6.9 Pharmacodynamics and Drug Receptor Mechanisms Flashcards Preview

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Flashcards in 6.9 Pharmacodynamics and Drug Receptor Mechanisms Deck (28)
1

What are common biologic targets for drugs?

1) Enzymes (activate/inhibit)
2) Receptors (G protein coupled; Tyrosine Kinase)
3) Ion channels
4) Transport proteins
5) DNA/RNA and ribosomes
6) Targets of monoclonal antibodies

2

What determines the magnitude of the response?

Depends on the number of receptors/drug interactions.

3

Describe receptor states

Receptors have active state and inactive states, most receptors work slightly even without ligand. The inverse agonist completely shuts this basal level off.

4

Which bond is the strongest?

Covalent bonds

5

What are other types of bonds?

-Electrostatic-more common but not as strong as covalent.
1) Ionic bonds
2) Hydrogen bonds
3) Dipole interaction
- Hydrophobic bonds

6

Describe the effects of receptors on drug effectiveness.

-Receptors are responsible for selectivity of drug action.
-Receptors mediate the actions of pharmacological agents.
-Receptors determine quantitative interaction between dose or concentration and pharmacological effects.
-Components of a cell or organism that interacts with a drug and initiates activity that leads to observed effects.

7

What is a full agonist?

Stimulates maximum effect

8

What is a partial agonist?

Stimulates partial effect

9

What is an inverse agonist?

Binds to a receptor and causes an opposite effect of the agonist, turns off basal activity of receptors.

10

What is an antagonist?

Binds to the receptor compete with and prevent binding by other molecules.

11

What are the two types of antagonist?

Competitive and non-competitive

12

Describe a competitive antagonist

-Binds to active site and prevents agonist from binding.
-reversible

13

Describe a non-competitive antatgonist

-Can bind to an active site or allosteric site and blocks binding.
-Irreversible
-Binds active site with covalent bond or high affinity
-At allosteric site prevents receptor activation by agonist.

14

What is a non-receptor antagonist?

-Chemical- two drugs combine and neutralize activity. Example Protamine (basic) binds to heparin (acid)
-Physical- Receptor is activated facilitates an effect that is opposite of the antagonist.

15

What does it mean if a molecule is chiral?

-Chiral substances possess a unique architecture such that despite sharing identical molecular formulas, atom-to-atom linkages, and bonding distances, they cannot be superimposed.
-Must have 4 unique side chains.

16

What handedness are most sugars?

D-sugars

17

What handedness are all amino acids for life?

L-amino acids

18

What direction is chiral L?

Counter-Clockwise

19

What direction is chiral D?

Clockwise

20

What is the most important amino acid?

Glutamate

21

How are most drugs sold in relation to chirality?

Racemix 50/50

22

What is tolerance?

Occurs when responsiveness decreases as a consequence of continued drug administration

23

What is tachyphylaxis?

Rapid appearance of progressive decrease in response to a given dose after repetitive administration of a pharmacologically or physiologically active substance.

24

What is desensitization?

When receptors and cell response diminishes by a drug or ligand, can have underlying tolerance but does not have to.

25

What is homologous desensitization?

Decrease response at a single type of receptor

26

What is heterologous desensitization?

Decreased response at two or more receptors

27

What is refractoriness?

State when time is required to pass before receptor can be stimulated again. Example voltage gated sodium channels

28

What is down-regulation?

Prolonged stimulation leads to endocytosis and sequestration of receptors.