Pharmacodynamics II - Darmani Flashcards

1
Q

Full agonist

A

Produce a maximal response which a given tissue is capable of producing

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2
Q

Partial agonist

A
  • Produce a smaller maximal effect
  • Occupy all of the available receptors to produce their effect
  • Can antagonize the effects of a full agonist
  • Can have a greater affinity for a particular receptor than a full agonist
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3
Q

Competitive antagonist

A

Do not produce any response

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4
Q

Efficacy

A
  • The ability or strength of a drug to produce a maximal effect subsequent to binding to its appropriate receptor
  • Dependent upon intrinsic efficacy and total receptor concentration
  • Varies among tissues because it is dependent on receptor number
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5
Q

Efficacy limit for competitive antagonists

A

0

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6
Q

Efficacy limit for full agonist

A

1

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7
Q

Efficacy limit for partial agonist

A

Between 0 and 1

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8
Q

Intrinsic efficacy

A
  • The amount of stimulus a drug molecule applies to the receptor
  • Does not vary among tissues, but is a property of the drug molecule itself for any given type of receptor
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9
Q

Inverse agonists

A

Drugs that produce changes opposite to those produced by other agonists

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10
Q

Efficacy limit for inverse agonists

A

From -1 to 0

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11
Q

R*

A

Active form of GPCRs

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12
Q

R

A

Inactive form of GPCRs

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13
Q

How do full agonists affect GPCRs?

A
  • Preferentially bind to and maximally enrich R*

* Maximally increase effector activity

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14
Q

How do partial agonists effect GPCRs?

A
  • Show a weaker preference for R*

* Shift eq to a smaller extent

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15
Q

How do inverse agonists effect GPCRs?

A
  • Bind preferentially to R

* Leads to a reduction in basal effector activity

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16
Q

How do silent antagonists effect GPCRs?

A
  • Bind equally well to both R* and R

* Do not alter eq or effector activity

17
Q

Extended Ternary Complex Model

A

Accounts for allosteric modulators and suggests that GPCRs may spontaneously adopt multiple active and inactive conformational states

18
Q

Functionally selective agonists (aka biased agonists)

A

A unique drug that recognizes and stabilizes a chimeric conformation of a specific signaling pathway via a GPCR that activates multiple signals

19
Q

Positive Allosteric Modulator

A

Increases affinity and/or efficacy of an agonist

20
Q

Negative Allosteric Modulator

A

Decreases affinity and/or efficacy of an agonist

21
Q

Potency

A

Refers to the dose or concentration of a drug required to produce a given effect

22
Q

Spare Receptor

A

When the maximal response can be elicited by an agonist at a concentration that does not result in full occupancy of all available receptors

23
Q

Protective Index

A
  • Important measure of safety

* The ratio of ED50 (bad side effect):ED50 (actually doing its job)

24
Q

Chemical Antagonism

A

Render the agonist pharmacologically inactive

25
Functional Antagonism
Interaction of two drugs whose independent opposing actions in the body tend to cancel each other out
26
Competitive Antagonism
Antagonist competes with the agonist for its binding site on the receptor
27
Noncompetitive Antagonism
Antagonist acts at a site other than the appropriate receptors for the agonist
28
Equilibrium Competitive
* Aka reversible competitive antagonism | * Key feature is surmountability expressed in a rightward parallel shift of the agonist log-dose response curve
29
Non-equilibrium Competitive
* Aka irreversible competitive antagonism * Occurs when the antagonist dissociates very slowly, or not at all, from the receptors * Results: no change in the antagonist occupancy takes place when the agonist is applied