication is reaching the systemic circulation. Undergoes a large amount of first pass metabolism

24
Q

what will be the Vd of a lipophilic drug that also binds to muscle proteins

A

high ask it can enter the fat and muscle compartments