Receptors and Basic Pharmacology - Part 1

Question 1

How do the vast majority of drugs function?

Answer 1

By interacting with receptor proteins

-they will either facilitate or block the protein/cell’s funcitons

Question 2

Receptors act as a what?

Answer 2

Signal transducer

Question 3

What does it mean for a receptor to act as a signal transducer?

Answer 3

When a drug binds to a receptor, it sends some sort of signal to the cell machinery to produce (or inhibit) a physiologic effect

Question 4

Agonist

Answer 4

A drug that actively produces a physiological effect

Question 5

Antagonist

Answer 5

A drug that blocks the action of an agonist

Question 6

What does the binding curve of a drug bound to receptor v free drug concentration look like?

Answer 6

A rectangular hyperbola

Question 7

Kd

Answer 7

The equilibrium or dissociation constant

The drug concentration required for 1/2 the maximum binding to the receptor

Question 8

100% of the drug bound to a receptor…

Answer 8

This is a limit approached as the drug concentration gets very high

Question 9

What do semilog plots v log plots provide?

Answer 9

Semilog = drugs bound to receptor
Log = free drug
They provide sigmoidal curves that allow a more complete range of data to be shown

Question 10

Is it possible that 2 drugs (L1 and L2) to act at the same receptor site, but require vastly different concentrations to achieve the same effect

Answer 10

Yes
The amount of drug bound to the receptor depends on the concentration and dissociation constant (Kd)
If L1 has a much higher Kd than L2…more of L1 is required to reach the binding equivalent to that of L2

Question 11

T/F - If x amount of drug produces a certain effect, 2x amount of drug will produce roughly double the effect.

Answer 11

False - it depends on where you are on the binding curve
If the amount of drug bound is low, doubling the amount of drug could produce double the effect
But if the amount bound is high, doubling the amount would have very little effect