Pharm - Drug Receptors And Pharmodynamics

Front 1

What is a receptor?

Back 1

The component of a cell that interacts with a drug and inititates the chain of biochemincal events leading to the drug's observed effects

Front 2

What is the importance of a receptor?

Back 2

1. Determines relationship btw dose and effect
2. Responsible for drug selectivity
3. Mediators of agonists and antagonists

Front 3

Explain and give an example of surface receptors linked directly to ion channels

Back 3

When a drug binds to the receptor, the receptor is activated and opens the ion channel
Ex; ACH binds to to mm cells @ NMJ, opening Na+ channel to allow Na+ influx

Front 4

Explain and give an example of surface receptors directly linked to enzymes

Back 4

Binding of receptor (binding domain) inititates phosphorylation of cetrain AAs, which increased enzymatic activity (catalytic domain)
ie. insulin causes inc glucose uptake inside cell

Front 5

Explain surface receptors linked to G proteins

Back 5

Drug binds to a surface receptor, which in turn moves laterally to bind to a G protein. The G protein can then stimulate or inhibit an intracellular effector (such as enzyme or ion channel)

Ex: glucagon-like-peptide 1, opiods

Front 6

How do intracellular receptors work?

Back 6

Endogenous hormone or hormone-like drug binds to a receptor in the cytoplasm, then the complex moves to the nucleus to affect gene expression

Front 7

What affects drug-receptor interactions?

Back 7

Drug's size and shape (lock and key)
Affinity (amt. of attraction between drug and receptor), which is measured by amt of drug needed to bind to unoccupied receptors
Allosteric modulators (proteings that bind to receptors that inc receptor's affinity for the drugs)
Fluidity of cell membrane
Chemical and physical factors

Front 8

What is a 100% selective drug?

Back 8

Means only primary beneficial effects in target tissue occur with no other side effects and drug does not go anywhere else

Front 9

What are the receptors effects of dose-response curves?

Back 9

The curve is proportional to number of receptors bound within a given drug concentration

Front 10

Full agonist vs. partial agonist

Back 10

Full: drug that binds to receptor and causes a functional response 100% of time
Partial: Binds to receptor but does not cause full response compared to the full agonist

Front 11

Antagonist and example

Back 11

Drug binds to a receptor that does not cause a physiological change in function. ie. Beta blockers bind to a recetor that block an endogenous chemical from binding and causing a physioogical change

Front 12

Competitive vs. noncompetitive antagonist

Back 12

Comp: equal opportunity to occupy same receptor as agonist. They fight each other.
Non-comp: The antagonist as such a high affinity for receptor that the agonist doesn't have a chance.. sometimes causes irreversible bonding

Front 13

Mixed agonist-antagonist

Back 13

Drug that acts as an agonist on some receptors and an antagonist on other receptors

Front 14

Inverse agonist

Back 14

Drug binds to receptor but has opposite effect as agonist (agonist being the endogenous chemical)

Front 15

Desensitization

Back 15

Dec in receptor responsiveness (same #, less receptive). You need to inc number of drug

Front 16

Down-regulation

Back 16

Dec in number of available receptors. Need to inc amt of drug

Front 17

Supersensitivity

Back 17

Inc in number of receptors.. need to dec amt of drug

Front 18

Examples of non-receptor drugs

Back 18

Alter synthesis of cell components
Direct chemical reactions
Direct alteration of enzyme function
Mop up harmful agents