#1 Flashcards
How do drugs exert their effects?
By binding to a receptor (Protein)
How do receptors interact with drugs?
They bind to the drugs and then act as a signal transducer to the cell machinery to produce a physiological effect.
Drugs that actively block a physiological effect are called ____.
Antagonists
Drugs that produce a physiological effect are called ____.
Agonists
What is a binding curve?
The relationship of drug bound to receptor vs. Free drug concentration. *It looks like a rectangular hyperbola.
The dissociation constant (Kd) describing drug binding to its receptor is defined as ______________.
The concentration of drug providing 1/2 maximum binding.
Semilog plots (drug bound to receptor) Vs. log (free drug) provides _______ which allow _________.
Provide sigmoidal curves that allow a more complete range of data to be shown.
What must happen for 100% of receptors to become bound?
drug concentration must be very high
Is it possible that two drugs that act at the same site can require vastly different concentrations to achieve the same effect?
Yes! The amount of binding is dependent on concentration of drug AS WELL as the Dissociation constant (Kd).
What is does a higher Kd vs a lower Kd mean?
A drug with a higher Kd will require more of the drug to achieve binding equivalent to a lower Kd.
If X amount of a drug produces a certain effect, will 2X amount of drug produce twice as much of an effect?
No! B/C it depends on where you are at on the binding curve. If the amount of drug bound to the receptor is low, than doubling drug might double effect, but not if the amount of drug bound to the receptor is already high.
